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* [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
@ 2021-11-10 22:06 Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot Brijesh Singh
                   ` (45 more replies)
  0 siblings, 46 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

This part of Secure Encrypted Paging (SEV-SNP) series focuses on the changes
required in a guest OS for SEV-SNP support.

SEV-SNP builds upon existing SEV and SEV-ES functionality while adding
new hardware-based memory protections. SEV-SNP adds strong memory integrity
protection to help prevent malicious hypervisor-based attacks like data
replay, memory re-mapping and more in order to create an isolated memory
encryption environment.
 
This series provides the basic building blocks to support booting the SEV-SNP
VMs, it does not cover all the security enhancement introduced by the SEV-SNP
such as interrupt protection.

Many of the integrity guarantees of SEV-SNP are enforced through a new
structure called the Reverse Map Table (RMP). Adding a new page to SEV-SNP
VM requires a 2-step process. First, the hypervisor assigns a page to the
guest using the new RMPUPDATE instruction. This transitions the page to
guest-invalid. Second, the guest validates the page using the new PVALIDATE
instruction. The SEV-SNP VMs can use the new "Page State Change Request NAE"
defined in the GHCB specification to ask hypervisor to add or remove page
from the RMP table.

Each page assigned to the SEV-SNP VM can either be validated or unvalidated,
as indicated by the Validated flag in the page's RMP entry. There are two
approaches that can be taken for the page validation: Pre-validation and
Lazy Validation.

Under pre-validation, the pages are validated prior to first use. And under
lazy validation, pages are validated when first accessed. An access to a
unvalidated page results in a #VC exception, at which time the exception
handler may validate the page. Lazy validation requires careful tracking of
the validated pages to avoid validating the same GPA more than once. The
recently introduced "Unaccepted" memory type can be used to communicate the
unvalidated memory ranges to the Guest OS.

At this time we only sypport the pre-validation, the OVMF guest BIOS
validates the entire RAM before the control is handed over to the guest kernel.
The early_set_memory_{encrypt,decrypt} and set_memory_{encrypt,decrypt} are
enlightened to perform the page validation or invalidation while setting or
clearing the encryption attribute from the page table.

This series does not provide support for the Interrupt security yet which will
be added after the base support.

The series is based on tip/master
  ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'

Additional resources
---------------------
SEV-SNP whitepaper
https://www.amd.com/system/files/TechDocs/SEV-SNP-strengthening-vm-isolation-with-integrity-protection-and-more.pdf
 
APM 2: https://www.amd.com/system/files/TechDocs/24593.pdf
(section 15.36)

GHCB spec:
https://developer.amd.com/wp-content/resources/56421.pdf

SEV-SNP firmware specification:
https://developer.amd.com/sev/

v6: https://lore.kernel.org/linux-mm/20211008180453.462291-1-brijesh.singh@amd.com/
v5: https://lore.kernel.org/lkml/20210820151933.22401-1-brijesh.singh@amd.com/

Changes since v6:
 * Add rmpadjust() helper to be used by AP creation and vmpl0 detect function.
 * Clear the VM communication key if guest detects that hypervisor is modifying
   the SNP_GUEST_REQ response header.
 * Move the per-cpu GHCB registration from first #VC to idt setup.
 * Consolidate initial SEV/SME setup into a common entry point that gets called
   early enough to also be used for SEV-SNP CPUID table setup.
 * SNP CPUID: separate initial SEV-SNP feature detection out into standalone
   snp_init() routines, then add CPUID table setup to it as a separate patch.
 * SNP CPUID: fix boot issue with Seabios due to ACPI relying on certain EFI
   config table lookup failures as fallthrough cases rather than error cases.
 * SNP CPUID: drop the use of a separate init routines to handle pointer fixups
   after switching to kernel virtual addresses, instead use a helper that uses
   RIP-relative addressing to access CPUID table when either on identity mapping
   or kernel virtual addresses.

Changes since v5:
 * move the seqno allocation in the sevguest driver.
 * extend snp_issue_guest_request() to accept the exit_info to simplify the logic.
 * use smaller structure names based on feedback.
 * explicitly clear the memory after the SNP guest request is completed.
 * cpuid validation: use a local copy of cpuid table instead of keeping
   firmware table mapped throughout boot.
 * cpuid validation: coding style fix-ups and refactor cpuid-related helpers
   as suggested.
 * cpuid validation: drop a number of BOOT_COMPRESSED-guarded defs/declarations
   by moving things like snp_cpuid_init*() out of sev-shared.c and keeping only
   the common bits there.
 * Break up EFI config table helpers and related acpi.c changes into separate
   patches.
 * re-enable stack protection for 32-bit kernels as well, not just 64-bit

Changes since v4:
 * Address the cpuid specific review comment
 * Simplified the macro based on the review feedback
 * Move macro definition to the patch that needs it
 * Fix the issues reported by the checkpath
 * Address the AP creation specific review comment

Changes since v3:
 * Add support to use the PSP filtered CPUID.
 * Add support for the extended guest request.
 * Move sevguest driver in driver/virt/coco.
 * Add documentation for sevguest ioctl.
 * Add support to check the vmpl0.
 * Pass the VM encryption key and id to be used for encrypting guest messages
   through the platform drv data.
 * Multiple cleanup and fixes to address the review feedbacks.

Changes since v2:
 * Add support for AP startup using SNP specific vmgexit.
 * Add snp_prep_memory() helper.
 * Drop sev_snp_active() helper.
 * Add sev_feature_enabled() helper to check which SEV feature is active.
 * Sync the SNP guest message request header with latest SNP FW spec.
 * Multiple cleanup and fixes to address the review feedbacks.

Changes since v1:
 * Integerate the SNP support in sev.{ch}.
 * Add support to query the hypervisor feature and detect whether SNP is supported.
 * Define Linux specific reason code for the SNP guest termination.
 * Extend the setup_header provide a way for hypervisor to pass secret and cpuid page.
 * Add support to create a platform device and driver to query the attestation report
   and the derive a key.
 * Multiple cleanup and fixes to address Boris's review fedback.

Borislav Petkov (3):
  x86/sev: Get rid of excessive use of defines
  x86/head64: Carve out the guest encryption postprocessing into a
    helper
  x86/sev: Remove do_early_exception() forward declarations

Brijesh Singh (22):
  x86/mm: Extend cc_attr to include AMD SEV-SNP
  x86/sev: Shorten GHCB terminate macro names
  x86/sev: Define the Linux specific guest termination reasons
  x86/sev: Save the negotiated GHCB version
  x86/sev: Add support for hypervisor feature VMGEXIT
  x86/sev: Check SEV-SNP features support
  x86/sev: Add a helper for the PVALIDATE instruction
  x86/sev: Check the vmpl level
  x86/compressed: Add helper for validating pages in the decompression
    stage
  x86/compressed: Register GHCB memory when SEV-SNP is active
  x86/sev: Register GHCB memory when SEV-SNP is active
  x86/sev: Add helper for validating pages in early enc attribute
    changes
  x86/kernel: Make the bss.decrypted section shared in RMP table
  x86/kernel: Validate rom memory before accessing when SEV-SNP is
    active
  x86/mm: Add support to validate memory when changing C-bit
  KVM: SVM: Define sev_features and vmpl field in the VMSA
  x86/boot: Add Confidential Computing type to setup_data
  x86/sev: Provide support for SNP guest request NAEs
  x86/sev: Register SNP guest request platform device
  virt: Add SEV-SNP guest driver
  virt: sevguest: Add support to derive key
  virt: sevguest: Add support to get extended report

Michael Roth (16):
  x86/compressed/64: detect/setup SEV/SME features earlier in boot
  x86/sev: detect/setup SEV/SME features earlier in boot
  x86/head: re-enable stack protection for 32/64-bit builds
  x86/sev: move MSR-based VMGEXITs for CPUID to helper
  KVM: x86: move lookup of indexed CPUID leafs to helper
  x86/compressed/acpi: move EFI system table lookup to helper
  x86/compressed/acpi: move EFI config table lookup to helper
  x86/compressed/acpi: move EFI vendor table lookup to helper
  KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement
  x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers
  x86/boot: add a pointer to Confidential Computing blob in bootparams
  x86/compressed: add SEV-SNP feature detection/setup
  x86/compressed: use firmware-validated CPUID for SEV-SNP guests
  x86/compressed/64: add identity mapping for Confidential Computing
    blob
  x86/sev: add SEV-SNP feature detection/setup
  x86/sev: use firmware-validated CPUID for SEV-SNP guests

Tom Lendacky (4):
  KVM: SVM: Create a separate mapping for the SEV-ES save area
  KVM: SVM: Create a separate mapping for the GHCB save area
  KVM: SVM: Update the SEV-ES save area mapping
  x86/sev: Use SEV-SNP AP creation to start secondary CPUs

 Documentation/virt/coco/sevguest.rst          | 117 +++
 .../virt/kvm/amd-memory-encryption.rst        |  28 +
 arch/x86/boot/compressed/Makefile             |   1 +
 arch/x86/boot/compressed/acpi.c               | 129 +--
 arch/x86/boot/compressed/efi.c                | 178 ++++
 arch/x86/boot/compressed/head_64.S            |   8 +-
 arch/x86/boot/compressed/ident_map_64.c       |  44 +-
 arch/x86/boot/compressed/mem_encrypt.S        |  36 -
 arch/x86/boot/compressed/misc.h               |  44 +-
 arch/x86/boot/compressed/sev.c                | 243 ++++-
 arch/x86/include/asm/bootparam_utils.h        |   1 +
 arch/x86/include/asm/cpuid.h                  |  26 +
 arch/x86/include/asm/msr-index.h              |   2 +
 arch/x86/include/asm/setup.h                  |   2 +-
 arch/x86/include/asm/sev-common.h             | 137 ++-
 arch/x86/include/asm/sev.h                    |  96 +-
 arch/x86/include/asm/svm.h                    | 171 +++-
 arch/x86/include/uapi/asm/bootparam.h         |   4 +-
 arch/x86/include/uapi/asm/svm.h               |  13 +
 arch/x86/kernel/Makefile                      |   1 -
 arch/x86/kernel/cc_platform.c                 |   2 +
 arch/x86/kernel/cpu/common.c                  |   5 +
 arch/x86/kernel/head64.c                      |  78 +-
 arch/x86/kernel/head_64.S                     |  24 +
 arch/x86/kernel/probe_roms.c                  |  13 +-
 arch/x86/kernel/sev-shared.c                  | 554 +++++++++++-
 arch/x86/kernel/sev.c                         | 838 ++++++++++++++++--
 arch/x86/kernel/smpboot.c                     |   3 +
 arch/x86/kvm/cpuid.c                          |  17 +-
 arch/x86/kvm/svm/sev.c                        |  24 +-
 arch/x86/kvm/svm/svm.c                        |   4 +-
 arch/x86/kvm/svm/svm.h                        |   2 +-
 arch/x86/mm/mem_encrypt.c                     |  55 +-
 arch/x86/mm/mem_encrypt_identity.c            |   8 +
 arch/x86/mm/pat/set_memory.c                  |  15 +
 drivers/virt/Kconfig                          |   3 +
 drivers/virt/Makefile                         |   1 +
 drivers/virt/coco/sevguest/Kconfig            |   9 +
 drivers/virt/coco/sevguest/Makefile           |   2 +
 drivers/virt/coco/sevguest/sevguest.c         | 743 ++++++++++++++++
 drivers/virt/coco/sevguest/sevguest.h         |  98 ++
 include/linux/cc_platform.h                   |   8 +
 include/linux/efi.h                           |   1 +
 include/uapi/linux/sev-guest.h                |  81 ++
 44 files changed, 3524 insertions(+), 345 deletions(-)
 create mode 100644 Documentation/virt/coco/sevguest.rst
 create mode 100644 arch/x86/boot/compressed/efi.c
 create mode 100644 arch/x86/include/asm/cpuid.h
 create mode 100644 drivers/virt/coco/sevguest/Kconfig
 create mode 100644 drivers/virt/coco/sevguest/Makefile
 create mode 100644 drivers/virt/coco/sevguest/sevguest.c
 create mode 100644 drivers/virt/coco/sevguest/sevguest.h
 create mode 100644 include/uapi/linux/sev-guest.h

-- 
2.25.1


^ permalink raw reply	[flat|nested] 80+ messages in thread

* [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-12 16:52   ` Borislav Petkov
  2021-11-10 22:06 ` [PATCH v7 02/45] x86/sev: " Brijesh Singh
                   ` (44 subsequent siblings)
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

With upcoming SEV-SNP support, SEV-related features need to be
initialized earlier in boot, at the same point the initial #VC handler
is set up, so that the SEV-SNP CPUID table can be utilized during the
initial feature checks. Also, SEV-SNP feature detection will rely on
EFI helper functions to scan the EFI config table for the Confidential
Computing blob, and so would need to be implemented at least partially
in C.

Currently set_sev_encryption_mask() is used to initialize the
sev_status and sme_me_mask globals that advertise what SEV/SME features
are available in a guest. Rename it to sev_enable() to better reflect
that (SME is only enabled in the case of SEV guests in the
boot/compressed kernel), and move it to just after the stage1 #VC
handler is set up so that it can be used to initialize SEV-SNP as well
in future patches.

While at it, re-implement it as C code so that all SEV feature
detection can be better consolidated with upcoming SEV-SNP feature
detection, which will also be in C.

The 32-bit entry path remains unchanged, as it never relied on the
set_sev_encryption_mask() initialization to begin with, possibly due to
the normal rva() helper for accessing globals only being usable by code
in .head.text. Either way, 32-bit entry for SEV-SNP would likely only
be supported for non-EFI boot paths, and so wouldn't rely on existing
EFI helper functions, and so could be handled by a separate/simpler
32-bit initializer in the future if needed.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/head_64.S     |  8 ++++-
 arch/x86/boot/compressed/mem_encrypt.S | 36 ---------------------
 arch/x86/boot/compressed/misc.h        |  4 +--
 arch/x86/boot/compressed/sev.c         | 45 ++++++++++++++++++++++++++
 4 files changed, 54 insertions(+), 39 deletions(-)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 572c535cf45b..84a922c27e6b 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -447,6 +447,13 @@ SYM_CODE_START(startup_64)
 	call	load_stage1_idt
 	popq	%rsi
 
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	pushq	%rsi
+	movq	%rsi, %rdi		/* real mode address */
+	call	sev_enable
+	popq	%rsi
+#endif
+
 	/*
 	 * paging_prepare() sets up the trampoline and checks if we need to
 	 * enable 5-level paging.
@@ -569,7 +576,6 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)
  * page-table.
  */
 	pushq	%rsi
-	call	set_sev_encryption_mask
 	call	load_stage2_idt
 
 	/* Pass boot_params to initialize_identity_maps() */
diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
index c1e81a848b2a..311d40f35a4b 100644
--- a/arch/x86/boot/compressed/mem_encrypt.S
+++ b/arch/x86/boot/compressed/mem_encrypt.S
@@ -187,42 +187,6 @@ SYM_CODE_END(startup32_vc_handler)
 	.code64
 
 #include "../../kernel/sev_verify_cbit.S"
-SYM_FUNC_START(set_sev_encryption_mask)
-#ifdef CONFIG_AMD_MEM_ENCRYPT
-	push	%rbp
-	push	%rdx
-
-	movq	%rsp, %rbp		/* Save current stack pointer */
-
-	call	get_sev_encryption_bit	/* Get the encryption bit position */
-	testl	%eax, %eax
-	jz	.Lno_sev_mask
-
-	bts	%rax, sme_me_mask(%rip)	/* Create the encryption mask */
-
-	/*
-	 * Read MSR_AMD64_SEV again and store it to sev_status. Can't do this in
-	 * get_sev_encryption_bit() because this function is 32-bit code and
-	 * shared between 64-bit and 32-bit boot path.
-	 */
-	movl	$MSR_AMD64_SEV, %ecx	/* Read the SEV MSR */
-	rdmsr
-
-	/* Store MSR value in sev_status */
-	shlq	$32, %rdx
-	orq	%rdx, %rax
-	movq	%rax, sev_status(%rip)
-
-.Lno_sev_mask:
-	movq	%rbp, %rsp		/* Restore original stack pointer */
-
-	pop	%rdx
-	pop	%rbp
-#endif
-
-	xor	%rax, %rax
-	ret
-SYM_FUNC_END(set_sev_encryption_mask)
 
 	.data
 
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 16ed360b6692..23e0e395084a 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -120,12 +120,12 @@ static inline void console_init(void)
 { }
 #endif
 
-void set_sev_encryption_mask(void);
-
 #ifdef CONFIG_AMD_MEM_ENCRYPT
+void sev_enable(struct boot_params *bp);
 void sev_es_shutdown_ghcb(void);
 extern bool sev_es_check_ghcb_fault(unsigned long address);
 #else
+static inline void sev_enable(struct boot_params *bp) { }
 static inline void sev_es_shutdown_ghcb(void) { }
 static inline bool sev_es_check_ghcb_fault(unsigned long address)
 {
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 670e998fe930..c91ad835b78e 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -204,3 +204,48 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	else if (result != ES_RETRY)
 		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 }
+
+static inline u64 rd_sev_status_msr(void)
+{
+	unsigned long low, high;
+
+	asm volatile("rdmsr" : "=a" (low), "=d" (high) :
+			"c" (MSR_AMD64_SEV));
+
+	return ((high << 32) | low);
+}
+
+void sev_enable(struct boot_params *bp)
+{
+	unsigned int eax, ebx, ecx, edx;
+
+	/* Check for the SME/SEV support leaf */
+	eax = 0x80000000;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+	if (eax < 0x8000001f)
+		return;
+
+	/*
+	 * Check for the SME/SEV feature:
+	 *   CPUID Fn8000_001F[EAX]
+	 *   - Bit 0 - Secure Memory Encryption support
+	 *   - Bit 1 - Secure Encrypted Virtualization support
+	 *   CPUID Fn8000_001F[EBX]
+	 *   - Bits 5:0 - Pagetable bit position used to indicate encryption
+	 */
+	eax = 0x8000001f;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+	/* Check whether SEV is supported */
+	if (!(eax & BIT(1)))
+		return;
+
+	/* Check the SEV MSR whether SEV or SME is enabled */
+	sev_status   = rd_sev_status_msr();
+
+	if (!(sev_status & MSR_AMD64_SEV_ENABLED))
+		error("SEV support indicated by CPUID, but not SEV status MSR.");
+
+	sme_me_mask = 1UL << (ebx & 0x3f);
+}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 02/45] x86/sev: detect/setup SEV/SME features earlier in boot
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-15 19:12   ` Borislav Petkov
  2021-12-06 23:47   ` Venu Busireddy
  2021-11-10 22:06 ` [PATCH v7 03/45] x86/mm: Extend cc_attr to include AMD SEV-SNP Brijesh Singh
                   ` (43 subsequent siblings)
  45 siblings, 2 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

sme_enable() handles feature detection for both SEV and SME. Future
patches will also use it for SEV-SNP feature detection/setup, which
will need to be done immediately after the first #VC handler is set up.
Move it now in preparation.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/setup.h | 2 +-
 arch/x86/kernel/head64.c     | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index a12458a7a8d4..cee1e816fdcd 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -50,7 +50,7 @@ extern void reserve_standard_io_resources(void);
 extern void i386_reserve_resources(void);
 extern unsigned long __startup_64(unsigned long physaddr, struct boot_params *bp);
 extern unsigned long __startup_secondary_64(void);
-extern void startup_64_setup_env(unsigned long physbase);
+extern void startup_64_setup_env(unsigned long physbase, struct boot_params *bp);
 extern void early_setup_idt(void);
 extern void __init do_early_exception(struct pt_regs *regs, int trapnr);
 
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index fc5371a7e9d1..4eb83ae7ceb8 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -163,9 +163,6 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	if (load_delta & ~PMD_PAGE_MASK)
 		for (;;);
 
-	/* Activate Secure Memory Encryption (SME) if supported and enabled */
-	sme_enable(bp);
-
 	/* Include the SME encryption mask in the fixup value */
 	load_delta += sme_get_me_mask();
 
@@ -594,7 +591,7 @@ void early_setup_idt(void)
 /*
  * Setup boot CPU state needed before kernel switches to virtual addresses.
  */
-void __head startup_64_setup_env(unsigned long physbase)
+void __head startup_64_setup_env(unsigned long physbase, struct boot_params *bp)
 {
 	/* Load GDT */
 	startup_gdt_descr.address = (unsigned long)fixup_pointer(startup_gdt, physbase);
@@ -606,4 +603,7 @@ void __head startup_64_setup_env(unsigned long physbase)
 		     "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");
 
 	startup_64_load_idt(physbase);
+
+	/* Activate SEV/SME memory encryption if supported/enabled. */
+	sme_enable(bp);
 }
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 03/45] x86/mm: Extend cc_attr to include AMD SEV-SNP
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 02/45] x86/sev: " Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 04/45] x86/sev: Shorten GHCB terminate macro names Brijesh Singh
                   ` (42 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The CC_ATTR_SEV_SNP can be used by the guest to query whether the SNP -
Secure Nested Paging feature is active.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/msr-index.h | 2 ++
 arch/x86/kernel/cc_platform.c    | 2 ++
 arch/x86/mm/mem_encrypt.c        | 4 ++++
 include/linux/cc_platform.h      | 8 ++++++++
 4 files changed, 16 insertions(+)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 01e2650b9585..98a64b230447 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -481,8 +481,10 @@
 #define MSR_AMD64_SEV			0xc0010131
 #define MSR_AMD64_SEV_ENABLED_BIT	0
 #define MSR_AMD64_SEV_ES_ENABLED_BIT	1
+#define MSR_AMD64_SEV_SNP_ENABLED_BIT	2
 #define MSR_AMD64_SEV_ENABLED		BIT_ULL(MSR_AMD64_SEV_ENABLED_BIT)
 #define MSR_AMD64_SEV_ES_ENABLED	BIT_ULL(MSR_AMD64_SEV_ES_ENABLED_BIT)
+#define MSR_AMD64_SEV_SNP_ENABLED	BIT_ULL(MSR_AMD64_SEV_SNP_ENABLED_BIT)
 
 #define MSR_AMD64_VIRT_SPEC_CTRL	0xc001011f
 
diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
index 03bb2f343ddb..e05310f5ec2f 100644
--- a/arch/x86/kernel/cc_platform.c
+++ b/arch/x86/kernel/cc_platform.c
@@ -50,6 +50,8 @@ static bool amd_cc_platform_has(enum cc_attr attr)
 	case CC_ATTR_GUEST_STATE_ENCRYPT:
 		return sev_status & MSR_AMD64_SEV_ES_ENABLED;
 
+	case CC_ATTR_SEV_SNP:
+		return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
 	default:
 		return false;
 	}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 23d54b810f08..534c2c82fbec 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -433,6 +433,10 @@ static void print_mem_encrypt_feature_info(void)
 	if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
 		pr_cont(" SEV-ES");
 
+	/* Secure Nested Paging */
+	if (cc_platform_has(CC_ATTR_SEV_SNP))
+		pr_cont(" SEV-SNP");
+
 	pr_cont("\n");
 }
 
diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
index a075b70b9a70..ef5e2209c9b8 100644
--- a/include/linux/cc_platform.h
+++ b/include/linux/cc_platform.h
@@ -61,6 +61,14 @@ enum cc_attr {
 	 * Examples include SEV-ES.
 	 */
 	CC_ATTR_GUEST_STATE_ENCRYPT,
+
+	/**
+	 * @CC_ATTR_SEV_SNP: Guest SNP is active.
+	 *
+	 * The platform/OS is running as a guest/virtual machine and actively
+	 * using AMD SEV-SNP features.
+	 */
+	CC_ATTR_SEV_SNP = 0x100,
 };
 
 #ifdef CONFIG_ARCH_HAS_CC_PLATFORM
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 04/45] x86/sev: Shorten GHCB terminate macro names
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (2 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 03/45] x86/mm: Extend cc_attr to include AMD SEV-SNP Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 05/45] x86/sev: Get rid of excessive use of defines Brijesh Singh
                   ` (41 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh, Venu Busireddy,
	Borislav Petkov

Shorten macro names for improved readability.

Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c    | 6 +++---
 arch/x86/include/asm/sev-common.h | 4 ++--
 arch/x86/kernel/sev-shared.c      | 2 +-
 arch/x86/kernel/sev.c             | 4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index c91ad835b78e..8c6410014d22 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -122,7 +122,7 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 static bool early_setup_sev_es(void)
 {
 	if (!sev_es_negotiate_protocol())
-		sev_es_terminate(GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED);
+		sev_es_terminate(GHCB_SEV_ES_PROT_UNSUPPORTED);
 
 	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
 		return false;
@@ -175,7 +175,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	enum es_result result;
 
 	if (!boot_ghcb && !early_setup_sev_es())
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
 	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -202,7 +202,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	if (result == ES_OK)
 		vc_finish_insn(&ctxt);
 	else if (result != ES_RETRY)
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 }
 
 static inline u64 rd_sev_status_msr(void)
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 2cef6c5a52c2..855b0ec9c4e8 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -68,8 +68,8 @@
 	(((((u64)reason_set) &  GHCB_MSR_TERM_REASON_SET_MASK) << GHCB_MSR_TERM_REASON_SET_POS) | \
 	((((u64)reason_val) & GHCB_MSR_TERM_REASON_MASK) << GHCB_MSR_TERM_REASON_POS))
 
-#define GHCB_SEV_ES_REASON_GENERAL_REQUEST	0
-#define GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED	1
+#define GHCB_SEV_ES_GEN_REQ		0
+#define GHCB_SEV_ES_PROT_UNSUPPORTED	1
 
 #define GHCB_RESP_CODE(v)		((v) & GHCB_MSR_INFO_MASK)
 
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 787dc5f568b5..ce987688bbc0 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -221,7 +221,7 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 
 fail:
 	/* Terminate the guest */
-	sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+	sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 }
 
 static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt,
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 74f0ec955384..0a6c82e060e0 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1411,7 +1411,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
 		show_regs(regs);
 
 		/* Ask hypervisor to sev_es_terminate */
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 
 		/* If that fails and we get here - just panic */
 		panic("Returned from Terminate-Request to Hypervisor\n");
@@ -1459,7 +1459,7 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 
 	/* Do initial setup or terminate the guest */
 	if (unlikely(boot_ghcb == NULL && !sev_es_setup_ghcb()))
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 05/45] x86/sev: Get rid of excessive use of defines
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (3 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 04/45] x86/sev: Shorten GHCB terminate macro names Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 06/45] x86/head64: Carve out the guest encryption postprocessing into a helper Brijesh Singh
                   ` (40 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Borislav Petkov, Brijesh Singh

From: Borislav Petkov <bp@suse.de>

Remove all the defines of masks and bit positions for the GHCB MSR
protocol and use comments instead which correspond directly to the spec
so that following those can be a lot easier and straightforward with the
spec opened in parallel to the code.

Aligh vertically while at it.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev-common.h | 51 +++++++++++++++++--------------
 1 file changed, 28 insertions(+), 23 deletions(-)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 855b0ec9c4e8..aac44c3f839c 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -18,20 +18,19 @@
 /* SEV Information Request/Response */
 #define GHCB_MSR_SEV_INFO_RESP		0x001
 #define GHCB_MSR_SEV_INFO_REQ		0x002
-#define GHCB_MSR_VER_MAX_POS		48
-#define GHCB_MSR_VER_MAX_MASK		0xffff
-#define GHCB_MSR_VER_MIN_POS		32
-#define GHCB_MSR_VER_MIN_MASK		0xffff
-#define GHCB_MSR_CBIT_POS		24
-#define GHCB_MSR_CBIT_MASK		0xff
-#define GHCB_MSR_SEV_INFO(_max, _min, _cbit)				\
-	((((_max) & GHCB_MSR_VER_MAX_MASK) << GHCB_MSR_VER_MAX_POS) |	\
-	 (((_min) & GHCB_MSR_VER_MIN_MASK) << GHCB_MSR_VER_MIN_POS) |	\
-	 (((_cbit) & GHCB_MSR_CBIT_MASK) << GHCB_MSR_CBIT_POS) |	\
+
+#define GHCB_MSR_SEV_INFO(_max, _min, _cbit)	\
+	/* GHCBData[63:48] */			\
+	((((_max) & 0xffff) << 48) |		\
+	 /* GHCBData[47:32] */			\
+	 (((_min) & 0xffff) << 32) |		\
+	 /* GHCBData[31:24] */			\
+	 (((_cbit) & 0xff)  << 24) |		\
 	 GHCB_MSR_SEV_INFO_RESP)
+
 #define GHCB_MSR_INFO(v)		((v) & 0xfffUL)
-#define GHCB_MSR_PROTO_MAX(v)		(((v) >> GHCB_MSR_VER_MAX_POS) & GHCB_MSR_VER_MAX_MASK)
-#define GHCB_MSR_PROTO_MIN(v)		(((v) >> GHCB_MSR_VER_MIN_POS) & GHCB_MSR_VER_MIN_MASK)
+#define GHCB_MSR_PROTO_MAX(v)		(((v) >> 48) & 0xffff)
+#define GHCB_MSR_PROTO_MIN(v)		(((v) >> 32) & 0xffff)
 
 /* CPUID Request/Response */
 #define GHCB_MSR_CPUID_REQ		0x004
@@ -46,27 +45,33 @@
 #define GHCB_CPUID_REQ_EBX		1
 #define GHCB_CPUID_REQ_ECX		2
 #define GHCB_CPUID_REQ_EDX		3
-#define GHCB_CPUID_REQ(fn, reg)		\
-		(GHCB_MSR_CPUID_REQ | \
-		(((unsigned long)reg & GHCB_MSR_CPUID_REG_MASK) << GHCB_MSR_CPUID_REG_POS) | \
-		(((unsigned long)fn) << GHCB_MSR_CPUID_FUNC_POS))
+#define GHCB_CPUID_REQ(fn, reg)				\
+	/* GHCBData[11:0] */				\
+	(GHCB_MSR_CPUID_REQ |				\
+	/* GHCBData[31:12] */				\
+	(((unsigned long)(reg) & 0x3) << 30) |		\
+	/* GHCBData[63:32] */				\
+	(((unsigned long)fn) << 32))
 
 /* AP Reset Hold */
-#define GHCB_MSR_AP_RESET_HOLD_REQ		0x006
-#define GHCB_MSR_AP_RESET_HOLD_RESP		0x007
+#define GHCB_MSR_AP_RESET_HOLD_REQ	0x006
+#define GHCB_MSR_AP_RESET_HOLD_RESP	0x007
 
 /* GHCB Hypervisor Feature Request/Response */
-#define GHCB_MSR_HV_FT_REQ			0x080
-#define GHCB_MSR_HV_FT_RESP			0x081
+#define GHCB_MSR_HV_FT_REQ		0x080
+#define GHCB_MSR_HV_FT_RESP		0x081
 
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf
 #define GHCB_MSR_TERM_REASON_POS	16
 #define GHCB_MSR_TERM_REASON_MASK	0xff
-#define GHCB_SEV_TERM_REASON(reason_set, reason_val)						  \
-	(((((u64)reason_set) &  GHCB_MSR_TERM_REASON_SET_MASK) << GHCB_MSR_TERM_REASON_SET_POS) | \
-	((((u64)reason_val) & GHCB_MSR_TERM_REASON_MASK) << GHCB_MSR_TERM_REASON_POS))
+
+#define GHCB_SEV_TERM_REASON(reason_set, reason_val)	\
+	/* GHCBData[15:12] */				\
+	(((((u64)reason_set) &  0xf) << 12) |		\
+	 /* GHCBData[23:16] */				\
+	((((u64)reason_val) & 0xff) << 16))
 
 #define GHCB_SEV_ES_GEN_REQ		0
 #define GHCB_SEV_ES_PROT_UNSUPPORTED	1
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 06/45] x86/head64: Carve out the guest encryption postprocessing into a helper
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (4 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 05/45] x86/sev: Get rid of excessive use of defines Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 07/45] x86/sev: Remove do_early_exception() forward declarations Brijesh Singh
                   ` (39 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Borislav Petkov, Brijesh Singh

From: Borislav Petkov <bp@suse.de>

Carve it out so that it is abstracted out of the main boot path. All
other encrypted guest-relevant processing should be placed in there.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/head64.c | 60 +++++++++++++++++++++-------------------
 1 file changed, 31 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 4eb83ae7ceb8..54bf0603002f 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -126,6 +126,36 @@ static bool __head check_la57_support(unsigned long physaddr)
 }
 #endif
 
+static unsigned long sme_postprocess_startup(struct boot_params *bp, pmdval_t *pmd)
+{
+	unsigned long vaddr, vaddr_end;
+	int i;
+
+	/* Encrypt the kernel and related (if SME is active) */
+	sme_encrypt_kernel(bp);
+
+	/*
+	 * Clear the memory encryption mask from the .bss..decrypted section.
+	 * The bss section will be memset to zero later in the initialization so
+	 * there is no need to zero it after changing the memory encryption
+	 * attribute.
+	 */
+	if (sme_get_me_mask()) {
+		vaddr = (unsigned long)__start_bss_decrypted;
+		vaddr_end = (unsigned long)__end_bss_decrypted;
+		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
+			i = pmd_index(vaddr);
+			pmd[i] -= sme_get_me_mask();
+		}
+	}
+
+	/*
+	 * Return the SME encryption mask (if SME is active) to be used as a
+	 * modifier for the initial pgdir entry programmed into CR3.
+	 */
+	return sme_get_me_mask();
+}
+
 /* Code in __startup_64() can be relocated during execution, but the compiler
  * doesn't have to generate PC-relative relocations when accessing globals from
  * that function. Clang actually does not generate them, which leads to
@@ -135,7 +165,6 @@ static bool __head check_la57_support(unsigned long physaddr)
 unsigned long __head __startup_64(unsigned long physaddr,
 				  struct boot_params *bp)
 {
-	unsigned long vaddr, vaddr_end;
 	unsigned long load_delta, *p;
 	unsigned long pgtable_flags;
 	pgdval_t *pgd;
@@ -273,34 +302,7 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	 */
 	*fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask();
 
-	/* Encrypt the kernel and related (if SME is active) */
-	sme_encrypt_kernel(bp);
-
-	/*
-	 * Clear the memory encryption mask from the .bss..decrypted section.
-	 * The bss section will be memset to zero later in the initialization so
-	 * there is no need to zero it after changing the memory encryption
-	 * attribute.
-	 *
-	 * This is early code, use an open coded check for SME instead of
-	 * using cc_platform_has(). This eliminates worries about removing
-	 * instrumentation or checking boot_cpu_data in the cc_platform_has()
-	 * function.
-	 */
-	if (sme_get_me_mask()) {
-		vaddr = (unsigned long)__start_bss_decrypted;
-		vaddr_end = (unsigned long)__end_bss_decrypted;
-		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
-			i = pmd_index(vaddr);
-			pmd[i] -= sme_get_me_mask();
-		}
-	}
-
-	/*
-	 * Return the SME encryption mask (if SME is active) to be used as a
-	 * modifier for the initial pgdir entry programmed into CR3.
-	 */
-	return sme_get_me_mask();
+	return sme_postprocess_startup(bp, pmd);
 }
 
 unsigned long __startup_secondary_64(void)
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 07/45] x86/sev: Remove do_early_exception() forward declarations
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (5 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 06/45] x86/head64: Carve out the guest encryption postprocessing into a helper Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 08/45] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
                   ` (38 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Borislav Petkov, Brijesh Singh

From: Borislav Petkov <bp@suse.de>

There's a perfectly fine prototype in the asm/setup.h header. Use it.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/sev.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 0a6c82e060e0..03f9aff9d1f7 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -26,6 +26,7 @@
 #include <asm/fpu/xcr.h>
 #include <asm/processor.h>
 #include <asm/realmode.h>
+#include <asm/setup.h>
 #include <asm/traps.h>
 #include <asm/svm.h>
 #include <asm/smp.h>
@@ -86,9 +87,6 @@ struct ghcb_state {
 static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
 DEFINE_STATIC_KEY_FALSE(sev_es_enable_key);
 
-/* Needed in vc_early_forward_exception */
-void do_early_exception(struct pt_regs *regs, int trapnr);
-
 static __always_inline bool on_vc_stack(struct pt_regs *regs)
 {
 	unsigned long sp = regs->sp;
@@ -209,9 +207,6 @@ static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state)
 	return ghcb;
 }
 
-/* Needed in vc_early_forward_exception */
-void do_early_exception(struct pt_regs *regs, int trapnr);
-
 static inline u64 sev_es_rd_ghcb_msr(void)
 {
 	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 08/45] x86/sev: Define the Linux specific guest termination reasons
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (6 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 07/45] x86/sev: Remove do_early_exception() forward declarations Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version Brijesh Singh
                   ` (37 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

GHCB specification defines the reason code for reason set 0. The reason
codes defined in the set 0 do not cover all possible causes for a guest
to request termination.

The reason set 1 to 255 is reserved for the vendor-specific codes.
Reseve the reason set 1 for the Linux guest. Define an error codes for
reason set 1.

While at it, change the sev_es_terminate() to accept the reason set
parameter.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c    |  6 +++---
 arch/x86/include/asm/sev-common.h |  8 ++++++++
 arch/x86/kernel/sev-shared.c      | 11 ++++-------
 arch/x86/kernel/sev.c             |  4 ++--
 4 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 8c6410014d22..78f8502e09b5 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -122,7 +122,7 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 static bool early_setup_sev_es(void)
 {
 	if (!sev_es_negotiate_protocol())
-		sev_es_terminate(GHCB_SEV_ES_PROT_UNSUPPORTED);
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED);
 
 	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
 		return false;
@@ -175,7 +175,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	enum es_result result;
 
 	if (!boot_ghcb && !early_setup_sev_es())
-		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
 	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -202,7 +202,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	if (result == ES_OK)
 		vc_finish_insn(&ctxt);
 	else if (result != ES_RETRY)
-		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 }
 
 static inline u64 rd_sev_status_msr(void)
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index aac44c3f839c..3278ee578937 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -73,9 +73,17 @@
 	 /* GHCBData[23:16] */				\
 	((((u64)reason_val) & 0xff) << 16))
 
+/* Error codes from reason set 0 */
+#define SEV_TERM_SET_GEN		0
 #define GHCB_SEV_ES_GEN_REQ		0
 #define GHCB_SEV_ES_PROT_UNSUPPORTED	1
 
+/* Linux-specific reason codes (used with reason set 1) */
+#define SEV_TERM_SET_LINUX		1
+#define GHCB_TERM_REGISTER		0	/* GHCB GPA registration failure */
+#define GHCB_TERM_PSC			1	/* Page State Change failure */
+#define GHCB_TERM_PVALIDATE		2	/* Pvalidate failure */
+
 #define GHCB_RESP_CODE(v)		((v) & GHCB_MSR_INFO_MASK)
 
 #endif
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index ce987688bbc0..2abf8a7d75e5 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -24,15 +24,12 @@ static bool __init sev_es_check_cpu_features(void)
 	return true;
 }
 
-static void __noreturn sev_es_terminate(unsigned int reason)
+static void __noreturn sev_es_terminate(unsigned int set, unsigned int reason)
 {
 	u64 val = GHCB_MSR_TERM_REQ;
 
-	/*
-	 * Tell the hypervisor what went wrong - only reason-set 0 is
-	 * currently supported.
-	 */
-	val |= GHCB_SEV_TERM_REASON(0, reason);
+	/* Tell the hypervisor what went wrong. */
+	val |= GHCB_SEV_TERM_REASON(set, reason);
 
 	/* Request Guest Termination from Hypvervisor */
 	sev_es_wr_ghcb_msr(val);
@@ -221,7 +218,7 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 
 fail:
 	/* Terminate the guest */
-	sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+	sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 }
 
 static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt,
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 03f9aff9d1f7..fb48e4ddd474 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1406,7 +1406,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
 		show_regs(regs);
 
 		/* Ask hypervisor to sev_es_terminate */
-		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
 		/* If that fails and we get here - just panic */
 		panic("Returned from Terminate-Request to Hypervisor\n");
@@ -1454,7 +1454,7 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 
 	/* Do initial setup or terminate the guest */
 	if (unlikely(boot_ghcb == NULL && !sev_es_setup_ghcb()))
-		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (7 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 08/45] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-12-07 12:51   ` Tianyu Lan
  2021-11-10 22:06 ` [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
                   ` (36 subsequent siblings)
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The SEV-ES guest calls the sev_es_negotiate_protocol() to negotiate the
GHCB protocol version before establishing the GHCB. Cache the negotiated
GHCB version so that it can be used later.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h   |  2 +-
 arch/x86/kernel/sev-shared.c | 17 ++++++++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index ec060c433589..9b9c190e8c3b 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -12,7 +12,7 @@
 #include <asm/insn.h>
 #include <asm/sev-common.h>
 
-#define GHCB_PROTO_OUR		0x0001UL
+#define GHCB_PROTOCOL_MIN	1ULL
 #define GHCB_PROTOCOL_MAX	1ULL
 #define GHCB_DEFAULT_USAGE	0ULL
 
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 2abf8a7d75e5..91105f5a02a8 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -14,6 +14,15 @@
 #define has_cpuflag(f)	boot_cpu_has(f)
 #endif
 
+/*
+ * Since feature negotiation related variables are set early in the boot
+ * process they must reside in the .data section so as not to be zeroed
+ * out when the .bss section is later cleared.
+ *
+ * GHCB protocol version negotiated with the hypervisor.
+ */
+static u16 ghcb_version __ro_after_init;
+
 static bool __init sev_es_check_cpu_features(void)
 {
 	if (!has_cpuflag(X86_FEATURE_RDRAND)) {
@@ -51,10 +60,12 @@ static bool sev_es_negotiate_protocol(void)
 	if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP)
 		return false;
 
-	if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTO_OUR ||
-	    GHCB_MSR_PROTO_MIN(val) > GHCB_PROTO_OUR)
+	if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN ||
+	    GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX)
 		return false;
 
+	ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val), GHCB_PROTOCOL_MAX);
+
 	return true;
 }
 
@@ -127,7 +138,7 @@ enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr,
 				   u64 exit_info_1, u64 exit_info_2)
 {
 	/* Fill in protocol and format specifiers */
-	ghcb->protocol_version = GHCB_PROTOCOL_MAX;
+	ghcb->protocol_version = ghcb_version;
 	ghcb->ghcb_usage       = GHCB_DEFAULT_USAGE;
 
 	ghcb_set_sw_exit_code(ghcb, exit_code);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (8 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-12-02 17:52   ` Borislav Petkov
  2021-11-10 22:06 ` [PATCH v7 11/45] x86/sev: Check SEV-SNP features support Brijesh Singh
                   ` (35 subsequent siblings)
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

Version 2 of GHCB specification introduced advertisement of a features
that are supported by the hypervisor. Add support to query the HV
features on boot.

Version 2 of GHCB specification adds several new NAEs, most of them are
optional except the hypervisor feature. Now that hypervisor feature NAE
is implemented, so bump the GHCB maximum support protocol version.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev-common.h |  3 +++
 arch/x86/include/asm/sev.h        |  2 +-
 arch/x86/include/uapi/asm/svm.h   |  2 ++
 arch/x86/kernel/sev-shared.c      | 30 ++++++++++++++++++++++++++++++
 4 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 3278ee578937..891569c07ed7 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -60,6 +60,9 @@
 /* GHCB Hypervisor Feature Request/Response */
 #define GHCB_MSR_HV_FT_REQ		0x080
 #define GHCB_MSR_HV_FT_RESP		0x081
+#define GHCB_MSR_HV_FT_RESP_VAL(v)			\
+	/* GHCBData[63:12] */				\
+	(((u64)(v) & GENMASK_ULL(63, 12)) >> 12)
 
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 9b9c190e8c3b..17b75f6ee11a 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -13,7 +13,7 @@
 #include <asm/sev-common.h>
 
 #define GHCB_PROTOCOL_MIN	1ULL
-#define GHCB_PROTOCOL_MAX	1ULL
+#define GHCB_PROTOCOL_MAX	2ULL
 #define GHCB_DEFAULT_USAGE	0ULL
 
 #define	VMGEXIT()			{ asm volatile("rep; vmmcall\n\r"); }
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index efa969325ede..b0ad00f4c1e1 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -108,6 +108,7 @@
 #define SVM_VMGEXIT_AP_JUMP_TABLE		0x80000005
 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE		0
 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE		1
+#define SVM_VMGEXIT_HV_FEATURES			0x8000fffd
 #define SVM_VMGEXIT_UNSUPPORTED_EVENT		0x8000ffff
 
 /* Exit code reserved for hypervisor/software use */
@@ -218,6 +219,7 @@
 	{ SVM_VMGEXIT_NMI_COMPLETE,	"vmgexit_nmi_complete" }, \
 	{ SVM_VMGEXIT_AP_HLT_LOOP,	"vmgexit_ap_hlt_loop" }, \
 	{ SVM_VMGEXIT_AP_JUMP_TABLE,	"vmgexit_ap_jump_table" }, \
+	{ SVM_VMGEXIT_HV_FEATURES,	"vmgexit_hypervisor_feature" }, \
 	{ SVM_EXIT_ERR,         "invalid_guest_state" }
 
 
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 91105f5a02a8..85b549f3ee1a 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -23,6 +23,9 @@
  */
 static u16 ghcb_version __ro_after_init;
 
+/* Bitmap of SEV features supported by the hypervisor */
+static u64 sev_hv_features __ro_after_init;
+
 static bool __init sev_es_check_cpu_features(void)
 {
 	if (!has_cpuflag(X86_FEATURE_RDRAND)) {
@@ -48,6 +51,30 @@ static void __noreturn sev_es_terminate(unsigned int set, unsigned int reason)
 		asm volatile("hlt\n" : : : "memory");
 }
 
+/*
+ * The hypervisor features are available from GHCB version 2 onward.
+ */
+static bool get_hv_features(void)
+{
+	u64 val;
+
+	sev_hv_features = 0;
+
+	if (ghcb_version < 2)
+		return false;
+
+	sev_es_wr_ghcb_msr(GHCB_MSR_HV_FT_REQ);
+	VMGEXIT();
+
+	val = sev_es_rd_ghcb_msr();
+	if (GHCB_RESP_CODE(val) != GHCB_MSR_HV_FT_RESP)
+		return false;
+
+	sev_hv_features = GHCB_MSR_HV_FT_RESP_VAL(val);
+
+	return true;
+}
+
 static bool sev_es_negotiate_protocol(void)
 {
 	u64 val;
@@ -66,6 +93,9 @@ static bool sev_es_negotiate_protocol(void)
 
 	ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val), GHCB_PROTOCOL_MAX);
 
+	if (!get_hv_features())
+		return false;
+
 	return true;
 }
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 11/45] x86/sev: Check SEV-SNP features support
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (9 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 12/45] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
                   ` (34 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

Version 2 of the GHCB specification added the advertisement of features
that are supported by the hypervisor. If hypervisor supports the SEV-SNP
then it must set the SEV-SNP features bit to indicate that the base
SEV-SNP is supported.

Check the SEV-SNP feature while establishing the GHCB, if failed,
terminate the guest.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c    | 17 +++++++++++++++--
 arch/x86/include/asm/sev-common.h |  3 +++
 arch/x86/kernel/sev.c             | 12 ++++++++++--
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 78f8502e09b5..e525fa74a551 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -119,11 +119,24 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 /* Include code for early handlers */
 #include "../../kernel/sev-shared.c"
 
-static bool early_setup_sev_es(void)
+static inline bool sev_snp_enabled(void)
+{
+	return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
+}
+
+static bool do_early_sev_setup(void)
 {
 	if (!sev_es_negotiate_protocol())
 		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED);
 
+	/*
+	 * SNP is supported in v2 of the GHCB spec which mandates support for HV
+	 * features. If SEV-SNP is enabled, then check if the hypervisor supports
+	 * the SEV-SNP features.
+	 */
+	if (sev_snp_enabled() && !(sev_hv_features & GHCB_HV_FT_SNP))
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
 	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
 		return false;
 
@@ -174,7 +187,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	struct es_em_ctxt ctxt;
 	enum es_result result;
 
-	if (!boot_ghcb && !early_setup_sev_es())
+	if (!boot_ghcb && !do_early_sev_setup())
 		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 891569c07ed7..f80a3cde2086 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -64,6 +64,8 @@
 	/* GHCBData[63:12] */				\
 	(((u64)(v) & GENMASK_ULL(63, 12)) >> 12)
 
+#define GHCB_HV_FT_SNP			BIT_ULL(0)
+
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf
@@ -80,6 +82,7 @@
 #define SEV_TERM_SET_GEN		0
 #define GHCB_SEV_ES_GEN_REQ		0
 #define GHCB_SEV_ES_PROT_UNSUPPORTED	1
+#define GHCB_SNP_UNSUPPORTED		2
 
 /* Linux-specific reason codes (used with reason set 1) */
 #define SEV_TERM_SET_LINUX		1
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index fb48e4ddd474..80a41e413cb8 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -627,12 +627,20 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
  * This function runs on the first #VC exception after the kernel
  * switched to virtual addresses.
  */
-static bool __init sev_es_setup_ghcb(void)
+static bool __init setup_ghcb(void)
 {
 	/* First make sure the hypervisor talks a supported protocol. */
 	if (!sev_es_negotiate_protocol())
 		return false;
 
+	/*
+	 * SNP is supported in v2 of the GHCB spec which mandates support for HV
+	 * features. If SEV-SNP is enabled, then check if the hypervisor supports
+	 * the SEV-SNP features.
+	 */
+	if (cc_platform_has(CC_ATTR_SEV_SNP) && !(sev_hv_features & GHCB_HV_FT_SNP))
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
 	/*
 	 * Clear the boot_ghcb. The first exception comes in before the bss
 	 * section is cleared.
@@ -1453,7 +1461,7 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 	enum es_result result;
 
 	/* Do initial setup or terminate the guest */
-	if (unlikely(boot_ghcb == NULL && !sev_es_setup_ghcb()))
+	if (unlikely(!boot_ghcb && !setup_ghcb()))
 		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 12/45] x86/sev: Add a helper for the PVALIDATE instruction
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (10 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 11/45] x86/sev: Check SEV-SNP features support Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-11-10 22:06 ` [PATCH v7 13/45] x86/sev: Check the vmpl level Brijesh Singh
                   ` (33 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

An SNP-active guest uses the PVALIDATE instruction to validate or
rescind the validation of a guest page’s RMP entry. Upon completion,
a return code is stored in EAX and rFLAGS bits are set based on the
return code. If the instruction completed successfully, the CF
indicates if the content of the RMP were changed or not.

See AMD APM Volume 3 for additional details.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 17b75f6ee11a..4ee98976aed8 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -60,6 +60,9 @@ extern void vc_no_ghcb(void);
 extern void vc_boot_ghcb(void);
 extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
 
+/* Software defined (when rFlags.CF = 1) */
+#define PVALIDATE_FAIL_NOUPDATE		255
+
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 extern struct static_key_false sev_es_enable_key;
 extern void __sev_es_ist_enter(struct pt_regs *regs);
@@ -87,12 +90,30 @@ extern enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
 					  struct es_em_ctxt *ctxt,
 					  u64 exit_code, u64 exit_info_1,
 					  u64 exit_info_2);
+static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate)
+{
+	bool no_rmpupdate;
+	int rc;
+
+	/* "pvalidate" mnemonic support in binutils 2.36 and newer */
+	asm volatile(".byte 0xF2, 0x0F, 0x01, 0xFF\n\t"
+		     CC_SET(c)
+		     : CC_OUT(c) (no_rmpupdate), "=a"(rc)
+		     : "a"(vaddr), "c"(rmp_psize), "d"(validate)
+		     : "memory", "cc");
+
+	if (no_rmpupdate)
+		return PVALIDATE_FAIL_NOUPDATE;
+
+	return rc;
+}
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
 static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { return 0; }
 static inline void sev_es_nmi_complete(void) { }
 static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; }
+static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) { return 0; }
 #endif
 
 #endif
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 13/45] x86/sev: Check the vmpl level
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (11 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 12/45] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
@ 2021-11-10 22:06 ` Brijesh Singh
  2021-12-06 18:25   ` Borislav Petkov
  2021-11-10 22:07 ` [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
                   ` (32 subsequent siblings)
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:06 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

Virtual Machine Privilege Level (VMPL) is an optional feature in the
SEV-SNP architecture, which allows a guest VM to divide its address space
into four levels. The level can be used to provide the hardware isolated
abstraction layers with a VM. The VMPL0 is the highest privilege, and
VMPL3 is the least privilege. Certain operations must be done by the VMPL0
software, such as:

* Validate or invalidate memory range (PVALIDATE instruction)
* Allocate VMSA page (RMPADJUST instruction when VMSA=1)

The initial SEV-SNP support assumes that the guest kernel is running on
VMPL0. Let's add a check to make sure that kernel is running at VMPL0
before continuing the boot. There is no easy method to query the current
VMPL level, so use the RMPADJUST instruction to determine whether its
booted at the VMPL0.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c    | 34 ++++++++++++++++++++++++++++---
 arch/x86/include/asm/sev-common.h |  1 +
 arch/x86/include/asm/sev.h        | 16 +++++++++++++++
 3 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index e525fa74a551..21feb7f4f76f 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -124,6 +124,29 @@ static inline bool sev_snp_enabled(void)
 	return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
 }
 
+static bool is_vmpl0(void)
+{
+	u64 attrs;
+	int err;
+
+	/*
+	 * There is no straightforward way to query the current VMPL level. The
+	 * simplest method is to use the RMPADJUST instruction to change a page
+	 * permission to a VMPL level-1, and if the guest kernel is launched at
+	 * a level <= 1, then RMPADJUST instruction will return an error.
+	 */
+	attrs = 1;
+
+	/*
+	 * Any page-aligned virtual address is sufficient to test the VMPL level.
+	 * The boot_ghcb_page is page aligned memory, so lets use for the test.
+	 */
+	if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, attrs))
+		return false;
+
+	return true;
+}
+
 static bool do_early_sev_setup(void)
 {
 	if (!sev_es_negotiate_protocol())
@@ -132,10 +155,15 @@ static bool do_early_sev_setup(void)
 	/*
 	 * SNP is supported in v2 of the GHCB spec which mandates support for HV
 	 * features. If SEV-SNP is enabled, then check if the hypervisor supports
-	 * the SEV-SNP features.
+	 * the SEV-SNP features and is launched at VMPL-0 level.
 	 */
-	if (sev_snp_enabled() && !(sev_hv_features & GHCB_HV_FT_SNP))
-		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+	if (sev_snp_enabled()) {
+		if (!(sev_hv_features & GHCB_HV_FT_SNP))
+			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+		if (!is_vmpl0())
+			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
+	}
 
 	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
 		return false;
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index f80a3cde2086..d426c30ae7b4 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -89,6 +89,7 @@
 #define GHCB_TERM_REGISTER		0	/* GHCB GPA registration failure */
 #define GHCB_TERM_PSC			1	/* Page State Change failure */
 #define GHCB_TERM_PVALIDATE		2	/* Pvalidate failure */
+#define GHCB_TERM_NOT_VMPL0		3	/* SNP guest is not running at VMPL-0 */
 
 #define GHCB_RESP_CODE(v)		((v) & GHCB_MSR_INFO_MASK)
 
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 4ee98976aed8..e37451849165 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -63,6 +63,9 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
 /* Software defined (when rFlags.CF = 1) */
 #define PVALIDATE_FAIL_NOUPDATE		255
 
+/* RMP page size */
+#define RMP_PG_SIZE_4K			0
+
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 extern struct static_key_false sev_es_enable_key;
 extern void __sev_es_ist_enter(struct pt_regs *regs);
@@ -90,6 +93,18 @@ extern enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
 					  struct es_em_ctxt *ctxt,
 					  u64 exit_code, u64 exit_info_1,
 					  u64 exit_info_2);
+static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs)
+{
+	int rc;
+
+	/* "rmpadjust" mnemonic support in binutils 2.36 and newer */
+	asm volatile(".byte 0xF3,0x0F,0x01,0xFE\n\t"
+		     : "=a"(rc)
+		     : "a"(vaddr), "c"(rmp_psize), "d"(attrs)
+		     : "memory", "cc");
+
+	return rc;
+}
 static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate)
 {
 	bool no_rmpupdate;
@@ -114,6 +129,7 @@ static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { ret
 static inline void sev_es_nmi_complete(void) { }
 static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; }
 static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) { return 0; }
+static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs) { return 0; }
 #endif
 
 #endif
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (12 preceding siblings ...)
  2021-11-10 22:06 ` [PATCH v7 13/45] x86/sev: Check the vmpl level Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-12-07 11:48   ` Borislav Petkov
  2021-11-10 22:07 ` [PATCH v7 15/45] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
                   ` (31 subsequent siblings)
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

Many of the integrity guarantees of SEV-SNP are enforced through the
Reverse Map Table (RMP). Each RMP entry contains the GPA at which a
particular page of DRAM should be mapped. The VMs can request the
hypervisor to add pages in the RMP table via the Page State Change VMGEXIT
defined in the GHCB specification. Inside each RMP entry is a Validated
flag; this flag is automatically cleared to 0 by the CPU hardware when a
new RMP entry is created for a guest. Each VM page can be either
validated or invalidated, as indicated by the Validated flag in the RMP
entry. Memory access to a private page that is not validated generates
a #VC. A VM must use PVALIDATE instruction to validate the private page
before using it.

To maintain the security guarantee of SEV-SNP guests, when transitioning
pages from private to shared, the guest must invalidate the pages before
asking the hypervisor to change the page state to shared in the RMP table.

After the pages are mapped private in the page table, the guest must issue
a page state change VMGEXIT to make the pages private in the RMP table and
validate it.

On boot, BIOS should have validated the entire system memory. During
the kernel decompression stage, the VC handler uses the
set_memory_decrypted() to make the GHCB page shared (i.e clear encryption
attribute). And while exiting from the decompression, it calls the
set_page_encrypted() to make the page private.

Add sev_snp_set_page_{private,shared}() helper that is used by the
set_memory_{decrypt,encrypt}() to change the page state in the RMP table.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/ident_map_64.c | 18 ++++++++++-
 arch/x86/boot/compressed/misc.h         |  4 +++
 arch/x86/boot/compressed/sev.c          | 41 +++++++++++++++++++++++++
 arch/x86/include/asm/sev-common.h       | 26 ++++++++++++++++
 4 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index f7213d0943b8..3cf7a7575f5c 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -275,15 +275,31 @@ static int set_clr_page_flags(struct x86_mapping_info *info,
 	 * Changing encryption attributes of a page requires to flush it from
 	 * the caches.
 	 */
-	if ((set | clr) & _PAGE_ENC)
+	if ((set | clr) & _PAGE_ENC) {
 		clflush_page(address);
 
+		/*
+		 * If the encryption attribute is being cleared, then change
+		 * the page state to shared in the RMP table.
+		 */
+		if (clr)
+			snp_set_page_shared(pte_pfn(*ptep) << PAGE_SHIFT);
+	}
+
 	/* Update PTE */
 	pte = *ptep;
 	pte = pte_set_flags(pte, set);
 	pte = pte_clear_flags(pte, clr);
 	set_pte(ptep, pte);
 
+	/*
+	 * If the encryption attribute is being set, then change the page state to
+	 * private in the RMP entry. The page state must be done after the PTE
+	 * is updated.
+	 */
+	if (set & _PAGE_ENC)
+		snp_set_page_private(pte_pfn(*ptep) << PAGE_SHIFT);
+
 	/* Flush TLB after changing encryption attribute */
 	write_cr3(top_level_pgt);
 
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 23e0e395084a..01cc13c12059 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -124,6 +124,8 @@ static inline void console_init(void)
 void sev_enable(struct boot_params *bp);
 void sev_es_shutdown_ghcb(void);
 extern bool sev_es_check_ghcb_fault(unsigned long address);
+void snp_set_page_private(unsigned long paddr);
+void snp_set_page_shared(unsigned long paddr);
 #else
 static inline void sev_enable(struct boot_params *bp) { }
 static inline void sev_es_shutdown_ghcb(void) { }
@@ -131,6 +133,8 @@ static inline bool sev_es_check_ghcb_fault(unsigned long address)
 {
 	return false;
 }
+static inline void snp_set_page_private(unsigned long paddr) { }
+static inline void snp_set_page_shared(unsigned long paddr) { }
 #endif
 
 /* acpi.c */
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 21feb7f4f76f..f85094dd957f 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -147,6 +147,47 @@ static bool is_vmpl0(void)
 	return true;
 }
 
+static void __page_state_change(unsigned long paddr, enum psc_op op)
+{
+	u64 val;
+
+	if (!sev_snp_enabled())
+		return;
+
+	/*
+	 * If private -> shared then invalidate the page before requesting the
+	 * state change in the RMP table.
+	 */
+	if (op == SNP_PAGE_STATE_SHARED && pvalidate(paddr, RMP_PG_SIZE_4K, 0))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+
+	/* Issue VMGEXIT to change the page state in RMP table. */
+	sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op));
+	VMGEXIT();
+
+	/* Read the response of the VMGEXIT. */
+	val = sev_es_rd_ghcb_msr();
+	if ((GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP) || GHCB_MSR_PSC_RESP_VAL(val))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+
+	/*
+	 * Now that page is added in the RMP table, validate it so that it is
+	 * consistent with the RMP entry.
+	 */
+	if (op == SNP_PAGE_STATE_PRIVATE && pvalidate(paddr, RMP_PG_SIZE_4K, 1))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+}
+
+void snp_set_page_private(unsigned long paddr)
+{
+	__page_state_change(paddr, SNP_PAGE_STATE_PRIVATE);
+}
+
+void snp_set_page_shared(unsigned long paddr)
+{
+	__page_state_change(paddr, SNP_PAGE_STATE_SHARED);
+}
+
 static bool do_early_sev_setup(void)
 {
 	if (!sev_es_negotiate_protocol())
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index d426c30ae7b4..1c76b6b775cc 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -57,6 +57,32 @@
 #define GHCB_MSR_AP_RESET_HOLD_REQ	0x006
 #define GHCB_MSR_AP_RESET_HOLD_RESP	0x007
 
+/*
+ * SNP Page State Change Operation
+ *
+ * GHCBData[55:52] - Page operation:
+ *   0x0001 – Page assignment, Private
+ *   0x0002 – Page assignment, Shared
+ */
+enum psc_op {
+	SNP_PAGE_STATE_PRIVATE = 1,
+	SNP_PAGE_STATE_SHARED,
+};
+
+#define GHCB_MSR_PSC_REQ		0x014
+#define GHCB_MSR_PSC_REQ_GFN(gfn, op)			\
+	/* GHCBData[55:52] */				\
+	(((u64)((op) & 0xf) << 52) |			\
+	/* GHCBData[51:12] */				\
+	((u64)((gfn) & GENMASK_ULL(39, 0)) << 12) |	\
+	/* GHCBData[11:0] */				\
+	GHCB_MSR_PSC_REQ)
+
+#define GHCB_MSR_PSC_RESP		0x015
+#define GHCB_MSR_PSC_RESP_VAL(val)			\
+	/* GHCBData[63:32] */				\
+	(((u64)(val) & GENMASK_ULL(63, 32)) >> 32)
+
 /* GHCB Hypervisor Feature Request/Response */
 #define GHCB_MSR_HV_FT_REQ		0x080
 #define GHCB_MSR_HV_FT_RESP		0x081
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 15/45] x86/compressed: Register GHCB memory when SEV-SNP is active
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (13 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-15 14:05   ` Jörg Rödel
  2021-11-10 22:07 ` [PATCH v7 16/45] x86/sev: " Brijesh Singh
                   ` (30 subsequent siblings)
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The SEV-SNP guest is required to perform GHCB GPA registration. This is
because the hypervisor may prefer that a guest use a consistent and/or
specific GPA for the GHCB associated with a vCPU. For more information,
see the GHCB specification.

If hypervisor can not work with the guest provided GPA then terminate the
guest boot.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c    |  4 ++++
 arch/x86/include/asm/sev-common.h | 13 +++++++++++++
 arch/x86/kernel/sev-shared.c      | 16 ++++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index f85094dd957f..fb2f763dfc19 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -217,6 +217,10 @@ static bool do_early_sev_setup(void)
 	/* Initialize lookup tables for the instruction decoder */
 	inat_init_tables();
 
+	/* SEV-SNP guest requires the GHCB GPA must be registered */
+	if (sev_snp_enabled())
+		snp_register_ghcb_early(__pa(&boot_ghcb_page));
+
 	return true;
 }
 
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 1c76b6b775cc..b82fff9d607b 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -57,6 +57,19 @@
 #define GHCB_MSR_AP_RESET_HOLD_REQ	0x006
 #define GHCB_MSR_AP_RESET_HOLD_RESP	0x007
 
+/* GHCB GPA Register */
+#define GHCB_MSR_REG_GPA_REQ		0x012
+#define GHCB_MSR_REG_GPA_REQ_VAL(v)			\
+	/* GHCBData[63:12] */				\
+	(((u64)((v) & GENMASK_ULL(51, 0)) << 12) |	\
+	/* GHCBData[11:0] */				\
+	GHCB_MSR_REG_GPA_REQ)
+
+#define GHCB_MSR_REG_GPA_RESP		0x013
+#define GHCB_MSR_REG_GPA_RESP_VAL(v)			\
+	/* GHCBData[63:12] */				\
+	(((u64)(v) & GENMASK_ULL(63, 12)) >> 12)
+
 /*
  * SNP Page State Change Operation
  *
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 85b549f3ee1a..b0ed64fc6520 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -75,6 +75,22 @@ static bool get_hv_features(void)
 	return true;
 }
 
+static void snp_register_ghcb_early(unsigned long paddr)
+{
+	unsigned long pfn = paddr >> PAGE_SHIFT;
+	u64 val;
+
+	sev_es_wr_ghcb_msr(GHCB_MSR_REG_GPA_REQ_VAL(pfn));
+	VMGEXIT();
+
+	val = sev_es_rd_ghcb_msr();
+
+	/* If the response GPA is not ours then abort the guest */
+	if ((GHCB_RESP_CODE(val) != GHCB_MSR_REG_GPA_RESP) ||
+	    (GHCB_MSR_REG_GPA_RESP_VAL(val) != pfn))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_REGISTER);
+}
+
 static bool sev_es_negotiate_protocol(void)
 {
 	u64 val;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 16/45] x86/sev: Register GHCB memory when SEV-SNP is active
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (14 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 15/45] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-12-08 17:41   ` Borislav Petkov
  2021-11-10 22:07 ` [PATCH v7 17/45] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
                   ` (29 subsequent siblings)
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The SEV-SNP guest is required to perform GHCB GPA registration. This is
because the hypervisor may prefer that a guest use a consistent and/or
specific GPA for the GHCB associated with a vCPU. For more information,
see the GHCB specification section GHCB GPA Registration.

During the boot, init_ghcb() allocates a per-cpu GHCB page. On very first
VC exception, the exception handler switch to using the per-cpu GHCB page
allocated during the init_ghcb(). The GHCB page must be registered in
the current vcpu context.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h   |   2 +
 arch/x86/kernel/cpu/common.c |   5 ++
 arch/x86/kernel/head64.c     |   3 +
 arch/x86/kernel/sev.c        | 116 ++++++++++++++++++++---------------
 4 files changed, 77 insertions(+), 49 deletions(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index e37451849165..0df508374a35 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -122,6 +122,7 @@ static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate)
 
 	return rc;
 }
+void sev_snp_register_ghcb(void);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -130,6 +131,7 @@ static inline void sev_es_nmi_complete(void) { }
 static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; }
 static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) { return 0; }
 static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs) { return 0; }
+static inline void sev_snp_register_ghcb(void) { }
 #endif
 
 #endif
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 0083464de5e3..16b5667bbfdb 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -59,6 +59,7 @@
 #include <asm/cpu_device_id.h>
 #include <asm/uv/uv.h>
 #include <asm/sigframe.h>
+#include <asm/sev.h>
 
 #include "cpu.h"
 
@@ -1977,6 +1978,10 @@ void cpu_init_exception_handling(void)
 
 	load_TR_desc();
 
+	/* Register the GHCB before taking any VC exception */
+	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
+		sev_snp_register_ghcb();
+
 	/* Finally load the IDT */
 	load_current_idt();
 }
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 54bf0603002f..968105cec364 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -588,6 +588,9 @@ void early_setup_idt(void)
 
 	bringup_idt_descr.address = (unsigned long)bringup_idt_table;
 	native_load_idt(&bringup_idt_descr);
+
+	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
+		sev_snp_register_ghcb();
 }
 
 /*
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 80a41e413cb8..30634e7e5c7b 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -158,55 +158,6 @@ void noinstr __sev_es_ist_exit(void)
 	this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], *(unsigned long *)ist);
 }
 
-/*
- * Nothing shall interrupt this code path while holding the per-CPU
- * GHCB. The backup GHCB is only for NMIs interrupting this path.
- *
- * Callers must disable local interrupts around it.
- */
-static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state)
-{
-	struct sev_es_runtime_data *data;
-	struct ghcb *ghcb;
-
-	WARN_ON(!irqs_disabled());
-
-	data = this_cpu_read(runtime_data);
-	ghcb = &data->ghcb_page;
-
-	if (unlikely(data->ghcb_active)) {
-		/* GHCB is already in use - save its contents */
-
-		if (unlikely(data->backup_ghcb_active)) {
-			/*
-			 * Backup-GHCB is also already in use. There is no way
-			 * to continue here so just kill the machine. To make
-			 * panic() work, mark GHCBs inactive so that messages
-			 * can be printed out.
-			 */
-			data->ghcb_active        = false;
-			data->backup_ghcb_active = false;
-
-			instrumentation_begin();
-			panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use");
-			instrumentation_end();
-		}
-
-		/* Mark backup_ghcb active before writing to it */
-		data->backup_ghcb_active = true;
-
-		state->ghcb = &data->backup_ghcb;
-
-		/* Backup GHCB content */
-		*state->ghcb = *ghcb;
-	} else {
-		state->ghcb = NULL;
-		data->ghcb_active = true;
-	}
-
-	return ghcb;
-}
-
 static inline u64 sev_es_rd_ghcb_msr(void)
 {
 	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
@@ -459,6 +410,55 @@ static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt
 /* Include code shared with pre-decompression boot stage */
 #include "sev-shared.c"
 
+/*
+ * Nothing shall interrupt this code path while holding the per-CPU
+ * GHCB. The backup GHCB is only for NMIs interrupting this path.
+ *
+ * Callers must disable local interrupts around it.
+ */
+static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state)
+{
+	struct sev_es_runtime_data *data;
+	struct ghcb *ghcb;
+
+	WARN_ON(!irqs_disabled());
+
+	data = this_cpu_read(runtime_data);
+	ghcb = &data->ghcb_page;
+
+	if (unlikely(data->ghcb_active)) {
+		/* GHCB is already in use - save its contents */
+
+		if (unlikely(data->backup_ghcb_active)) {
+			/*
+			 * Backup-GHCB is also already in use. There is no way
+			 * to continue here so just kill the machine. To make
+			 * panic() work, mark GHCBs inactive so that messages
+			 * can be printed out.
+			 */
+			data->ghcb_active        = false;
+			data->backup_ghcb_active = false;
+
+			instrumentation_begin();
+			panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use");
+			instrumentation_end();
+		}
+
+		/* Mark backup_ghcb active before writing to it */
+		data->backup_ghcb_active = true;
+
+		state->ghcb = &data->backup_ghcb;
+
+		/* Backup GHCB content */
+		*state->ghcb = *ghcb;
+	} else {
+		state->ghcb = NULL;
+		data->ghcb_active = true;
+	}
+
+	return ghcb;
+}
+
 static noinstr void __sev_put_ghcb(struct ghcb_state *state)
 {
 	struct sev_es_runtime_data *data;
@@ -650,6 +650,10 @@ static bool __init setup_ghcb(void)
 	/* Alright - Make the boot-ghcb public */
 	boot_ghcb = &boot_ghcb_page;
 
+	/* SEV-SNP guest requires that GHCB GPA must be registered. */
+	if (cc_platform_has(CC_ATTR_SEV_SNP))
+		snp_register_ghcb_early(__pa(&boot_ghcb_page));
+
 	return true;
 }
 
@@ -741,6 +745,20 @@ static void __init init_ghcb(int cpu)
 	data->backup_ghcb_active = false;
 }
 
+void sev_snp_register_ghcb(void)
+{
+	struct sev_es_runtime_data *data;
+	struct ghcb *ghcb;
+
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return;
+
+	data = this_cpu_read(runtime_data);
+	ghcb = &data->ghcb_page;
+
+	snp_register_ghcb_early(__pa(ghcb));
+}
+
 void __init sev_es_init_vc_handling(void)
 {
 	int cpu;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 17/45] x86/sev: Add helper for validating pages in early enc attribute changes
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (15 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 16/45] x86/sev: " Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 18/45] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
                   ` (28 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The early_set_memory_{encrypt,decrypt}() are used for changing the
page from decrypted (shared) to encrypted (private) and vice versa.
When SEV-SNP is active, the page state transition needs to go through
additional steps.

If the page is transitioned from shared to private, then perform the
following after the encryption attribute is set in the page table:

1. Issue the page state change VMGEXIT to add the page as a private
   in the RMP table.
2. Validate the page after its successfully added in the RMP table.

To maintain the security guarantees, if the page is transitioned from
private to shared, then perform the following before clearing the
encryption attribute from the page table.

1. Invalidate the page.
2. Issue the page state change VMGEXIT to make the page shared in the
   RMP table.

The early_set_memory_{encrypt,decrypt} can be called before the GHCB
is setup, use the SNP page state MSR protocol VMGEXIT defined in the GHCB
specification to request the page state change in the RMP table.

While at it, add a helper snp_prep_memory() that can be used outside
the sev specific files to change the page state for a specified memory
range.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h |  10 ++++
 arch/x86/kernel/sev.c      | 102 +++++++++++++++++++++++++++++++++++++
 arch/x86/mm/mem_encrypt.c  |  51 +++++++++++++++++--
 3 files changed, 159 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 0df508374a35..eec2e1b9d557 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -123,6 +123,11 @@ static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate)
 	return rc;
 }
 void sev_snp_register_ghcb(void);
+void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
+					 unsigned int npages);
+void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
+					unsigned int npages);
+void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -132,6 +137,11 @@ static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; }
 static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) { return 0; }
 static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs) { return 0; }
 static inline void sev_snp_register_ghcb(void) { }
+static inline void __init
+early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned int npages) { }
+static inline void __init
+early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned int npages) { }
+static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op) { }
 #endif
 
 #endif
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 30634e7e5c7b..3c3b96a2990f 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -532,6 +532,108 @@ static u64 get_jump_table_addr(void)
 	return ret;
 }
 
+static void pvalidate_pages(unsigned long vaddr, unsigned int npages, bool validate)
+{
+	unsigned long vaddr_end;
+	int rc;
+
+	vaddr = vaddr & PAGE_MASK;
+	vaddr_end = vaddr + (npages << PAGE_SHIFT);
+
+	while (vaddr < vaddr_end) {
+		rc = pvalidate(vaddr, RMP_PG_SIZE_4K, validate);
+		if (WARN(rc, "Failed to validate address 0x%lx ret %d", vaddr, rc))
+			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+
+		vaddr = vaddr + PAGE_SIZE;
+	}
+}
+
+static void __init early_set_page_state(unsigned long paddr, unsigned int npages, enum psc_op op)
+{
+	unsigned long paddr_end;
+	u64 val;
+
+	paddr = paddr & PAGE_MASK;
+	paddr_end = paddr + (npages << PAGE_SHIFT);
+
+	while (paddr < paddr_end) {
+		/*
+		 * Use the MSR protocol because this function can be called before the GHCB
+		 * is established.
+		 */
+		sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op));
+		VMGEXIT();
+
+		val = sev_es_rd_ghcb_msr();
+
+		if (WARN(GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP,
+			 "Wrong PSC response code: 0x%x\n",
+			 (unsigned int)GHCB_RESP_CODE(val)))
+			goto e_term;
+
+		if (WARN(GHCB_MSR_PSC_RESP_VAL(val),
+			 "Failed to change page state to '%s' paddr 0x%lx error 0x%llx\n",
+			 op == SNP_PAGE_STATE_PRIVATE ? "private" : "shared",
+			 paddr, GHCB_MSR_PSC_RESP_VAL(val)))
+			goto e_term;
+
+		paddr = paddr + PAGE_SIZE;
+	}
+
+	return;
+
+e_term:
+	sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+}
+
+void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
+					 unsigned int npages)
+{
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return;
+
+	 /*
+	  * Ask the hypervisor to mark the memory pages as private in the RMP
+	  * table.
+	  */
+	early_set_page_state(paddr, npages, SNP_PAGE_STATE_PRIVATE);
+
+	/* Validate the memory pages after they've been added in the RMP table. */
+	pvalidate_pages(vaddr, npages, 1);
+}
+
+void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
+					unsigned int npages)
+{
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return;
+
+	/*
+	 * Invalidate the memory pages before they are marked shared in the
+	 * RMP table.
+	 */
+	pvalidate_pages(vaddr, npages, 0);
+
+	 /* Ask hypervisor to mark the memory pages shared in the RMP table. */
+	early_set_page_state(paddr, npages, SNP_PAGE_STATE_SHARED);
+}
+
+void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op)
+{
+	unsigned long vaddr, npages;
+
+	vaddr = (unsigned long)__va(paddr);
+	npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+
+	if (op == SNP_PAGE_STATE_PRIVATE)
+		early_snp_set_memory_private(vaddr, paddr, npages);
+	else if (op == SNP_PAGE_STATE_SHARED)
+		early_snp_set_memory_shared(vaddr, paddr, npages);
+	else
+		WARN(1, "invalid memory op %d\n", op);
+}
+
 int sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
 {
 	u16 startup_cs, startup_ip;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 534c2c82fbec..d01bb95f7aef 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -31,6 +31,7 @@
 #include <asm/processor-flags.h>
 #include <asm/msr.h>
 #include <asm/cmdline.h>
+#include <asm/sev.h>
 
 #include "mm_internal.h"
 
@@ -49,6 +50,34 @@ EXPORT_SYMBOL_GPL(sev_enable_key);
 /* Buffer used for early in-place encryption by BSP, no locking needed */
 static char sme_early_buffer[PAGE_SIZE] __initdata __aligned(PAGE_SIZE);
 
+/*
+ * When SNP is active, change the page state from private to shared before
+ * copying the data from the source to destination and restore after the copy.
+ * This is required because the source address is mapped as decrypted by the
+ * caller of the routine.
+ */
+static inline void __init snp_memcpy(void *dst, void *src, size_t sz,
+				     unsigned long paddr, bool decrypt)
+{
+	unsigned long npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+
+	if (!cc_platform_has(CC_ATTR_SEV_SNP) || !decrypt) {
+		memcpy(dst, src, sz);
+		return;
+	}
+
+	/*
+	 * With SNP, the paddr needs to be accessed decrypted, mark the page
+	 * shared in the RMP table before copying it.
+	 */
+	early_snp_set_memory_shared((unsigned long)__va(paddr), paddr, npages);
+
+	memcpy(dst, src, sz);
+
+	/* Restore the page state after the memcpy. */
+	early_snp_set_memory_private((unsigned long)__va(paddr), paddr, npages);
+}
+
 /*
  * This routine does not change the underlying encryption setting of the
  * page(s) that map this memory. It assumes that eventually the memory is
@@ -97,8 +126,8 @@ static void __init __sme_early_enc_dec(resource_size_t paddr,
 		 * Use a temporary buffer, of cache-line multiple size, to
 		 * avoid data corruption as documented in the APM.
 		 */
-		memcpy(sme_early_buffer, src, len);
-		memcpy(dst, sme_early_buffer, len);
+		snp_memcpy(sme_early_buffer, src, len, paddr, enc);
+		snp_memcpy(dst, sme_early_buffer, len, paddr, !enc);
 
 		early_memunmap(dst, len);
 		early_memunmap(src, len);
@@ -273,14 +302,28 @@ static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
 	clflush_cache_range(__va(pa), size);
 
 	/* Encrypt/decrypt the contents in-place */
-	if (enc)
+	if (enc) {
 		sme_early_encrypt(pa, size);
-	else
+	} else {
 		sme_early_decrypt(pa, size);
 
+		/*
+		 * ON SNP, the page state in the RMP table must happen
+		 * before the page table updates.
+		 */
+		early_snp_set_memory_shared((unsigned long)__va(pa), pa, 1);
+	}
+
 	/* Change the page encryption mask. */
 	new_pte = pfn_pte(pfn, new_prot);
 	set_pte_atomic(kpte, new_pte);
+
+	/*
+	 * If page is set encrypted in the page table, then update the RMP table to
+	 * add this page as private.
+	 */
+	if (enc)
+		early_snp_set_memory_private((unsigned long)__va(pa), pa, 1);
 }
 
 static int __init early_set_memory_enc_dec(unsigned long vaddr,
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 18/45] x86/kernel: Make the bss.decrypted section shared in RMP table
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (16 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 17/45] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 19/45] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
                   ` (27 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The encryption attribute for the bss.decrypted region is cleared in the
initial page table build. This is because the section contains the data
that need to be shared between the guest and the hypervisor.

When SEV-SNP is active, just clearing the encryption attribute in the
page table is not enough. The page state need to be updated in the RMP
table.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/head64.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 968105cec364..ca8536404ed3 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -143,7 +143,14 @@ static unsigned long sme_postprocess_startup(struct boot_params *bp, pmdval_t *p
 	if (sme_get_me_mask()) {
 		vaddr = (unsigned long)__start_bss_decrypted;
 		vaddr_end = (unsigned long)__end_bss_decrypted;
+
 		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
+			/*
+			 * When SEV-SNP is active then transition the page to shared in the RMP
+			 * table so that it is consistent with the page table attribute change.
+			 */
+			early_snp_set_memory_shared(__pa(vaddr), __pa(vaddr), PTRS_PER_PMD);
+
 			i = pmd_index(vaddr);
 			pmd[i] -= sme_get_me_mask();
 		}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 19/45] x86/kernel: Validate rom memory before accessing when SEV-SNP is active
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (17 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 18/45] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 20/45] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
                   ` (26 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The probe_roms() access the memory range (0xc0000 - 0x10000) to probe
various ROMs. The memory range is not part of the E820 system RAM
range. The memory range is mapped as private (i.e encrypted) in page
table.

When SEV-SNP is active, all the private memory must be validated before
the access. The ROM range was not part of E820 map, so the guest BIOS
did not validate it. An access to invalidated memory will cause a VC
exception. The guest does not support handling not-validated VC exception
yet, so validate the ROM memory regions before it is accessed.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/probe_roms.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/probe_roms.c b/arch/x86/kernel/probe_roms.c
index 9e1def3744f2..9c09df86d167 100644
--- a/arch/x86/kernel/probe_roms.c
+++ b/arch/x86/kernel/probe_roms.c
@@ -21,6 +21,7 @@
 #include <asm/sections.h>
 #include <asm/io.h>
 #include <asm/setup_arch.h>
+#include <asm/sev.h>
 
 static struct resource system_rom_resource = {
 	.name	= "System ROM",
@@ -197,11 +198,21 @@ static int __init romchecksum(const unsigned char *rom, unsigned long length)
 
 void __init probe_roms(void)
 {
-	const unsigned char *rom;
 	unsigned long start, length, upper;
+	const unsigned char *rom;
 	unsigned char c;
 	int i;
 
+	/*
+	 * The ROM memory is not part of the E820 system RAM and is not pre-validated
+	 * by the BIOS. The kernel page table maps the ROM region as encrypted memory,
+	 * the SEV-SNP requires the encrypted memory must be validated before the
+	 * access. Validate the ROM before accessing it.
+	 */
+	snp_prep_memory(video_rom_resource.start,
+			((system_rom_resource.end + 1) - video_rom_resource.start),
+			SNP_PAGE_STATE_PRIVATE);
+
 	/* video rom */
 	upper = adapter_rom_resources[0].start;
 	for (start = video_rom_resource.start; start < upper; start += 2048) {
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 20/45] x86/mm: Add support to validate memory when changing C-bit
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (18 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 19/45] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 21/45] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
                   ` (25 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The set_memory_{encrypt,decrypt}() are used for changing the pages
from decrypted (shared) to encrypted (private) and vice versa.
When SEV-SNP is active, the page state transition needs to go through
additional steps.

If the page is transitioned from shared to private, then perform the
following after the encryption attribute is set in the page table:

1. Issue the page state change VMGEXIT to add the memory region in
   the RMP table.
2. Validate the memory region after the RMP entry is added.

To maintain the security guarantees, if the page is transitioned from
private to shared, then perform the following before encryption attribute
is removed from the page table:

1. Invalidate the page.
2. Issue the page state change VMGEXIT to remove the page from RMP table.

To change the page state in the RMP table, use the Page State Change
VMGEXIT defined in the GHCB specification.

The GHCB specification provides the flexibility to use either 4K or 2MB
page size in during the page state change (PSC) request. For now use the
4K page size for all the PSC until page size tracking is supported in the
kernel.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev-common.h |  22 ++++
 arch/x86/include/asm/sev.h        |   4 +
 arch/x86/include/asm/svm.h        |   4 +-
 arch/x86/include/uapi/asm/svm.h   |   2 +
 arch/x86/kernel/sev.c             | 161 +++++++++++++++++++++++++++++-
 arch/x86/mm/pat/set_memory.c      |  15 +++
 6 files changed, 204 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index b82fff9d607b..c2c5d60f0da0 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -105,6 +105,28 @@ enum psc_op {
 
 #define GHCB_HV_FT_SNP			BIT_ULL(0)
 
+/* SNP Page State Change NAE event */
+#define VMGEXIT_PSC_MAX_ENTRY		253
+
+struct psc_hdr {
+	u16 cur_entry;
+	u16 end_entry;
+	u32 reserved;
+} __packed;
+
+struct psc_entry {
+	u64	cur_page	: 12,
+		gfn		: 40,
+		operation	: 4,
+		pagesize	: 1,
+		reserved	: 7;
+} __packed;
+
+struct snp_psc_desc {
+	struct psc_hdr hdr;
+	struct psc_entry entries[VMGEXIT_PSC_MAX_ENTRY];
+} __packed;
+
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index eec2e1b9d557..f5d0569fd02b 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -128,6 +128,8 @@ void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long padd
 void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
 					unsigned int npages);
 void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op);
+void snp_set_memory_shared(unsigned long vaddr, unsigned int npages);
+void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -142,6 +144,8 @@ early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned
 static inline void __init
 early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned int npages) { }
 static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op) { }
+static inline void snp_set_memory_shared(unsigned long vaddr, unsigned int npages) { }
+static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npages) { }
 #endif
 
 #endif
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index b00dbc5fac2b..d3277486a6c0 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -309,11 +309,13 @@ struct vmcb_save_area {
 	u64 x87_state_gpa;
 } __packed;
 
+#define GHCB_SHARED_BUF_SIZE	2032
+
 struct ghcb {
 	struct vmcb_save_area save;
 	u8 reserved_save[2048 - sizeof(struct vmcb_save_area)];
 
-	u8 shared_buffer[2032];
+	u8 shared_buffer[GHCB_SHARED_BUF_SIZE];
 
 	u8 reserved_1[10];
 	u16 protocol_version;	/* negotiated SEV-ES/GHCB protocol version */
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index b0ad00f4c1e1..0dcdb6e0c913 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -108,6 +108,7 @@
 #define SVM_VMGEXIT_AP_JUMP_TABLE		0x80000005
 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE		0
 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE		1
+#define SVM_VMGEXIT_PSC				0x80000010
 #define SVM_VMGEXIT_HV_FEATURES			0x8000fffd
 #define SVM_VMGEXIT_UNSUPPORTED_EVENT		0x8000ffff
 
@@ -219,6 +220,7 @@
 	{ SVM_VMGEXIT_NMI_COMPLETE,	"vmgexit_nmi_complete" }, \
 	{ SVM_VMGEXIT_AP_HLT_LOOP,	"vmgexit_ap_hlt_loop" }, \
 	{ SVM_VMGEXIT_AP_JUMP_TABLE,	"vmgexit_ap_jump_table" }, \
+	{ SVM_VMGEXIT_PSC,	"vmgexit_page_state_change" }, \
 	{ SVM_VMGEXIT_HV_FEATURES,	"vmgexit_hypervisor_feature" }, \
 	{ SVM_EXIT_ERR,         "invalid_guest_state" }
 
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 3c3b96a2990f..156026cfd9be 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -549,7 +549,7 @@ static void pvalidate_pages(unsigned long vaddr, unsigned int npages, bool valid
 	}
 }
 
-static void __init early_set_page_state(unsigned long paddr, unsigned int npages, enum psc_op op)
+static void __init early_set_pages_state(unsigned long paddr, unsigned int npages, enum psc_op op)
 {
 	unsigned long paddr_end;
 	u64 val;
@@ -597,7 +597,7 @@ void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long padd
 	  * Ask the hypervisor to mark the memory pages as private in the RMP
 	  * table.
 	  */
-	early_set_page_state(paddr, npages, SNP_PAGE_STATE_PRIVATE);
+	early_set_pages_state(paddr, npages, SNP_PAGE_STATE_PRIVATE);
 
 	/* Validate the memory pages after they've been added in the RMP table. */
 	pvalidate_pages(vaddr, npages, 1);
@@ -616,7 +616,7 @@ void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr
 	pvalidate_pages(vaddr, npages, 0);
 
 	 /* Ask hypervisor to mark the memory pages shared in the RMP table. */
-	early_set_page_state(paddr, npages, SNP_PAGE_STATE_SHARED);
+	early_set_pages_state(paddr, npages, SNP_PAGE_STATE_SHARED);
 }
 
 void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op)
@@ -634,6 +634,161 @@ void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op
 		WARN(1, "invalid memory op %d\n", op);
 }
 
+static int vmgexit_psc(struct snp_psc_desc *desc)
+{
+	int cur_entry, end_entry, ret = 0;
+	struct snp_psc_desc *data;
+	struct ghcb_state state;
+	unsigned long flags;
+	struct ghcb *ghcb;
+
+	/* __sev_get_ghcb() need to run with IRQs disabled because it using per-cpu GHCB */
+	local_irq_save(flags);
+
+	ghcb = __sev_get_ghcb(&state);
+	if (unlikely(!ghcb))
+		panic("SEV-SNP: Failed to get GHCB\n");
+
+	/* Copy the input desc into GHCB shared buffer */
+	data = (struct snp_psc_desc *)ghcb->shared_buffer;
+	memcpy(ghcb->shared_buffer, desc, min_t(int, GHCB_SHARED_BUF_SIZE, sizeof(*desc)));
+
+	/*
+	 * As per the GHCB specification, the hypervisor can resume the guest
+	 * before processing all the entries. Check whether all the entries
+	 * are processed. If not, then keep retrying.
+	 *
+	 * The stragtegy here is to wait for the hypervisor to change the page
+	 * state in the RMP table before guest accesses the memory pages. If the
+	 * page state change was not successful, then later memory access will result
+	 * in a crash.
+	 */
+	cur_entry = data->hdr.cur_entry;
+	end_entry = data->hdr.end_entry;
+
+	while (data->hdr.cur_entry <= data->hdr.end_entry) {
+		ghcb_set_sw_scratch(ghcb, (u64)__pa(data));
+
+		ret = sev_es_ghcb_hv_call(ghcb, true, NULL, SVM_VMGEXIT_PSC, 0, 0);
+
+		/*
+		 * Page State Change VMGEXIT can pass error code through
+		 * exit_info_2.
+		 */
+		if (WARN(ret || ghcb->save.sw_exit_info_2,
+			 "SEV-SNP: PSC failed ret=%d exit_info_2=%llx\n",
+			 ret, ghcb->save.sw_exit_info_2)) {
+			ret = 1;
+			goto out;
+		}
+
+		/* Verify that reserved bit is not set */
+		if (WARN(data->hdr.reserved, "Reserved bit is set in the PSC header\n")) {
+			ret = 1;
+			goto out;
+		}
+
+		/*
+		 * Sanity check that entry processing is not going backward.
+		 * This will happen only if hypervisor is tricking us.
+		 */
+		if (WARN(data->hdr.end_entry > end_entry || cur_entry > data->hdr.cur_entry,
+"SEV-SNP:  PSC processing going backward, end_entry %d (got %d) cur_entry %d (got %d)\n",
+			 end_entry, data->hdr.end_entry, cur_entry, data->hdr.cur_entry)) {
+			ret = 1;
+			goto out;
+		}
+	}
+
+out:
+	__sev_put_ghcb(&state);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static void __set_pages_state(struct snp_psc_desc *data, unsigned long vaddr,
+			      unsigned long vaddr_end, int op)
+{
+	struct psc_hdr *hdr;
+	struct psc_entry *e;
+	unsigned long pfn;
+	int i;
+
+	hdr = &data->hdr;
+	e = data->entries;
+
+	memset(data, 0, sizeof(*data));
+	i = 0;
+
+	while (vaddr < vaddr_end) {
+		if (is_vmalloc_addr((void *)vaddr))
+			pfn = vmalloc_to_pfn((void *)vaddr);
+		else
+			pfn = __pa(vaddr) >> PAGE_SHIFT;
+
+		e->gfn = pfn;
+		e->operation = op;
+		hdr->end_entry = i;
+		e->pagesize = RMP_PG_SIZE_4K;
+
+		vaddr = vaddr + PAGE_SIZE;
+		e++;
+		i++;
+	}
+
+	if (vmgexit_psc(data))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+}
+
+static void set_pages_state(unsigned long vaddr, unsigned int npages, int op)
+{
+	unsigned long vaddr_end, next_vaddr;
+	struct snp_psc_desc *desc;
+
+	desc = kmalloc(sizeof(*desc), GFP_KERNEL_ACCOUNT);
+	if (!desc)
+		panic("SEV-SNP: failed to allocate memory for PSC descriptor\n");
+
+	vaddr = vaddr & PAGE_MASK;
+	vaddr_end = vaddr + (npages << PAGE_SHIFT);
+
+	while (vaddr < vaddr_end) {
+		/*
+		 * Calculate the last vaddr that can be fit in one
+		 * struct snp_psc_desc.
+		 */
+		next_vaddr = min_t(unsigned long, vaddr_end,
+				   (VMGEXIT_PSC_MAX_ENTRY * PAGE_SIZE) + vaddr);
+
+		__set_pages_state(desc, vaddr, next_vaddr, op);
+
+		vaddr = next_vaddr;
+	}
+
+	kfree(desc);
+}
+
+void snp_set_memory_shared(unsigned long vaddr, unsigned int npages)
+{
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return;
+
+	pvalidate_pages(vaddr, npages, 0);
+
+	set_pages_state(vaddr, npages, SNP_PAGE_STATE_SHARED);
+}
+
+void snp_set_memory_private(unsigned long vaddr, unsigned int npages)
+{
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return;
+
+	set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE);
+
+	pvalidate_pages(vaddr, npages, 1);
+}
+
 int sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
 {
 	u16 startup_cs, startup_ip;
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 527957586f3c..9b13770a633e 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -30,6 +30,7 @@
 #include <asm/proto.h>
 #include <asm/memtype.h>
 #include <asm/set_memory.h>
+#include <asm/sev.h>
 
 #include "../mm_internal.h"
 
@@ -2010,8 +2011,22 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
 	 */
 	cpa_flush(&cpa, !this_cpu_has(X86_FEATURE_SME_COHERENT));
 
+	/*
+	 * To maintain the security guarantees of SEV-SNP guest invalidate the memory
+	 * before clearing the encryption attribute.
+	 */
+	if (!enc)
+		snp_set_memory_shared(addr, numpages);
+
 	ret = __change_page_attr_set_clr(&cpa, 1);
 
+	/*
+	 * Now that memory is mapped encrypted in the page table, validate it
+	 * so that is consistent with the above page state.
+	 */
+	if (!ret && enc)
+		snp_set_memory_private(addr, numpages);
+
 	/*
 	 * After changing the encryption attribute, we need to flush TLBs again
 	 * in case any speculative TLB caching occurred (but no need to flush
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 21/45] KVM: SVM: Define sev_features and vmpl field in the VMSA
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (19 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 20/45] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 22/45] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
                   ` (24 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The hypervisor uses the sev_features field (offset 3B0h) in the Save State
Area to control the SEV-SNP guest features such as SNPActive, vTOM,
ReflectVC etc. An SEV-SNP guest can read the SEV_FEATURES fields through
the SEV_STATUS MSR.

While at it, update the dump_vmcb() to log the VMPL level.

See APM2 Table 15-34 and B-4 for more details.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/svm.h | 6 ++++--
 arch/x86/kvm/svm/svm.c     | 4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index d3277486a6c0..c3fad5172584 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -238,7 +238,8 @@ struct vmcb_save_area {
 	struct vmcb_seg ldtr;
 	struct vmcb_seg idtr;
 	struct vmcb_seg tr;
-	u8 reserved_1[43];
+	u8 reserved_1[42];
+	u8 vmpl;
 	u8 cpl;
 	u8 reserved_2[4];
 	u64 efer;
@@ -303,7 +304,8 @@ struct vmcb_save_area {
 	u64 sw_exit_info_1;
 	u64 sw_exit_info_2;
 	u64 sw_scratch;
-	u8 reserved_11[56];
+	u64 sev_features;
+	u8 reserved_11[48];
 	u64 xcr0;
 	u8 valid_bitmap[16];
 	u64 x87_state_gpa;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 226482daa6eb..6d2d3f024f5d 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3211,8 +3211,8 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
 	       "tr:",
 	       save01->tr.selector, save01->tr.attrib,
 	       save01->tr.limit, save01->tr.base);
-	pr_err("cpl:            %d                efer:         %016llx\n",
-		save->cpl, save->efer);
+	pr_err("vmpl: %d   cpl:  %d               efer:          %016llx\n",
+	       save->vmpl, save->cpl, save->efer);
 	pr_err("%-15s %016llx %-13s %016llx\n",
 	       "cr0:", save->cr0, "cr2:", save->cr2);
 	pr_err("%-15s %016llx %-13s %016llx\n",
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 22/45] KVM: SVM: Create a separate mapping for the SEV-ES save area
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (20 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 21/45] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 23/45] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
                   ` (23 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Tom Lendacky <thomas.lendacky@amd.com>

The save area for SEV-ES/SEV-SNP guests, as used by the hardware, is
different from the save area of a non SEV-ES/SEV-SNP guest.

This is the first step in defining the multiple save areas to keep them
separate and ensuring proper operation amongst the different types of
guests. Create an SEV-ES/SEV-SNP save area and adjust usage to the new
save area definition where needed.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/svm.h | 83 +++++++++++++++++++++++++++++---------
 arch/x86/kvm/svm/sev.c     | 24 +++++------
 arch/x86/kvm/svm/svm.h     |  2 +-
 3 files changed, 77 insertions(+), 32 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index c3fad5172584..3ce2e575a2de 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -227,6 +227,7 @@ struct vmcb_seg {
 	u64 base;
 } __packed;
 
+/* Save area definition for legacy and SEV-MEM guests */
 struct vmcb_save_area {
 	struct vmcb_seg es;
 	struct vmcb_seg cs;
@@ -243,8 +244,58 @@ struct vmcb_save_area {
 	u8 cpl;
 	u8 reserved_2[4];
 	u64 efer;
+	u8 reserved_3[112];
+	u64 cr4;
+	u64 cr3;
+	u64 cr0;
+	u64 dr7;
+	u64 dr6;
+	u64 rflags;
+	u64 rip;
+	u8 reserved_4[88];
+	u64 rsp;
+	u64 s_cet;
+	u64 ssp;
+	u64 isst_addr;
+	u64 rax;
+	u64 star;
+	u64 lstar;
+	u64 cstar;
+	u64 sfmask;
+	u64 kernel_gs_base;
+	u64 sysenter_cs;
+	u64 sysenter_esp;
+	u64 sysenter_eip;
+	u64 cr2;
+	u8 reserved_5[32];
+	u64 g_pat;
+	u64 dbgctl;
+	u64 br_from;
+	u64 br_to;
+	u64 last_excp_from;
+	u64 last_excp_to;
+	u8 reserved_6[72];
+	u32 spec_ctrl;		/* Guest version of SPEC_CTRL at 0x2E0 */
+} __packed;
+
+/* Save area definition for SEV-ES and SEV-SNP guests */
+struct sev_es_save_area {
+	struct vmcb_seg es;
+	struct vmcb_seg cs;
+	struct vmcb_seg ss;
+	struct vmcb_seg ds;
+	struct vmcb_seg fs;
+	struct vmcb_seg gs;
+	struct vmcb_seg gdtr;
+	struct vmcb_seg ldtr;
+	struct vmcb_seg idtr;
+	struct vmcb_seg tr;
+	u8 reserved_1[43];
+	u8 cpl;
+	u8 reserved_2[4];
+	u64 efer;
 	u8 reserved_3[104];
-	u64 xss;		/* Valid for SEV-ES only */
+	u64 xss;
 	u64 cr4;
 	u64 cr3;
 	u64 cr0;
@@ -272,22 +323,14 @@ struct vmcb_save_area {
 	u64 br_to;
 	u64 last_excp_from;
 	u64 last_excp_to;
-
-	/*
-	 * The following part of the save area is valid only for
-	 * SEV-ES guests when referenced through the GHCB or for
-	 * saving to the host save area.
-	 */
-	u8 reserved_7[72];
-	u32 spec_ctrl;		/* Guest version of SPEC_CTRL at 0x2E0 */
-	u8 reserved_7b[4];
+	u8 reserved_7[80];
 	u32 pkru;
-	u8 reserved_7a[20];
-	u64 reserved_8;		/* rax already available at 0x01f8 */
+	u8 reserved_9[20];
+	u64 reserved_10;	/* rax already available at 0x01f8 */
 	u64 rcx;
 	u64 rdx;
 	u64 rbx;
-	u64 reserved_9;		/* rsp already available at 0x01d8 */
+	u64 reserved_11;	/* rsp already available at 0x01d8 */
 	u64 rbp;
 	u64 rsi;
 	u64 rdi;
@@ -299,13 +342,13 @@ struct vmcb_save_area {
 	u64 r13;
 	u64 r14;
 	u64 r15;
-	u8 reserved_10[16];
+	u8 reserved_12[16];
 	u64 sw_exit_code;
 	u64 sw_exit_info_1;
 	u64 sw_exit_info_2;
 	u64 sw_scratch;
 	u64 sev_features;
-	u8 reserved_11[48];
+	u8 reserved_13[48];
 	u64 xcr0;
 	u8 valid_bitmap[16];
 	u64 x87_state_gpa;
@@ -314,8 +357,8 @@ struct vmcb_save_area {
 #define GHCB_SHARED_BUF_SIZE	2032
 
 struct ghcb {
-	struct vmcb_save_area save;
-	u8 reserved_save[2048 - sizeof(struct vmcb_save_area)];
+	struct sev_es_save_area save;
+	u8 reserved_save[2048 - sizeof(struct sev_es_save_area)];
 
 	u8 shared_buffer[GHCB_SHARED_BUF_SIZE];
 
@@ -325,13 +368,15 @@ struct ghcb {
 } __packed;
 
 
-#define EXPECTED_VMCB_SAVE_AREA_SIZE		1032
+#define EXPECTED_VMCB_SAVE_AREA_SIZE		740
+#define EXPECTED_SEV_ES_SAVE_AREA_SIZE		1032
 #define EXPECTED_VMCB_CONTROL_AREA_SIZE		1024
 #define EXPECTED_GHCB_SIZE			PAGE_SIZE
 
 static inline void __unused_size_checks(void)
 {
 	BUILD_BUG_ON(sizeof(struct vmcb_save_area)	!= EXPECTED_VMCB_SAVE_AREA_SIZE);
+	BUILD_BUG_ON(sizeof(struct sev_es_save_area)	!= EXPECTED_SEV_ES_SAVE_AREA_SIZE);
 	BUILD_BUG_ON(sizeof(struct vmcb_control_area)	!= EXPECTED_VMCB_CONTROL_AREA_SIZE);
 	BUILD_BUG_ON(sizeof(struct ghcb)		!= EXPECTED_GHCB_SIZE);
 }
@@ -401,7 +446,7 @@ struct vmcb {
 /* GHCB Accessor functions */
 
 #define GHCB_BITMAP_IDX(field)							\
-	(offsetof(struct vmcb_save_area, field) / sizeof(u64))
+	(offsetof(struct sev_es_save_area, field) / sizeof(u64))
 
 #define DEFINE_GHCB_ACCESSORS(field)						\
 	static inline bool ghcb_##field##_is_valid(const struct ghcb *ghcb)	\
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 5847b05d29da..9896c5835e3e 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -551,12 +551,20 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 {
-	struct vmcb_save_area *save = &svm->vmcb->save;
+	struct sev_es_save_area *save = svm->vmsa;
 
 	/* Check some debug related fields before encrypting the VMSA */
-	if (svm->vcpu.guest_debug || (save->dr7 & ~DR7_FIXED_1))
+	if (svm->vcpu.guest_debug || (svm->vmcb->save.dr7 & ~DR7_FIXED_1))
 		return -EINVAL;
 
+	/*
+	 * SEV-ES will use a VMSA that is pointed to by the VMCB, not
+	 * the traditional VMSA that is part of the VMCB. Copy the
+	 * traditional VMSA as it has been built so far (in prep
+	 * for LAUNCH_UPDATE_VMSA) to be the initial SEV-ES state.
+	 */
+	memcpy(save, &svm->vmcb->save, sizeof(svm->vmcb->save));
+
 	/* Sync registgers */
 	save->rax = svm->vcpu.arch.regs[VCPU_REGS_RAX];
 	save->rbx = svm->vcpu.arch.regs[VCPU_REGS_RBX];
@@ -584,14 +592,6 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 	save->xss  = svm->vcpu.arch.ia32_xss;
 	save->dr6  = svm->vcpu.arch.dr6;
 
-	/*
-	 * SEV-ES will use a VMSA that is pointed to by the VMCB, not
-	 * the traditional VMSA that is part of the VMCB. Copy the
-	 * traditional VMSA as it has been built so far (in prep
-	 * for LAUNCH_UPDATE_VMSA) to be the initial SEV-ES state.
-	 */
-	memcpy(svm->vmsa, save, sizeof(*save));
-
 	return 0;
 }
 
@@ -2666,7 +2666,7 @@ void sev_es_create_vcpu(struct vcpu_svm *svm)
 void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu)
 {
 	struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
-	struct vmcb_save_area *hostsa;
+	struct sev_es_save_area *hostsa;
 
 	/*
 	 * As an SEV-ES guest, hardware will restore the host state on VMEXIT,
@@ -2676,7 +2676,7 @@ void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu)
 	vmsave(__sme_page_pa(sd->save_area));
 
 	/* XCR0 is restored on VMEXIT, save the current host value */
-	hostsa = (struct vmcb_save_area *)(page_address(sd->save_area) + 0x400);
+	hostsa = (struct sev_es_save_area *)(page_address(sd->save_area) + 0x400);
 	hostsa->xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
 
 	/* PKRU is restored on VMEXIT, save the current host value */
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index e63ac08115cf..a511f6bd65bd 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -184,7 +184,7 @@ struct vcpu_svm {
 	} shadow_msr_intercept;
 
 	/* SEV-ES support */
-	struct vmcb_save_area *vmsa;
+	struct sev_es_save_area *vmsa;
 	struct ghcb *ghcb;
 	struct kvm_host_map ghcb_map;
 	bool received_first_sipi;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 23/45] KVM: SVM: Create a separate mapping for the GHCB save area
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (21 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 22/45] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 24/45] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
                   ` (22 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Tom Lendacky <thomas.lendacky@amd.com>

The initial implementation of the GHCB spec was based on trying to keep
the register state offsets the same relative to the VM save area. However,
the save area for SEV-ES has changed within the hardware causing the
relation between the SEV-ES save area to change relative to the GHCB save
area.

This is the second step in defining the multiple save areas to keep them
separate and ensuring proper operation amongst the different types of
guests. Create a GHCB save area that matches the GHCB specification.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/svm.h | 48 +++++++++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 3ce2e575a2de..5ff1fa364a31 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -354,11 +354,51 @@ struct sev_es_save_area {
 	u64 x87_state_gpa;
 } __packed;
 
+struct ghcb_save_area {
+	u8 reserved_1[203];
+	u8 cpl;
+	u8 reserved_2[116];
+	u64 xss;
+	u8 reserved_3[24];
+	u64 dr7;
+	u8 reserved_4[16];
+	u64 rip;
+	u8 reserved_5[88];
+	u64 rsp;
+	u8 reserved_6[24];
+	u64 rax;
+	u8 reserved_7[264];
+	u64 rcx;
+	u64 rdx;
+	u64 rbx;
+	u8 reserved_8[8];
+	u64 rbp;
+	u64 rsi;
+	u64 rdi;
+	u64 r8;
+	u64 r9;
+	u64 r10;
+	u64 r11;
+	u64 r12;
+	u64 r13;
+	u64 r14;
+	u64 r15;
+	u8 reserved_9[16];
+	u64 sw_exit_code;
+	u64 sw_exit_info_1;
+	u64 sw_exit_info_2;
+	u64 sw_scratch;
+	u8 reserved_10[56];
+	u64 xcr0;
+	u8 valid_bitmap[16];
+	u64 x87_state_gpa;
+} __packed;
+
 #define GHCB_SHARED_BUF_SIZE	2032
 
 struct ghcb {
-	struct sev_es_save_area save;
-	u8 reserved_save[2048 - sizeof(struct sev_es_save_area)];
+	struct ghcb_save_area save;
+	u8 reserved_save[2048 - sizeof(struct ghcb_save_area)];
 
 	u8 shared_buffer[GHCB_SHARED_BUF_SIZE];
 
@@ -369,6 +409,7 @@ struct ghcb {
 
 
 #define EXPECTED_VMCB_SAVE_AREA_SIZE		740
+#define EXPECTED_GHCB_SAVE_AREA_SIZE		1032
 #define EXPECTED_SEV_ES_SAVE_AREA_SIZE		1032
 #define EXPECTED_VMCB_CONTROL_AREA_SIZE		1024
 #define EXPECTED_GHCB_SIZE			PAGE_SIZE
@@ -376,6 +417,7 @@ struct ghcb {
 static inline void __unused_size_checks(void)
 {
 	BUILD_BUG_ON(sizeof(struct vmcb_save_area)	!= EXPECTED_VMCB_SAVE_AREA_SIZE);
+	BUILD_BUG_ON(sizeof(struct ghcb_save_area)	!= EXPECTED_GHCB_SAVE_AREA_SIZE);
 	BUILD_BUG_ON(sizeof(struct sev_es_save_area)	!= EXPECTED_SEV_ES_SAVE_AREA_SIZE);
 	BUILD_BUG_ON(sizeof(struct vmcb_control_area)	!= EXPECTED_VMCB_CONTROL_AREA_SIZE);
 	BUILD_BUG_ON(sizeof(struct ghcb)		!= EXPECTED_GHCB_SIZE);
@@ -446,7 +488,7 @@ struct vmcb {
 /* GHCB Accessor functions */
 
 #define GHCB_BITMAP_IDX(field)							\
-	(offsetof(struct sev_es_save_area, field) / sizeof(u64))
+	(offsetof(struct ghcb_save_area, field) / sizeof(u64))
 
 #define DEFINE_GHCB_ACCESSORS(field)						\
 	static inline bool ghcb_##field##_is_valid(const struct ghcb *ghcb)	\
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 24/45] KVM: SVM: Update the SEV-ES save area mapping
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (22 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 23/45] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 25/45] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
                   ` (21 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Tom Lendacky <thomas.lendacky@amd.com>

This is the final step in defining the multiple save areas to keep them
separate and ensuring proper operation amongst the different types of
guests. Update the SEV-ES/SEV-SNP save area to match the APM. This save
area will be used for the upcoming SEV-SNP AP Creation NAE event support.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/svm.h | 66 +++++++++++++++++++++++++++++---------
 1 file changed, 50 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 5ff1fa364a31..7d90321e7775 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -290,7 +290,13 @@ struct sev_es_save_area {
 	struct vmcb_seg ldtr;
 	struct vmcb_seg idtr;
 	struct vmcb_seg tr;
-	u8 reserved_1[43];
+	u64 vmpl0_ssp;
+	u64 vmpl1_ssp;
+	u64 vmpl2_ssp;
+	u64 vmpl3_ssp;
+	u64 u_cet;
+	u8 reserved_1[2];
+	u8 vmpl;
 	u8 cpl;
 	u8 reserved_2[4];
 	u64 efer;
@@ -303,9 +309,19 @@ struct sev_es_save_area {
 	u64 dr6;
 	u64 rflags;
 	u64 rip;
-	u8 reserved_4[88];
+	u64 dr0;
+	u64 dr1;
+	u64 dr2;
+	u64 dr3;
+	u64 dr0_addr_mask;
+	u64 dr1_addr_mask;
+	u64 dr2_addr_mask;
+	u64 dr3_addr_mask;
+	u8 reserved_4[24];
 	u64 rsp;
-	u8 reserved_5[24];
+	u64 s_cet;
+	u64 ssp;
+	u64 isst_addr;
 	u64 rax;
 	u64 star;
 	u64 lstar;
@@ -316,7 +332,7 @@ struct sev_es_save_area {
 	u64 sysenter_esp;
 	u64 sysenter_eip;
 	u64 cr2;
-	u8 reserved_6[32];
+	u8 reserved_5[32];
 	u64 g_pat;
 	u64 dbgctl;
 	u64 br_from;
@@ -325,12 +341,12 @@ struct sev_es_save_area {
 	u64 last_excp_to;
 	u8 reserved_7[80];
 	u32 pkru;
-	u8 reserved_9[20];
-	u64 reserved_10;	/* rax already available at 0x01f8 */
+	u8 reserved_8[20];
+	u64 reserved_9;		/* rax already available at 0x01f8 */
 	u64 rcx;
 	u64 rdx;
 	u64 rbx;
-	u64 reserved_11;	/* rsp already available at 0x01d8 */
+	u64 reserved_10;	/* rsp already available at 0x01d8 */
 	u64 rbp;
 	u64 rsi;
 	u64 rdi;
@@ -342,16 +358,34 @@ struct sev_es_save_area {
 	u64 r13;
 	u64 r14;
 	u64 r15;
-	u8 reserved_12[16];
-	u64 sw_exit_code;
-	u64 sw_exit_info_1;
-	u64 sw_exit_info_2;
-	u64 sw_scratch;
+	u8 reserved_11[16];
+	u64 guest_exit_info_1;
+	u64 guest_exit_info_2;
+	u64 guest_exit_int_info;
+	u64 guest_nrip;
 	u64 sev_features;
-	u8 reserved_13[48];
+	u64 vintr_ctrl;
+	u64 guest_exit_code;
+	u64 virtual_tom;
+	u64 tlb_id;
+	u64 pcpu_id;
+	u64 event_inj;
 	u64 xcr0;
-	u8 valid_bitmap[16];
-	u64 x87_state_gpa;
+	u8 reserved_12[16];
+
+	/* Floating point area */
+	u64 x87_dp;
+	u32 mxcsr;
+	u16 x87_ftw;
+	u16 x87_fsw;
+	u16 x87_fcw;
+	u16 x87_fop;
+	u16 x87_ds;
+	u16 x87_cs;
+	u64 x87_rip;
+	u8 fpreg_x87[80];
+	u8 fpreg_xmm[256];
+	u8 fpreg_ymm[256];
 } __packed;
 
 struct ghcb_save_area {
@@ -410,7 +444,7 @@ struct ghcb {
 
 #define EXPECTED_VMCB_SAVE_AREA_SIZE		740
 #define EXPECTED_GHCB_SAVE_AREA_SIZE		1032
-#define EXPECTED_SEV_ES_SAVE_AREA_SIZE		1032
+#define EXPECTED_SEV_ES_SAVE_AREA_SIZE		1648
 #define EXPECTED_VMCB_CONTROL_AREA_SIZE		1024
 #define EXPECTED_GHCB_SIZE			PAGE_SIZE
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 25/45] x86/sev: Use SEV-SNP AP creation to start secondary CPUs
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (23 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 24/45] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 26/45] x86/head: re-enable stack protection for 32/64-bit builds Brijesh Singh
                   ` (20 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Tom Lendacky <thomas.lendacky@amd.com>

To provide a more secure way to start APs under SEV-SNP, use the SEV-SNP
AP Creation NAE event. This allows for guest control over the AP register
state rather than trusting the hypervisor with the SEV-ES Jump Table
address.

During native_smp_prepare_cpus(), invoke an SEV-SNP function that, if
SEV-SNP is active, will set/override apic->wakeup_secondary_cpu. This
will allow the SEV-SNP AP Creation NAE event method to be used to boot
the APs. As a result of installing the override when SEV-SNP is active,
this method of starting the APs becomes the required method. The override
function will fail to start the AP if the hypervisor does not have
support for AP creation.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev-common.h |   1 +
 arch/x86/include/asm/sev.h        |   4 +
 arch/x86/include/uapi/asm/svm.h   |   5 +
 arch/x86/kernel/sev.c             | 229 ++++++++++++++++++++++++++++++
 arch/x86/kernel/smpboot.c         |   3 +
 5 files changed, 242 insertions(+)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index c2c5d60f0da0..c380aba9fc8d 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -104,6 +104,7 @@ enum psc_op {
 	(((u64)(v) & GENMASK_ULL(63, 12)) >> 12)
 
 #define GHCB_HV_FT_SNP			BIT_ULL(0)
+#define GHCB_HV_FT_SNP_AP_CREATION	(BIT_ULL(1) | GHCB_HV_FT_SNP)
 
 /* SNP Page State Change NAE event */
 #define VMGEXIT_PSC_MAX_ENTRY		253
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index f5d0569fd02b..f7cbd5164136 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -66,6 +66,8 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
 /* RMP page size */
 #define RMP_PG_SIZE_4K			0
 
+#define RMPADJUST_VMSA_PAGE_BIT		BIT(16)
+
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 extern struct static_key_false sev_es_enable_key;
 extern void __sev_es_ist_enter(struct pt_regs *regs);
@@ -130,6 +132,7 @@ void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr
 void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op);
 void snp_set_memory_shared(unsigned long vaddr, unsigned int npages);
 void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
+void snp_set_wakeup_secondary_cpu(void);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -146,6 +149,7 @@ early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned i
 static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op) { }
 static inline void snp_set_memory_shared(unsigned long vaddr, unsigned int npages) { }
 static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npages) { }
+static inline void snp_set_wakeup_secondary_cpu(void) { }
 #endif
 
 #endif
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index 0dcdb6e0c913..8b4c57baec52 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -109,6 +109,10 @@
 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE		0
 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE		1
 #define SVM_VMGEXIT_PSC				0x80000010
+#define SVM_VMGEXIT_AP_CREATION			0x80000013
+#define SVM_VMGEXIT_AP_CREATE_ON_INIT		0
+#define SVM_VMGEXIT_AP_CREATE			1
+#define SVM_VMGEXIT_AP_DESTROY			2
 #define SVM_VMGEXIT_HV_FEATURES			0x8000fffd
 #define SVM_VMGEXIT_UNSUPPORTED_EVENT		0x8000ffff
 
@@ -221,6 +225,7 @@
 	{ SVM_VMGEXIT_AP_HLT_LOOP,	"vmgexit_ap_hlt_loop" }, \
 	{ SVM_VMGEXIT_AP_JUMP_TABLE,	"vmgexit_ap_jump_table" }, \
 	{ SVM_VMGEXIT_PSC,	"vmgexit_page_state_change" }, \
+	{ SVM_VMGEXIT_AP_CREATION,	"vmgexit_ap_creation" }, \
 	{ SVM_VMGEXIT_HV_FEATURES,	"vmgexit_hypervisor_feature" }, \
 	{ SVM_EXIT_ERR,         "invalid_guest_state" }
 
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 156026cfd9be..e966b93212c7 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -18,6 +18,7 @@
 #include <linux/memblock.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/cpumask.h>
 
 #include <asm/cpu_entry_area.h>
 #include <asm/stacktrace.h>
@@ -31,6 +32,7 @@
 #include <asm/svm.h>
 #include <asm/smp.h>
 #include <asm/cpu.h>
+#include <asm/apic.h>
 
 #define DR7_RESET_VALUE        0x400
 
@@ -87,6 +89,8 @@ struct ghcb_state {
 static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
 DEFINE_STATIC_KEY_FALSE(sev_es_enable_key);
 
+static DEFINE_PER_CPU(struct sev_es_save_area *, snp_vmsa);
+
 static __always_inline bool on_vc_stack(struct pt_regs *regs)
 {
 	unsigned long sp = regs->sp;
@@ -789,6 +793,231 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages)
 	pvalidate_pages(vaddr, npages, 1);
 }
 
+static int snp_set_vmsa(void *va, bool vmsa)
+{
+	u64 attrs;
+
+	/*
+	 * The RMPADJUST instruction is used to set or clear the VMSA bit for
+	 * a page. A change to the VMSA bit is only performed when running
+	 * at VMPL0 and is ignored at other VMPL levels. If too low of a target
+	 * VMPL level is specified, the instruction can succeed without changing
+	 * the VMSA bit should the kernel not be in VMPL0. Using a target VMPL
+	 * level of 1 will return a FAIL_PERMISSION error if the kernel is not
+	 * at VMPL0, thus ensuring that the VMSA bit has been properly set when
+	 * no error is returned.
+	 */
+	attrs = 1;
+	if (vmsa)
+		attrs |= RMPADJUST_VMSA_PAGE_BIT;
+
+	return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
+}
+
+#define __ATTR_BASE		(SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK)
+#define INIT_CS_ATTRIBS		(__ATTR_BASE | SVM_SELECTOR_READ_MASK | SVM_SELECTOR_CODE_MASK)
+#define INIT_DS_ATTRIBS		(__ATTR_BASE | SVM_SELECTOR_WRITE_MASK)
+
+#define INIT_LDTR_ATTRIBS	(SVM_SELECTOR_P_MASK | 2)
+#define INIT_TR_ATTRIBS		(SVM_SELECTOR_P_MASK | 3)
+
+static void *snp_safe_alloc_page(void)
+{
+	unsigned long pfn;
+	struct page *p;
+
+	/*
+	 * Allocate an SNP safe page to workaround the SNP erratum where
+	 * the CPU will incorrectly signal an RMP violation  #PF if a
+	 * hugepage (2mb or 1gb) collides with the RMP entry of VMSA page.
+	 * The recommeded workaround is to not use the large page.
+	 *
+	 * Allocate one extra page, use a page which is not 2mb aligned
+	 * and free the other.
+	 */
+	p = alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_ZERO, 1);
+	if (!p)
+		return NULL;
+
+	split_page(p, 1);
+
+	pfn = page_to_pfn(p);
+	if (IS_ALIGNED(__pfn_to_phys(pfn), PMD_SIZE)) {
+		pfn++;
+		__free_page(p);
+	} else {
+		__free_page(pfn_to_page(pfn + 1));
+	}
+
+	return page_address(pfn_to_page(pfn));
+}
+
+static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
+{
+	struct sev_es_save_area *cur_vmsa, *vmsa;
+	struct ghcb_state state;
+	unsigned long flags;
+	struct ghcb *ghcb;
+	int cpu, err, ret;
+	u8 sipi_vector;
+	u64 cr4;
+
+	if ((sev_hv_features & GHCB_HV_FT_SNP_AP_CREATION) != GHCB_HV_FT_SNP_AP_CREATION)
+		return -EOPNOTSUPP;
+
+	/*
+	 * Verify the desired start IP against the known trampoline start IP
+	 * to catch any future new trampolines that may be introduced that
+	 * would require a new protected guest entry point.
+	 */
+	if (WARN_ONCE(start_ip != real_mode_header->trampoline_start,
+		      "Unsupported SEV-SNP start_ip: %lx\n", start_ip))
+		return -EINVAL;
+
+	/* Override start_ip with known protected guest start IP */
+	start_ip = real_mode_header->sev_es_trampoline_start;
+
+	/* Find the logical CPU for the APIC ID */
+	for_each_present_cpu(cpu) {
+		if (arch_match_cpu_phys_id(cpu, apic_id))
+			break;
+	}
+	if (cpu >= nr_cpu_ids)
+		return -EINVAL;
+
+	cur_vmsa = per_cpu(snp_vmsa, cpu);
+
+	/*
+	 * A new VMSA is created each time because there is no guarantee that
+	 * the current VMSA is the kernels or that the vCPU is not running. If
+	 * an attempt was done to use the current VMSA with a running vCPU, a
+	 * #VMEXIT of that vCPU would wipe out all of the settings being done
+	 * here.
+	 */
+	vmsa = (struct sev_es_save_area *)snp_safe_alloc_page();
+	if (!vmsa)
+		return -ENOMEM;
+
+	/* CR4 should maintain the MCE value */
+	cr4 = native_read_cr4() & X86_CR4_MCE;
+
+	/* Set the CS value based on the start_ip converted to a SIPI vector */
+	sipi_vector		= (start_ip >> 12);
+	vmsa->cs.base		= sipi_vector << 12;
+	vmsa->cs.limit		= 0xffff;
+	vmsa->cs.attrib		= INIT_CS_ATTRIBS;
+	vmsa->cs.selector	= sipi_vector << 8;
+
+	/* Set the RIP value based on start_ip */
+	vmsa->rip		= start_ip & 0xfff;
+
+	/* Set VMSA entries to the INIT values as documented in the APM */
+	vmsa->ds.limit		= 0xffff;
+	vmsa->ds.attrib		= INIT_DS_ATTRIBS;
+	vmsa->es		= vmsa->ds;
+	vmsa->fs		= vmsa->ds;
+	vmsa->gs		= vmsa->ds;
+	vmsa->ss		= vmsa->ds;
+
+	vmsa->gdtr.limit	= 0xffff;
+	vmsa->ldtr.limit	= 0xffff;
+	vmsa->ldtr.attrib	= INIT_LDTR_ATTRIBS;
+	vmsa->idtr.limit	= 0xffff;
+	vmsa->tr.limit		= 0xffff;
+	vmsa->tr.attrib		= INIT_TR_ATTRIBS;
+
+	vmsa->efer		= 0x1000;	/* Must set SVME bit */
+	vmsa->cr4		= cr4;
+	vmsa->cr0		= 0x60000010;
+	vmsa->dr7		= 0x400;
+	vmsa->dr6		= 0xffff0ff0;
+	vmsa->rflags		= 0x2;
+	vmsa->g_pat		= 0x0007040600070406ULL;
+	vmsa->xcr0		= 0x1;
+	vmsa->mxcsr		= 0x1f80;
+	vmsa->x87_ftw		= 0x5555;
+	vmsa->x87_fcw		= 0x0040;
+
+	/*
+	 * Set the SNP-specific fields for this VMSA:
+	 *   VMPL level
+	 *   SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
+	 */
+	vmsa->vmpl		= 0;
+	vmsa->sev_features	= sev_status >> 2;
+
+	/* Switch the page over to a VMSA page now that it is initialized */
+	ret = snp_set_vmsa(vmsa, true);
+	if (ret) {
+		pr_err("set VMSA page failed (%u)\n", ret);
+		free_page((unsigned long)vmsa);
+
+		return -EINVAL;
+	}
+
+	/* Issue VMGEXIT AP Creation NAE event */
+	local_irq_save(flags);
+
+	ghcb = __sev_get_ghcb(&state);
+
+	vc_ghcb_invalidate(ghcb);
+	ghcb_set_rax(ghcb, vmsa->sev_features);
+	ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION);
+	ghcb_set_sw_exit_info_1(ghcb, ((u64)apic_id << 32) | SVM_VMGEXIT_AP_CREATE);
+	ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa));
+
+	sev_es_wr_ghcb_msr(__pa(ghcb));
+	VMGEXIT();
+
+	if (!ghcb_sw_exit_info_1_is_valid(ghcb) ||
+	    lower_32_bits(ghcb->save.sw_exit_info_1)) {
+		pr_alert("SNP AP Creation error\n");
+		ret = -EINVAL;
+	}
+
+	__sev_put_ghcb(&state);
+
+	local_irq_restore(flags);
+
+	/* Perform cleanup if there was an error */
+	if (ret) {
+		err = snp_set_vmsa(vmsa, false);
+		if (err)
+			pr_err("clear VMSA page failed (%u), leaking page\n", err);
+		else
+			free_page((unsigned long)vmsa);
+
+		vmsa = NULL;
+	}
+
+	/* Free up any previous VMSA page */
+	if (cur_vmsa) {
+		err = snp_set_vmsa(cur_vmsa, false);
+		if (err)
+			pr_err("clear VMSA page failed (%u), leaking page\n", err);
+		else
+			free_page((unsigned long)cur_vmsa);
+	}
+
+	/* Record the current VMSA page */
+	per_cpu(snp_vmsa, cpu) = vmsa;
+
+	return ret;
+}
+
+void snp_set_wakeup_secondary_cpu(void)
+{
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return;
+
+	/*
+	 * Always set this override if SEV-SNP is enabled. This makes it the
+	 * required method to start APs under SEV-SNP. If the hypervisor does
+	 * not support AP creation, then no APs will be started.
+	 */
+	apic->wakeup_secondary_cpu = wakeup_cpu_via_vmgexit;
+}
+
 int sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
 {
 	u16 startup_cs, startup_ip;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 8241927addff..2bf8d9ce7d94 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -82,6 +82,7 @@
 #include <asm/spec-ctrl.h>
 #include <asm/hw_irq.h>
 #include <asm/stackprotector.h>
+#include <asm/sev.h>
 
 #ifdef CONFIG_ACPI_CPPC_LIB
 #include <acpi/cppc_acpi.h>
@@ -1419,6 +1420,8 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
 	smp_quirk_init_udelay();
 
 	speculative_store_bypass_ht_init();
+
+	snp_set_wakeup_secondary_cpu();
 }
 
 void arch_thaw_secondary_cpus_begin(void)
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 26/45] x86/head: re-enable stack protection for 32/64-bit builds
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (24 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 25/45] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 27/45] x86/sev: move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
                   ` (19 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

As of commit 103a4908ad4d ("x86/head/64: Disable stack protection for
head$(BITS).o") kernel/head64.c is compiled with -fno-stack-protector
to allow a call to set_bringup_idt_handler(), which would otherwise
have stack protection enabled with CONFIG_STACKPROTECTOR_STRONG. While
sufficient for that case, there may still be issues with calls to any
external functions that were compiled with stack protection enabled that
in-turn make stack-protected calls, or if the exception handlers set up
by set_bringup_idt_handler() make calls to stack-protected functions.
As part of 103a4908ad4d, stack protection was also disabled for
kernel/head32.c as a precaution.

Subsequent patches for SEV-SNP CPUID validation support will introduce
both such cases. Attempting to disable stack protection for everything
in scope to address that is prohibitive since much of the code, like
SEV-ES #VC handler, is shared code that remains in use after boot and
could benefit from having stack protection enabled. Attempting to inline
calls is brittle and can quickly balloon out to library/helper code
where that's not really an option.

Instead, re-enable stack protection for head32.c/head64.c and make the
appropriate changes to ensure the segment used for the stack canary is
initialized in advance of any stack-protected C calls.

for head64.c:

- The BSP will enter from startup_64 and call into C code
  (startup_64_setup_env) shortly after setting up the stack, which may
  result in calls to stack-protected code. Set up %gs early to allow
  for this safely.
- APs will enter from secondary_startup_64*, and %gs will be set up
  soon after. There is one call to C code prior to this
  (__startup_secondary_64), but it is only to fetch sme_me_mask, and
  unlikely to be stack-protected, so leave things as they are, but add
  a note about this in case things change in the future.

for head32.c:

- BSPs/APs will set %fs to __BOOT_DS prior to any C calls. In recent
  kernels, the compiler is configured to access the stack canary at
  %fs:__stack_chk_guard, which overlaps with the initial per-cpu
  __stack_chk_guard variable in the initial/'master' .data..percpu
  area. This is sufficient to allow access to the canary for use
  during initial startup, so no changes are needed there.

Suggested-by: Joerg Roedel <jroedel@suse.de> #for 64-bit %gs set up
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/Makefile  |  1 -
 arch/x86/kernel/head_64.S | 24 ++++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 2ff3e600f426..4df8c8f7d2ac 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -48,7 +48,6 @@ endif
 # non-deterministic coverage.
 KCOV_INSTRUMENT		:= n
 
-CFLAGS_head$(BITS).o	+= -fno-stack-protector
 CFLAGS_cc_platform.o	+= -fno-stack-protector
 
 CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index d8b3ebd2bb85..7074ebf2b47b 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -65,6 +65,22 @@ SYM_CODE_START_NOALIGN(startup_64)
 	leaq	(__end_init_task - FRAME_SIZE)(%rip), %rsp
 
 	leaq	_text(%rip), %rdi
+
+	/*
+	 * initial_gs points to initial fixed_per_cpu struct with storage for
+	 * the stack protector canary. Global pointer fixups are needed at this
+	 * stage, so apply them as is done in fixup_pointer(), and initialize %gs
+	 * such that the canary can be accessed at %gs:40 for subsequent C calls.
+	 */
+	movl	$MSR_GS_BASE, %ecx
+	movq	initial_gs(%rip), %rax
+	movq	$_text, %rdx
+	subq	%rdx, %rax
+	addq	%rdi, %rax
+	movq	%rax, %rdx
+	shrq	$32,  %rdx
+	wrmsr
+
 	pushq	%rsi
 	call	startup_64_setup_env
 	popq	%rsi
@@ -133,6 +149,14 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
 	 * added to the initial pgdir entry that will be programmed into CR3.
 	 */
 	pushq	%rsi
+	/*
+	 * NOTE: %gs at this point is a stale data segment left over from the
+	 * real-mode trampoline, so the default stack protector canary location
+	 * at %gs:40 does not yet coincide with the expected fixed_per_cpu struct
+	 * that contains storage for the stack canary. So take care not to add
+	 * anything to the C functions in this path that would result in stack
+	 * protected C code being generated.
+	 */
 	call	__startup_secondary_64
 	popq	%rsi
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 27/45] x86/sev: move MSR-based VMGEXITs for CPUID to helper
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (25 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 26/45] x86/head: re-enable stack protection for 32/64-bit builds Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 28/45] KVM: x86: move lookup of indexed CPUID leafs " Brijesh Singh
                   ` (18 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

This code will also be used later for SEV-SNP-validated CPUID code in
some cases, so move it to a common helper.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/sev-shared.c | 84 +++++++++++++++++++++++++-----------
 1 file changed, 58 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index b0ed64fc6520..9f81d78ab061 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -204,6 +204,58 @@ enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr,
 	return verify_exception_info(ghcb, ctxt);
 }
 
+static int sev_cpuid_hv(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
+			u32 *ecx, u32 *edx)
+{
+	u64 val;
+
+	if (eax) {
+		sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_EAX));
+		VMGEXIT();
+		val = sev_es_rd_ghcb_msr();
+
+		if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
+			return -EIO;
+
+		*eax = (val >> 32);
+	}
+
+	if (ebx) {
+		sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_EBX));
+		VMGEXIT();
+		val = sev_es_rd_ghcb_msr();
+
+		if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
+			return -EIO;
+
+		*ebx = (val >> 32);
+	}
+
+	if (ecx) {
+		sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_ECX));
+		VMGEXIT();
+		val = sev_es_rd_ghcb_msr();
+
+		if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
+			return -EIO;
+
+		*ecx = (val >> 32);
+	}
+
+	if (edx) {
+		sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_EDX));
+		VMGEXIT();
+		val = sev_es_rd_ghcb_msr();
+
+		if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
+			return -EIO;
+
+		*edx = (val >> 32);
+	}
+
+	return 0;
+}
+
 /*
  * Boot VC Handler - This is the first VC handler during boot, there is no GHCB
  * page yet, so it only supports the MSR based communication with the
@@ -212,39 +264,19 @@ enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr,
 void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 {
 	unsigned int fn = lower_bits(regs->ax, 32);
-	unsigned long val;
+	u32 eax, ebx, ecx, edx;
 
 	/* Only CPUID is supported via MSR protocol */
 	if (exit_code != SVM_EXIT_CPUID)
 		goto fail;
 
-	sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(fn, GHCB_CPUID_REQ_EAX));
-	VMGEXIT();
-	val = sev_es_rd_ghcb_msr();
-	if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
+	if (sev_cpuid_hv(fn, 0, &eax, &ebx, &ecx, &edx))
 		goto fail;
-	regs->ax = val >> 32;
 
-	sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(fn, GHCB_CPUID_REQ_EBX));
-	VMGEXIT();
-	val = sev_es_rd_ghcb_msr();
-	if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
-		goto fail;
-	regs->bx = val >> 32;
-
-	sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(fn, GHCB_CPUID_REQ_ECX));
-	VMGEXIT();
-	val = sev_es_rd_ghcb_msr();
-	if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
-		goto fail;
-	regs->cx = val >> 32;
-
-	sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(fn, GHCB_CPUID_REQ_EDX));
-	VMGEXIT();
-	val = sev_es_rd_ghcb_msr();
-	if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
-		goto fail;
-	regs->dx = val >> 32;
+	regs->ax = eax;
+	regs->bx = ebx;
+	regs->cx = ecx;
+	regs->dx = edx;
 
 	/*
 	 * This is a VC handler and the #VC is only raised when SEV-ES is
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 28/45] KVM: x86: move lookup of indexed CPUID leafs to helper
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (26 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 27/45] x86/sev: move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 29/45] x86/compressed/acpi: move EFI system table lookup " Brijesh Singh
                   ` (17 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

Determining which CPUID leafs have significant ECX/index values is
also needed by guest kernel code when doing SEV-SNP-validated CPUID
lookups. Move this to common code to keep future updates in sync.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/cpuid.h | 26 ++++++++++++++++++++++++++
 arch/x86/kvm/cpuid.c         | 17 ++---------------
 2 files changed, 28 insertions(+), 15 deletions(-)
 create mode 100644 arch/x86/include/asm/cpuid.h

diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h
new file mode 100644
index 000000000000..61426eb1f665
--- /dev/null
+++ b/arch/x86/include/asm/cpuid.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_CPUID_H
+#define _ASM_X86_CPUID_H
+
+static __always_inline bool cpuid_function_is_indexed(u32 function)
+{
+	switch (function) {
+	case 4:
+	case 7:
+	case 0xb:
+	case 0xd:
+	case 0xf:
+	case 0x10:
+	case 0x12:
+	case 0x14:
+	case 0x17:
+	case 0x18:
+	case 0x1f:
+	case 0x8000001d:
+		return true;
+	}
+
+	return false;
+}
+
+#endif /* _ASM_X86_CPUID_H */
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 751aa85a3001..312b0382e541 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -19,6 +19,7 @@
 #include <asm/user.h>
 #include <asm/fpu/xstate.h>
 #include <asm/sgx.h>
+#include <asm/cpuid.h>
 #include "cpuid.h"
 #include "lapic.h"
 #include "mmu.h"
@@ -582,22 +583,8 @@ static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array,
 	cpuid_count(entry->function, entry->index,
 		    &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
 
-	switch (function) {
-	case 4:
-	case 7:
-	case 0xb:
-	case 0xd:
-	case 0xf:
-	case 0x10:
-	case 0x12:
-	case 0x14:
-	case 0x17:
-	case 0x18:
-	case 0x1f:
-	case 0x8000001d:
+	if (cpuid_function_is_indexed(function))
 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
-		break;
-	}
 
 	return entry;
 }
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 29/45] x86/compressed/acpi: move EFI system table lookup to helper
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (27 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 28/45] KVM: x86: move lookup of indexed CPUID leafs " Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 30/45] x86/compressed/acpi: move EFI config " Brijesh Singh
                   ` (16 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

Future patches for SEV-SNP-validated CPUID will also require early
parsing of the EFI configuration. Incrementally move the related code
into a set of helpers that can be re-used for that purpose.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/Makefile |  1 +
 arch/x86/boot/compressed/acpi.c   | 60 ++++++++++----------------
 arch/x86/boot/compressed/efi.c    | 71 +++++++++++++++++++++++++++++++
 arch/x86/boot/compressed/misc.h   | 14 ++++++
 4 files changed, 108 insertions(+), 38 deletions(-)
 create mode 100644 arch/x86/boot/compressed/efi.c

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 431bf7f846c3..d364192c2367 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -100,6 +100,7 @@ endif
 vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o
 
 vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o
+vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o
 efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a
 
 $(obj)/vmlinux: $(vmlinux-objs-y) $(efi-obj-y) FORCE
diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index 8bcbcee54aa1..9e784bd7b2e6 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -86,8 +86,8 @@ static acpi_physical_address kexec_get_rsdp_addr(void)
 {
 	efi_system_table_64_t *systab;
 	struct efi_setup_data *esd;
-	struct efi_info *ei;
-	char *sig;
+	bool efi_64;
+	int ret;
 
 	esd = (struct efi_setup_data *)get_kexec_setup_data_addr();
 	if (!esd)
@@ -98,18 +98,16 @@ static acpi_physical_address kexec_get_rsdp_addr(void)
 		return 0;
 	}
 
-	ei = &boot_params->efi_info;
-	sig = (char *)&ei->efi_loader_signature;
-	if (strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
+	/* Get systab from boot params. */
+	ret = efi_get_system_table(boot_params, (unsigned long *)&systab, &efi_64);
+	if (ret)
+		error("EFI system table not found in kexec boot_params.");
+
+	if (!efi_64) {
 		debug_putstr("Wrong kexec EFI loader signature.\n");
 		return 0;
 	}
 
-	/* Get systab from boot params. */
-	systab = (efi_system_table_64_t *) (ei->efi_systab | ((__u64)ei->efi_systab_hi << 32));
-	if (!systab)
-		error("EFI system table not found in kexec boot_params.");
-
 	return __efi_get_rsdp_addr((unsigned long)esd->tables, systab->nr_tables, true);
 }
 #else
@@ -119,45 +117,31 @@ static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
 static acpi_physical_address efi_get_rsdp_addr(void)
 {
 #ifdef CONFIG_EFI
-	unsigned long systab, config_tables;
+	unsigned long systab_tbl_pa, config_tables;
 	unsigned int nr_tables;
-	struct efi_info *ei;
 	bool efi_64;
-	char *sig;
-
-	ei = &boot_params->efi_info;
-	sig = (char *)&ei->efi_loader_signature;
-
-	if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
-		efi_64 = true;
-	} else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) {
-		efi_64 = false;
-	} else {
-		debug_putstr("Wrong EFI loader signature.\n");
-		return 0;
-	}
+	int ret;
 
-	/* Get systab from boot params. */
-#ifdef CONFIG_X86_64
-	systab = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32);
-#else
-	if (ei->efi_systab_hi || ei->efi_memmap_hi) {
-		debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n");
+	/*
+	 * This function is called even for non-EFI BIOSes, and callers expect
+	 * failure to locate the EFI system table to result in 0 being returned
+	 * as indication that EFI is not available, rather than outright
+	 * failure/abort.
+	 */
+	ret = efi_get_system_table(boot_params, &systab_tbl_pa, &efi_64);
+	if (ret == -EOPNOTSUPP)
 		return 0;
-	}
-	systab = ei->efi_systab;
-#endif
-	if (!systab)
-		error("EFI system table not found.");
+	if (ret)
+		error("EFI support advertised, but unable to locate system table.");
 
 	/* Handle EFI bitness properly */
 	if (efi_64) {
-		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab;
+		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab_tbl_pa;
 
 		config_tables	= stbl->tables;
 		nr_tables	= stbl->nr_tables;
 	} else {
-		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab;
+		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab_tbl_pa;
 
 		config_tables	= stbl->tables;
 		nr_tables	= stbl->nr_tables;
diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c
new file mode 100644
index 000000000000..bcf1d5650e26
--- /dev/null
+++ b/arch/x86/boot/compressed/efi.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for early access to EFI configuration table
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Michael Roth <michael.roth@amd.com>
+ */
+
+#include "misc.h"
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+/**
+ * Given boot_params, retrieve the physical address of EFI system table.
+ *
+ * @boot_params:        pointer to boot_params
+ * @sys_tbl_pa:         location to store physical address of system table
+ * @is_efi_64:          location to store whether using 64-bit EFI or not
+ *
+ * Returns 0 on success. On error, return params are left unchanged.
+ *
+ * Note: Existing callers like ACPI will call this unconditionally even for
+ * non-EFI BIOSes. In such cases, those callers may treat cases where
+ * bootparams doesn't indicate that a valid EFI system table is available as
+ * non-fatal errors to allow fall-through to non-EFI alternatives. This
+ * class of errors are reported as EOPNOTSUPP and should be kept in sync with
+ * callers who check for that specific error.
+ */
+int efi_get_system_table(struct boot_params *boot_params, unsigned long *sys_tbl_pa,
+			 bool *is_efi_64)
+{
+	unsigned long sys_tbl;
+	struct efi_info *ei;
+	bool efi_64;
+	char *sig;
+
+	if (!sys_tbl_pa || !is_efi_64)
+		return -EINVAL;
+
+	ei = &boot_params->efi_info;
+	sig = (char *)&ei->efi_loader_signature;
+
+	if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
+		efi_64 = true;
+	} else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) {
+		efi_64 = false;
+	} else {
+		debug_putstr("Wrong EFI loader signature.\n");
+		return -EOPNOTSUPP;
+	}
+
+	/* Get systab from boot params. */
+#ifdef CONFIG_X86_64
+	sys_tbl = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32);
+#else
+	if (ei->efi_systab_hi || ei->efi_memmap_hi) {
+		debug_putstr("Error: EFI system table located above 4GB.\n");
+		return -EOPNOTSUPP;
+	}
+	sys_tbl = ei->efi_systab;
+#endif
+	if (!sys_tbl) {
+		debug_putstr("EFI system table not found.");
+		return -ENOENT;
+	}
+
+	*sys_tbl_pa = sys_tbl;
+	*is_efi_64 = efi_64;
+	return 0;
+}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 01cc13c12059..165640f64b71 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -23,6 +23,7 @@
 #include <linux/screen_info.h>
 #include <linux/elf.h>
 #include <linux/io.h>
+#include <linux/efi.h>
 #include <asm/page.h>
 #include <asm/boot.h>
 #include <asm/bootparam.h>
@@ -176,4 +177,17 @@ void boot_stage2_vc(void);
 
 unsigned long sev_verify_cbit(unsigned long cr3);
 
+#ifdef CONFIG_EFI
+/* helpers for early EFI config table access */
+int efi_get_system_table(struct boot_params *boot_params,
+			 unsigned long *sys_tbl_pa, bool *is_efi_64);
+#else
+static inline int
+efi_get_system_table(struct boot_params *boot_params,
+		     unsigned long *sys_tbl_pa, bool *is_efi_64)
+{
+	return -ENOENT;
+}
+#endif /* CONFIG_EFI */
+
 #endif /* BOOT_COMPRESSED_MISC_H */
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 30/45] x86/compressed/acpi: move EFI config table lookup to helper
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (28 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 29/45] x86/compressed/acpi: move EFI system table lookup " Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 31/45] x86/compressed/acpi: move EFI vendor " Brijesh Singh
                   ` (15 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

Future patches for SEV-SNP-validated CPUID will also require early
parsing of the EFI configuration. Incrementally move the related code
into a set of helpers that can be re-used for that purpose.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/acpi.c | 25 ++++++--------------
 arch/x86/boot/compressed/efi.c  | 42 +++++++++++++++++++++++++++++++++
 arch/x86/boot/compressed/misc.h |  9 +++++++
 3 files changed, 58 insertions(+), 18 deletions(-)

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index 9e784bd7b2e6..fea72a1504ff 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -117,8 +117,9 @@ static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
 static acpi_physical_address efi_get_rsdp_addr(void)
 {
 #ifdef CONFIG_EFI
-	unsigned long systab_tbl_pa, config_tables;
-	unsigned int nr_tables;
+	unsigned long cfg_tbl_pa = 0;
+	unsigned long systab_tbl_pa;
+	unsigned int cfg_tbl_len;
 	bool efi_64;
 	int ret;
 
@@ -134,23 +135,11 @@ static acpi_physical_address efi_get_rsdp_addr(void)
 	if (ret)
 		error("EFI support advertised, but unable to locate system table.");
 
-	/* Handle EFI bitness properly */
-	if (efi_64) {
-		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab_tbl_pa;
+	ret = efi_get_conf_table(boot_params, &cfg_tbl_pa, &cfg_tbl_len, &efi_64);
+	if (ret || !cfg_tbl_pa)
+		error("EFI config table not found.");
 
-		config_tables	= stbl->tables;
-		nr_tables	= stbl->nr_tables;
-	} else {
-		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab_tbl_pa;
-
-		config_tables	= stbl->tables;
-		nr_tables	= stbl->nr_tables;
-	}
-
-	if (!config_tables)
-		error("EFI config tables not found.");
-
-	return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);
+	return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len, efi_64);
 #else
 	return 0;
 #endif
diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c
index bcf1d5650e26..4398b55acd9f 100644
--- a/arch/x86/boot/compressed/efi.c
+++ b/arch/x86/boot/compressed/efi.c
@@ -69,3 +69,45 @@ int efi_get_system_table(struct boot_params *boot_params, unsigned long *sys_tbl
 	*is_efi_64 = efi_64;
 	return 0;
 }
+
+/**
+ * Given boot_params, locate EFI system table from it and return the physical
+ * address EFI configuration table.
+ *
+ * @boot_params:        pointer to boot_params
+ * @cfg_tbl_pa:         location to store physical address of config table
+ * @cfg_tbl_len:        location to store number of config table entries
+ * @is_efi_64:          location to store whether using 64-bit EFI or not
+ *
+ * Returns 0 on success. On error, return params are left unchanged.
+ */
+int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
+		       unsigned int *cfg_tbl_len, bool *is_efi_64)
+{
+	unsigned long sys_tbl_pa = 0;
+	int ret;
+
+	if (!cfg_tbl_pa || !cfg_tbl_len || !is_efi_64)
+		return -EINVAL;
+
+	ret = efi_get_system_table(boot_params, &sys_tbl_pa, is_efi_64);
+	if (ret)
+		return ret;
+
+	/* Handle EFI bitness properly */
+	if (*is_efi_64) {
+		efi_system_table_64_t *stbl =
+			(efi_system_table_64_t *)sys_tbl_pa;
+
+		*cfg_tbl_pa	= stbl->tables;
+		*cfg_tbl_len	= stbl->nr_tables;
+	} else {
+		efi_system_table_32_t *stbl =
+			(efi_system_table_32_t *)sys_tbl_pa;
+
+		*cfg_tbl_pa	= stbl->tables;
+		*cfg_tbl_len	= stbl->nr_tables;
+	}
+
+	return 0;
+}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 165640f64b71..074674b89925 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -181,6 +181,8 @@ unsigned long sev_verify_cbit(unsigned long cr3);
 /* helpers for early EFI config table access */
 int efi_get_system_table(struct boot_params *boot_params,
 			 unsigned long *sys_tbl_pa, bool *is_efi_64);
+int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
+			unsigned int *cfg_tbl_len, bool *is_efi_64);
 #else
 static inline int
 efi_get_system_table(struct boot_params *boot_params,
@@ -188,6 +190,13 @@ efi_get_system_table(struct boot_params *boot_params,
 {
 	return -ENOENT;
 }
+
+static inline int
+efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
+		   unsigned int *cfg_tbl_len, bool *is_efi_64)
+{
+	return -ENOENT;
+}
 #endif /* CONFIG_EFI */
 
 #endif /* BOOT_COMPRESSED_MISC_H */
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 31/45] x86/compressed/acpi: move EFI vendor table lookup to helper
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (29 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 30/45] x86/compressed/acpi: move EFI config " Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 32/45] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
                   ` (14 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

Future patches for SEV-SNP-validated CPUID will also require early
parsing of the EFI configuration. Incrementally move the related code
into a set of helpers that can be re-used for that purpose.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/acpi.c | 50 ++++++++-----------------
 arch/x86/boot/compressed/efi.c  | 65 +++++++++++++++++++++++++++++++++
 arch/x86/boot/compressed/misc.h |  9 +++++
 3 files changed, 90 insertions(+), 34 deletions(-)

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index fea72a1504ff..0670c8f8888a 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -20,46 +20,28 @@
  */
 struct mem_vector immovable_mem[MAX_NUMNODES*2];
 
-/*
- * Search EFI system tables for RSDP.  If both ACPI_20_TABLE_GUID and
- * ACPI_TABLE_GUID are found, take the former, which has more features.
- */
 static acpi_physical_address
-__efi_get_rsdp_addr(unsigned long config_tables, unsigned int nr_tables,
-		    bool efi_64)
+__efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len, bool efi_64)
 {
 	acpi_physical_address rsdp_addr = 0;
 
 #ifdef CONFIG_EFI
-	int i;
-
-	/* Get EFI tables from systab. */
-	for (i = 0; i < nr_tables; i++) {
-		acpi_physical_address table;
-		efi_guid_t guid;
-
-		if (efi_64) {
-			efi_config_table_64_t *tbl = (efi_config_table_64_t *)config_tables + i;
-
-			guid  = tbl->guid;
-			table = tbl->table;
-
-			if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
-				debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
-				return 0;
-			}
-		} else {
-			efi_config_table_32_t *tbl = (efi_config_table_32_t *)config_tables + i;
-
-			guid  = tbl->guid;
-			table = tbl->table;
-		}
+	int ret;
 
-		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
-			rsdp_addr = table;
-		else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
-			return table;
-	}
+	/*
+	 * Search EFI system tables for RSDP. Preferred is ACPI_20_TABLE_GUID to
+	 * ACPI_TABLE_GUID because it has more features.
+	 */
+	ret = efi_find_vendor_table(cfg_tbl_pa, cfg_tbl_len, ACPI_20_TABLE_GUID,
+				    efi_64, (unsigned long *)&rsdp_addr);
+	if (!ret)
+		return rsdp_addr;
+
+	/* No ACPI_20_TABLE_GUID found, fallback to ACPI_TABLE_GUID. */
+	ret = efi_find_vendor_table(cfg_tbl_pa, cfg_tbl_len, ACPI_TABLE_GUID,
+				    efi_64, (unsigned long *)&rsdp_addr);
+	if (ret)
+		debug_putstr("Error getting RSDP address.\n");
 #endif
 	return rsdp_addr;
 }
diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c
index 4398b55acd9f..db01af5d9a4a 100644
--- a/arch/x86/boot/compressed/efi.c
+++ b/arch/x86/boot/compressed/efi.c
@@ -111,3 +111,68 @@ int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_p
 
 	return 0;
 }
+
+/* Get vendor table address/guid from EFI config table at the given index */
+static int get_vendor_table(void *cfg_tbl, unsigned int idx,
+			    unsigned long *vendor_tbl_pa,
+			    efi_guid_t *vendor_tbl_guid,
+			    bool efi_64)
+{
+	if (efi_64) {
+		efi_config_table_64_t *tbl_entry =
+			(efi_config_table_64_t *)cfg_tbl + idx;
+
+		if (!IS_ENABLED(CONFIG_X86_64) && tbl_entry->table >> 32) {
+			debug_putstr("Error: EFI config table entry located above 4GB.\n");
+			return -EINVAL;
+		}
+
+		*vendor_tbl_pa		= tbl_entry->table;
+		*vendor_tbl_guid	= tbl_entry->guid;
+
+	} else {
+		efi_config_table_32_t *tbl_entry =
+			(efi_config_table_32_t *)cfg_tbl + idx;
+
+		*vendor_tbl_pa		= tbl_entry->table;
+		*vendor_tbl_guid	= tbl_entry->guid;
+	}
+
+	return 0;
+}
+
+/**
+ * Given EFI config table, search it for the physical address of the vendor
+ * table associated with GUID.
+ *
+ * @cfg_tbl_pa:        pointer to EFI configuration table
+ * @cfg_tbl_len:       number of entries in EFI configuration table
+ * @guid:              GUID of vendor table
+ * @efi_64:            true if using 64-bit EFI
+ * @vendor_tbl_pa:     location to store physical address of vendor table
+ *
+ * Returns 0 on success. On error, return params are left unchanged.
+ */
+int efi_find_vendor_table(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len,
+			  efi_guid_t guid, bool efi_64, unsigned long *vendor_tbl_pa)
+{
+	unsigned int i;
+
+	for (i = 0; i < cfg_tbl_len; i++) {
+		unsigned long vendor_tbl_pa_tmp;
+		efi_guid_t vendor_tbl_guid;
+		int ret;
+
+		if (get_vendor_table((void *)cfg_tbl_pa, i,
+				     &vendor_tbl_pa_tmp,
+				     &vendor_tbl_guid, efi_64))
+			return -EINVAL;
+
+		if (!efi_guidcmp(guid, vendor_tbl_guid)) {
+			*vendor_tbl_pa = vendor_tbl_pa_tmp;
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 074674b89925..bb2e884467db 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -183,6 +183,8 @@ int efi_get_system_table(struct boot_params *boot_params,
 			 unsigned long *sys_tbl_pa, bool *is_efi_64);
 int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
 			unsigned int *cfg_tbl_len, bool *is_efi_64);
+int efi_find_vendor_table(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len,
+			  efi_guid_t guid, bool efi_64, unsigned long *vendor_tbl_pa);
 #else
 static inline int
 efi_get_system_table(struct boot_params *boot_params,
@@ -197,6 +199,13 @@ efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
 {
 	return -ENOENT;
 }
+
+static inline int
+efi_find_vendor_table(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len,
+		      efi_guid_t guid, bool efi_64, unsigned long *vendor_tbl_pa)
+{
+	return -ENOENT;
+}
 #endif /* CONFIG_EFI */
 
 #endif /* BOOT_COMPRESSED_MISC_H */
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 32/45] x86/boot: Add Confidential Computing type to setup_data
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (30 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 31/45] x86/compressed/acpi: move EFI vendor " Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 33/45] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement Brijesh Singh
                   ` (13 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

While launching the encrypted guests, the hypervisor may need to provide
some additional information during the guest boot. When booting under the
EFI based BIOS, the EFI configuration table contains an entry for the
confidential computing blob that contains the required information.

To support booting encrypted guests on non-EFI VM, the hypervisor needs to
pass this additional information to the kernel with a different method.

For this purpose, introduce SETUP_CC_BLOB type in setup_data to hold the
physical address of the confidential computing blob location. The boot
loader or hypervisor may choose to use this method instead of EFI
configuration table. The CC blob location scanning should give preference
to setup_data data over the EFI configuration table.

In AMD SEV-SNP, the CC blob contains the address of the secrets and CPUID
pages. The secrets page includes information such as a VM to PSP
communication key and CPUID page contains PSP filtered CPUID values.
Define the AMD SEV confidential computing blob structure.

While at it, define the EFI GUID for the confidential computing blob.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h            | 12 ++++++++++++
 arch/x86/include/uapi/asm/bootparam.h |  1 +
 include/linux/efi.h                   |  1 +
 3 files changed, 14 insertions(+)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index f7cbd5164136..f42fbe3c332f 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -44,6 +44,18 @@ struct es_em_ctxt {
 
 void do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code);
 
+/* AMD SEV Confidential computing blob structure */
+#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
+struct cc_blob_sev_info {
+	u32 magic;
+	u16 version;
+	u16 reserved;
+	u64 secrets_phys;
+	u32 secrets_len;
+	u64 cpuid_phys;
+	u32 cpuid_len;
+};
+
 static inline u64 lower_bits(u64 val, unsigned int bits)
 {
 	u64 mask = (1ULL << bits) - 1;
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index b25d3f82c2f3..1ac5acca72ce 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -10,6 +10,7 @@
 #define SETUP_EFI			4
 #define SETUP_APPLE_PROPERTIES		5
 #define SETUP_JAILHOUSE			6
+#define SETUP_CC_BLOB			7
 
 #define SETUP_INDIRECT			(1<<31)
 
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 6b5d36babfcc..75aeb2a56888 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -344,6 +344,7 @@ void efi_native_runtime_setup(void);
 #define EFI_CERT_SHA256_GUID			EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28)
 #define EFI_CERT_X509_GUID			EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72)
 #define EFI_CERT_X509_SHA256_GUID		EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed)
+#define EFI_CC_BLOB_GUID			EFI_GUID(0x067b1f5f, 0xcf26, 0x44c5, 0x85, 0x54, 0x93, 0xd7, 0x77, 0x91, 0x2d, 0x42)
 
 /*
  * This GUID is used to pass to the kernel proper the struct screen_info
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 33/45] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (31 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 32/45] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 34/45] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers Brijesh Singh
                   ` (12 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

Update the documentation with SEV-SNP CPUID enforcement.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 .../virt/kvm/amd-memory-encryption.rst        | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
index 5c081c8c7164..aa8292fa579a 100644
--- a/Documentation/virt/kvm/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/amd-memory-encryption.rst
@@ -427,6 +427,34 @@ issued by the hypervisor to make the guest ready for execution.
 
 Returns: 0 on success, -negative on error
 
+SEV-SNP CPUID Enforcement
+=========================
+
+SEV-SNP guests can access a special page that contains a table of CPUID values
+that have been validated by the PSP as part of SNP_LAUNCH_UPDATE firmware
+command. It provides the following assurances regarding the validity of CPUID
+values:
+
+ - Its address is obtained via bootloader/firmware (via CC blob), whose
+   binares will be measured as part of the SEV-SNP attestation report.
+ - Its initial state will be encrypted/pvalidated, so attempts to modify
+   it during run-time will be result in garbage being written, or #VC
+   exceptions being generated due to changes in validation state if the
+   hypervisor tries to swap the backing page.
+ - Attempts to bypass PSP checks by hypervisor by using a normal page, or a
+   non-CPUID encrypted page will change the measurement provided by the
+   SEV-SNP attestation report.
+ - The CPUID page contents are *not* measured, but attempts to modify the
+   expected contents of a CPUID page as part of guest initialization will be
+   gated by the PSP CPUID enforcement policy checks performed on the page
+   during SNP_LAUNCH_UPDATE, and noticeable later if the guest owner
+   implements their own checks of the CPUID values.
+
+It is important to note that this last assurance is only useful if the kernel
+has taken care to make use of the SEV-SNP CPUID throughout all stages of boot.
+Otherwise guest owner attestation provides no assurance that the kernel wasn't
+fed incorrect values at some point during boot.
+
 References
 ==========
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 34/45] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (32 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 33/45] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 35/45] x86/boot: add a pointer to Confidential Computing blob in bootparams Brijesh Singh
                   ` (11 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

CPUID instructions generate a #VC exception for SEV-ES/SEV-SNP guests,
for which early handlers are currently set up to handle. In the case
of SEV-SNP, guests can use a configurable location in guest memory
that has been pre-populated with a firmware-validated CPUID table to
look up the relevant CPUID values rather than requesting them from
hypervisor via a VMGEXIT. Add the various hooks in the #VC handlers to
allow CPUID instructions to be handled via the table. The code to
actually configure/enable the table will be added in a subsequent
commit.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c    |   1 +
 arch/x86/include/asm/sev-common.h |   2 +
 arch/x86/kernel/sev-shared.c      | 320 ++++++++++++++++++++++++++++++
 arch/x86/kernel/sev.c             |   1 +
 4 files changed, 324 insertions(+)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index fb2f763dfc19..2d9db9dc149b 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -20,6 +20,7 @@
 #include <asm/fpu/xcr.h>
 #include <asm/ptrace.h>
 #include <asm/svm.h>
+#include <asm/cpuid.h>
 
 #include "error.h"
 
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index c380aba9fc8d..45c535eb75f1 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -152,6 +152,8 @@ struct snp_psc_desc {
 #define GHCB_TERM_PSC			1	/* Page State Change failure */
 #define GHCB_TERM_PVALIDATE		2	/* Pvalidate failure */
 #define GHCB_TERM_NOT_VMPL0		3	/* SNP guest is not running at VMPL-0 */
+#define GHCB_TERM_CPUID			4	/* CPUID-validation failure */
+#define GHCB_TERM_CPUID_HV		5	/* CPUID failure during hypervisor fallback */
 
 #define GHCB_RESP_CODE(v)		((v) & GHCB_MSR_INFO_MASK)
 
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 9f81d78ab061..b1ed5a1b1a90 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -14,6 +14,41 @@
 #define has_cpuflag(f)	boot_cpu_has(f)
 #endif
 
+/*
+ * Individual entries of the SEV-SNP CPUID table, as defined by the SEV-SNP
+ * Firmware ABI, Revision 0.9, Section 7.1, Table 14. Note that the XCR0_IN
+ * and XSS_IN are denoted here as __unused/__unused2, since they are not
+ * needed for the current guest implementation, where the size of the buffers
+ * needed to store enabled XSAVE-saved features are calculated rather than
+ * encoded in the CPUID table for each possible combination of XCR0_IN/XSS_IN
+ * to save space.
+ */
+struct snp_cpuid_fn {
+	u32 eax_in;
+	u32 ecx_in;
+	u64 __unused;
+	u64 __unused2;
+	u32 eax;
+	u32 ebx;
+	u32 ecx;
+	u32 edx;
+	u64 __reserved;
+} __packed;
+
+/*
+ * SEV-SNP CPUID table header, as defined by the SEV-SNP Firmware ABI,
+ * Revision 0.9, Section 8.14.2.6. Also noted there is the SEV-SNP
+ * firmware-enforced limit of 64 entries per CPUID table.
+ */
+#define SNP_CPUID_COUNT_MAX 64
+
+struct snp_cpuid_info {
+	u32 count;
+	u32 __reserved1;
+	u64 __reserved2;
+	struct snp_cpuid_fn fn[SNP_CPUID_COUNT_MAX];
+} __packed;
+
 /*
  * Since feature negotiation related variables are set early in the boot
  * process they must reside in the .data section so as not to be zeroed
@@ -26,6 +61,20 @@ static u16 ghcb_version __ro_after_init;
 /* Bitmap of SEV features supported by the hypervisor */
 static u64 sev_hv_features __ro_after_init;
 
+/* Copy of the SNP firmware's CPUID page. */
+static struct snp_cpuid_info cpuid_info_copy __ro_after_init;
+static bool snp_cpuid_initialized __ro_after_init;
+
+/*
+ * These will be initialized based on CPUID table so that non-present
+ * all-zero leaves (for sparse tables) can be differentiated from
+ * invalid/out-of-range leaves. This is needed since all-zero leaves
+ * still need to be post-processed.
+ */
+u32 cpuid_std_range_max __ro_after_init;
+u32 cpuid_hyp_range_max __ro_after_init;
+u32 cpuid_ext_range_max __ro_after_init;
+
 static bool __init sev_es_check_cpu_features(void)
 {
 	if (!has_cpuflag(X86_FEATURE_RDRAND)) {
@@ -256,6 +305,244 @@ static int sev_cpuid_hv(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
 	return 0;
 }
 
+static const struct snp_cpuid_info *
+snp_cpuid_info_get_ptr(void)
+{
+	void *ptr;
+
+	/*
+	 * This may be called early while still running on the initial identity
+	 * mapping. Use RIP-relative addressing to obtain the correct address
+	 * in both for identity mapping and after switch-over to kernel virtual
+	 * addresses.
+	 */
+	asm ("lea cpuid_info_copy(%%rip), %0"
+	     : "=r" (ptr)
+	     : "p" (&cpuid_info_copy));
+
+	return ptr;
+}
+
+static inline bool snp_cpuid_active(void)
+{
+	return snp_cpuid_initialized;
+}
+
+static int snp_cpuid_calc_xsave_size(u64 xfeatures_en, u32 base_size,
+				     u32 *xsave_size, bool compacted)
+{
+	const struct snp_cpuid_info *cpuid_info = snp_cpuid_info_get_ptr();
+	u32 xsave_size_total = base_size;
+	u64 xfeatures_found = 0;
+	int i;
+
+	for (i = 0; i < cpuid_info->count; i++) {
+		const struct snp_cpuid_fn *fn = &cpuid_info->fn[i];
+
+		if (!(fn->eax_in == 0xD && fn->ecx_in > 1 && fn->ecx_in < 64))
+			continue;
+		if (!(xfeatures_en & (BIT_ULL(fn->ecx_in))))
+			continue;
+		if (xfeatures_found & (BIT_ULL(fn->ecx_in)))
+			continue;
+
+		xfeatures_found |= (BIT_ULL(fn->ecx_in));
+
+		if (compacted)
+			xsave_size_total += fn->eax;
+		else
+			xsave_size_total = max(xsave_size_total,
+					       fn->eax + fn->ebx);
+	}
+
+	/*
+	 * Either the guest set unsupported XCR0/XSS bits, or the corresponding
+	 * entries in the CPUID table were not present. This is not a valid
+	 * state to be in.
+	 */
+	if (xfeatures_found != (xfeatures_en & GENMASK_ULL(63, 2)))
+		return -EINVAL;
+
+	*xsave_size = xsave_size_total;
+
+	return 0;
+}
+
+static void snp_cpuid_hv(u32 func, u32 subfunc, u32 *eax, u32 *ebx, u32 *ecx,
+			 u32 *edx)
+{
+	/*
+	 * MSR protocol does not support fetching indexed subfunction, but is
+	 * sufficient to handle current fallback cases. Should that change,
+	 * make sure to terminate rather than ignoring the index and grabbing
+	 * random values. If this issue arises in the future, handling can be
+	 * added here to use GHCB-page protocol for cases that occur late
+	 * enough in boot that GHCB page is available.
+	 */
+	if (cpuid_function_is_indexed(func) && subfunc)
+		sev_es_terminate(1, GHCB_TERM_CPUID_HV);
+
+	if (sev_cpuid_hv(func, 0, eax, ebx, ecx, edx))
+		sev_es_terminate(1, GHCB_TERM_CPUID_HV);
+}
+
+static bool
+snp_cpuid_find_validated_func(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
+			      u32 *ecx, u32 *edx)
+{
+	const struct snp_cpuid_info *cpuid_info = snp_cpuid_info_get_ptr();
+	int i;
+
+	for (i = 0; i < cpuid_info->count; i++) {
+		const struct snp_cpuid_fn *fn = &cpuid_info->fn[i];
+
+		if (fn->eax_in != func)
+			continue;
+
+		if (cpuid_function_is_indexed(func) && fn->ecx_in != subfunc)
+			continue;
+
+		*eax = fn->eax;
+		*ebx = fn->ebx;
+		*ecx = fn->ecx;
+		*edx = fn->edx;
+
+		return true;
+	}
+
+	return false;
+}
+
+static bool snp_cpuid_check_range(u32 func)
+{
+	if (func <= cpuid_std_range_max ||
+	    (func >= 0x40000000 && func <= cpuid_hyp_range_max) ||
+	    (func >= 0x80000000 && func <= cpuid_ext_range_max))
+		return true;
+
+	return false;
+}
+
+static int snp_cpuid_postprocess(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
+				 u32 *ecx, u32 *edx)
+{
+	u32 ebx2, ecx2, edx2;
+
+	switch (func) {
+	case 0x1:
+		snp_cpuid_hv(func, subfunc, NULL, &ebx2, NULL, &edx2);
+
+		/* initial APIC ID */
+		*ebx = (ebx2 & GENMASK(31, 24)) | (*ebx & GENMASK(23, 0));
+		/* APIC enabled bit */
+		*edx = (edx2 & BIT(9)) | (*edx & ~BIT(9));
+
+		/* OSXSAVE enabled bit */
+		if (native_read_cr4() & X86_CR4_OSXSAVE)
+			*ecx |= BIT(27);
+		break;
+	case 0x7:
+		/* OSPKE enabled bit */
+		*ecx &= ~BIT(4);
+		if (native_read_cr4() & X86_CR4_PKE)
+			*ecx |= BIT(4);
+		break;
+	case 0xB:
+		/* extended APIC ID */
+		snp_cpuid_hv(func, 0, NULL, NULL, NULL, edx);
+		break;
+	case 0xD: {
+		bool compacted = false;
+		u64 xcr0 = 1, xss = 0;
+		u32 xsave_size;
+
+		if (subfunc != 0 && subfunc != 1)
+			return 0;
+
+		if (native_read_cr4() & X86_CR4_OSXSAVE)
+			xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
+		if (subfunc == 1) {
+			/* Get XSS value if XSAVES is enabled. */
+			if (*eax & BIT(3)) {
+				unsigned long lo, hi;
+
+				asm volatile("rdmsr" : "=a" (lo), "=d" (hi)
+						     : "c" (MSR_IA32_XSS));
+				xss = (hi << 32) | lo;
+			}
+
+			/*
+			 * The PPR and APM aren't clear on what size should be
+			 * encoded in 0xD:0x1:EBX when compaction is not enabled
+			 * by either XSAVEC (feature bit 1) or XSAVES (feature
+			 * bit 3) since SNP-capable hardware has these feature
+			 * bits fixed as 1. KVM sets it to 0 in this case, but
+			 * to avoid this becoming an issue it's safer to simply
+			 * treat this as unsupported for SEV-SNP guests.
+			 */
+			if (!(*eax & (BIT(1) | BIT(3))))
+				return -EINVAL;
+
+			compacted = true;
+		}
+
+		if (snp_cpuid_calc_xsave_size(xcr0 | xss, *ebx, &xsave_size,
+					      compacted))
+			return -EINVAL;
+
+		*ebx = xsave_size;
+		}
+		break;
+	case 0x8000001E:
+		/* extended APIC ID */
+		snp_cpuid_hv(func, subfunc, eax, &ebx2, &ecx2, NULL);
+		/* compute ID */
+		*ebx = (*ebx & GENMASK(31, 8)) | (ebx2 & GENMASK(7, 0));
+		/* node ID */
+		*ecx = (*ecx & GENMASK(31, 8)) | (ecx2 & GENMASK(7, 0));
+		break;
+	default:
+		/* No fix-ups needed, use values as-is. */
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * Returns -EOPNOTSUPP if feature not enabled. Any other return value should be
+ * treated as fatal by caller.
+ */
+static int snp_cpuid(u32 func, u32 subfunc, u32 *eax, u32 *ebx, u32 *ecx,
+		     u32 *edx)
+{
+	if (!snp_cpuid_active())
+		return -EOPNOTSUPP;
+
+	if (!snp_cpuid_find_validated_func(func, subfunc, eax, ebx, ecx, edx)) {
+		/*
+		 * Some hypervisors will avoid keeping track of CPUID entries
+		 * where all values are zero, since they can be handled the
+		 * same as out-of-range values (all-zero). This is useful here
+		 * as well as it allows virtually all guest configurations to
+		 * work using a single SEV-SNP CPUID table.
+		 *
+		 * To allow for this, there is a need to distinguish between
+		 * out-of-range entries and in-range zero entries, since the
+		 * CPUID table entries are only a template that may need to be
+		 * augmented with additional values for things like
+		 * CPU-specific information during post-processing. So if it's
+		 * not in the table, but is still in the valid range, proceed
+		 * with the post-processing. Otherwise, just return zeros.
+		 */
+		*eax = *ebx = *ecx = *edx = 0;
+		if (!snp_cpuid_check_range(func))
+			return 0;
+	}
+
+	return snp_cpuid_postprocess(func, subfunc, eax, ebx, ecx, edx);
+}
+
 /*
  * Boot VC Handler - This is the first VC handler during boot, there is no GHCB
  * page yet, so it only supports the MSR based communication with the
@@ -263,16 +550,26 @@ static int sev_cpuid_hv(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
  */
 void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 {
+	unsigned int subfn = lower_bits(regs->cx, 32);
 	unsigned int fn = lower_bits(regs->ax, 32);
 	u32 eax, ebx, ecx, edx;
+	int ret;
 
 	/* Only CPUID is supported via MSR protocol */
 	if (exit_code != SVM_EXIT_CPUID)
 		goto fail;
 
+	ret = snp_cpuid(fn, subfn, &eax, &ebx, &ecx, &edx);
+	if (ret == 0)
+		goto cpuid_done;
+
+	if (ret != -EOPNOTSUPP)
+		goto fail;
+
 	if (sev_cpuid_hv(fn, 0, &eax, &ebx, &ecx, &edx))
 		goto fail;
 
+cpuid_done:
 	regs->ax = eax;
 	regs->bx = ebx;
 	regs->cx = ecx;
@@ -567,12 +864,35 @@ static enum es_result vc_handle_ioio(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
 	return ret;
 }
 
+static int vc_handle_cpuid_snp(struct pt_regs *regs)
+{
+	u32 eax, ebx, ecx, edx;
+	int ret;
+
+	ret = snp_cpuid(regs->ax, regs->cx, &eax, &ebx, &ecx, &edx);
+	if (ret == 0) {
+		regs->ax = eax;
+		regs->bx = ebx;
+		regs->cx = ecx;
+		regs->dx = edx;
+	}
+
+	return ret;
+}
+
 static enum es_result vc_handle_cpuid(struct ghcb *ghcb,
 				      struct es_em_ctxt *ctxt)
 {
 	struct pt_regs *regs = ctxt->regs;
 	u32 cr4 = native_read_cr4();
 	enum es_result ret;
+	int snp_cpuid_ret;
+
+	snp_cpuid_ret = vc_handle_cpuid_snp(regs);
+	if (snp_cpuid_ret == 0)
+		return ES_OK;
+	if (snp_cpuid_ret != -EOPNOTSUPP)
+		return ES_VMM_ERROR;
 
 	ghcb_set_rax(ghcb, regs->ax);
 	ghcb_set_rcx(ghcb, regs->cx);
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index e966b93212c7..403ae5cddbe8 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -33,6 +33,7 @@
 #include <asm/smp.h>
 #include <asm/cpu.h>
 #include <asm/apic.h>
+#include <asm/cpuid.h>
 
 #define DR7_RESET_VALUE        0x400
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 35/45] x86/boot: add a pointer to Confidential Computing blob in bootparams
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (33 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 34/45] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 36/45] x86/compressed: add SEV-SNP feature detection/setup Brijesh Singh
                   ` (10 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

The previously defined Confidential Computing blob is provided to the
kernel via a setup_data structure or EFI config table entry. Currently
these are both checked for by boot/compressed kernel to access the
CPUID table address within it for use with SEV-SNP CPUID enforcement.

To also enable SEV-SNP CPUID enforcement for the run-time kernel,
similar early access to the CPUID table is needed early on while it's
still using the identity-mapped page table set up by boot/compressed,
where global pointers need to be accessed via fixup_pointer().

This isn't much of an issue for accessing setup_data, and the EFI
config table helper code currently used in boot/compressed *could* be
used in this case as well since they both rely on identity-mapping.
However, it has some reliance on EFI helpers/string constants that
would need to be accessed via fixup_pointer(), and fixing it up while
making it shareable between boot/compressed and run-time kernel is
fragile and introduces a good bit of uglyness.

Instead, add a boot_params->cc_blob_address pointer that the
boot/compressed kernel can initialize so that the run-time kernel can
access the CC blob from there instead of re-scanning the EFI config
table.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/bootparam_utils.h | 1 +
 arch/x86/include/uapi/asm/bootparam.h  | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
index 981fe923a59f..53e9b0620d96 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -74,6 +74,7 @@ static void sanitize_boot_params(struct boot_params *boot_params)
 			BOOT_PARAM_PRESERVE(hdr),
 			BOOT_PARAM_PRESERVE(e820_table),
 			BOOT_PARAM_PRESERVE(eddbuf),
+			BOOT_PARAM_PRESERVE(cc_blob_address),
 		};
 
 		memset(&scratch, 0, sizeof(scratch));
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 1ac5acca72ce..bea5cdcdf532 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -188,7 +188,8 @@ struct boot_params {
 	__u32 ext_ramdisk_image;			/* 0x0c0 */
 	__u32 ext_ramdisk_size;				/* 0x0c4 */
 	__u32 ext_cmd_line_ptr;				/* 0x0c8 */
-	__u8  _pad4[116];				/* 0x0cc */
+	__u8  _pad4[112];				/* 0x0cc */
+	__u32 cc_blob_address;				/* 0x13c */
 	struct edid_info edid_info;			/* 0x140 */
 	struct efi_info efi_info;			/* 0x1c0 */
 	__u32 alt_mem_k;				/* 0x1e0 */
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 36/45] x86/compressed: add SEV-SNP feature detection/setup
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (34 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 35/45] x86/boot: add a pointer to Confidential Computing blob in bootparams Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 37/45] x86/compressed: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
                   ` (9 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

Initial/preliminary detection of SEV-SNP is done via the Confidential
Computing blob. Check for it prior to the normal SEV/SME feature
initialization, and add some sanity checks to confirm it agrees with
SEV-SNP CPUID/MSR bits.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c | 90 +++++++++++++++++++++++++++++++++-
 arch/x86/include/asm/sev.h     | 13 +++++
 arch/x86/kernel/sev-shared.c   | 34 +++++++++++++
 3 files changed, 136 insertions(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 2d9db9dc149b..a41e7d29f328 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -305,6 +305,13 @@ static inline u64 rd_sev_status_msr(void)
 void sev_enable(struct boot_params *bp)
 {
 	unsigned int eax, ebx, ecx, edx;
+	bool snp;
+
+	/*
+	 * Setup/preliminary detection of SEV-SNP. This will be sanity-checked
+	 * against CPUID/MSR values later.
+	 */
+	snp = snp_init(bp);
 
 	/* Check for the SME/SEV support leaf */
 	eax = 0x80000000;
@@ -325,14 +332,95 @@ void sev_enable(struct boot_params *bp)
 	ecx = 0;
 	native_cpuid(&eax, &ebx, &ecx, &edx);
 	/* Check whether SEV is supported */
-	if (!(eax & BIT(1)))
+	if (!(eax & BIT(1))) {
+		if (snp)
+			error("SEV-SNP support indicated by CC blob, but not CPUID.");
 		return;
+	}
 
 	/* Check the SEV MSR whether SEV or SME is enabled */
 	sev_status   = rd_sev_status_msr();
 
 	if (!(sev_status & MSR_AMD64_SEV_ENABLED))
 		error("SEV support indicated by CPUID, but not SEV status MSR.");
+	if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
+		error("SEV-SNP supported indicated by CC blob, but not SEV status MSR.");
 
 	sme_me_mask = 1UL << (ebx & 0x3f);
 }
+
+/* Search for Confidential Computing blob in the EFI config table. */
+static struct cc_blob_sev_info *snp_find_cc_blob_efi(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+	unsigned long conf_table_pa;
+	unsigned int conf_table_len;
+	bool efi_64;
+	int ret;
+
+	ret = efi_get_conf_table(bp, &conf_table_pa, &conf_table_len, &efi_64);
+	if (ret)
+		return NULL;
+
+	ret = efi_find_vendor_table(conf_table_pa, conf_table_len,
+				    EFI_CC_BLOB_GUID, efi_64,
+				    (unsigned long *)&cc_info);
+	if (ret)
+		return NULL;
+
+	return cc_info;
+}
+
+/*
+ * Initial set up of SEV-SNP relies on information provided by the
+ * Confidential Computing blob, which can be passed to the boot kernel
+ * by firmware/bootloader in the following ways:
+ *
+ * - via an entry in the EFI config table
+ * - via a setup_data structure, as defined by the Linux Boot Protocol
+ *
+ * Scan for the blob in that order.
+ */
+struct cc_blob_sev_info *snp_find_cc_blob(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	cc_info = snp_find_cc_blob_efi(bp);
+	if (cc_info)
+		goto found_cc_info;
+
+	cc_info = snp_find_cc_blob_setup_data(bp);
+	if (!cc_info)
+		return NULL;
+
+found_cc_info:
+	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
+		sev_es_terminate(0, GHCB_SNP_UNSUPPORTED);
+
+	return cc_info;
+}
+
+bool snp_init(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	if (!bp)
+		return false;
+
+	cc_info = snp_find_cc_blob(bp);
+	if (!cc_info)
+		return false;
+
+	/*
+	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
+	 * config table doesn't need to be searched again during early startup
+	 * phase.
+	 */
+	bp->cc_blob_address = (u32)(unsigned long)cc_info;
+
+	/*
+	 * Indicate SEV-SNP based on presence of SEV-SNP-specific CC blob.
+	 * Subsequent checks will verify SEV-SNP CPUID/MSR bits.
+	 */
+	return true;
+}
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index f42fbe3c332f..cd189c20bcc4 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -11,6 +11,7 @@
 #include <linux/types.h>
 #include <asm/insn.h>
 #include <asm/sev-common.h>
+#include <asm/bootparam.h>
 
 #define GHCB_PROTOCOL_MIN	1ULL
 #define GHCB_PROTOCOL_MAX	2ULL
@@ -145,6 +146,17 @@ void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op
 void snp_set_memory_shared(unsigned long vaddr, unsigned int npages);
 void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
 void snp_set_wakeup_secondary_cpu(void);
+bool snp_init(struct boot_params *bp);
+/*
+ * TODO: These are exported only temporarily while boot/compressed/sev.c is
+ * the only user. This is to avoid unused function warnings for kernel/sev.c
+ * during the build of kernel proper.
+ *
+ * Once the code is added to consume these in kernel proper these functions
+ * can be moved back to being statically-scoped to units that pull in
+ * sev-shared.c via #include and these declarations can be dropped.
+ */
+struct cc_blob_sev_info *snp_find_cc_blob_setup_data(struct boot_params *bp);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -162,6 +174,7 @@ static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz,
 static inline void snp_set_memory_shared(unsigned long vaddr, unsigned int npages) { }
 static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npages) { }
 static inline void snp_set_wakeup_secondary_cpu(void) { }
+static inline bool snp_init(struct boot_params *bp) { return false; }
 #endif
 
 #endif
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index b1ed5a1b1a90..05cb88fa1437 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -944,3 +944,37 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb,
 
 	return ES_OK;
 }
+
+struct cc_setup_data {
+	struct setup_data header;
+	u32 cc_blob_address;
+};
+
+static struct cc_setup_data *get_cc_setup_data(struct boot_params *bp)
+{
+	struct setup_data *hdr = (struct setup_data *)bp->hdr.setup_data;
+
+	while (hdr) {
+		if (hdr->type == SETUP_CC_BLOB)
+			return (struct cc_setup_data *)hdr;
+		hdr = (struct setup_data *)hdr->next;
+	}
+
+	return NULL;
+}
+
+/*
+ * Search for a Confidential Computing blob passed in as a setup_data entry
+ * via the Linux Boot Protocol.
+ */
+struct cc_blob_sev_info *
+snp_find_cc_blob_setup_data(struct boot_params *bp)
+{
+	struct cc_setup_data *sd;
+
+	sd = get_cc_setup_data(bp);
+	if (!sd)
+		return NULL;
+
+	return (struct cc_blob_sev_info *)(unsigned long)sd->cc_blob_address;
+}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 37/45] x86/compressed: use firmware-validated CPUID for SEV-SNP guests
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (35 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 36/45] x86/compressed: add SEV-SNP feature detection/setup Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 38/45] x86/compressed/64: add identity mapping for Confidential Computing blob Brijesh Singh
                   ` (8 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

SEV-SNP guests will be provided the location of special 'secrets'
'CPUID' pages via the Confidential Computing blob. This blob is
provided to the boot kernel either through an EFI config table entry,
or via a setup_data structure as defined by the Linux Boot Protocol.

Locate the Confidential Computing from these sources and, if found,
use the provided CPUID page/table address to create a copy that the
boot kernel will use when servicing cpuid instructions via a #VC
handler.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c | 13 +++++++++
 arch/x86/include/asm/sev.h     |  1 +
 arch/x86/kernel/sev-shared.c   | 48 ++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index a41e7d29f328..d109ec982961 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -411,6 +411,19 @@ bool snp_init(struct boot_params *bp)
 	if (!cc_info)
 		return false;
 
+	/*
+	 * If SEV-SNP-specific Confidential Computing blob is present, then
+	 * firmware/bootloader have indicated SEV-SNP support. Verifying this
+	 * involves CPUID checks which will be more reliable if the SEV-SNP
+	 * CPUID table is used. See comments for snp_cpuid_info_create() for
+	 * more details.
+	 */
+	snp_cpuid_info_create(cc_info);
+
+	/* SEV-SNP CPUID table should be set up now. */
+	if (!snp_cpuid_active())
+		sev_es_terminate(1, GHCB_TERM_CPUID);
+
 	/*
 	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
 	 * config table doesn't need to be searched again during early startup
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index cd189c20bcc4..b6a97863b71f 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -157,6 +157,7 @@ bool snp_init(struct boot_params *bp);
  * sev-shared.c via #include and these declarations can be dropped.
  */
 struct cc_blob_sev_info *snp_find_cc_blob_setup_data(struct boot_params *bp);
+void __init snp_cpuid_info_create(const struct cc_blob_sev_info *cc_info);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 05cb88fa1437..4189d2808ff4 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -65,6 +65,11 @@ static u64 sev_hv_features __ro_after_init;
 static struct snp_cpuid_info cpuid_info_copy __ro_after_init;
 static bool snp_cpuid_initialized __ro_after_init;
 
+/* Copy of the SNP firmware's CPUID page. */
+static struct snp_cpuid_info cpuid_info_copy __ro_after_init;
+
+static bool snp_cpuid_initialized __ro_after_init;
+
 /*
  * These will be initialized based on CPUID table so that non-present
  * all-zero leaves (for sparse tables) can be differentiated from
@@ -413,6 +418,23 @@ snp_cpuid_find_validated_func(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
 	return false;
 }
 
+static void __init snp_cpuid_set_ranges(void)
+{
+	const struct snp_cpuid_info *cpuid_info = snp_cpuid_info_get_ptr();
+	int i;
+
+	for (i = 0; i < cpuid_info->count; i++) {
+		const struct snp_cpuid_fn *fn = &cpuid_info->fn[i];
+
+		if (fn->eax_in == 0x0)
+			cpuid_std_range_max = fn->eax;
+		else if (fn->eax_in == 0x40000000)
+			cpuid_hyp_range_max = fn->eax;
+		else if (fn->eax_in == 0x80000000)
+			cpuid_ext_range_max = fn->eax;
+	}
+}
+
 static bool snp_cpuid_check_range(u32 func)
 {
 	if (func <= cpuid_std_range_max ||
@@ -978,3 +1000,29 @@ snp_find_cc_blob_setup_data(struct boot_params *bp)
 
 	return (struct cc_blob_sev_info *)(unsigned long)sd->cc_blob_address;
 }
+
+/*
+ * Initialize the kernel's copy of the SEV-SNP CPUID table, and set up the
+ * pointer that will be used to access it.
+ *
+ * Maintaining a direct mapping of the SEV-SNP CPUID table used by firmware
+ * would be possible as an alternative, but the approach is brittle since the
+ * mapping needs to be updated in sync with all the changes to virtual memory
+ * layout and related mapping facilities throughout the boot process.
+ */
+void __init snp_cpuid_info_create(const struct cc_blob_sev_info *cc_info)
+{
+	const struct snp_cpuid_info *cpuid_info_fw, *cpuid_info;
+
+	if (!cc_info || !cc_info->cpuid_phys || cc_info->cpuid_len < PAGE_SIZE)
+		sev_es_terminate(1, GHCB_TERM_CPUID);
+
+	cpuid_info_fw = (const struct snp_cpuid_info *)cc_info->cpuid_phys;
+	if (!cpuid_info_fw->count || cpuid_info_fw->count > SNP_CPUID_COUNT_MAX)
+		sev_es_terminate(1, GHCB_TERM_CPUID);
+
+	cpuid_info = snp_cpuid_info_get_ptr();
+	memcpy((void *)cpuid_info, cpuid_info_fw, sizeof(*cpuid_info));
+	snp_cpuid_initialized = true;
+	snp_cpuid_set_ranges();
+}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 38/45] x86/compressed/64: add identity mapping for Confidential Computing blob
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (36 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 37/45] x86/compressed: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 39/45] x86/sev: add SEV-SNP feature detection/setup Brijesh Singh
                   ` (7 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

The run-time kernel will need to access the Confidential Computing
blob very early in boot to access the CPUID table it points to. At
that stage of boot it will be relying on the identity-mapped page table
set up by boot/compressed kernel, so make sure the blob and the CPUID
table it points to are mapped in advance.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/ident_map_64.c | 26 ++++++++++++++++++++++++-
 arch/x86/boot/compressed/misc.h         |  4 ++++
 arch/x86/boot/compressed/sev.c          |  2 +-
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index 3cf7a7575f5c..10ecbc53f8bc 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -37,6 +37,8 @@
 #include <asm/setup.h>	/* For COMMAND_LINE_SIZE */
 #undef _SETUP
 
+#include <asm/sev.h> /* For ConfidentialComputing blob */
+
 extern unsigned long get_cmd_line_ptr(void);
 
 /* Used by PAGE_KERN* macros: */
@@ -106,6 +108,27 @@ static void add_identity_map(unsigned long start, unsigned long end)
 		error("Error: kernel_ident_mapping_init() failed\n");
 }
 
+void sev_prep_identity_maps(void)
+{
+	/*
+	 * The ConfidentialComputing blob is used very early in uncompressed
+	 * kernel to find the in-memory cpuid table to handle cpuid
+	 * instructions. Make sure an identity-mapping exists so it can be
+	 * accessed after switchover.
+	 */
+	if (sev_snp_enabled()) {
+		struct cc_blob_sev_info *cc_info =
+			(void *)(unsigned long)boot_params->cc_blob_address;
+
+		add_identity_map((unsigned long)cc_info,
+				 (unsigned long)cc_info + sizeof(*cc_info));
+		add_identity_map((unsigned long)cc_info->cpuid_phys,
+				 (unsigned long)cc_info->cpuid_phys + cc_info->cpuid_len);
+	}
+
+	sev_verify_cbit(top_level_pgt);
+}
+
 /* Locates and clears a region for a new top level page table. */
 void initialize_identity_maps(void *rmode)
 {
@@ -163,8 +186,9 @@ void initialize_identity_maps(void *rmode)
 	cmdline = get_cmd_line_ptr();
 	add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);
 
+	sev_prep_identity_maps();
+
 	/* Load the new page-table. */
-	sev_verify_cbit(top_level_pgt);
 	write_cr3(top_level_pgt);
 }
 
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index bb2e884467db..61abcb885f5c 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -127,6 +127,8 @@ void sev_es_shutdown_ghcb(void);
 extern bool sev_es_check_ghcb_fault(unsigned long address);
 void snp_set_page_private(unsigned long paddr);
 void snp_set_page_shared(unsigned long paddr);
+bool sev_snp_enabled(void);
+
 #else
 static inline void sev_enable(struct boot_params *bp) { }
 static inline void sev_es_shutdown_ghcb(void) { }
@@ -136,6 +138,8 @@ static inline bool sev_es_check_ghcb_fault(unsigned long address)
 }
 static inline void snp_set_page_private(unsigned long paddr) { }
 static inline void snp_set_page_shared(unsigned long paddr) { }
+static inline bool sev_snp_enabled(void) { return false; }
+
 #endif
 
 /* acpi.c */
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index d109ec982961..d24ea53f997f 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -120,7 +120,7 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 /* Include code for early handlers */
 #include "../../kernel/sev-shared.c"
 
-static inline bool sev_snp_enabled(void)
+bool sev_snp_enabled(void)
 {
 	return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
 }
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 39/45] x86/sev: add SEV-SNP feature detection/setup
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (37 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 38/45] x86/compressed/64: add identity mapping for Confidential Computing blob Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 40/45] x86/sev: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
                   ` (6 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

Initial/preliminary detection of SEV-SNP is done via the Confidential
Computing blob. Check for it prior to the normal SEV/SME feature
initialization, and add some sanity checks to confirm it agrees with
SEV-SNP CPUID/MSR bits.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h         |  3 +-
 arch/x86/kernel/sev-shared.c       |  2 +-
 arch/x86/kernel/sev.c              | 65 ++++++++++++++++++++++++++++++
 arch/x86/mm/mem_encrypt_identity.c |  8 ++++
 4 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index b6a97863b71f..2c382533aeea 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -147,6 +147,7 @@ void snp_set_memory_shared(unsigned long vaddr, unsigned int npages);
 void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
 void snp_set_wakeup_secondary_cpu(void);
 bool snp_init(struct boot_params *bp);
+void snp_abort(void);
 /*
  * TODO: These are exported only temporarily while boot/compressed/sev.c is
  * the only user. This is to avoid unused function warnings for kernel/sev.c
@@ -156,7 +157,6 @@ bool snp_init(struct boot_params *bp);
  * can be moved back to being statically-scoped to units that pull in
  * sev-shared.c via #include and these declarations can be dropped.
  */
-struct cc_blob_sev_info *snp_find_cc_blob_setup_data(struct boot_params *bp);
 void __init snp_cpuid_info_create(const struct cc_blob_sev_info *cc_info);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
@@ -176,6 +176,7 @@ static inline void snp_set_memory_shared(unsigned long vaddr, unsigned int npage
 static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npages) { }
 static inline void snp_set_wakeup_secondary_cpu(void) { }
 static inline bool snp_init(struct boot_params *bp) { return false; }
+static inline void snp_abort(void) { }
 #endif
 
 #endif
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 4189d2808ff4..d91b61061b1d 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -989,7 +989,7 @@ static struct cc_setup_data *get_cc_setup_data(struct boot_params *bp)
  * Search for a Confidential Computing blob passed in as a setup_data entry
  * via the Linux Boot Protocol.
  */
-struct cc_blob_sev_info *
+static struct cc_blob_sev_info *
 snp_find_cc_blob_setup_data(struct boot_params *bp)
 {
 	struct cc_setup_data *sd;
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 403ae5cddbe8..b794606c7ab2 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2010,3 +2010,68 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 	while (true)
 		halt();
 }
+
+/*
+ * Initial set up of SEV-SNP relies on information provided by the
+ * Confidential Computing blob, which can be passed to the kernel
+ * in the following ways, depending on how it is booted:
+ *
+ * - when booted via the boot/decompress kernel:
+ *   - via boot_params
+ *
+ * - when booted directly by firmware/bootloader (e.g. CONFIG_PVH):
+ *   - via a setup_data entry, as defined by the Linux Boot Protocol
+ *
+ * Scan for the blob in that order.
+ */
+struct cc_blob_sev_info *snp_find_cc_blob(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	/* Boot kernel would have passed the CC blob via boot_params. */
+	if (bp->cc_blob_address) {
+		cc_info = (struct cc_blob_sev_info *)
+			  (unsigned long)bp->cc_blob_address;
+		goto found_cc_info;
+	}
+
+	/*
+	 * If kernel was booted directly, without the use of the
+	 * boot/decompression kernel, the CC blob may have been passed via
+	 * setup_data instead.
+	 */
+	cc_info = snp_find_cc_blob_setup_data(bp);
+	if (!cc_info)
+		return NULL;
+
+found_cc_info:
+	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
+		sev_es_terminate(1, GHCB_SNP_UNSUPPORTED);
+
+	return cc_info;
+}
+
+bool __init snp_init(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	if (!bp)
+		return false;
+
+	cc_info = snp_find_cc_blob(bp);
+	if (!cc_info)
+		return false;
+
+	/*
+	 * The CC blob will be used later to access the secrets page. Cache
+	 * it here like the boot kernel does.
+	 */
+	bp->cc_blob_address = (u32)(unsigned long)cc_info;
+
+	return true;
+}
+
+void __init snp_abort(void)
+{
+	sev_es_terminate(1, GHCB_SNP_UNSUPPORTED);
+}
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index 3f0abb403340..2f723e106ed3 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -44,6 +44,7 @@
 #include <asm/setup.h>
 #include <asm/sections.h>
 #include <asm/cmdline.h>
+#include <asm/sev.h>
 
 #include "mm_internal.h"
 
@@ -508,8 +509,11 @@ void __init sme_enable(struct boot_params *bp)
 	bool active_by_default;
 	unsigned long me_mask;
 	char buffer[16];
+	bool snp;
 	u64 msr;
 
+	snp = snp_init(bp);
+
 	/* Check for the SME/SEV support leaf */
 	eax = 0x80000000;
 	ecx = 0;
@@ -541,6 +545,10 @@ void __init sme_enable(struct boot_params *bp)
 	sev_status   = __rdmsr(MSR_AMD64_SEV);
 	feature_mask = (sev_status & MSR_AMD64_SEV_ENABLED) ? AMD_SEV_BIT : AMD_SME_BIT;
 
+	/* The SEV-SNP CC blob should never be present unless SEV-SNP is enabled. */
+	if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
+		snp_abort();
+
 	/* Check if memory encryption is enabled */
 	if (feature_mask == AMD_SME_BIT) {
 		/*
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 40/45] x86/sev: use firmware-validated CPUID for SEV-SNP guests
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (38 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 39/45] x86/sev: add SEV-SNP feature detection/setup Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 41/45] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
                   ` (5 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

From: Michael Roth <michael.roth@amd.com>

SEV-SNP guests will be provided the location of special 'secrets' and
'CPUID' pages via the Confidential Computing blob. This blob is
provided to the run-time kernel either through bootparams field that
was initialized by the boot/compressed kernel, or via a setup_data
structure as defined by the Linux Boot Protocol.

Locate the Confidential Computing from these sources and, if found,
use the provided CPUID page/table address to create a copy that the
run-time kernel will use when servicing cpuid instructions via a #VC
handler.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h   | 10 ----------
 arch/x86/kernel/sev-shared.c |  2 +-
 arch/x86/kernel/sev.c        | 37 ++++++++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 2c382533aeea..76a208fd451b 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -148,16 +148,6 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
 void snp_set_wakeup_secondary_cpu(void);
 bool snp_init(struct boot_params *bp);
 void snp_abort(void);
-/*
- * TODO: These are exported only temporarily while boot/compressed/sev.c is
- * the only user. This is to avoid unused function warnings for kernel/sev.c
- * during the build of kernel proper.
- *
- * Once the code is added to consume these in kernel proper these functions
- * can be moved back to being statically-scoped to units that pull in
- * sev-shared.c via #include and these declarations can be dropped.
- */
-void __init snp_cpuid_info_create(const struct cc_blob_sev_info *cc_info);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index d91b61061b1d..ce06cb7c8ed0 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -1010,7 +1010,7 @@ snp_find_cc_blob_setup_data(struct boot_params *bp)
  * mapping needs to be updated in sync with all the changes to virtual memory
  * layout and related mapping facilities throughout the boot process.
  */
-void __init snp_cpuid_info_create(const struct cc_blob_sev_info *cc_info)
+static void __init snp_cpuid_info_create(const struct cc_blob_sev_info *cc_info)
 {
 	const struct snp_cpuid_info *cpuid_info_fw, *cpuid_info;
 
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index b794606c7ab2..5d17f665124a 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2062,6 +2062,12 @@ bool __init snp_init(struct boot_params *bp)
 	if (!cc_info)
 		return false;
 
+	snp_cpuid_info_create(cc_info);
+
+	/* SEV-SNP CPUID table is set up now. Do some sanity checks. */
+	if (!snp_cpuid_active())
+		sev_es_terminate(1, GHCB_TERM_CPUID);
+
 	/*
 	 * The CC blob will be used later to access the secrets page. Cache
 	 * it here like the boot kernel does.
@@ -2075,3 +2081,34 @@ void __init snp_abort(void)
 {
 	sev_es_terminate(1, GHCB_SNP_UNSUPPORTED);
 }
+
+/*
+ * It is useful from an auditing/testing perspective to provide an easy way
+ * for the guest owner to know that the CPUID table has been initialized as
+ * expected, but that initialization happens too early in boot to print any
+ * sort of indicator, and there's not really any other good place to do it. So
+ * do it here, and while at it, go ahead and re-verify that nothing strange has
+ * happened between early boot and now.
+ */
+static int __init snp_cpuid_check_status(void)
+{
+	const struct snp_cpuid_info *cpuid_info = snp_cpuid_info_get_ptr();
+
+	if (!cc_platform_has(CC_ATTR_SEV_SNP)) {
+		/* Firmware should not have advertised the feature. */
+		if (snp_cpuid_active())
+			panic("Invalid use of SEV-SNP CPUID table.");
+		return 0;
+	}
+
+	/* CPUID table should always be available when SEV-SNP is enabled. */
+	if (!snp_cpuid_active())
+		sev_es_terminate(1, GHCB_TERM_CPUID);
+
+	pr_info("Using SEV-SNP CPUID table, %d entries present.\n",
+		cpuid_info->count);
+
+	return 0;
+}
+
+arch_initcall(snp_cpuid_check_status);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 41/45] x86/sev: Provide support for SNP guest request NAEs
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (39 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 40/45] x86/sev: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 42/45] x86/sev: Register SNP guest request platform device Brijesh Singh
                   ` (4 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

Version 2 of GHCB specification provides SNP_GUEST_REQUEST and
SNP_EXT_GUEST_REQUEST NAE that can be used by the SNP guest to communicate
with the PSP.

While at it, add a snp_issue_guest_request() helper that can be used by
driver or other subsystem to issue the request to PSP.

See SEV-SNP and GHCB spec for more details.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev-common.h |  3 ++
 arch/x86/include/asm/sev.h        | 14 +++++++++
 arch/x86/include/uapi/asm/svm.h   |  4 +++
 arch/x86/kernel/sev.c             | 51 +++++++++++++++++++++++++++++++
 4 files changed, 72 insertions(+)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 45c535eb75f1..cf66600b1c68 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -128,6 +128,9 @@ struct snp_psc_desc {
 	struct psc_entry entries[VMGEXIT_PSC_MAX_ENTRY];
 } __packed;
 
+/* Guest message request error code */
+#define SNP_GUEST_REQ_INVALID_LEN	BIT_ULL(32)
+
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 76a208fd451b..a47fa0f2547e 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -81,6 +81,14 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
 
 #define RMPADJUST_VMSA_PAGE_BIT		BIT(16)
 
+/* SNP Guest message request */
+struct snp_req_data {
+	unsigned long req_gpa;
+	unsigned long resp_gpa;
+	unsigned long data_gpa;
+	unsigned int data_npages;
+};
+
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 extern struct static_key_false sev_es_enable_key;
 extern void __sev_es_ist_enter(struct pt_regs *regs);
@@ -148,6 +156,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
 void snp_set_wakeup_secondary_cpu(void);
 bool snp_init(struct boot_params *bp);
 void snp_abort(void);
+int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -167,6 +176,11 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npag
 static inline void snp_set_wakeup_secondary_cpu(void) { }
 static inline bool snp_init(struct boot_params *bp) { return false; }
 static inline void snp_abort(void) { }
+static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input,
+					  unsigned long *fw_err)
+{
+	return -ENOTTY;
+}
 #endif
 
 #endif
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index 8b4c57baec52..5b8bc2b65a5e 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -109,6 +109,8 @@
 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE		0
 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE		1
 #define SVM_VMGEXIT_PSC				0x80000010
+#define SVM_VMGEXIT_GUEST_REQUEST		0x80000011
+#define SVM_VMGEXIT_EXT_GUEST_REQUEST		0x80000012
 #define SVM_VMGEXIT_AP_CREATION			0x80000013
 #define SVM_VMGEXIT_AP_CREATE_ON_INIT		0
 #define SVM_VMGEXIT_AP_CREATE			1
@@ -225,6 +227,8 @@
 	{ SVM_VMGEXIT_AP_HLT_LOOP,	"vmgexit_ap_hlt_loop" }, \
 	{ SVM_VMGEXIT_AP_JUMP_TABLE,	"vmgexit_ap_jump_table" }, \
 	{ SVM_VMGEXIT_PSC,	"vmgexit_page_state_change" }, \
+	{ SVM_VMGEXIT_GUEST_REQUEST,		"vmgexit_guest_request" }, \
+	{ SVM_VMGEXIT_EXT_GUEST_REQUEST,	"vmgexit_ext_guest_request" }, \
 	{ SVM_VMGEXIT_AP_CREATION,	"vmgexit_ap_creation" }, \
 	{ SVM_VMGEXIT_HV_FEATURES,	"vmgexit_hypervisor_feature" }, \
 	{ SVM_EXIT_ERR,         "invalid_guest_state" }
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 5d17f665124a..0faf8d749d48 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2112,3 +2112,54 @@ static int __init snp_cpuid_check_status(void)
 }
 
 arch_initcall(snp_cpuid_check_status);
+
+int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err)
+{
+	struct ghcb_state state;
+	unsigned long flags;
+	struct ghcb *ghcb;
+	int ret;
+
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return -ENODEV;
+
+	/* __sev_get_ghcb() need to run with IRQs disabled because it using per-cpu GHCB */
+	local_irq_save(flags);
+
+	ghcb = __sev_get_ghcb(&state);
+	if (!ghcb) {
+		ret = -EIO;
+		goto e_restore_irq;
+	}
+
+	vc_ghcb_invalidate(ghcb);
+
+	if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
+		ghcb_set_rax(ghcb, input->data_gpa);
+		ghcb_set_rbx(ghcb, input->data_npages);
+	}
+
+	ret = sev_es_ghcb_hv_call(ghcb, true, NULL, exit_code, input->req_gpa, input->resp_gpa);
+	if (ret)
+		goto e_put;
+
+	if (ghcb->save.sw_exit_info_2) {
+		/* Number of expected pages are returned in RBX */
+		if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST &&
+		    ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN)
+			input->data_npages = ghcb_get_rbx(ghcb);
+
+		if (fw_err)
+			*fw_err = ghcb->save.sw_exit_info_2;
+
+		ret = -EIO;
+	}
+
+e_put:
+	__sev_put_ghcb(&state);
+e_restore_irq:
+	local_irq_restore(flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snp_issue_guest_request);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 42/45] x86/sev: Register SNP guest request platform device
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (40 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 41/45] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:07 ` [PATCH v7 43/45] virt: Add SEV-SNP guest driver Brijesh Singh
                   ` (3 subsequent siblings)
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

Version 2 of GHCB specification provides Non Automatic Exit (NAE) that can
be used by the SNP guest to communicate with the PSP without risk from a
malicious hypervisor who wishes to read, alter, drop or replay the messages
sent.

SNP_LAUNCH_UPDATE can insert two special pages into the guest’s memory:
the secrets page and the CPUID page. The PSP firmware populate the contents
of the secrets page. The secrets page contains encryption keys used by the
guest to interact with the firmware. Because the secrets page is encrypted
with the guest’s memory encryption key, the hypervisor cannot read the keys.
See SNP FW ABI spec for further details about the secrets page.

Create a platform device that the SNP guest driver can bind to get the
platform resources such as encryption key and message id to use to
communicate with the PSP. The SNP guest driver provides a userspace
interface to get the attestation report, key derivation, extended
attestation report etc.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/sev.h |  4 +++
 arch/x86/kernel/sev.c      | 61 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index a47fa0f2547e..7a5934af9d47 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -89,6 +89,10 @@ struct snp_req_data {
 	unsigned int data_npages;
 };
 
+struct snp_guest_platform_data {
+	u64 secrets_gpa;
+};
+
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 extern struct static_key_false sev_es_enable_key;
 extern void __sev_es_ist_enter(struct pt_regs *regs);
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 0faf8d749d48..3568b3303314 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -19,6 +19,9 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/cpumask.h>
+#include <linux/efi.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
 
 #include <asm/cpu_entry_area.h>
 #include <asm/stacktrace.h>
@@ -34,6 +37,7 @@
 #include <asm/cpu.h>
 #include <asm/apic.h>
 #include <asm/cpuid.h>
+#include <asm/setup.h>
 
 #define DR7_RESET_VALUE        0x400
 
@@ -2163,3 +2167,60 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned
 	return ret;
 }
 EXPORT_SYMBOL_GPL(snp_issue_guest_request);
+
+static struct platform_device guest_req_device = {
+	.name		= "snp-guest",
+	.id		= -1,
+};
+
+static u64 get_secrets_page(void)
+{
+	u64 pa_data = boot_params.cc_blob_address;
+	struct cc_blob_sev_info info;
+	void *map;
+
+	/*
+	 * The CC blob contains the address of the secrets page, check if the
+	 * blob is present.
+	 */
+	if (!pa_data)
+		return 0;
+
+	map = early_memremap(pa_data, sizeof(info));
+	memcpy(&info, map, sizeof(info));
+	early_memunmap(map, sizeof(info));
+
+	/* smoke-test the secrets page passed */
+	if (!info.secrets_phys || info.secrets_len != PAGE_SIZE)
+		return 0;
+
+	return info.secrets_phys;
+}
+
+static int __init init_snp_platform_device(void)
+{
+	struct snp_guest_platform_data data;
+	u64 gpa;
+
+	if (!cc_platform_has(CC_ATTR_SEV_SNP))
+		return -ENODEV;
+
+	gpa = get_secrets_page();
+	if (!gpa)
+		return -ENODEV;
+
+	data.secrets_gpa = gpa;
+	if (platform_device_add_data(&guest_req_device, &data, sizeof(data)))
+		goto e_fail;
+
+	if (platform_device_register(&guest_req_device))
+		goto e_fail;
+
+	pr_info("SNP guest platform device initialized.\n");
+	return 0;
+
+e_fail:
+	pr_err("Failed to initialize SNP guest device\n");
+	return -ENODEV;
+}
+device_initcall(init_snp_platform_device);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (41 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 42/45] x86/sev: Register SNP guest request platform device Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-10 22:27   ` Randy Dunlap
  2021-11-17 23:34   ` Peter Gonda
  2021-11-10 22:07 ` [PATCH v7 44/45] virt: sevguest: Add support to derive key Brijesh Singh
                   ` (2 subsequent siblings)
  45 siblings, 2 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

SEV-SNP specification provides the guest a mechanisum to communicate with
the PSP without risk from a malicious hypervisor who wishes to read, alter,
drop or replay the messages sent. The driver uses snp_issue_guest_request()
to issue GHCB SNP_GUEST_REQUEST or SNP_EXT_GUEST_REQUEST NAE events to
submit the request to PSP.

The PSP requires that all communication should be encrypted using key
specified through the platform_data.

The userspace can use SNP_GET_REPORT ioctl() to query the guest
attestation report.

See SEV-SNP spec section Guest Messages for more details.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 Documentation/virt/coco/sevguest.rst  |  77 ++++
 drivers/virt/Kconfig                  |   3 +
 drivers/virt/Makefile                 |   1 +
 drivers/virt/coco/sevguest/Kconfig    |   9 +
 drivers/virt/coco/sevguest/Makefile   |   2 +
 drivers/virt/coco/sevguest/sevguest.c | 601 ++++++++++++++++++++++++++
 drivers/virt/coco/sevguest/sevguest.h |  98 +++++
 include/uapi/linux/sev-guest.h        |  44 ++
 8 files changed, 835 insertions(+)
 create mode 100644 Documentation/virt/coco/sevguest.rst
 create mode 100644 drivers/virt/coco/sevguest/Kconfig
 create mode 100644 drivers/virt/coco/sevguest/Makefile
 create mode 100644 drivers/virt/coco/sevguest/sevguest.c
 create mode 100644 drivers/virt/coco/sevguest/sevguest.h
 create mode 100644 include/uapi/linux/sev-guest.h

diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
new file mode 100644
index 000000000000..002c90946b8a
--- /dev/null
+++ b/Documentation/virt/coco/sevguest.rst
@@ -0,0 +1,77 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===================================================================
+The Definitive SEV Guest API Documentation
+===================================================================
+
+1. General description
+======================
+
+The SEV API is a set of ioctls that are used by the guest or hypervisor
+to get or set certain aspect of the SEV virtual machine. The ioctls belong
+to the following classes:
+
+ - Hypervisor ioctls: These query and set global attributes which affect the
+   whole SEV firmware.  These ioctl are used by platform provision tools.
+
+ - Guest ioctls: These query and set attributes of the SEV virtual machine.
+
+2. API description
+==================
+
+This section describes ioctls that can be used to query or set SEV guests.
+For each ioctl, the following information is provided along with a
+description:
+
+  Technology:
+      which SEV techology provides this ioctl. sev, sev-es, sev-snp or all.
+
+  Type:
+      hypervisor or guest. The ioctl can be used inside the guest or the
+      hypervisor.
+
+  Parameters:
+      what parameters are accepted by the ioctl.
+
+  Returns:
+      the return value.  General error numbers (ENOMEM, EINVAL)
+      are not detailed, but errors with specific meanings are.
+
+The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
+The ioctl accepts struct snp_user_guest_request. The input and output structure is
+specified through the req_data and resp_data field respectively. If the ioctl fails
+to execute due to a firmware error, then fw_err code will be set.
+
+::
+        struct snp_guest_request_ioctl {
+                /* Request and response structure address */
+                __u64 req_data;
+                __u64 resp_data;
+
+                /* firmware error code on failure (see psp-sev.h) */
+                __u64 fw_err;
+        };
+
+2.1 SNP_GET_REPORT
+------------------
+
+:Technology: sev-snp
+:Type: guest ioctl
+:Parameters (in): struct snp_report_req
+:Returns (out): struct snp_report_resp on success, -negative on error
+
+The SNP_GET_REPORT ioctl can be used to query the attestation report from the
+SEV-SNP firmware. The ioctl uses the SNP_GUEST_REQUEST (MSG_REPORT_REQ) command
+provided by the SEV-SNP firmware to query the attestation report.
+
+On success, the snp_report_resp.data will contains the report. The report
+will contain the format described in the SEV-SNP specification. See the SEV-SNP
+specification for further details.
+
+
+Reference
+---------
+
+SEV-SNP and GHCB specification: developer.amd.com/sev
+
+The driver is based on SEV-SNP firmware spec 0.9 and GHCB spec version 2.0.
diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
index 8061e8ef449f..e457e47610d3 100644
--- a/drivers/virt/Kconfig
+++ b/drivers/virt/Kconfig
@@ -36,4 +36,7 @@ source "drivers/virt/vboxguest/Kconfig"
 source "drivers/virt/nitro_enclaves/Kconfig"
 
 source "drivers/virt/acrn/Kconfig"
+
+source "drivers/virt/coco/sevguest/Kconfig"
+
 endif
diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
index 3e272ea60cd9..9c704a6fdcda 100644
--- a/drivers/virt/Makefile
+++ b/drivers/virt/Makefile
@@ -8,3 +8,4 @@ obj-y				+= vboxguest/
 
 obj-$(CONFIG_NITRO_ENCLAVES)	+= nitro_enclaves/
 obj-$(CONFIG_ACRN_HSM)		+= acrn/
+obj-$(CONFIG_SEV_GUEST)		+= coco/sevguest/
diff --git a/drivers/virt/coco/sevguest/Kconfig b/drivers/virt/coco/sevguest/Kconfig
new file mode 100644
index 000000000000..96190919cca8
--- /dev/null
+++ b/drivers/virt/coco/sevguest/Kconfig
@@ -0,0 +1,9 @@
+config SEV_GUEST
+	tristate "AMD SEV Guest driver"
+	default y
+	depends on AMD_MEM_ENCRYPT && CRYPTO_AEAD2
+	help
+	  The driver can be used by the SEV-SNP guest to communicate with the PSP to
+	  request the attestation report and more.
+
+	  If you choose 'M' here, this module will be called sevguest.
diff --git a/drivers/virt/coco/sevguest/Makefile b/drivers/virt/coco/sevguest/Makefile
new file mode 100644
index 000000000000..b1ffb2b4177b
--- /dev/null
+++ b/drivers/virt/coco/sevguest/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_SEV_GUEST) += sevguest.o
diff --git a/drivers/virt/coco/sevguest/sevguest.c b/drivers/virt/coco/sevguest/sevguest.c
new file mode 100644
index 000000000000..982714c1b4ca
--- /dev/null
+++ b/drivers/virt/coco/sevguest/sevguest.c
@@ -0,0 +1,601 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Secure Encrypted Virtualization Nested Paging (SEV-SNP) guest request interface
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/set_memory.h>
+#include <linux/fs.h>
+#include <crypto/aead.h>
+#include <linux/scatterlist.h>
+#include <linux/psp-sev.h>
+#include <uapi/linux/sev-guest.h>
+#include <uapi/linux/psp-sev.h>
+
+#include <asm/svm.h>
+#include <asm/sev.h>
+
+#include "sevguest.h"
+
+#define DEVICE_NAME	"sev-guest"
+#define AAD_LEN		48
+#define MSG_HDR_VER	1
+
+struct snp_guest_crypto {
+	struct crypto_aead *tfm;
+	u8 *iv, *authtag;
+	int iv_len, a_len;
+};
+
+struct snp_guest_dev {
+	struct device *dev;
+	struct miscdevice misc;
+
+	struct snp_guest_crypto *crypto;
+	struct snp_guest_msg *request, *response;
+	struct snp_secrets_page_layout *layout;
+	struct snp_req_data input;
+	u32 *os_area_msg_seqno;
+	u8 *vmpck;
+};
+
+static u32 vmpck_id;
+module_param(vmpck_id, uint, 0444);
+MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
+
+static DEFINE_MUTEX(snp_cmd_mutex);
+
+static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
+{
+	char zero_key[VMPCK_KEY_LEN] = {0};
+
+	if (snp_dev->vmpck)
+		return memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN) == 0;
+
+	return true;
+}
+
+static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
+{
+	memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
+	snp_dev->vmpck = NULL;
+}
+
+static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+	u64 count;
+
+	/* Read the current message sequence counter from secrets pages */
+	count = *snp_dev->os_area_msg_seqno;
+
+	return count + 1;
+}
+
+/* Return a non-zero on success */
+static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+	u64 count = __snp_get_msg_seqno(snp_dev);
+
+	/*
+	 * The message sequence counter for the SNP guest request is a  64-bit
+	 * value but the version 2 of GHCB specification defines a 32-bit storage
+	 * for the it. If the counter exceeds the 32-bit value then return zero.
+	 * The caller should check the return value, but if the caller happen to
+	 * not check the value and use it, then the firmware treats zero as an
+	 * invalid number and will fail the  message request.
+	 */
+	if (count >= UINT_MAX) {
+		pr_err_ratelimited("SNP guest request message sequence counter overflow\n");
+		return 0;
+	}
+
+	return count;
+}
+
+static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+	/*
+	 * The counter is also incremented by the PSP, so increment it by 2
+	 * and save in secrets page.
+	 */
+	*snp_dev->os_area_msg_seqno += 2;
+}
+
+static inline struct snp_guest_dev *to_snp_dev(struct file *file)
+{
+	struct miscdevice *dev = file->private_data;
+
+	return container_of(dev, struct snp_guest_dev, misc);
+}
+
+static struct snp_guest_crypto *init_crypto(struct snp_guest_dev *snp_dev, u8 *key, size_t keylen)
+{
+	struct snp_guest_crypto *crypto;
+
+	crypto = kzalloc(sizeof(*crypto), GFP_KERNEL_ACCOUNT);
+	if (!crypto)
+		return NULL;
+
+	crypto->tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
+	if (IS_ERR(crypto->tfm))
+		goto e_free;
+
+	if (crypto_aead_setkey(crypto->tfm, key, keylen))
+		goto e_free_crypto;
+
+	crypto->iv_len = crypto_aead_ivsize(crypto->tfm);
+	if (crypto->iv_len < 12) {
+		dev_err(snp_dev->dev, "IV length is less than 12.\n");
+		goto e_free_crypto;
+	}
+
+	crypto->iv = kmalloc(crypto->iv_len, GFP_KERNEL_ACCOUNT);
+	if (!crypto->iv)
+		goto e_free_crypto;
+
+	if (crypto_aead_authsize(crypto->tfm) > MAX_AUTHTAG_LEN) {
+		if (crypto_aead_setauthsize(crypto->tfm, MAX_AUTHTAG_LEN)) {
+			dev_err(snp_dev->dev, "failed to set authsize to %d\n", MAX_AUTHTAG_LEN);
+			goto e_free_crypto;
+		}
+	}
+
+	crypto->a_len = crypto_aead_authsize(crypto->tfm);
+	crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT);
+	if (!crypto->authtag)
+		goto e_free_crypto;
+
+	return crypto;
+
+e_free_crypto:
+	crypto_free_aead(crypto->tfm);
+e_free:
+	kfree(crypto->iv);
+	kfree(crypto->authtag);
+	kfree(crypto);
+
+	return NULL;
+}
+
+static void deinit_crypto(struct snp_guest_crypto *crypto)
+{
+	crypto_free_aead(crypto->tfm);
+	kfree(crypto->iv);
+	kfree(crypto->authtag);
+	kfree(crypto);
+}
+
+static int enc_dec_message(struct snp_guest_crypto *crypto, struct snp_guest_msg *msg,
+			   u8 *src_buf, u8 *dst_buf, size_t len, bool enc)
+{
+	struct snp_guest_msg_hdr *hdr = &msg->hdr;
+	struct scatterlist src[3], dst[3];
+	DECLARE_CRYPTO_WAIT(wait);
+	struct aead_request *req;
+	int ret;
+
+	req = aead_request_alloc(crypto->tfm, GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	/*
+	 * AEAD memory operations:
+	 * +------ AAD -------+------- DATA -----+---- AUTHTAG----+
+	 * |  msg header      |  plaintext       |  hdr->authtag  |
+	 * | bytes 30h - 5Fh  |    or            |                |
+	 * |                  |   cipher         |                |
+	 * +------------------+------------------+----------------+
+	 */
+	sg_init_table(src, 3);
+	sg_set_buf(&src[0], &hdr->algo, AAD_LEN);
+	sg_set_buf(&src[1], src_buf, hdr->msg_sz);
+	sg_set_buf(&src[2], hdr->authtag, crypto->a_len);
+
+	sg_init_table(dst, 3);
+	sg_set_buf(&dst[0], &hdr->algo, AAD_LEN);
+	sg_set_buf(&dst[1], dst_buf, hdr->msg_sz);
+	sg_set_buf(&dst[2], hdr->authtag, crypto->a_len);
+
+	aead_request_set_ad(req, AAD_LEN);
+	aead_request_set_tfm(req, crypto->tfm);
+	aead_request_set_callback(req, 0, crypto_req_done, &wait);
+
+	aead_request_set_crypt(req, src, dst, len, crypto->iv);
+	ret = crypto_wait_req(enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req), &wait);
+
+	aead_request_free(req);
+	return ret;
+}
+
+static int __enc_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
+			 void *plaintext, size_t len)
+{
+	struct snp_guest_crypto *crypto = snp_dev->crypto;
+	struct snp_guest_msg_hdr *hdr = &msg->hdr;
+
+	memset(crypto->iv, 0, crypto->iv_len);
+	memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+
+	return enc_dec_message(crypto, msg, plaintext, msg->payload, len, true);
+}
+
+static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
+		       void *plaintext, size_t len)
+{
+	struct snp_guest_crypto *crypto = snp_dev->crypto;
+	struct snp_guest_msg_hdr *hdr = &msg->hdr;
+
+	/* Build IV with response buffer sequence number */
+	memset(crypto->iv, 0, crypto->iv_len);
+	memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+
+	return enc_dec_message(crypto, msg, msg->payload, plaintext, len, false);
+}
+
+static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
+{
+	struct snp_guest_crypto *crypto = snp_dev->crypto;
+	struct snp_guest_msg *resp = snp_dev->response;
+	struct snp_guest_msg *req = snp_dev->request;
+	struct snp_guest_msg_hdr *req_hdr = &req->hdr;
+	struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+
+	dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
+		resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
+
+	/* Verify that the sequence counter is incremented by 1 */
+	if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
+		return -EBADMSG;
+
+	/* Verify response message type and version number. */
+	if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
+	    resp_hdr->msg_version != req_hdr->msg_version)
+		return -EBADMSG;
+
+	/*
+	 * If the message size is greater than our buffer length then return
+	 * an error.
+	 */
+	if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
+		return -EBADMSG;
+
+	/* Decrypt the payload */
+	return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
+}
+
+static bool enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
+			void *payload, size_t sz)
+{
+	struct snp_guest_msg *req = snp_dev->request;
+	struct snp_guest_msg_hdr *hdr = &req->hdr;
+
+	memset(req, 0, sizeof(*req));
+
+	hdr->algo = SNP_AEAD_AES_256_GCM;
+	hdr->hdr_version = MSG_HDR_VER;
+	hdr->hdr_sz = sizeof(*hdr);
+	hdr->msg_type = type;
+	hdr->msg_version = version;
+	hdr->msg_seqno = seqno;
+	hdr->msg_vmpck = vmpck_id;
+	hdr->msg_sz = sz;
+
+	/* Verify the sequence number is non-zero */
+	if (!hdr->msg_seqno)
+		return -ENOSR;
+
+	dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
+		hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
+
+	return __enc_payload(snp_dev, req, payload, sz);
+}
+
+static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
+				u8 type, void *req_buf, size_t req_sz, void *resp_buf,
+				u32 resp_sz, __u64 *fw_err)
+{
+	unsigned long err;
+	u64 seqno;
+	int rc;
+
+	/* Get message sequence and verify that its a non-zero */
+	seqno = snp_get_msg_seqno(snp_dev);
+	if (!seqno)
+		return -EIO;
+
+	memset(snp_dev->response, 0, sizeof(*snp_dev->response));
+
+	/* Encrypt the userspace provided payload */
+	rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
+	if (rc)
+		return rc;
+
+	/* Call firmware to process the request */
+	rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
+	if (fw_err)
+		*fw_err = err;
+
+	if (rc)
+		return rc;
+
+	rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
+	if (rc) {
+		/*
+		 * The verify_and_dec_payload() will fail only if the hypervisor is
+		 * actively modifiying the message header or corrupting the encrypted payload.
+		 * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that
+		 * the key cannot be used for any communication.
+		 */
+		dev_alert(snp_dev->dev,
+			  "Detected unexpected decode failure, disabling the vmpck_id %d\n", vmpck_id);
+		snp_disable_vmpck(snp_dev);
+		return rc;
+	}
+
+	/* Increment to new message sequence after payload descryption was successful. */
+	snp_inc_msg_seqno(snp_dev);
+
+	return 0;
+}
+
+static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
+{
+	struct snp_guest_crypto *crypto = snp_dev->crypto;
+	struct snp_report_resp *resp;
+	struct snp_report_req req;
+	int rc, resp_len;
+
+	if (!arg->req_data || !arg->resp_data)
+		return -EINVAL;
+
+	/* Copy the request payload from userspace */
+	if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
+		return -EFAULT;
+
+	/* Message version must be non-zero */
+	if (!req.msg_version)
+		return -EINVAL;
+
+	/*
+	 * The intermediate response buffer is used while decrypting the
+	 * response payload. Make sure that it has enough space to cover the
+	 * authtag.
+	 */
+	resp_len = sizeof(resp->data) + crypto->a_len;
+	resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+	if (!resp)
+		return -ENOMEM;
+
+	/* Issue the command to get the attestation report */
+	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, req.msg_version,
+				  SNP_MSG_REPORT_REQ, &req.user_data, sizeof(req.user_data),
+				  resp->data, resp_len, &arg->fw_err);
+	if (rc)
+		goto e_free;
+
+	/* Copy the response payload to userspace */
+	if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+		rc = -EFAULT;
+
+e_free:
+	kfree(resp);
+	return rc;
+}
+
+static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
+{
+	struct snp_guest_dev *snp_dev = to_snp_dev(file);
+	void __user *argp = (void __user *)arg;
+	struct snp_guest_request_ioctl input;
+	int ret = -ENOTTY;
+
+	if (copy_from_user(&input, argp, sizeof(input)))
+		return -EFAULT;
+
+	input.fw_err = 0;
+
+	mutex_lock(&snp_cmd_mutex);
+
+	/* Check if the VMPCK is not empty */
+	if (is_vmpck_empty(snp_dev)) {
+		dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
+		mutex_unlock(&snp_cmd_mutex);
+		return -ENOTTY;
+	}
+
+	switch (ioctl) {
+	case SNP_GET_REPORT:
+		ret = get_report(snp_dev, &input);
+		break;
+	default:
+		break;
+	}
+
+	mutex_unlock(&snp_cmd_mutex);
+
+	if (input.fw_err && copy_to_user(argp, &input, sizeof(input)))
+		return -EFAULT;
+
+	return ret;
+}
+
+static void free_shared_pages(void *buf, size_t sz)
+{
+	unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+
+	if (!buf)
+		return;
+
+	/* If fail to restore the encryption mask then leak it. */
+	if (WARN_ONCE(set_memory_encrypted((unsigned long)buf, npages),
+		      "Failed to restore encryption mask (leak it)\n"))
+		return;
+
+	__free_pages(virt_to_page(buf), get_order(sz));
+}
+
+static void *alloc_shared_pages(size_t sz)
+{
+	unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+	struct page *page;
+	int ret;
+
+	page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
+	if (IS_ERR(page))
+		return NULL;
+
+	ret = set_memory_decrypted((unsigned long)page_address(page), npages);
+	if (ret) {
+		pr_err("SEV-SNP: failed to mark page shared, ret=%d\n", ret);
+		__free_pages(page, get_order(sz));
+		return NULL;
+	}
+
+	return page_address(page);
+}
+
+static const struct file_operations snp_guest_fops = {
+	.owner	= THIS_MODULE,
+	.unlocked_ioctl = snp_guest_ioctl,
+};
+
+static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
+{
+	u8 *key = NULL;
+
+	switch (id) {
+	case 0:
+		*seqno = &layout->os_area.msg_seqno_0;
+		key = layout->vmpck0;
+		break;
+	case 1:
+		*seqno = &layout->os_area.msg_seqno_1;
+		key = layout->vmpck1;
+		break;
+	case 2:
+		*seqno = &layout->os_area.msg_seqno_2;
+		key = layout->vmpck2;
+		break;
+	case 3:
+		*seqno = &layout->os_area.msg_seqno_3;
+		key = layout->vmpck3;
+		break;
+	default:
+		break;
+	}
+
+	return key;
+}
+
+static int __init snp_guest_probe(struct platform_device *pdev)
+{
+	struct snp_secrets_page_layout *layout;
+	struct snp_guest_platform_data *data;
+	struct device *dev = &pdev->dev;
+	struct snp_guest_dev *snp_dev;
+	struct miscdevice *misc;
+	int ret;
+
+	if (!dev->platform_data)
+		return -ENODEV;
+
+	data = (struct snp_guest_platform_data *)dev->platform_data;
+	layout = (__force void *)ioremap_encrypted(data->secrets_gpa, PAGE_SIZE);
+	if (!layout)
+		return -ENODEV;
+
+	ret = -ENOMEM;
+	snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
+	if (!snp_dev)
+		goto e_fail;
+
+	ret = -EINVAL;
+	snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
+	if (!snp_dev->vmpck) {
+		dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
+		goto e_fail;
+	}
+
+	/* Verify that VMPCK is not zero. */
+	if (is_vmpck_empty(snp_dev)) {
+		dev_err(dev, "vmpck id %d is null\n", vmpck_id);
+		goto e_fail;
+	}
+
+	platform_set_drvdata(pdev, snp_dev);
+	snp_dev->dev = dev;
+	snp_dev->layout = layout;
+
+	/* Allocate the shared page used for the request and response message. */
+	snp_dev->request = alloc_shared_pages(sizeof(struct snp_guest_msg));
+	if (!snp_dev->request)
+		goto e_fail;
+
+	snp_dev->response = alloc_shared_pages(sizeof(struct snp_guest_msg));
+	if (!snp_dev->response)
+		goto e_fail;
+
+	ret = -EIO;
+	snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN);
+	if (!snp_dev->crypto)
+		goto e_fail;
+
+	misc = &snp_dev->misc;
+	misc->minor = MISC_DYNAMIC_MINOR;
+	misc->name = DEVICE_NAME;
+	misc->fops = &snp_guest_fops;
+
+	/* initial the input address for guest request */
+	snp_dev->input.req_gpa = __pa(snp_dev->request);
+	snp_dev->input.resp_gpa = __pa(snp_dev->response);
+
+	ret =  misc_register(misc);
+	if (ret)
+		goto e_fail;
+
+	dev_info(dev, "Initialized SNP guest driver (using vmpck_id %d)\n", vmpck_id);
+	return 0;
+
+e_fail:
+	iounmap(layout);
+	free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
+	free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
+
+	return ret;
+}
+
+static int __exit snp_guest_remove(struct platform_device *pdev)
+{
+	struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev);
+
+	free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
+	free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
+	deinit_crypto(snp_dev->crypto);
+	misc_deregister(&snp_dev->misc);
+
+	return 0;
+}
+
+static struct platform_driver snp_guest_driver = {
+	.remove		= __exit_p(snp_guest_remove),
+	.driver		= {
+		.name = "snp-guest",
+	},
+};
+
+module_platform_driver_probe(snp_guest_driver, snp_guest_probe);
+
+MODULE_AUTHOR("Brijesh Singh <brijesh.singh@amd.com>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0.0");
+MODULE_DESCRIPTION("AMD SNP Guest Driver");
diff --git a/drivers/virt/coco/sevguest/sevguest.h b/drivers/virt/coco/sevguest/sevguest.h
new file mode 100644
index 000000000000..cfa76cf8a21a
--- /dev/null
+++ b/drivers/virt/coco/sevguest/sevguest.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ *
+ * SEV-SNP API spec is available at https://developer.amd.com/sev
+ */
+
+#ifndef __LINUX_SEVGUEST_H_
+#define __LINUX_SEVGUEST_H_
+
+#include <linux/types.h>
+
+#define MAX_AUTHTAG_LEN		32
+
+/* See SNP spec SNP_GUEST_REQUEST section for the structure */
+enum msg_type {
+	SNP_MSG_TYPE_INVALID = 0,
+	SNP_MSG_CPUID_REQ,
+	SNP_MSG_CPUID_RSP,
+	SNP_MSG_KEY_REQ,
+	SNP_MSG_KEY_RSP,
+	SNP_MSG_REPORT_REQ,
+	SNP_MSG_REPORT_RSP,
+	SNP_MSG_EXPORT_REQ,
+	SNP_MSG_EXPORT_RSP,
+	SNP_MSG_IMPORT_REQ,
+	SNP_MSG_IMPORT_RSP,
+	SNP_MSG_ABSORB_REQ,
+	SNP_MSG_ABSORB_RSP,
+	SNP_MSG_VMRK_REQ,
+	SNP_MSG_VMRK_RSP,
+
+	SNP_MSG_TYPE_MAX
+};
+
+enum aead_algo {
+	SNP_AEAD_INVALID,
+	SNP_AEAD_AES_256_GCM,
+};
+
+struct snp_guest_msg_hdr {
+	u8 authtag[MAX_AUTHTAG_LEN];
+	u64 msg_seqno;
+	u8 rsvd1[8];
+	u8 algo;
+	u8 hdr_version;
+	u16 hdr_sz;
+	u8 msg_type;
+	u8 msg_version;
+	u16 msg_sz;
+	u32 rsvd2;
+	u8 msg_vmpck;
+	u8 rsvd3[35];
+} __packed;
+
+struct snp_guest_msg {
+	struct snp_guest_msg_hdr hdr;
+	u8 payload[4000];
+} __packed;
+
+/*
+ * The secrets page contains 96-bytes of reserved field that can be used by
+ * the guest OS. The guest OS uses the area to save the message sequence
+ * number for each VMPCK.
+ *
+ * See the GHCB spec section Secret page layout for the format for this area.
+ */
+struct secrets_os_area {
+	u32 msg_seqno_0;
+	u32 msg_seqno_1;
+	u32 msg_seqno_2;
+	u32 msg_seqno_3;
+	u64 ap_jump_table_pa;
+	u8 rsvd[40];
+	u8 guest_usage[32];
+} __packed;
+
+#define VMPCK_KEY_LEN		32
+
+/* See the SNP spec version 0.9 for secrets page format */
+struct snp_secrets_page_layout {
+	u32 version;
+	u32 imien	: 1,
+	    rsvd1	: 31;
+	u32 fms;
+	u32 rsvd2;
+	u8 gosvw[16];
+	u8 vmpck0[VMPCK_KEY_LEN];
+	u8 vmpck1[VMPCK_KEY_LEN];
+	u8 vmpck2[VMPCK_KEY_LEN];
+	u8 vmpck3[VMPCK_KEY_LEN];
+	struct secrets_os_area os_area;
+	u8 rsvd3[3840];
+} __packed;
+
+#endif /* __LINUX_SNP_GUEST_H__ */
diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h
new file mode 100644
index 000000000000..eda7edcffda8
--- /dev/null
+++ b/include/uapi/linux/sev-guest.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * Userspace interface for AMD SEV and SEV-SNP guest driver.
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ *
+ * SEV API specification is available at: https://developer.amd.com/sev/
+ */
+
+#ifndef __UAPI_LINUX_SEV_GUEST_H_
+#define __UAPI_LINUX_SEV_GUEST_H_
+
+#include <linux/types.h>
+
+struct snp_report_req {
+	/* message version number (must be non-zero) */
+	__u8 msg_version;
+
+	/* user data that should be included in the report */
+	__u8 user_data[64];
+};
+
+struct snp_report_resp {
+	/* response data, see SEV-SNP spec for the format */
+	__u8 data[4000];
+};
+
+struct snp_guest_request_ioctl {
+	/* Request and response structure address */
+	__u64 req_data;
+	__u64 resp_data;
+
+	/* firmware error code on failure (see psp-sev.h) */
+	__u64 fw_err;
+};
+
+#define SNP_GUEST_REQ_IOC_TYPE	'S'
+
+/* Get SNP attestation report */
+#define SNP_GET_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x0, struct snp_guest_request_ioctl)
+
+#endif /* __UAPI_LINUX_SEV_GUEST_H_ */
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 44/45] virt: sevguest: Add support to derive key
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (42 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 43/45] virt: Add SEV-SNP guest driver Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-18 16:43   ` Peter Gonda
  2021-11-10 22:07 ` [PATCH v7 45/45] virt: sevguest: Add support to get extended report Brijesh Singh
  2021-11-15 15:56 ` [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Venu Busireddy
  45 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

The SNP_GET_DERIVED_KEY ioctl interface can be used by the SNP guest to
ask the firmware to provide a key derived from a root key. The derived
key may be used by the guest for any purposes it choose, such as a
sealing key or communicating with the external entities.

See SEV-SNP firmware spec for more information.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 Documentation/virt/coco/sevguest.rst  | 19 ++++++++++-
 drivers/virt/coco/sevguest/sevguest.c | 49 +++++++++++++++++++++++++++
 include/uapi/linux/sev-guest.h        | 24 +++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)

diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
index 002c90946b8a..0bd9a65e0370 100644
--- a/Documentation/virt/coco/sevguest.rst
+++ b/Documentation/virt/coco/sevguest.rst
@@ -64,10 +64,27 @@ The SNP_GET_REPORT ioctl can be used to query the attestation report from the
 SEV-SNP firmware. The ioctl uses the SNP_GUEST_REQUEST (MSG_REPORT_REQ) command
 provided by the SEV-SNP firmware to query the attestation report.
 
-On success, the snp_report_resp.data will contains the report. The report
+On success, the snp_report_resp.data will contain the report. The report
 will contain the format described in the SEV-SNP specification. See the SEV-SNP
 specification for further details.
 
+2.2 SNP_GET_DERIVED_KEY
+-----------------------
+:Technology: sev-snp
+:Type: guest ioctl
+:Parameters (in): struct snp_derived_key_req
+:Returns (out): struct snp_derived_key_req on success, -negative on error
+
+The SNP_GET_DERIVED_KEY ioctl can be used to get a key derive from a root key.
+The derived key can be used by the guest for any purpose, such as sealing keys
+or communicating with external entities.
+
+The ioctl uses the SNP_GUEST_REQUEST (MSG_KEY_REQ) command provided by the
+SEV-SNP firmware to derive the key. See SEV-SNP specification for further details
+on the various fields passed in the key derivation request.
+
+On success, the snp_derived_key_resp.data will contains the derived key value. See
+the SEV-SNP specification for further details.
 
 Reference
 ---------
diff --git a/drivers/virt/coco/sevguest/sevguest.c b/drivers/virt/coco/sevguest/sevguest.c
index 982714c1b4ca..bece6856573e 100644
--- a/drivers/virt/coco/sevguest/sevguest.c
+++ b/drivers/virt/coco/sevguest/sevguest.c
@@ -392,6 +392,52 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
 	return rc;
 }
 
+static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
+{
+	struct snp_guest_crypto *crypto = snp_dev->crypto;
+	struct snp_derived_key_resp resp = {0};
+	struct snp_derived_key_req req;
+	int rc, resp_len;
+	u8 buf[89];
+
+	if (!arg->req_data || !arg->resp_data)
+		return -EINVAL;
+
+	/* Copy the request payload from userspace */
+	if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
+		return -EFAULT;
+
+	/* Message version must be non-zero */
+	if (!req.msg_version)
+		return -EINVAL;
+
+	/*
+	 * The intermediate response buffer is used while decrypting the
+	 * response payload. Make sure that it has enough space to cover the
+	 * authtag.
+	 */
+	resp_len = sizeof(resp.data) + crypto->a_len;
+	if (sizeof(buf) < resp_len)
+		return -ENOMEM;
+
+	/* Issue the command to get the attestation report */
+	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, req.msg_version,
+				  SNP_MSG_KEY_REQ, &req.data, sizeof(req.data), buf, resp_len,
+				  &arg->fw_err);
+	if (rc)
+		goto e_free;
+
+	/* Copy the response payload to userspace */
+	memcpy(resp.data, buf, sizeof(resp.data));
+	if (copy_to_user((void __user *)arg->resp_data, &resp, sizeof(resp)))
+		rc = -EFAULT;
+
+e_free:
+	memzero_explicit(buf, sizeof(buf));
+	memzero_explicit(&resp, sizeof(resp));
+	return rc;
+}
+
 static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 {
 	struct snp_guest_dev *snp_dev = to_snp_dev(file);
@@ -417,6 +463,9 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
 	case SNP_GET_REPORT:
 		ret = get_report(snp_dev, &input);
 		break;
+	case SNP_GET_DERIVED_KEY:
+		ret = get_derived_key(snp_dev, &input);
+		break;
 	default:
 		break;
 	}
diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h
index eda7edcffda8..f6d9c136ff4d 100644
--- a/include/uapi/linux/sev-guest.h
+++ b/include/uapi/linux/sev-guest.h
@@ -36,9 +36,33 @@ struct snp_guest_request_ioctl {
 	__u64 fw_err;
 };
 
+struct __snp_derived_key_req {
+	__u32 root_key_select;
+	__u32 rsvd;
+	__u64 guest_field_select;
+	__u32 vmpl;
+	__u32 guest_svn;
+	__u64 tcb_version;
+};
+
+struct snp_derived_key_req {
+	/* message version number (must be non-zero) */
+	__u8 msg_version;
+
+	struct __snp_derived_key_req data;
+};
+
+struct snp_derived_key_resp {
+	/* response data, see SEV-SNP spec for the format */
+	__u8 data[64];
+};
+
 #define SNP_GUEST_REQ_IOC_TYPE	'S'
 
 /* Get SNP attestation report */
 #define SNP_GET_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x0, struct snp_guest_request_ioctl)
 
+/* Get a derived key from the root */
+#define SNP_GET_DERIVED_KEY _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x1, struct snp_guest_request_ioctl)
+
 #endif /* __UAPI_LINUX_SEV_GUEST_H_ */
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* [PATCH v7 45/45] virt: sevguest: Add support to get extended report
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (43 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 44/45] virt: sevguest: Add support to derive key Brijesh Singh
@ 2021-11-10 22:07 ` Brijesh Singh
  2021-11-15 15:56 ` [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Venu Busireddy
  45 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-10 22:07 UTC (permalink / raw)
  To: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy, Brijesh Singh

Version 2 of GHCB specification defines Non-Automatic-Exit(NAE) to get
the extended guest report. It is similar to the SNP_GET_REPORT ioctl.
The main difference is related to the additional data that will be
returned. The additional data returned is a certificate blob that can
be used by the SNP guest user. The certificate blob layout is defined
in the GHCB specification. The driver simply treats the blob as a opaque
data and copies it to userspace.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 Documentation/virt/coco/sevguest.rst  | 23 +++++++
 drivers/virt/coco/sevguest/sevguest.c | 93 +++++++++++++++++++++++++++
 include/uapi/linux/sev-guest.h        | 13 ++++
 3 files changed, 129 insertions(+)

diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
index 0bd9a65e0370..5217a9176fb9 100644
--- a/Documentation/virt/coco/sevguest.rst
+++ b/Documentation/virt/coco/sevguest.rst
@@ -86,6 +86,29 @@ on the various fields passed in the key derivation request.
 On success, the snp_derived_key_resp.data will contains the derived key value. See
 the SEV-SNP specification for further details.
 
+
+2.3 SNP_GET_EXT_REPORT
+----------------------
+:Technology: sev-snp
+:Type: guest ioctl
+:Parameters (in/out): struct snp_ext_report_req
+:Returns (out): struct snp_report_resp on success, -negative on error
+
+The SNP_GET_EXT_REPORT ioctl is similar to the SNP_GET_REPORT. The difference is
+related to the additional certificate data that is returned with the report.
+The certificate data returned is being provided by the hypervisor through the
+SNP_SET_EXT_CONFIG.
+
+The ioctl uses the SNP_GUEST_REQUEST (MSG_REPORT_REQ) command provided by the SEV-SNP
+firmware to get the attestation report.
+
+On success, the snp_ext_report_resp.data will contain the attestation report
+and snp_ext_report_req.certs_address will contain the certificate blob. If the
+length of the blob is smaller than expected then snp_ext_report_req.certs_len will
+be updated with the expected value.
+
+See GHCB specification for further detail on how to parse the certificate blob.
+
 Reference
 ---------
 
diff --git a/drivers/virt/coco/sevguest/sevguest.c b/drivers/virt/coco/sevguest/sevguest.c
index bece6856573e..15e37f3a0bb1 100644
--- a/drivers/virt/coco/sevguest/sevguest.c
+++ b/drivers/virt/coco/sevguest/sevguest.c
@@ -41,6 +41,7 @@ struct snp_guest_dev {
 	struct device *dev;
 	struct miscdevice misc;
 
+	void *certs_data;
 	struct snp_guest_crypto *crypto;
 	struct snp_guest_msg *request, *response;
 	struct snp_secrets_page_layout *layout;
@@ -438,6 +439,88 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
 	return rc;
 }
 
+static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
+{
+	struct snp_guest_crypto *crypto = snp_dev->crypto;
+	struct snp_ext_report_req req;
+	struct snp_report_resp *resp;
+	int ret, npages = 0, resp_len;
+
+	if (!arg->req_data || !arg->resp_data)
+		return -EINVAL;
+
+	/* Copy the request payload from userspace */
+	if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
+		return -EFAULT;
+
+	/* Message version must be non-zero */
+	if (!req.data.msg_version)
+		return -EINVAL;
+
+	if (req.certs_len) {
+		if (req.certs_len > SEV_FW_BLOB_MAX_SIZE ||
+		    !IS_ALIGNED(req.certs_len, PAGE_SIZE))
+			return -EINVAL;
+	}
+
+	if (req.certs_address && req.certs_len) {
+		if (!access_ok(req.certs_address, req.certs_len))
+			return -EFAULT;
+
+		/*
+		 * Initialize the intermediate buffer with all zero's. This buffer
+		 * is used in the guest request message to get the certs blob from
+		 * the host. If host does not supply any certs in it, then copy
+		 * zeros to indicate that certificate data was not provided.
+		 */
+		memset(snp_dev->certs_data, 0, req.certs_len);
+
+		npages = req.certs_len >> PAGE_SHIFT;
+	}
+
+	/*
+	 * The intermediate response buffer is used while decrypting the
+	 * response payload. Make sure that it has enough space to cover the
+	 * authtag.
+	 */
+	resp_len = sizeof(resp->data) + crypto->a_len;
+	resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
+	if (!resp)
+		return -ENOMEM;
+
+	snp_dev->input.data_npages = npages;
+	ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, req.data.msg_version,
+				   SNP_MSG_REPORT_REQ, &req.data.user_data,
+				   sizeof(req.data.user_data), resp->data, resp_len, &arg->fw_err);
+
+	/* If certs length is invalid then copy the returned length */
+	if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) {
+		req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
+
+		if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req)))
+			ret = -EFAULT;
+	}
+
+	if (ret)
+		goto e_free;
+
+	/* Copy the certificate data blob to userspace */
+	if (req.certs_address && req.certs_len &&
+	    copy_to_user((void __user *)req.certs_address, snp_dev->certs_data,
+			 req.certs_len)) {
+		ret = -EFAULT;
+		goto e_free;
+	}
+
+	/* Copy the response payload to userspace */
+	if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+		ret = -EFAULT;
+
+e_free:
+	kfree(resp);
+	return ret;
+}
+
 static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 {
 	struct snp_guest_dev *snp_dev = to_snp_dev(file);
@@ -466,6 +549,9 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
 	case SNP_GET_DERIVED_KEY:
 		ret = get_derived_key(snp_dev, &input);
 		break;
+	case SNP_GET_EXT_REPORT:
+		ret = get_ext_report(snp_dev, &input);
+		break;
 	default:
 		break;
 	}
@@ -594,6 +680,10 @@ static int __init snp_guest_probe(struct platform_device *pdev)
 	if (!snp_dev->response)
 		goto e_fail;
 
+	snp_dev->certs_data = alloc_shared_pages(SEV_FW_BLOB_MAX_SIZE);
+	if (!snp_dev->certs_data)
+		goto e_fail;
+
 	ret = -EIO;
 	snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN);
 	if (!snp_dev->crypto)
@@ -607,6 +697,7 @@ static int __init snp_guest_probe(struct platform_device *pdev)
 	/* initial the input address for guest request */
 	snp_dev->input.req_gpa = __pa(snp_dev->request);
 	snp_dev->input.resp_gpa = __pa(snp_dev->response);
+	snp_dev->input.data_gpa = __pa(snp_dev->certs_data);
 
 	ret =  misc_register(misc);
 	if (ret)
@@ -617,6 +708,7 @@ static int __init snp_guest_probe(struct platform_device *pdev)
 
 e_fail:
 	iounmap(layout);
+	free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
 	free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
 	free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
 
@@ -629,6 +721,7 @@ static int __exit snp_guest_remove(struct platform_device *pdev)
 
 	free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
 	free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
+	free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
 	deinit_crypto(snp_dev->crypto);
 	misc_deregister(&snp_dev->misc);
 
diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h
index f6d9c136ff4d..3f6a9d694a47 100644
--- a/include/uapi/linux/sev-guest.h
+++ b/include/uapi/linux/sev-guest.h
@@ -57,6 +57,16 @@ struct snp_derived_key_resp {
 	__u8 data[64];
 };
 
+struct snp_ext_report_req {
+	struct snp_report_req data;
+
+	/* where to copy the certificate blob */
+	__u64 certs_address;
+
+	/* length of the certificate blob */
+	__u32 certs_len;
+};
+
 #define SNP_GUEST_REQ_IOC_TYPE	'S'
 
 /* Get SNP attestation report */
@@ -65,4 +75,7 @@ struct snp_derived_key_resp {
 /* Get a derived key from the root */
 #define SNP_GET_DERIVED_KEY _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x1, struct snp_guest_request_ioctl)
 
+/* Get SNP extended report as defined in the GHCB specification version 2. */
+#define SNP_GET_EXT_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x2, struct snp_guest_request_ioctl)
+
 #endif /* __UAPI_LINUX_SEV_GUEST_H_ */
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-10 22:07 ` [PATCH v7 43/45] virt: Add SEV-SNP guest driver Brijesh Singh
@ 2021-11-10 22:27   ` Randy Dunlap
  2021-11-11 19:27     ` Brijesh Singh
  2021-11-17 23:34   ` Peter Gonda
  1 sibling, 1 reply; 80+ messages in thread
From: Randy Dunlap @ 2021-11-10 22:27 UTC (permalink / raw)
  To: Brijesh Singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

Hi,

On 11/10/21 2:07 PM, Brijesh Singh wrote:
> diff --git a/drivers/virt/coco/sevguest/Kconfig b/drivers/virt/coco/sevguest/Kconfig
> new file mode 100644
> index 000000000000..96190919cca8
> --- /dev/null
> +++ b/drivers/virt/coco/sevguest/Kconfig
> @@ -0,0 +1,9 @@
> +config SEV_GUEST
> +	tristate "AMD SEV Guest driver"
> +	default y

For this to remain as "default y", you need to justify it.
E.g., if a board cannot boot with an interrupt controller,
the driver for the interrupt controller can be "default y".

So why is this default y?
No other drivers in drivers/virt/ are default y.

> +	depends on AMD_MEM_ENCRYPT && CRYPTO_AEAD2
> +	help
> +	  The driver can be used by the SEV-SNP guest to communicate with the PSP to
> +	  request the attestation report and more.
> +
> +	  If you choose 'M' here, this module will be called sevguest.

thanks.
-- 
~Randy

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-10 22:27   ` Randy Dunlap
@ 2021-11-11 19:27     ` Brijesh Singh
  2021-11-11 22:57       ` Randy Dunlap
  0 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-11 19:27 UTC (permalink / raw)
  To: Randy Dunlap, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm
  Cc: brijesh.singh, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

Hi Randy,

On 11/10/21 4:27 PM, Randy Dunlap wrote:
> Hi,
> 
> On 11/10/21 2:07 PM, Brijesh Singh wrote:
>> diff --git a/drivers/virt/coco/sevguest/Kconfig 
>> b/drivers/virt/coco/sevguest/Kconfig
>> new file mode 100644
>> index 000000000000..96190919cca8
>> --- /dev/null
>> +++ b/drivers/virt/coco/sevguest/Kconfig
>> @@ -0,0 +1,9 @@
>> +config SEV_GUEST
>> +    tristate "AMD SEV Guest driver"
>> +    default y
> 
> For this to remain as "default y", you need to justify it.
> E.g., if a board cannot boot with an interrupt controller,
> the driver for the interrupt controller can be "default y".
> 
> So why is this default y?
> No other drivers in drivers/virt/ are default y.
> 

I choose the default "y" for two reasons:

1.  The driver is built if the user enables the AMD memory encryption 
support. If the user has selected the AMD memory encryption support, 
they will be querying an attestation report to verify that the guest is 
running on AMD memory encryption enabled hardware.

2. Typically, an attestation report is retrieved from an initial ramdisk 
(before mounting the disk). IIUC, the standard initramfs build tools may 
not include the driver by default and requires the user to go through hoops.

However, I have no strong reason to keep it to "y" if other prefers "m".

thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-11 19:27     ` Brijesh Singh
@ 2021-11-11 22:57       ` Randy Dunlap
  0 siblings, 0 replies; 80+ messages in thread
From: Randy Dunlap @ 2021-11-11 22:57 UTC (permalink / raw)
  To: Brijesh Singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On 11/11/21 11:27 AM, Brijesh Singh wrote:
> Hi Randy,
> 
> On 11/10/21 4:27 PM, Randy Dunlap wrote:
>> Hi,
>>
>> On 11/10/21 2:07 PM, Brijesh Singh wrote:
>>> diff --git a/drivers/virt/coco/sevguest/Kconfig b/drivers/virt/coco/sevguest/Kconfig
>>> new file mode 100644
>>> index 000000000000..96190919cca8
>>> --- /dev/null
>>> +++ b/drivers/virt/coco/sevguest/Kconfig
>>> @@ -0,0 +1,9 @@
>>> +config SEV_GUEST
>>> +    tristate "AMD SEV Guest driver"
>>> +    default y
>>
>> For this to remain as "default y", you need to justify it.
>> E.g., if a board cannot boot with an interrupt controller,
>> the driver for the interrupt controller can be "default y".
>>
>> So why is this default y?
>> No other drivers in drivers/virt/ are default y.
>>
> 
> I choose the default "y" for two reasons:
> 
> 1.  The driver is built if the user enables the AMD memory encryption support. If the user has selected the AMD memory encryption support, they will be querying an attestation report to verify that the guest is running on AMD memory encryption enabled hardware.

OK, I see. I'm OK with this.

> 2. Typically, an attestation report is retrieved from an initial ramdisk (before mounting the disk). IIUC, the standard initramfs build tools may not include the driver by default and requires the user to go through hoops.
> 
> However, I have no strong reason to keep it to "y" if other prefers "m".

"m" is no better than "y" in this case.

thanks.
-- 
~Randy

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot
  2021-11-10 22:06 ` [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot Brijesh Singh
@ 2021-11-12 16:52   ` Borislav Petkov
  2021-11-12 20:30     ` Michael Roth
  0 siblings, 1 reply; 80+ messages in thread
From: Borislav Petkov @ 2021-11-12 16:52 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 04:06:47PM -0600, Brijesh Singh wrote:
> +void sev_enable(struct boot_params *bp)
> +{
> +	unsigned int eax, ebx, ecx, edx;
> +
> +	/* Check for the SME/SEV support leaf */
> +	eax = 0x80000000;
> +	ecx = 0;
> +	native_cpuid(&eax, &ebx, &ecx, &edx);
> +	if (eax < 0x8000001f)
> +		return;
> +
> +	/*
> +	 * Check for the SME/SEV feature:
> +	 *   CPUID Fn8000_001F[EAX]
> +	 *   - Bit 0 - Secure Memory Encryption support
> +	 *   - Bit 1 - Secure Encrypted Virtualization support
> +	 *   CPUID Fn8000_001F[EBX]
> +	 *   - Bits 5:0 - Pagetable bit position used to indicate encryption
> +	 */
> +	eax = 0x8000001f;
> +	ecx = 0;
> +	native_cpuid(&eax, &ebx, &ecx, &edx);
> +	/* Check whether SEV is supported */
> +	if (!(eax & BIT(1)))
> +		return;
> +
> +	/* Check the SEV MSR whether SEV or SME is enabled */
> +	sev_status   = rd_sev_status_msr();
> +
> +	if (!(sev_status & MSR_AMD64_SEV_ENABLED))
> +		error("SEV support indicated by CPUID, but not SEV status MSR.");

What is the practical purpose of this test?

> +	sme_me_mask = 1UL << (ebx & 0x3f);

	sme_me_mask = BIT_ULL(ebx & 0x3f);

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot
  2021-11-12 16:52   ` Borislav Petkov
@ 2021-11-12 20:30     ` Michael Roth
  2021-11-23 21:55       ` Venu Busireddy
  0 siblings, 1 reply; 80+ messages in thread
From: Michael Roth @ 2021-11-12 20:30 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Brijesh Singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On Fri, Nov 12, 2021 at 05:52:51PM +0100, Borislav Petkov wrote:
> On Wed, Nov 10, 2021 at 04:06:47PM -0600, Brijesh Singh wrote:
> > +void sev_enable(struct boot_params *bp)
> > +{
> > +	unsigned int eax, ebx, ecx, edx;
> > +
> > +	/* Check for the SME/SEV support leaf */
> > +	eax = 0x80000000;
> > +	ecx = 0;
> > +	native_cpuid(&eax, &ebx, &ecx, &edx);
> > +	if (eax < 0x8000001f)
> > +		return;
> > +
> > +	/*
> > +	 * Check for the SME/SEV feature:
> > +	 *   CPUID Fn8000_001F[EAX]
> > +	 *   - Bit 0 - Secure Memory Encryption support
> > +	 *   - Bit 1 - Secure Encrypted Virtualization support
> > +	 *   CPUID Fn8000_001F[EBX]
> > +	 *   - Bits 5:0 - Pagetable bit position used to indicate encryption
> > +	 */
> > +	eax = 0x8000001f;
> > +	ecx = 0;
> > +	native_cpuid(&eax, &ebx, &ecx, &edx);
> > +	/* Check whether SEV is supported */
> > +	if (!(eax & BIT(1)))
> > +		return;
> > +
> > +	/* Check the SEV MSR whether SEV or SME is enabled */
> > +	sev_status   = rd_sev_status_msr();
> > +
> > +	if (!(sev_status & MSR_AMD64_SEV_ENABLED))
> > +		error("SEV support indicated by CPUID, but not SEV status MSR.");
> 
> What is the practical purpose of this test?

In the current QEMU/KVM implementation the SEV* CPUID bits are only
exposed for SEV guests, so this was more of a sanity check on that. But
looking at things more closely: that's more of a VMM-specific behavior
and isn't necessarily an invalid guest configuration as far as the spec
is concerned, so I think this check should be dropped.

> 
> > +	sme_me_mask = 1UL << (ebx & 0x3f);
> 
> 	sme_me_mask = BIT_ULL(ebx & 0x3f);

Will do.

Thanks,

Mike

> 
> Thx.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpeople.kernel.org%2Ftglx%2Fnotes-about-netiquette&amp;data=04%7C01%7Cmichael.roth%40amd.com%7Ca6bf3479fffa4b5eee8b08d9a5fce2e2%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637723327924654730%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=SRy8YSe8a2njNc6IT8CGKv0hUefSOW55DJV%2Fi2Lhkic%3D&amp;reserved=0

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 15/45] x86/compressed: Register GHCB memory when SEV-SNP is active
  2021-11-10 22:07 ` [PATCH v7 15/45] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
@ 2021-11-15 14:05   ` Jörg Rödel
  0 siblings, 0 replies; 80+ messages in thread
From: Jörg Rödel @ 2021-11-15 14:05 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 04:07:01PM -0600, Brijesh Singh wrote:
> +static void snp_register_ghcb_early(unsigned long paddr)

This needs __maybe_unused, otherwise it triggers a warning:

arch/x86/kernel/sev-shared.c:78:13: warning: ‘snp_register_ghcb_early’ defined but not used [-Wunused-function]
   78 | static void snp_register_ghcb_early(unsigned long paddr)
      |             ^~~~~~~~~~~~~~~~~~~~~~~


^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
  2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
                   ` (44 preceding siblings ...)
  2021-11-10 22:07 ` [PATCH v7 45/45] virt: sevguest: Add support to get extended report Brijesh Singh
@ 2021-11-15 15:56 ` Venu Busireddy
  2021-11-15 16:02   ` Brijesh Singh
  45 siblings, 1 reply; 80+ messages in thread
From: Venu Busireddy @ 2021-11-15 15:56 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On 2021-11-10 16:06:46 -0600, Brijesh Singh wrote:
> This part of Secure Encrypted Paging (SEV-SNP) series focuses on the changes
> required in a guest OS for SEV-SNP support.
> 
> SEV-SNP builds upon existing SEV and SEV-ES functionality while adding
> new hardware-based memory protections. SEV-SNP adds strong memory integrity
> protection to help prevent malicious hypervisor-based attacks like data
> replay, memory re-mapping and more in order to create an isolated memory
> encryption environment.
>  
> This series provides the basic building blocks to support booting the SEV-SNP
> VMs, it does not cover all the security enhancement introduced by the SEV-SNP
> such as interrupt protection.
> 
> Many of the integrity guarantees of SEV-SNP are enforced through a new
> structure called the Reverse Map Table (RMP). Adding a new page to SEV-SNP
> VM requires a 2-step process. First, the hypervisor assigns a page to the
> guest using the new RMPUPDATE instruction. This transitions the page to
> guest-invalid. Second, the guest validates the page using the new PVALIDATE
> instruction. The SEV-SNP VMs can use the new "Page State Change Request NAE"
> defined in the GHCB specification to ask hypervisor to add or remove page
> from the RMP table.
> 
> Each page assigned to the SEV-SNP VM can either be validated or unvalidated,
> as indicated by the Validated flag in the page's RMP entry. There are two
> approaches that can be taken for the page validation: Pre-validation and
> Lazy Validation.
> 
> Under pre-validation, the pages are validated prior to first use. And under
> lazy validation, pages are validated when first accessed. An access to a
> unvalidated page results in a #VC exception, at which time the exception
> handler may validate the page. Lazy validation requires careful tracking of
> the validated pages to avoid validating the same GPA more than once. The
> recently introduced "Unaccepted" memory type can be used to communicate the
> unvalidated memory ranges to the Guest OS.
> 
> At this time we only sypport the pre-validation, the OVMF guest BIOS
> validates the entire RAM before the control is handed over to the guest kernel.
> The early_set_memory_{encrypt,decrypt} and set_memory_{encrypt,decrypt} are
> enlightened to perform the page validation or invalidation while setting or
> clearing the encryption attribute from the page table.
> 
> This series does not provide support for the Interrupt security yet which will
> be added after the base support.
> 
> The series is based on tip/master
>   ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'

I am looking at
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git,
and I cannot find the commit ea79c24a30aa there. Am I looking at the
wrong tree?

Venu

> 
> Additional resources
> ---------------------
> SEV-SNP whitepaper
> https://www.amd.com/system/files/TechDocs/SEV-SNP-strengthening-vm-isolation-with-integrity-protection-and-more.pdf
>  
> APM 2: https://www.amd.com/system/files/TechDocs/24593.pdf
> (section 15.36)
> 
> GHCB spec:
> https://developer.amd.com/wp-content/resources/56421.pdf
> 
> SEV-SNP firmware specification:
> https://developer.amd.com/sev/
> 
> v6: https://lore.kernel.org/linux-mm/20211008180453.462291-1-brijesh.singh@amd.com/
> v5: https://lore.kernel.org/lkml/20210820151933.22401-1-brijesh.singh@amd.com/
> 
> Changes since v6:
>  * Add rmpadjust() helper to be used by AP creation and vmpl0 detect function.
>  * Clear the VM communication key if guest detects that hypervisor is modifying
>    the SNP_GUEST_REQ response header.
>  * Move the per-cpu GHCB registration from first #VC to idt setup.
>  * Consolidate initial SEV/SME setup into a common entry point that gets called
>    early enough to also be used for SEV-SNP CPUID table setup.
>  * SNP CPUID: separate initial SEV-SNP feature detection out into standalone
>    snp_init() routines, then add CPUID table setup to it as a separate patch.
>  * SNP CPUID: fix boot issue with Seabios due to ACPI relying on certain EFI
>    config table lookup failures as fallthrough cases rather than error cases.
>  * SNP CPUID: drop the use of a separate init routines to handle pointer fixups
>    after switching to kernel virtual addresses, instead use a helper that uses
>    RIP-relative addressing to access CPUID table when either on identity mapping
>    or kernel virtual addresses.
> 
> Changes since v5:
>  * move the seqno allocation in the sevguest driver.
>  * extend snp_issue_guest_request() to accept the exit_info to simplify the logic.
>  * use smaller structure names based on feedback.
>  * explicitly clear the memory after the SNP guest request is completed.
>  * cpuid validation: use a local copy of cpuid table instead of keeping
>    firmware table mapped throughout boot.
>  * cpuid validation: coding style fix-ups and refactor cpuid-related helpers
>    as suggested.
>  * cpuid validation: drop a number of BOOT_COMPRESSED-guarded defs/declarations
>    by moving things like snp_cpuid_init*() out of sev-shared.c and keeping only
>    the common bits there.
>  * Break up EFI config table helpers and related acpi.c changes into separate
>    patches.
>  * re-enable stack protection for 32-bit kernels as well, not just 64-bit
> 
> Changes since v4:
>  * Address the cpuid specific review comment
>  * Simplified the macro based on the review feedback
>  * Move macro definition to the patch that needs it
>  * Fix the issues reported by the checkpath
>  * Address the AP creation specific review comment
> 
> Changes since v3:
>  * Add support to use the PSP filtered CPUID.
>  * Add support for the extended guest request.
>  * Move sevguest driver in driver/virt/coco.
>  * Add documentation for sevguest ioctl.
>  * Add support to check the vmpl0.
>  * Pass the VM encryption key and id to be used for encrypting guest messages
>    through the platform drv data.
>  * Multiple cleanup and fixes to address the review feedbacks.
> 
> Changes since v2:
>  * Add support for AP startup using SNP specific vmgexit.
>  * Add snp_prep_memory() helper.
>  * Drop sev_snp_active() helper.
>  * Add sev_feature_enabled() helper to check which SEV feature is active.
>  * Sync the SNP guest message request header with latest SNP FW spec.
>  * Multiple cleanup and fixes to address the review feedbacks.
> 
> Changes since v1:
>  * Integerate the SNP support in sev.{ch}.
>  * Add support to query the hypervisor feature and detect whether SNP is supported.
>  * Define Linux specific reason code for the SNP guest termination.
>  * Extend the setup_header provide a way for hypervisor to pass secret and cpuid page.
>  * Add support to create a platform device and driver to query the attestation report
>    and the derive a key.
>  * Multiple cleanup and fixes to address Boris's review fedback.
> 
> Borislav Petkov (3):
>   x86/sev: Get rid of excessive use of defines
>   x86/head64: Carve out the guest encryption postprocessing into a
>     helper
>   x86/sev: Remove do_early_exception() forward declarations
> 
> Brijesh Singh (22):
>   x86/mm: Extend cc_attr to include AMD SEV-SNP
>   x86/sev: Shorten GHCB terminate macro names
>   x86/sev: Define the Linux specific guest termination reasons
>   x86/sev: Save the negotiated GHCB version
>   x86/sev: Add support for hypervisor feature VMGEXIT
>   x86/sev: Check SEV-SNP features support
>   x86/sev: Add a helper for the PVALIDATE instruction
>   x86/sev: Check the vmpl level
>   x86/compressed: Add helper for validating pages in the decompression
>     stage
>   x86/compressed: Register GHCB memory when SEV-SNP is active
>   x86/sev: Register GHCB memory when SEV-SNP is active
>   x86/sev: Add helper for validating pages in early enc attribute
>     changes
>   x86/kernel: Make the bss.decrypted section shared in RMP table
>   x86/kernel: Validate rom memory before accessing when SEV-SNP is
>     active
>   x86/mm: Add support to validate memory when changing C-bit
>   KVM: SVM: Define sev_features and vmpl field in the VMSA
>   x86/boot: Add Confidential Computing type to setup_data
>   x86/sev: Provide support for SNP guest request NAEs
>   x86/sev: Register SNP guest request platform device
>   virt: Add SEV-SNP guest driver
>   virt: sevguest: Add support to derive key
>   virt: sevguest: Add support to get extended report
> 
> Michael Roth (16):
>   x86/compressed/64: detect/setup SEV/SME features earlier in boot
>   x86/sev: detect/setup SEV/SME features earlier in boot
>   x86/head: re-enable stack protection for 32/64-bit builds
>   x86/sev: move MSR-based VMGEXITs for CPUID to helper
>   KVM: x86: move lookup of indexed CPUID leafs to helper
>   x86/compressed/acpi: move EFI system table lookup to helper
>   x86/compressed/acpi: move EFI config table lookup to helper
>   x86/compressed/acpi: move EFI vendor table lookup to helper
>   KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement
>   x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers
>   x86/boot: add a pointer to Confidential Computing blob in bootparams
>   x86/compressed: add SEV-SNP feature detection/setup
>   x86/compressed: use firmware-validated CPUID for SEV-SNP guests
>   x86/compressed/64: add identity mapping for Confidential Computing
>     blob
>   x86/sev: add SEV-SNP feature detection/setup
>   x86/sev: use firmware-validated CPUID for SEV-SNP guests
> 
> Tom Lendacky (4):
>   KVM: SVM: Create a separate mapping for the SEV-ES save area
>   KVM: SVM: Create a separate mapping for the GHCB save area
>   KVM: SVM: Update the SEV-ES save area mapping
>   x86/sev: Use SEV-SNP AP creation to start secondary CPUs
> 
>  Documentation/virt/coco/sevguest.rst          | 117 +++
>  .../virt/kvm/amd-memory-encryption.rst        |  28 +
>  arch/x86/boot/compressed/Makefile             |   1 +
>  arch/x86/boot/compressed/acpi.c               | 129 +--
>  arch/x86/boot/compressed/efi.c                | 178 ++++
>  arch/x86/boot/compressed/head_64.S            |   8 +-
>  arch/x86/boot/compressed/ident_map_64.c       |  44 +-
>  arch/x86/boot/compressed/mem_encrypt.S        |  36 -
>  arch/x86/boot/compressed/misc.h               |  44 +-
>  arch/x86/boot/compressed/sev.c                | 243 ++++-
>  arch/x86/include/asm/bootparam_utils.h        |   1 +
>  arch/x86/include/asm/cpuid.h                  |  26 +
>  arch/x86/include/asm/msr-index.h              |   2 +
>  arch/x86/include/asm/setup.h                  |   2 +-
>  arch/x86/include/asm/sev-common.h             | 137 ++-
>  arch/x86/include/asm/sev.h                    |  96 +-
>  arch/x86/include/asm/svm.h                    | 171 +++-
>  arch/x86/include/uapi/asm/bootparam.h         |   4 +-
>  arch/x86/include/uapi/asm/svm.h               |  13 +
>  arch/x86/kernel/Makefile                      |   1 -
>  arch/x86/kernel/cc_platform.c                 |   2 +
>  arch/x86/kernel/cpu/common.c                  |   5 +
>  arch/x86/kernel/head64.c                      |  78 +-
>  arch/x86/kernel/head_64.S                     |  24 +
>  arch/x86/kernel/probe_roms.c                  |  13 +-
>  arch/x86/kernel/sev-shared.c                  | 554 +++++++++++-
>  arch/x86/kernel/sev.c                         | 838 ++++++++++++++++--
>  arch/x86/kernel/smpboot.c                     |   3 +
>  arch/x86/kvm/cpuid.c                          |  17 +-
>  arch/x86/kvm/svm/sev.c                        |  24 +-
>  arch/x86/kvm/svm/svm.c                        |   4 +-
>  arch/x86/kvm/svm/svm.h                        |   2 +-
>  arch/x86/mm/mem_encrypt.c                     |  55 +-
>  arch/x86/mm/mem_encrypt_identity.c            |   8 +
>  arch/x86/mm/pat/set_memory.c                  |  15 +
>  drivers/virt/Kconfig                          |   3 +
>  drivers/virt/Makefile                         |   1 +
>  drivers/virt/coco/sevguest/Kconfig            |   9 +
>  drivers/virt/coco/sevguest/Makefile           |   2 +
>  drivers/virt/coco/sevguest/sevguest.c         | 743 ++++++++++++++++
>  drivers/virt/coco/sevguest/sevguest.h         |  98 ++
>  include/linux/cc_platform.h                   |   8 +
>  include/linux/efi.h                           |   1 +
>  include/uapi/linux/sev-guest.h                |  81 ++
>  44 files changed, 3524 insertions(+), 345 deletions(-)
>  create mode 100644 Documentation/virt/coco/sevguest.rst
>  create mode 100644 arch/x86/boot/compressed/efi.c
>  create mode 100644 arch/x86/include/asm/cpuid.h
>  create mode 100644 drivers/virt/coco/sevguest/Kconfig
>  create mode 100644 drivers/virt/coco/sevguest/Makefile
>  create mode 100644 drivers/virt/coco/sevguest/sevguest.c
>  create mode 100644 drivers/virt/coco/sevguest/sevguest.h
>  create mode 100644 include/uapi/linux/sev-guest.h
> 
> -- 
> 2.25.1
> 

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
  2021-11-15 15:56 ` [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Venu Busireddy
@ 2021-11-15 16:02   ` Brijesh Singh
  2021-11-15 16:37     ` Venu Busireddy
  0 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-15 16:02 UTC (permalink / raw)
  To: Venu Busireddy
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Borislav Petkov, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy



On 11/15/21 9:56 AM, Venu Busireddy wrote:
...

>> The series is based on tip/master
>>    ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'
> 
> I am looking at
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7Cb83627413bf24921b15e08d9a8508a4a%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725887206373140%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&amp;sdata=pZvyYsg1crWmsLTpGO4amfYxgUnI9TUy414burkbcdY%3D&amp;reserved=0,
> and I cannot find the commit ea79c24a30aa there. Am I looking at the
> wrong tree?
> 

Yes.

You should use the tip [1] tree .

[1] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/

thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
  2021-11-15 16:02   ` Brijesh Singh
@ 2021-11-15 16:37     ` Venu Busireddy
  2021-11-15 16:45       ` Brijesh Singh
  0 siblings, 1 reply; 80+ messages in thread
From: Venu Busireddy @ 2021-11-15 16:37 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On 2021-11-15 10:02:24 -0600, Brijesh Singh wrote:
> 
> 
> On 11/15/21 9:56 AM, Venu Busireddy wrote:
> ...
> 
> > > The series is based on tip/master
> > >    ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'
> > 
> > I am looking at
> > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7Cb83627413bf24921b15e08d9a8508a4a%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725887206373140%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&amp;sdata=pZvyYsg1crWmsLTpGO4amfYxgUnI9TUy414burkbcdY%3D&amp;reserved=0,
> > and I cannot find the commit ea79c24a30aa there. Am I looking at the
> > wrong tree?
> > 
> 
> Yes.
> 
> You should use the tip [1] tree .
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/

Same problem with tip.git too.

bash-4.2$ git remote -v
origin  https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git (fetch)
origin  https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git (push)
bash-4.2$ git branch
* master
bash-4.2$ git log --oneline | grep ea79c24a30aa
bash-4.2$

Still missing something?

Venu


^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
  2021-11-15 16:37     ` Venu Busireddy
@ 2021-11-15 16:45       ` Brijesh Singh
  2021-11-15 16:55         ` Venu Busireddy
  0 siblings, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-15 16:45 UTC (permalink / raw)
  To: Venu Busireddy
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Borislav Petkov, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy



On 11/15/21 10:37 AM, Venu Busireddy wrote:
> On 2021-11-15 10:02:24 -0600, Brijesh Singh wrote:
>>
>>
>> On 11/15/21 9:56 AM, Venu Busireddy wrote:
>> ...
>>
>>>> The series is based on tip/master
>>>>     ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'
>>>
>>> I am looking at
>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063489322%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=CT%2BZ6Nm6pnvVGY%2B%2FmzK4gG1zxlMNQ1fn7ie6K%2FYueTQ%3D&amp;reserved=0,
>>> and I cannot find the commit ea79c24a30aa there. Am I looking at the
>>> wrong tree?
>>>
>>
>> Yes.
>>
>> You should use the tip [1] tree .
>>
>> [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git%2F&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=XnWIcW62nTrAcDLCkHFpOPv5%2BClg11wfyh0pJ9Dug2c%3D&amp;reserved=0
> 
> Same problem with tip.git too.
> 
> bash-4.2$ git remote -v
> origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=W%2BA8qZwPicXo7OSslFPqL8s8QRxzW9n68TX1B7MXFYQ%3D&amp;reserved=0 (fetch)
> origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=W%2BA8qZwPicXo7OSslFPqL8s8QRxzW9n68TX1B7MXFYQ%3D&amp;reserved=0 (push)
> bash-4.2$ git branch
> * master
> bash-4.2$ git log --oneline | grep ea79c24a30aa
> bash-4.2$
> 
> Still missing something?
> 

I can see the base commit on my local clone and also on web interface

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=ea79c24a30aa27ccc4aac26be33f8b73f3f1f59c

thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
  2021-11-15 16:45       ` Brijesh Singh
@ 2021-11-15 16:55         ` Venu Busireddy
  2021-11-16 15:45           ` Venu Busireddy
  0 siblings, 1 reply; 80+ messages in thread
From: Venu Busireddy @ 2021-11-15 16:55 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On 2021-11-15 10:45:48 -0600, Brijesh Singh wrote:
> 
> 
> On 11/15/21 10:37 AM, Venu Busireddy wrote:
> > On 2021-11-15 10:02:24 -0600, Brijesh Singh wrote:
> > > 
> > > 
> > > On 11/15/21 9:56 AM, Venu Busireddy wrote:
> > > ...
> > > 
> > > > > The series is based on tip/master
> > > > >     ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'
> > > > 
> > > > I am looking at
> > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063489322%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=CT%2BZ6Nm6pnvVGY%2B%2FmzK4gG1zxlMNQ1fn7ie6K%2FYueTQ%3D&amp;reserved=0,
> > > > and I cannot find the commit ea79c24a30aa there. Am I looking at the
> > > > wrong tree?
> > > > 
> > > 
> > > Yes.
> > > 
> > > You should use the tip [1] tree .
> > > 
> > > [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git%2F&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=XnWIcW62nTrAcDLCkHFpOPv5%2BClg11wfyh0pJ9Dug2c%3D&amp;reserved=0
> > 
> > Same problem with tip.git too.
> > 
> > bash-4.2$ git remote -v
> > origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=W%2BA8qZwPicXo7OSslFPqL8s8QRxzW9n68TX1B7MXFYQ%3D&amp;reserved=0 (fetch)
> > origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=W%2BA8qZwPicXo7OSslFPqL8s8QRxzW9n68TX1B7MXFYQ%3D&amp;reserved=0 (push)
> > bash-4.2$ git branch
> > * master
> > bash-4.2$ git log --oneline | grep ea79c24a30aa
> > bash-4.2$
> > 
> > Still missing something?
> > 
> 
> I can see the base commit on my local clone and also on web interface

But can you see the commit ea79c24a30aa if you clone
git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git?

> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=ea79c24a30aa27ccc4aac26be33f8b73f3f1f59c

The web interface has the weird warning "Notice: this object is not
reachable from any branch." Don't know what to make of that.

Venu

> 
> thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 02/45] x86/sev: detect/setup SEV/SME features earlier in boot
  2021-11-10 22:06 ` [PATCH v7 02/45] x86/sev: " Brijesh Singh
@ 2021-11-15 19:12   ` Borislav Petkov
  2021-11-15 20:17     ` Michael Roth
  2021-12-06 23:47   ` Venu Busireddy
  1 sibling, 1 reply; 80+ messages in thread
From: Borislav Petkov @ 2021-11-15 19:12 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 04:06:48PM -0600, Brijesh Singh wrote:
> From: Michael Roth <michael.roth@amd.com>
> 
> sme_enable() handles feature detection for both SEV and SME. Future
> patches will also use it for SEV-SNP feature detection/setup, which
> will need to be done immediately after the first #VC handler is set up.
> Move it now in preparation.

I don't mind the move - what I miss is the reason why you're moving it
up.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 02/45] x86/sev: detect/setup SEV/SME features earlier in boot
  2021-11-15 19:12   ` Borislav Petkov
@ 2021-11-15 20:17     ` Michael Roth
  2021-11-17 13:11       ` Borislav Petkov
  0 siblings, 1 reply; 80+ messages in thread
From: Michael Roth @ 2021-11-15 20:17 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Brijesh Singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On Mon, Nov 15, 2021 at 08:12:09PM +0100, Borislav Petkov wrote:
> On Wed, Nov 10, 2021 at 04:06:48PM -0600, Brijesh Singh wrote:
> > From: Michael Roth <michael.roth@amd.com>
> > 
> > sme_enable() handles feature detection for both SEV and SME. Future
> > patches will also use it for SEV-SNP feature detection/setup, which
> > will need to be done immediately after the first #VC handler is set up.
> > Move it now in preparation.
> 
> I don't mind the move - what I miss is the reason why you're moving it
> up.

The early #VC handlers are needed mainly so that early cpuid instructions
can be handled for SEV-ES. In the case of SNP, the cpuid table needs to be
set up at the same time so those #VC handlers can handle cpuid lookups for
SEV-SNP guests. Previously in v6, that CPUID table setup was done with a
separate routine, snp_cpuid_init(), which was awkward because between
the point snp_cpuid_init() was called, and sme_enable() was called, we
were in an in-between state where some SEV-ES/SEV-SNP features were in
use, but they weren't actually sanity-checked against SEV status MSR and
CPUID bits until later in sme_enable(). I tried adding some of those checks
from sme_enable() into snp_cpuid_init(), but you'd suggested instead moving
the CPUID table setup into sme_enable() to avoid the duplication:

https://lore.kernel.org/linux-mm/20211027151325.v3w3nghq5z2o5dto@amd.com/

but in order for that to happen soon enough to make use of the CPUID
table for all CPUID intructions, it needs to be moved to just after the first
#VC handler is setup (where snp_cpuid_init() used to be in v6).

As for why CPUID table needs to be used for all CPUID, it's mainly so
that the CPUID values used throughout boot can be attested to later
if the guest owner validates the CPUID values in the CPUID page. I
added some documentation for why this is the case in:

 [PATCH 33/45] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement

> 
> Thx.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpeople.kernel.org%2Ftglx%2Fnotes-about-netiquette&amp;data=04%7C01%7Cmichael.roth%40amd.com%7C29ab37203c1a4c796bdc08d9a86bd7a4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637726003477466910%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=xxIMC4PM7kJ2O79gQKK7I%2BhnOsuEbckVPA9Gicz0S9w%3D&amp;reserved=0

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
  2021-11-15 16:55         ` Venu Busireddy
@ 2021-11-16 15:45           ` Venu Busireddy
  2021-11-16 16:03             ` Brijesh Singh
  0 siblings, 1 reply; 80+ messages in thread
From: Venu Busireddy @ 2021-11-16 15:45 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On 2021-11-15 10:55:32 -0600, Venu Busireddy wrote:
> On 2021-11-15 10:45:48 -0600, Brijesh Singh wrote:
> > 
> > 
> > On 11/15/21 10:37 AM, Venu Busireddy wrote:
> > > On 2021-11-15 10:02:24 -0600, Brijesh Singh wrote:
> > > > 
> > > > 
> > > > On 11/15/21 9:56 AM, Venu Busireddy wrote:
> > > > ...
> > > > 
> > > > > > The series is based on tip/master
> > > > > >     ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'
> > > > > 
> > > > > I am looking at
> > > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063489322%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=CT%2BZ6Nm6pnvVGY%2B%2FmzK4gG1zxlMNQ1fn7ie6K%2FYueTQ%3D&amp;reserved=0,
> > > > > and I cannot find the commit ea79c24a30aa there. Am I looking at the
> > > > > wrong tree?
> > > > > 
> > > > 
> > > > Yes.
> > > > 
> > > > You should use the tip [1] tree .
> > > > 
> > > > [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git%2F&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=XnWIcW62nTrAcDLCkHFpOPv5%2BClg11wfyh0pJ9Dug2c%3D&amp;reserved=0
> > > 
> > > Same problem with tip.git too.
> > > 
> > > bash-4.2$ git remote -v
> > > origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=W%2BA8qZwPicXo7OSslFPqL8s8QRxzW9n68TX1B7MXFYQ%3D&amp;reserved=0 (fetch)
> > > origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C566cca1a4ceb44dac52f08d9a85639fd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637725911063499319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=W%2BA8qZwPicXo7OSslFPqL8s8QRxzW9n68TX1B7MXFYQ%3D&amp;reserved=0 (push)
> > > bash-4.2$ git branch
> > > * master
> > > bash-4.2$ git log --oneline | grep ea79c24a30aa
> > > bash-4.2$
> > > 
> > > Still missing something?
> > > 
> > 
> > I can see the base commit on my local clone and also on web interface
> 
> But can you see the commit ea79c24a30aa if you clone
> git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git?
> 
> > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=ea79c24a30aa27ccc4aac26be33f8b73f3f1f59c
> 
> The web interface has the weird warning "Notice: this object is not
> reachable from any branch." Don't know what to make of that.

Just wanted to clarify. I am not interested in the commit ea79c24a30aa
per se. I am trying to apply this patch series to a local copy of the
tip. I tried applying to the top of the tree, and that failed. I tried
to apply on top of commit ca7752caeaa7 (which appeared to be the closest
commit to your description), and that also failed. I just need a commit
on which I can successfully apply this series.

Thanks,

Venu

> 
> Venu
> 
> > 
> > thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support
  2021-11-16 15:45           ` Venu Busireddy
@ 2021-11-16 16:03             ` Brijesh Singh
  0 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-16 16:03 UTC (permalink / raw)
  To: Venu Busireddy
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Borislav Petkov, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy



On 11/16/21 9:45 AM, Venu Busireddy wrote:
> On 2021-11-15 10:55:32 -0600, Venu Busireddy wrote:
>> On 2021-11-15 10:45:48 -0600, Brijesh Singh wrote:
>>>
>>>
>>> On 11/15/21 10:37 AM, Venu Busireddy wrote:
>>>> On 2021-11-15 10:02:24 -0600, Brijesh Singh wrote:
>>>>>
>>>>>
>>>>> On 11/15/21 9:56 AM, Venu Busireddy wrote:
>>>>> ...
>>>>>
>>>>>>> The series is based on tip/master
>>>>>>>      ea79c24a30aa (origin/master, origin/HEAD, master) Merge branch 'timers/urgent'
>>>>>>
>>>>>> I am looking at
>>>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C527b875208904981677108d9a9183dba%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637726744508270539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=hfqoF4d95hWAY8%2BKW4t5UyrWIPAUuHOTvzTQGXyxQik%3D&amp;reserved=0,
>>>>>> and I cannot find the commit ea79c24a30aa there. Am I looking at the
>>>>>> wrong tree?
>>>>>>
>>>>>
>>>>> Yes.
>>>>>
>>>>> You should use the tip [1] tree .
>>>>>
>>>>> [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git%2F&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C527b875208904981677108d9a9183dba%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637726744508270539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=TDbL2dnzCp%2FlFHv6Tr%2Fn6QhFKL2kL3DFWj5BT6Abcms%3D&amp;reserved=0
>>>>
>>>> Same problem with tip.git too.
>>>>
>>>> bash-4.2$ git remote -v
>>>> origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C527b875208904981677108d9a9183dba%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637726744508270539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=0qPjqphHSBSnpxOrPGDyJ7BF5O3fnTJtXQgnO0ZwCXY%3D&amp;reserved=0 (fetch)
>>>> origin  https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C527b875208904981677108d9a9183dba%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637726744508270539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=0qPjqphHSBSnpxOrPGDyJ7BF5O3fnTJtXQgnO0ZwCXY%3D&amp;reserved=0 (push)
>>>> bash-4.2$ git branch
>>>> * master
>>>> bash-4.2$ git log --oneline | grep ea79c24a30aa
>>>> bash-4.2$
>>>>
>>>> Still missing something?
>>>>
>>>
>>> I can see the base commit on my local clone and also on web interface
>>
>> But can you see the commit ea79c24a30aa if you clone
>> git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git?
>>
>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftip%2Ftip.git%2Fcommit%2F%3Fid%3Dea79c24a30aa27ccc4aac26be33f8b73f3f1f59c&amp;data=04%7C01%7Cbrijesh.singh%40amd.com%7C527b875208904981677108d9a9183dba%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637726744508270539%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=mG4i3ZNHgyrS3Xkdxw%2BhkmfxvzFkS%2FpX0B3xHlxN0Nc%3D&amp;reserved=0
>>
>> The web interface has the weird warning "Notice: this object is not
>> reachable from any branch." Don't know what to make of that.
> 
> Just wanted to clarify. I am not interested in the commit ea79c24a30aa
> per se. I am trying to apply this patch series to a local copy of the
> tip. I tried applying to the top of the tree, and that failed. I tried
> to apply on top of commit ca7752caeaa7 (which appeared to be the closest
> commit to your description), and that also failed. I just need a commit
> on which I can successfully apply this series.
> 

At the time I pulled the tip, the said commit was valid and my entire 
series was generated against it. Its possible that commit is no longer 
valid in the recent tip (maybe due to force push). You can grab a 
staging tree from here https://github.com/AMDESE/linux/tree/snp-part1-v7.


> Thanks,
> 
> Venu
> 
>>
>> Venu
>>
>>>
>>> thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 02/45] x86/sev: detect/setup SEV/SME features earlier in boot
  2021-11-15 20:17     ` Michael Roth
@ 2021-11-17 13:11       ` Borislav Petkov
  0 siblings, 0 replies; 80+ messages in thread
From: Borislav Petkov @ 2021-11-17 13:11 UTC (permalink / raw)
  To: Michael Roth
  Cc: Brijesh Singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On Mon, Nov 15, 2021 at 02:17:15PM -0600, Michael Roth wrote:
> but in order for that to happen soon enough to make use of the CPUID
> table for all CPUID intructions, it needs to be moved to just after the first
> #VC handler is setup (where snp_cpuid_init() used to be in v6).

So, it needs to happen after the initial IDT is loaded on the BSP in
startup_64_setup_env().

So why don't you call sme_enable() right after the
startup_64_setup_env() call and add a comment above it to explain why
this call needs to happen there?

Instead of sticking that call in startup_64_setup_env() where it doesn't
belong conceptually - enabling SME doesn't really have anything to do
with setting up early environment...

Hmm.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-10 22:07 ` [PATCH v7 43/45] virt: Add SEV-SNP guest driver Brijesh Singh
  2021-11-10 22:27   ` Randy Dunlap
@ 2021-11-17 23:34   ` Peter Gonda
  2021-11-18 17:08     ` Peter Gonda
  2021-11-18 17:32     ` Brijesh Singh
  1 sibling, 2 replies; 80+ messages in thread
From: Peter Gonda @ 2021-11-17 23:34 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Zijlstra,
	Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 3:09 PM Brijesh Singh <brijesh.singh@amd.com> wrote:
>
> SEV-SNP specification provides the guest a mechanisum to communicate with

mechanism

> the PSP without risk from a malicious hypervisor who wishes to read, alter,
> drop or replay the messages sent. The driver uses snp_issue_guest_request()
> to issue GHCB SNP_GUEST_REQUEST or SNP_EXT_GUEST_REQUEST NAE events to
> submit the request to PSP.
>
> The PSP requires that all communication should be encrypted using key
> specified through the platform_data.
>
> The userspace can use SNP_GET_REPORT ioctl() to query the guest
> attestation report.
>
> See SEV-SNP spec section Guest Messages for more details.
>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  Documentation/virt/coco/sevguest.rst  |  77 ++++
>  drivers/virt/Kconfig                  |   3 +
>  drivers/virt/Makefile                 |   1 +
>  drivers/virt/coco/sevguest/Kconfig    |   9 +
>  drivers/virt/coco/sevguest/Makefile   |   2 +
>  drivers/virt/coco/sevguest/sevguest.c | 601 ++++++++++++++++++++++++++
>  drivers/virt/coco/sevguest/sevguest.h |  98 +++++
>  include/uapi/linux/sev-guest.h        |  44 ++
>  8 files changed, 835 insertions(+)
>  create mode 100644 Documentation/virt/coco/sevguest.rst
>  create mode 100644 drivers/virt/coco/sevguest/Kconfig
>  create mode 100644 drivers/virt/coco/sevguest/Makefile
>  create mode 100644 drivers/virt/coco/sevguest/sevguest.c
>  create mode 100644 drivers/virt/coco/sevguest/sevguest.h
>  create mode 100644 include/uapi/linux/sev-guest.h
>
> diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
> new file mode 100644
> index 000000000000..002c90946b8a
> --- /dev/null
> +++ b/Documentation/virt/coco/sevguest.rst
> @@ -0,0 +1,77 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===================================================================
> +The Definitive SEV Guest API Documentation
> +===================================================================
> +
> +1. General description
> +======================
> +
> +The SEV API is a set of ioctls that are used by the guest or hypervisor
> +to get or set certain aspect of the SEV virtual machine. The ioctls belong
> +to the following classes:
> +
> + - Hypervisor ioctls: These query and set global attributes which affect the
> +   whole SEV firmware.  These ioctl are used by platform provision tools.
> +
> + - Guest ioctls: These query and set attributes of the SEV virtual machine.
> +
> +2. API description
> +==================
> +
> +This section describes ioctls that can be used to query or set SEV guests.
> +For each ioctl, the following information is provided along with a
> +description:
> +
> +  Technology:
> +      which SEV techology provides this ioctl. sev, sev-es, sev-snp or all.

technology

> +
> +  Type:
> +      hypervisor or guest. The ioctl can be used inside the guest or the
> +      hypervisor.
> +
> +  Parameters:
> +      what parameters are accepted by the ioctl.
> +
> +  Returns:
> +      the return value.  General error numbers (ENOMEM, EINVAL)
> +      are not detailed, but errors with specific meanings are.
> +
> +The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
> +The ioctl accepts struct snp_user_guest_request. The input and output structure is
> +specified through the req_data and resp_data field respectively. If the ioctl fails
> +to execute due to a firmware error, then fw_err code will be set.

Should way say what it will be set to? Also Sean pointed out on CCP
driver that 0 is strange to set the error to, its a uint so we cannot
do -1 like we did there. What about all FFs?

> +
> +::
> +        struct snp_guest_request_ioctl {
> +                /* Request and response structure address */
> +                __u64 req_data;
> +                __u64 resp_data;
> +
> +                /* firmware error code on failure (see psp-sev.h) */
> +                __u64 fw_err;
> +        };
> +
> +2.1 SNP_GET_REPORT
> +------------------
> +
> +:Technology: sev-snp
> +:Type: guest ioctl
> +:Parameters (in): struct snp_report_req
> +:Returns (out): struct snp_report_resp on success, -negative on error
> +
> +The SNP_GET_REPORT ioctl can be used to query the attestation report from the
> +SEV-SNP firmware. The ioctl uses the SNP_GUEST_REQUEST (MSG_REPORT_REQ) command
> +provided by the SEV-SNP firmware to query the attestation report.
> +
> +On success, the snp_report_resp.data will contains the report. The report

contain

> +will contain the format described in the SEV-SNP specification. See the SEV-SNP
> +specification for further details.
> +
> +
> +Reference
> +---------
> +
> +SEV-SNP and GHCB specification: developer.amd.com/sev
> +
> +The driver is based on SEV-SNP firmware spec 0.9 and GHCB spec version 2.0.
> diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
> index 8061e8ef449f..e457e47610d3 100644
> --- a/drivers/virt/Kconfig
> +++ b/drivers/virt/Kconfig
> @@ -36,4 +36,7 @@ source "drivers/virt/vboxguest/Kconfig"
>  source "drivers/virt/nitro_enclaves/Kconfig"
>
>  source "drivers/virt/acrn/Kconfig"
> +
> +source "drivers/virt/coco/sevguest/Kconfig"
> +
>  endif
> diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
> index 3e272ea60cd9..9c704a6fdcda 100644
> --- a/drivers/virt/Makefile
> +++ b/drivers/virt/Makefile
> @@ -8,3 +8,4 @@ obj-y                           += vboxguest/
>
>  obj-$(CONFIG_NITRO_ENCLAVES)   += nitro_enclaves/
>  obj-$(CONFIG_ACRN_HSM)         += acrn/
> +obj-$(CONFIG_SEV_GUEST)                += coco/sevguest/
> diff --git a/drivers/virt/coco/sevguest/Kconfig b/drivers/virt/coco/sevguest/Kconfig
> new file mode 100644
> index 000000000000..96190919cca8
> --- /dev/null
> +++ b/drivers/virt/coco/sevguest/Kconfig
> @@ -0,0 +1,9 @@
> +config SEV_GUEST
> +       tristate "AMD SEV Guest driver"
> +       default y
> +       depends on AMD_MEM_ENCRYPT && CRYPTO_AEAD2
> +       help
> +         The driver can be used by the SEV-SNP guest to communicate with the PSP to
> +         request the attestation report and more.
> +
> +         If you choose 'M' here, this module will be called sevguest.
> diff --git a/drivers/virt/coco/sevguest/Makefile b/drivers/virt/coco/sevguest/Makefile
> new file mode 100644
> index 000000000000..b1ffb2b4177b
> --- /dev/null
> +++ b/drivers/virt/coco/sevguest/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_SEV_GUEST) += sevguest.o
> diff --git a/drivers/virt/coco/sevguest/sevguest.c b/drivers/virt/coco/sevguest/sevguest.c
> new file mode 100644
> index 000000000000..982714c1b4ca
> --- /dev/null
> +++ b/drivers/virt/coco/sevguest/sevguest.c
> @@ -0,0 +1,601 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * AMD Secure Encrypted Virtualization Nested Paging (SEV-SNP) guest request interface
> + *
> + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> + *
> + * Author: Brijesh Singh <brijesh.singh@amd.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/types.h>
> +#include <linux/mutex.h>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +#include <linux/miscdevice.h>
> +#include <linux/set_memory.h>
> +#include <linux/fs.h>
> +#include <crypto/aead.h>
> +#include <linux/scatterlist.h>
> +#include <linux/psp-sev.h>
> +#include <uapi/linux/sev-guest.h>
> +#include <uapi/linux/psp-sev.h>
> +
> +#include <asm/svm.h>
> +#include <asm/sev.h>
> +
> +#include "sevguest.h"
> +
> +#define DEVICE_NAME    "sev-guest"
> +#define AAD_LEN                48
> +#define MSG_HDR_VER    1
> +
> +struct snp_guest_crypto {
> +       struct crypto_aead *tfm;
> +       u8 *iv, *authtag;
> +       int iv_len, a_len;
> +};
> +
> +struct snp_guest_dev {
> +       struct device *dev;
> +       struct miscdevice misc;
> +
> +       struct snp_guest_crypto *crypto;
> +       struct snp_guest_msg *request, *response;
> +       struct snp_secrets_page_layout *layout;
> +       struct snp_req_data input;
> +       u32 *os_area_msg_seqno;
> +       u8 *vmpck;
> +};
> +
> +static u32 vmpck_id;
> +module_param(vmpck_id, uint, 0444);
> +MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
> +
> +static DEFINE_MUTEX(snp_cmd_mutex);
> +
> +static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
> +{
> +       char zero_key[VMPCK_KEY_LEN] = {0};
> +
> +       if (snp_dev->vmpck)
> +               return memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN) == 0;
> +
> +       return true;
> +}
> +
> +static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
> +{
> +       memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
> +       snp_dev->vmpck = NULL;
> +}
> +
> +static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> +{
> +       u64 count;

I may be overly paranoid here but how about
`lockdep_assert_held(&snp_cmd_mutex);` when writing or reading
directly from this data?

> +
> +       /* Read the current message sequence counter from secrets pages */
> +       count = *snp_dev->os_area_msg_seqno;
> +
> +       return count + 1;
> +}
> +
> +/* Return a non-zero on success */
> +static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> +{
> +       u64 count = __snp_get_msg_seqno(snp_dev);
> +
> +       /*
> +        * The message sequence counter for the SNP guest request is a  64-bit
> +        * value but the version 2 of GHCB specification defines a 32-bit storage
> +        * for the it. If the counter exceeds the 32-bit value then return zero.

"for it. ..." or maybe "defines 32-bit field for the sequence counter"

> +        * The caller should check the return value, but if the caller happen to

happens

> +        * not check the value and use it, then the firmware treats zero as an
> +        * invalid number and will fail the  message request.
> +        */
> +       if (count >= UINT_MAX) {
> +               pr_err_ratelimited("SNP guest request message sequence counter overflow\n");
> +               return 0;
> +       }
> +
> +       return count;
> +}
> +
> +static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
> +{
> +       /*
> +        * The counter is also incremented by the PSP, so increment it by 2
> +        * and save in secrets page.
> +        */
> +       *snp_dev->os_area_msg_seqno += 2;
> +}
> +
> +static inline struct snp_guest_dev *to_snp_dev(struct file *file)
> +{
> +       struct miscdevice *dev = file->private_data;
> +
> +       return container_of(dev, struct snp_guest_dev, misc);
> +}
> +
> +static struct snp_guest_crypto *init_crypto(struct snp_guest_dev *snp_dev, u8 *key, size_t keylen)
> +{
> +       struct snp_guest_crypto *crypto;
> +
> +       crypto = kzalloc(sizeof(*crypto), GFP_KERNEL_ACCOUNT);
> +       if (!crypto)
> +               return NULL;
> +
> +       crypto->tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
> +       if (IS_ERR(crypto->tfm))
> +               goto e_free;
> +
> +       if (crypto_aead_setkey(crypto->tfm, key, keylen))
> +               goto e_free_crypto;
> +
> +       crypto->iv_len = crypto_aead_ivsize(crypto->tfm);
> +       if (crypto->iv_len < 12) {
> +               dev_err(snp_dev->dev, "IV length is less than 12.\n");
> +               goto e_free_crypto;
> +       }
> +
> +       crypto->iv = kmalloc(crypto->iv_len, GFP_KERNEL_ACCOUNT);
> +       if (!crypto->iv)
> +               goto e_free_crypto;
> +
> +       if (crypto_aead_authsize(crypto->tfm) > MAX_AUTHTAG_LEN) {
> +               if (crypto_aead_setauthsize(crypto->tfm, MAX_AUTHTAG_LEN)) {
> +                       dev_err(snp_dev->dev, "failed to set authsize to %d\n", MAX_AUTHTAG_LEN);
> +                       goto e_free_crypto;
> +               }
> +       }
> +
> +       crypto->a_len = crypto_aead_authsize(crypto->tfm);
> +       crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT);
> +       if (!crypto->authtag)
> +               goto e_free_crypto;
> +
> +       return crypto;
> +
> +e_free_crypto:
> +       crypto_free_aead(crypto->tfm);
> +e_free:
> +       kfree(crypto->iv);
> +       kfree(crypto->authtag);
> +       kfree(crypto);
> +
> +       return NULL;
> +}
> +
> +static void deinit_crypto(struct snp_guest_crypto *crypto)
> +{
> +       crypto_free_aead(crypto->tfm);
> +       kfree(crypto->iv);
> +       kfree(crypto->authtag);
> +       kfree(crypto);
> +}
> +
> +static int enc_dec_message(struct snp_guest_crypto *crypto, struct snp_guest_msg *msg,
> +                          u8 *src_buf, u8 *dst_buf, size_t len, bool enc)
> +{
> +       struct snp_guest_msg_hdr *hdr = &msg->hdr;
> +       struct scatterlist src[3], dst[3];
> +       DECLARE_CRYPTO_WAIT(wait);
> +       struct aead_request *req;
> +       int ret;
> +
> +       req = aead_request_alloc(crypto->tfm, GFP_KERNEL);
> +       if (!req)
> +               return -ENOMEM;
> +
> +       /*
> +        * AEAD memory operations:
> +        * +------ AAD -------+------- DATA -----+---- AUTHTAG----+
> +        * |  msg header      |  plaintext       |  hdr->authtag  |
> +        * | bytes 30h - 5Fh  |    or            |                |
> +        * |                  |   cipher         |                |
> +        * +------------------+------------------+----------------+
> +        */
> +       sg_init_table(src, 3);
> +       sg_set_buf(&src[0], &hdr->algo, AAD_LEN);
> +       sg_set_buf(&src[1], src_buf, hdr->msg_sz);
> +       sg_set_buf(&src[2], hdr->authtag, crypto->a_len);
> +
> +       sg_init_table(dst, 3);
> +       sg_set_buf(&dst[0], &hdr->algo, AAD_LEN);
> +       sg_set_buf(&dst[1], dst_buf, hdr->msg_sz);
> +       sg_set_buf(&dst[2], hdr->authtag, crypto->a_len);
> +
> +       aead_request_set_ad(req, AAD_LEN);
> +       aead_request_set_tfm(req, crypto->tfm);
> +       aead_request_set_callback(req, 0, crypto_req_done, &wait);
> +
> +       aead_request_set_crypt(req, src, dst, len, crypto->iv);
> +       ret = crypto_wait_req(enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req), &wait);
> +
> +       aead_request_free(req);
> +       return ret;
> +}
> +
> +static int __enc_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
> +                        void *plaintext, size_t len)
> +{
> +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> +       struct snp_guest_msg_hdr *hdr = &msg->hdr;
> +
> +       memset(crypto->iv, 0, crypto->iv_len);
> +       memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> +
> +       return enc_dec_message(crypto, msg, plaintext, msg->payload, len, true);
> +}
> +
> +static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
> +                      void *plaintext, size_t len)
> +{
> +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> +       struct snp_guest_msg_hdr *hdr = &msg->hdr;
> +
> +       /* Build IV with response buffer sequence number */
> +       memset(crypto->iv, 0, crypto->iv_len);
> +       memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> +
> +       return enc_dec_message(crypto, msg, msg->payload, plaintext, len, false);
> +}
> +
> +static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
> +{
> +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> +       struct snp_guest_msg *resp = snp_dev->response;
> +       struct snp_guest_msg *req = snp_dev->request;
> +       struct snp_guest_msg_hdr *req_hdr = &req->hdr;
> +       struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
> +
> +       dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
> +               resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
> +
> +       /* Verify that the sequence counter is incremented by 1 */
> +       if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
> +               return -EBADMSG;
> +
> +       /* Verify response message type and version number. */
> +       if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
> +           resp_hdr->msg_version != req_hdr->msg_version)
> +               return -EBADMSG;
> +
> +       /*
> +        * If the message size is greater than our buffer length then return
> +        * an error.
> +        */
> +       if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
> +               return -EBADMSG;
> +
> +       /* Decrypt the payload */
> +       return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
> +}
> +
> +static bool enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
> +                       void *payload, size_t sz)
> +{
> +       struct snp_guest_msg *req = snp_dev->request;
> +       struct snp_guest_msg_hdr *hdr = &req->hdr;
> +
> +       memset(req, 0, sizeof(*req));
> +
> +       hdr->algo = SNP_AEAD_AES_256_GCM;
> +       hdr->hdr_version = MSG_HDR_VER;
> +       hdr->hdr_sz = sizeof(*hdr);
> +       hdr->msg_type = type;
> +       hdr->msg_version = version;
> +       hdr->msg_seqno = seqno;
> +       hdr->msg_vmpck = vmpck_id;
> +       hdr->msg_sz = sz;
> +
> +       /* Verify the sequence number is non-zero */
> +       if (!hdr->msg_seqno)
> +               return -ENOSR;
> +
> +       dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
> +               hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
> +
> +       return __enc_payload(snp_dev, req, payload, sz);
> +}
> +
> +static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
> +                               u8 type, void *req_buf, size_t req_sz, void *resp_buf,
> +                               u32 resp_sz, __u64 *fw_err)
> +{
> +       unsigned long err;
> +       u64 seqno;
> +       int rc;
> +
> +       /* Get message sequence and verify that its a non-zero */
> +       seqno = snp_get_msg_seqno(snp_dev);
> +       if (!seqno)
> +               return -EIO;
> +
> +       memset(snp_dev->response, 0, sizeof(*snp_dev->response));
> +
> +       /* Encrypt the userspace provided payload */
> +       rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
> +       if (rc)
> +               return rc;
> +
> +       /* Call firmware to process the request */
> +       rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);

Isn't everything in the file going to be calling this with
SVM_VMGEXIT_EXT_GUEST_REQUEST because they are all placing guest
requests? If so, why not drop the @exit_code parameter and just
hardcode SVM_VMGEXIT_EXT_GUEST_REQUEST here?

> +       if (fw_err)
> +               *fw_err = err;
> +
> +       if (rc)
> +               return rc;
> +
> +       rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
> +       if (rc) {
> +               /*
> +                * The verify_and_dec_payload() will fail only if the hypervisor is
> +                * actively modifiying the message header or corrupting the encrypted payload.
modifiying
> +                * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that
> +                * the key cannot be used for any communication.
> +                */

This looks great, thanks for changes Brijesh. Should we mention in
comment here or at snp_disable_vmpck() the AES-GCM issues with
continuing to use the key? Or will future updaters to this code
understand already?


> +               dev_alert(snp_dev->dev,
> +                         "Detected unexpected decode failure, disabling the vmpck_id %d\n", vmpck_id);
> +               snp_disable_vmpck(snp_dev);
> +               return rc;
> +       }
> +
> +       /* Increment to new message sequence after payload descryption was successful. */
> +       snp_inc_msg_seqno(snp_dev);
> +
> +       return 0;
> +}
> +
> +static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> +{
> +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> +       struct snp_report_resp *resp;
> +       struct snp_report_req req;
> +       int rc, resp_len;
> +
> +       if (!arg->req_data || !arg->resp_data)
> +               return -EINVAL;
> +
> +       /* Copy the request payload from userspace */
> +       if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
> +               return -EFAULT;
> +
> +       /* Message version must be non-zero */
> +       if (!req.msg_version)
> +               return -EINVAL;
> +
> +       /*
> +        * The intermediate response buffer is used while decrypting the
> +        * response payload. Make sure that it has enough space to cover the
> +        * authtag.
> +        */
> +       resp_len = sizeof(resp->data) + crypto->a_len;
> +       resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
> +       if (!resp)
> +               return -ENOMEM;
> +
> +       /* Issue the command to get the attestation report */
> +       rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, req.msg_version,
> +                                 SNP_MSG_REPORT_REQ, &req.user_data, sizeof(req.user_data),
> +                                 resp->data, resp_len, &arg->fw_err);
> +       if (rc)
> +               goto e_free;
> +
> +       /* Copy the response payload to userspace */
> +       if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
> +               rc = -EFAULT;
> +
> +e_free:
> +       kfree(resp);
> +       return rc;
> +}
> +
> +static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
> +{
> +       struct snp_guest_dev *snp_dev = to_snp_dev(file);
> +       void __user *argp = (void __user *)arg;
> +       struct snp_guest_request_ioctl input;
> +       int ret = -ENOTTY;
> +
> +       if (copy_from_user(&input, argp, sizeof(input)))
> +               return -EFAULT;
> +
> +       input.fw_err = 0;
> +
> +       mutex_lock(&snp_cmd_mutex);
> +
> +       /* Check if the VMPCK is not empty */
> +       if (is_vmpck_empty(snp_dev)) {
> +               dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
> +               mutex_unlock(&snp_cmd_mutex);
> +               return -ENOTTY;
> +       }
> +
> +       switch (ioctl) {
> +       case SNP_GET_REPORT:
> +               ret = get_report(snp_dev, &input);
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       mutex_unlock(&snp_cmd_mutex);
> +
> +       if (input.fw_err && copy_to_user(argp, &input, sizeof(input)))
> +               return -EFAULT;
> +
> +       return ret;
> +}
> +
> +static void free_shared_pages(void *buf, size_t sz)
> +{
> +       unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> +
> +       if (!buf)
> +               return;
> +
> +       /* If fail to restore the encryption mask then leak it. */
> +       if (WARN_ONCE(set_memory_encrypted((unsigned long)buf, npages),
> +                     "Failed to restore encryption mask (leak it)\n"))
> +               return;
> +
> +       __free_pages(virt_to_page(buf), get_order(sz));
> +}
> +
> +static void *alloc_shared_pages(size_t sz)
> +{
> +       unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> +       struct page *page;
> +       int ret;
> +
> +       page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
> +       if (IS_ERR(page))
> +               return NULL;
> +
> +       ret = set_memory_decrypted((unsigned long)page_address(page), npages);
> +       if (ret) {
> +               pr_err("SEV-SNP: failed to mark page shared, ret=%d\n", ret);
> +               __free_pages(page, get_order(sz));
> +               return NULL;
> +       }

No strong preference or anything just curious. Why not allocate from
SWIOTLB or use the DMA pool that supports decrypted memory:
https://lkml.org/lkml/2020/4/14/1508.


> +
> +       return page_address(page);
> +}
> +
> +static const struct file_operations snp_guest_fops = {
> +       .owner  = THIS_MODULE,
> +       .unlocked_ioctl = snp_guest_ioctl,
> +};
> +
> +static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
> +{
> +       u8 *key = NULL;
> +
> +       switch (id) {
> +       case 0:
> +               *seqno = &layout->os_area.msg_seqno_0;
> +               key = layout->vmpck0;
> +               break;
> +       case 1:
> +               *seqno = &layout->os_area.msg_seqno_1;
> +               key = layout->vmpck1;
> +               break;
> +       case 2:
> +               *seqno = &layout->os_area.msg_seqno_2;
> +               key = layout->vmpck2;
> +               break;
> +       case 3:
> +               *seqno = &layout->os_area.msg_seqno_3;
> +               key = layout->vmpck3;
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       return key;
> +}
> +
> +static int __init snp_guest_probe(struct platform_device *pdev)
> +{
> +       struct snp_secrets_page_layout *layout;
> +       struct snp_guest_platform_data *data;
> +       struct device *dev = &pdev->dev;
> +       struct snp_guest_dev *snp_dev;
> +       struct miscdevice *misc;
> +       int ret;
> +
> +       if (!dev->platform_data)
> +               return -ENODEV;
> +
> +       data = (struct snp_guest_platform_data *)dev->platform_data;
> +       layout = (__force void *)ioremap_encrypted(data->secrets_gpa, PAGE_SIZE);
> +       if (!layout)
> +               return -ENODEV;
> +
> +       ret = -ENOMEM;
> +       snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
> +       if (!snp_dev)
> +               goto e_fail;
> +
> +       ret = -EINVAL;
> +       snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
> +       if (!snp_dev->vmpck) {
> +               dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
> +               goto e_fail;
> +       }
> +
> +       /* Verify that VMPCK is not zero. */
> +       if (is_vmpck_empty(snp_dev)) {
> +               dev_err(dev, "vmpck id %d is null\n", vmpck_id);
> +               goto e_fail;
> +       }
> +
> +       platform_set_drvdata(pdev, snp_dev);
> +       snp_dev->dev = dev;
> +       snp_dev->layout = layout;
> +
> +       /* Allocate the shared page used for the request and response message. */
> +       snp_dev->request = alloc_shared_pages(sizeof(struct snp_guest_msg));
> +       if (!snp_dev->request)
> +               goto e_fail;
> +
> +       snp_dev->response = alloc_shared_pages(sizeof(struct snp_guest_msg));
> +       if (!snp_dev->response)
> +               goto e_fail;
> +
> +       ret = -EIO;
> +       snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN);
> +       if (!snp_dev->crypto)
> +               goto e_fail;
> +
> +       misc = &snp_dev->misc;
> +       misc->minor = MISC_DYNAMIC_MINOR;
> +       misc->name = DEVICE_NAME;
> +       misc->fops = &snp_guest_fops;
> +
> +       /* initial the input address for guest request */
> +       snp_dev->input.req_gpa = __pa(snp_dev->request);
> +       snp_dev->input.resp_gpa = __pa(snp_dev->response);
> +
> +       ret =  misc_register(misc);
> +       if (ret)
> +               goto e_fail;
> +
> +       dev_info(dev, "Initialized SNP guest driver (using vmpck_id %d)\n", vmpck_id);
> +       return 0;
> +
> +e_fail:
> +       iounmap(layout);
> +       free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
> +       free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
> +
> +       return ret;
> +}
> +
> +static int __exit snp_guest_remove(struct platform_device *pdev)
> +{
> +       struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev);
> +
> +       free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
> +       free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
> +       deinit_crypto(snp_dev->crypto);
> +       misc_deregister(&snp_dev->misc);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver snp_guest_driver = {
> +       .remove         = __exit_p(snp_guest_remove),
> +       .driver         = {
> +               .name = "snp-guest",
> +       },
> +};
> +
> +module_platform_driver_probe(snp_guest_driver, snp_guest_probe);
> +
> +MODULE_AUTHOR("Brijesh Singh <brijesh.singh@amd.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION("1.0.0");
> +MODULE_DESCRIPTION("AMD SNP Guest Driver");
> diff --git a/drivers/virt/coco/sevguest/sevguest.h b/drivers/virt/coco/sevguest/sevguest.h
> new file mode 100644
> index 000000000000..cfa76cf8a21a
> --- /dev/null
> +++ b/drivers/virt/coco/sevguest/sevguest.h
> @@ -0,0 +1,98 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> + *
> + * Author: Brijesh Singh <brijesh.singh@amd.com>
> + *
> + * SEV-SNP API spec is available at https://developer.amd.com/sev
> + */
> +
> +#ifndef __LINUX_SEVGUEST_H_
> +#define __LINUX_SEVGUEST_H_
> +
> +#include <linux/types.h>
> +
> +#define MAX_AUTHTAG_LEN                32
> +
> +/* See SNP spec SNP_GUEST_REQUEST section for the structure */
> +enum msg_type {
> +       SNP_MSG_TYPE_INVALID = 0,
> +       SNP_MSG_CPUID_REQ,
> +       SNP_MSG_CPUID_RSP,
> +       SNP_MSG_KEY_REQ,
> +       SNP_MSG_KEY_RSP,
> +       SNP_MSG_REPORT_REQ,
> +       SNP_MSG_REPORT_RSP,
> +       SNP_MSG_EXPORT_REQ,
> +       SNP_MSG_EXPORT_RSP,
> +       SNP_MSG_IMPORT_REQ,
> +       SNP_MSG_IMPORT_RSP,
> +       SNP_MSG_ABSORB_REQ,
> +       SNP_MSG_ABSORB_RSP,
> +       SNP_MSG_VMRK_REQ,
> +       SNP_MSG_VMRK_RSP,

Did you want to include MSG_ABSORB_NOMA_REQ and MSG_ABSORB_NOMA_RESP here?


> +
> +       SNP_MSG_TYPE_MAX
> +};
> +
> +enum aead_algo {
> +       SNP_AEAD_INVALID,
> +       SNP_AEAD_AES_256_GCM,
> +};
> +
> +struct snp_guest_msg_hdr {
> +       u8 authtag[MAX_AUTHTAG_LEN];
> +       u64 msg_seqno;
> +       u8 rsvd1[8];
> +       u8 algo;
> +       u8 hdr_version;
> +       u16 hdr_sz;
> +       u8 msg_type;
> +       u8 msg_version;
> +       u16 msg_sz;
> +       u32 rsvd2;
> +       u8 msg_vmpck;
> +       u8 rsvd3[35];
> +} __packed;
> +
> +struct snp_guest_msg {
> +       struct snp_guest_msg_hdr hdr;
> +       u8 payload[4000];
> +} __packed;
> +
> +/*
> + * The secrets page contains 96-bytes of reserved field that can be used by
> + * the guest OS. The guest OS uses the area to save the message sequence
> + * number for each VMPCK.
> + *
> + * See the GHCB spec section Secret page layout for the format for this area.
> + */
> +struct secrets_os_area {
> +       u32 msg_seqno_0;
> +       u32 msg_seqno_1;
> +       u32 msg_seqno_2;
> +       u32 msg_seqno_3;
> +       u64 ap_jump_table_pa;
> +       u8 rsvd[40];
> +       u8 guest_usage[32];
> +} __packed;
> +
> +#define VMPCK_KEY_LEN          32
> +
> +/* See the SNP spec version 0.9 for secrets page format */
> +struct snp_secrets_page_layout {
> +       u32 version;
> +       u32 imien       : 1,
> +           rsvd1       : 31;
> +       u32 fms;
> +       u32 rsvd2;
> +       u8 gosvw[16];
> +       u8 vmpck0[VMPCK_KEY_LEN];
> +       u8 vmpck1[VMPCK_KEY_LEN];
> +       u8 vmpck2[VMPCK_KEY_LEN];
> +       u8 vmpck3[VMPCK_KEY_LEN];
> +       struct secrets_os_area os_area;
> +       u8 rsvd3[3840];
> +} __packed;
> +
> +#endif /* __LINUX_SNP_GUEST_H__ */
> diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h
> new file mode 100644
> index 000000000000..eda7edcffda8
> --- /dev/null
> +++ b/include/uapi/linux/sev-guest.h
> @@ -0,0 +1,44 @@
> +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
> +/*
> + * Userspace interface for AMD SEV and SEV-SNP guest driver.
> + *
> + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> + *
> + * Author: Brijesh Singh <brijesh.singh@amd.com>
> + *
> + * SEV API specification is available at: https://developer.amd.com/sev/
> + */
> +
> +#ifndef __UAPI_LINUX_SEV_GUEST_H_
> +#define __UAPI_LINUX_SEV_GUEST_H_
> +
> +#include <linux/types.h>
> +
> +struct snp_report_req {
> +       /* message version number (must be non-zero) */
> +       __u8 msg_version;
> +
> +       /* user data that should be included in the report */
> +       __u8 user_data[64];

Are we missing the 'vmpl' field here? Does those default all requests
to be signed with VMPL0? Users might want to change that, they could
be using a paravisor.

> +};
> +
> +struct snp_report_resp {
> +       /* response data, see SEV-SNP spec for the format */
> +       __u8 data[4000];
> +};
> +
> +struct snp_guest_request_ioctl {
> +       /* Request and response structure address */
> +       __u64 req_data;
> +       __u64 resp_data;
> +
> +       /* firmware error code on failure (see psp-sev.h) */
> +       __u64 fw_err;
> +};
> +
> +#define SNP_GUEST_REQ_IOC_TYPE 'S'
> +
> +/* Get SNP attestation report */
> +#define SNP_GET_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x0, struct snp_guest_request_ioctl)
> +
> +#endif /* __UAPI_LINUX_SEV_GUEST_H_ */
> --
> 2.25.1
>

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 44/45] virt: sevguest: Add support to derive key
  2021-11-10 22:07 ` [PATCH v7 44/45] virt: sevguest: Add support to derive key Brijesh Singh
@ 2021-11-18 16:43   ` Peter Gonda
  2021-11-18 17:43     ` Brijesh Singh
  0 siblings, 1 reply; 80+ messages in thread
From: Peter Gonda @ 2021-11-18 16:43 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Zijlstra,
	Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 3:09 PM Brijesh Singh <brijesh.singh@amd.com> wrote:
>
> The SNP_GET_DERIVED_KEY ioctl interface can be used by the SNP guest to
> ask the firmware to provide a key derived from a root key. The derived
> key may be used by the guest for any purposes it choose, such as a
> sealing key or communicating with the external entities.
>
> See SEV-SNP firmware spec for more information.
>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  Documentation/virt/coco/sevguest.rst  | 19 ++++++++++-
>  drivers/virt/coco/sevguest/sevguest.c | 49 +++++++++++++++++++++++++++
>  include/uapi/linux/sev-guest.h        | 24 +++++++++++++
>  3 files changed, 91 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
> index 002c90946b8a..0bd9a65e0370 100644
> --- a/Documentation/virt/coco/sevguest.rst
> +++ b/Documentation/virt/coco/sevguest.rst
> @@ -64,10 +64,27 @@ The SNP_GET_REPORT ioctl can be used to query the attestation report from the
>  SEV-SNP firmware. The ioctl uses the SNP_GUEST_REQUEST (MSG_REPORT_REQ) command
>  provided by the SEV-SNP firmware to query the attestation report.
>
> -On success, the snp_report_resp.data will contains the report. The report
> +On success, the snp_report_resp.data will contain the report. The report
>  will contain the format described in the SEV-SNP specification. See the SEV-SNP
>  specification for further details.
>
> +2.2 SNP_GET_DERIVED_KEY
> +-----------------------
> +:Technology: sev-snp
> +:Type: guest ioctl
> +:Parameters (in): struct snp_derived_key_req
> +:Returns (out): struct snp_derived_key_req on success, -negative on error
> +
> +The SNP_GET_DERIVED_KEY ioctl can be used to get a key derive from a root key.

derived

> +The derived key can be used by the guest for any purpose, such as sealing keys
> +or communicating with external entities.
> +
> +The ioctl uses the SNP_GUEST_REQUEST (MSG_KEY_REQ) command provided by the
> +SEV-SNP firmware to derive the key. See SEV-SNP specification for further details
> +on the various fields passed in the key derivation request.
> +
> +On success, the snp_derived_key_resp.data will contains the derived key value. See
".data will contain the..." or ".data contains the derived key..."


> +the SEV-SNP specification for further details.
>
>  Reference
>  ---------
> diff --git a/drivers/virt/coco/sevguest/sevguest.c b/drivers/virt/coco/sevguest/sevguest.c
> index 982714c1b4ca..bece6856573e 100644
> --- a/drivers/virt/coco/sevguest/sevguest.c
> +++ b/drivers/virt/coco/sevguest/sevguest.c
> @@ -392,6 +392,52 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
>         return rc;
>  }
>
> +static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> +{
> +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> +       struct snp_derived_key_resp resp = {0};
> +       struct snp_derived_key_req req;
> +       int rc, resp_len;
> +       u8 buf[89];

Could we document this magic number?

> +
> +       if (!arg->req_data || !arg->resp_data)
> +               return -EINVAL;
> +
> +       /* Copy the request payload from userspace */
> +       if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
> +               return -EFAULT;
> +
> +       /* Message version must be non-zero */
> +       if (!req.msg_version)
> +               return -EINVAL;
> +
> +       /*
> +        * The intermediate response buffer is used while decrypting the
> +        * response payload. Make sure that it has enough space to cover the
> +        * authtag.
> +        */
> +       resp_len = sizeof(resp.data) + crypto->a_len;
> +       if (sizeof(buf) < resp_len)
> +               return -ENOMEM;
> +
> +       /* Issue the command to get the attestation report */
> +       rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, req.msg_version,
> +                                 SNP_MSG_KEY_REQ, &req.data, sizeof(req.data), buf, resp_len,
> +                                 &arg->fw_err);
> +       if (rc)
> +               goto e_free;

Should we check the first 32 bits of |data| here since that is a
status field? If we see 16h here we could return -EINVAL, or better to
let userspace deal with that error handling?

> +
> +       /* Copy the response payload to userspace */
> +       memcpy(resp.data, buf, sizeof(resp.data));
> +       if (copy_to_user((void __user *)arg->resp_data, &resp, sizeof(resp)))
> +               rc = -EFAULT;
> +
> +e_free:
> +       memzero_explicit(buf, sizeof(buf));
> +       memzero_explicit(&resp, sizeof(resp));
> +       return rc;
> +}
> +
>  static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
>  {
>         struct snp_guest_dev *snp_dev = to_snp_dev(file);
> @@ -417,6 +463,9 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
>         case SNP_GET_REPORT:
>                 ret = get_report(snp_dev, &input);
>                 break;
> +       case SNP_GET_DERIVED_KEY:
> +               ret = get_derived_key(snp_dev, &input);
> +               break;
>         default:
>                 break;
>         }
> diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h
> index eda7edcffda8..f6d9c136ff4d 100644
> --- a/include/uapi/linux/sev-guest.h
> +++ b/include/uapi/linux/sev-guest.h
> @@ -36,9 +36,33 @@ struct snp_guest_request_ioctl {
>         __u64 fw_err;
>  };
>
> +struct __snp_derived_key_req {
> +       __u32 root_key_select;
> +       __u32 rsvd;
> +       __u64 guest_field_select;
> +       __u32 vmpl;
> +       __u32 guest_svn;
> +       __u64 tcb_version;
> +};
> +
> +struct snp_derived_key_req {
> +       /* message version number (must be non-zero) */
> +       __u8 msg_version;
> +
> +       struct __snp_derived_key_req data;
> +};
> +
> +struct snp_derived_key_resp {
> +       /* response data, see SEV-SNP spec for the format */
> +       __u8 data[64];
> +};
> +
>  #define SNP_GUEST_REQ_IOC_TYPE 'S'
>
>  /* Get SNP attestation report */
>  #define SNP_GET_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x0, struct snp_guest_request_ioctl)
>
> +/* Get a derived key from the root */
> +#define SNP_GET_DERIVED_KEY _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x1, struct snp_guest_request_ioctl)
> +
>  #endif /* __UAPI_LINUX_SEV_GUEST_H_ */
> --
> 2.25.1
>

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-17 23:34   ` Peter Gonda
@ 2021-11-18 17:08     ` Peter Gonda
  2021-11-18 17:32     ` Brijesh Singh
  1 sibling, 0 replies; 80+ messages in thread
From: Peter Gonda @ 2021-11-18 17:08 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Zijlstra,
	Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

. and

On Wed, Nov 17, 2021 at 4:34 PM Peter Gonda <pgonda@google.com> wrote:
>
> On Wed, Nov 10, 2021 at 3:09 PM Brijesh Singh <brijesh.singh@amd.com> wrote:
> >
> > SEV-SNP specification provides the guest a mechanisum to communicate with
>
> mechanism
>
> > the PSP without risk from a malicious hypervisor who wishes to read, alter,
> > drop or replay the messages sent. The driver uses snp_issue_guest_request()
> > to issue GHCB SNP_GUEST_REQUEST or SNP_EXT_GUEST_REQUEST NAE events to
> > submit the request to PSP.
> >
> > The PSP requires that all communication should be encrypted using key
> > specified through the platform_data.
> >
> > The userspace can use SNP_GET_REPORT ioctl() to query the guest
> > attestation report.
> >
> > See SEV-SNP spec section Guest Messages for more details.
> >
> > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> > ---
> >  Documentation/virt/coco/sevguest.rst  |  77 ++++
> >  drivers/virt/Kconfig                  |   3 +
> >  drivers/virt/Makefile                 |   1 +
> >  drivers/virt/coco/sevguest/Kconfig    |   9 +
> >  drivers/virt/coco/sevguest/Makefile   |   2 +
> >  drivers/virt/coco/sevguest/sevguest.c | 601 ++++++++++++++++++++++++++
> >  drivers/virt/coco/sevguest/sevguest.h |  98 +++++
> >  include/uapi/linux/sev-guest.h        |  44 ++
> >  8 files changed, 835 insertions(+)
> >  create mode 100644 Documentation/virt/coco/sevguest.rst
> >  create mode 100644 drivers/virt/coco/sevguest/Kconfig
> >  create mode 100644 drivers/virt/coco/sevguest/Makefile
> >  create mode 100644 drivers/virt/coco/sevguest/sevguest.c
> >  create mode 100644 drivers/virt/coco/sevguest/sevguest.h
> >  create mode 100644 include/uapi/linux/sev-guest.h
> >
> > diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst
> > new file mode 100644
> > index 000000000000..002c90946b8a
> > --- /dev/null
> > +++ b/Documentation/virt/coco/sevguest.rst
> > @@ -0,0 +1,77 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +===================================================================
> > +The Definitive SEV Guest API Documentation
> > +===================================================================
> > +
> > +1. General description
> > +======================
> > +
> > +The SEV API is a set of ioctls that are used by the guest or hypervisor
> > +to get or set certain aspect of the SEV virtual machine. The ioctls belong
> > +to the following classes:
> > +
> > + - Hypervisor ioctls: These query and set global attributes which affect the
> > +   whole SEV firmware.  These ioctl are used by platform provision tools.
> > +
> > + - Guest ioctls: These query and set attributes of the SEV virtual machine.
> > +
> > +2. API description
> > +==================
> > +
> > +This section describes ioctls that can be used to query or set SEV guests.
> > +For each ioctl, the following information is provided along with a
> > +description:
> > +
> > +  Technology:
> > +      which SEV techology provides this ioctl. sev, sev-es, sev-snp or all.
>
> technology
>
> > +
> > +  Type:
> > +      hypervisor or guest. The ioctl can be used inside the guest or the
> > +      hypervisor.
> > +
> > +  Parameters:
> > +      what parameters are accepted by the ioctl.
> > +
> > +  Returns:
> > +      the return value.  General error numbers (ENOMEM, EINVAL)
> > +      are not detailed, but errors with specific meanings are.
> > +
> > +The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
> > +The ioctl accepts struct snp_user_guest_request. The input and output structure is
> > +specified through the req_data and resp_data field respectively. If the ioctl fails
> > +to execute due to a firmware error, then fw_err code will be set.
>
> Should way say what it will be set to? Also Sean pointed out on CCP
> driver that 0 is strange to set the error to, its a uint so we cannot
> do -1 like we did there. What about all FFs?
>
> > +
> > +::
> > +        struct snp_guest_request_ioctl {
> > +                /* Request and response structure address */
> > +                __u64 req_data;
> > +                __u64 resp_data;
> > +
> > +                /* firmware error code on failure (see psp-sev.h) */
> > +                __u64 fw_err;
> > +        };
> > +
> > +2.1 SNP_GET_REPORT
> > +------------------
> > +
> > +:Technology: sev-snp
> > +:Type: guest ioctl
> > +:Parameters (in): struct snp_report_req
> > +:Returns (out): struct snp_report_resp on success, -negative on error
> > +
> > +The SNP_GET_REPORT ioctl can be used to query the attestation report from the
> > +SEV-SNP firmware. The ioctl uses the SNP_GUEST_REQUEST (MSG_REPORT_REQ) command
> > +provided by the SEV-SNP firmware to query the attestation report.
> > +
> > +On success, the snp_report_resp.data will contains the report. The report
>
> contain
>
> > +will contain the format described in the SEV-SNP specification. See the SEV-SNP
> > +specification for further details.
> > +
> > +
> > +Reference
> > +---------
> > +
> > +SEV-SNP and GHCB specification: developer.amd.com/sev
> > +
> > +The driver is based on SEV-SNP firmware spec 0.9 and GHCB spec version 2.0.
> > diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
> > index 8061e8ef449f..e457e47610d3 100644
> > --- a/drivers/virt/Kconfig
> > +++ b/drivers/virt/Kconfig
> > @@ -36,4 +36,7 @@ source "drivers/virt/vboxguest/Kconfig"
> >  source "drivers/virt/nitro_enclaves/Kconfig"
> >
> >  source "drivers/virt/acrn/Kconfig"
> > +
> > +source "drivers/virt/coco/sevguest/Kconfig"
> > +
> >  endif
> > diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
> > index 3e272ea60cd9..9c704a6fdcda 100644
> > --- a/drivers/virt/Makefile
> > +++ b/drivers/virt/Makefile
> > @@ -8,3 +8,4 @@ obj-y                           += vboxguest/
> >
> >  obj-$(CONFIG_NITRO_ENCLAVES)   += nitro_enclaves/
> >  obj-$(CONFIG_ACRN_HSM)         += acrn/
> > +obj-$(CONFIG_SEV_GUEST)                += coco/sevguest/
> > diff --git a/drivers/virt/coco/sevguest/Kconfig b/drivers/virt/coco/sevguest/Kconfig
> > new file mode 100644
> > index 000000000000..96190919cca8
> > --- /dev/null
> > +++ b/drivers/virt/coco/sevguest/Kconfig
> > @@ -0,0 +1,9 @@
> > +config SEV_GUEST
> > +       tristate "AMD SEV Guest driver"
> > +       default y
> > +       depends on AMD_MEM_ENCRYPT && CRYPTO_AEAD2
> > +       help
> > +         The driver can be used by the SEV-SNP guest to communicate with the PSP to
> > +         request the attestation report and more.
> > +
> > +         If you choose 'M' here, this module will be called sevguest.
> > diff --git a/drivers/virt/coco/sevguest/Makefile b/drivers/virt/coco/sevguest/Makefile
> > new file mode 100644
> > index 000000000000..b1ffb2b4177b
> > --- /dev/null
> > +++ b/drivers/virt/coco/sevguest/Makefile
> > @@ -0,0 +1,2 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +obj-$(CONFIG_SEV_GUEST) += sevguest.o
> > diff --git a/drivers/virt/coco/sevguest/sevguest.c b/drivers/virt/coco/sevguest/sevguest.c
> > new file mode 100644
> > index 000000000000..982714c1b4ca
> > --- /dev/null
> > +++ b/drivers/virt/coco/sevguest/sevguest.c
> > @@ -0,0 +1,601 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * AMD Secure Encrypted Virtualization Nested Paging (SEV-SNP) guest request interface
> > + *
> > + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> > + *
> > + * Author: Brijesh Singh <brijesh.singh@amd.com>
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/types.h>
> > +#include <linux/mutex.h>
> > +#include <linux/io.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/miscdevice.h>
> > +#include <linux/set_memory.h>
> > +#include <linux/fs.h>
> > +#include <crypto/aead.h>
> > +#include <linux/scatterlist.h>
> > +#include <linux/psp-sev.h>
> > +#include <uapi/linux/sev-guest.h>
> > +#include <uapi/linux/psp-sev.h>
> > +
> > +#include <asm/svm.h>
> > +#include <asm/sev.h>
> > +
> > +#include "sevguest.h"
> > +
> > +#define DEVICE_NAME    "sev-guest"
> > +#define AAD_LEN                48
> > +#define MSG_HDR_VER    1
> > +
> > +struct snp_guest_crypto {
> > +       struct crypto_aead *tfm;
> > +       u8 *iv, *authtag;
> > +       int iv_len, a_len;
> > +};
> > +
> > +struct snp_guest_dev {
> > +       struct device *dev;
> > +       struct miscdevice misc;
> > +
> > +       struct snp_guest_crypto *crypto;
> > +       struct snp_guest_msg *request, *response;
> > +       struct snp_secrets_page_layout *layout;
> > +       struct snp_req_data input;
> > +       u32 *os_area_msg_seqno;
> > +       u8 *vmpck;
> > +};
> > +
> > +static u32 vmpck_id;
> > +module_param(vmpck_id, uint, 0444);
> > +MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
> > +
> > +static DEFINE_MUTEX(snp_cmd_mutex);
> > +
> > +static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
> > +{
> > +       char zero_key[VMPCK_KEY_LEN] = {0};
> > +
> > +       if (snp_dev->vmpck)
> > +               return memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN) == 0;
> > +
> > +       return true;
> > +}
> > +
> > +static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
> > +{
> > +       memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
> > +       snp_dev->vmpck = NULL;
> > +}
> > +
> > +static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> > +{
> > +       u64 count;
>
> I may be overly paranoid here but how about
> `lockdep_assert_held(&snp_cmd_mutex);` when writing or reading
> directly from this data?
>
> > +
> > +       /* Read the current message sequence counter from secrets pages */
> > +       count = *snp_dev->os_area_msg_seqno;
> > +
> > +       return count + 1;
> > +}
> > +
> > +/* Return a non-zero on success */
> > +static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> > +{
> > +       u64 count = __snp_get_msg_seqno(snp_dev);
> > +
> > +       /*
> > +        * The message sequence counter for the SNP guest request is a  64-bit
> > +        * value but the version 2 of GHCB specification defines a 32-bit storage
> > +        * for the it. If the counter exceeds the 32-bit value then return zero.
>
> "for it. ..." or maybe "defines 32-bit field for the sequence counter"
>
> > +        * The caller should check the return value, but if the caller happen to
>
> happens
>
> > +        * not check the value and use it, then the firmware treats zero as an
> > +        * invalid number and will fail the  message request.
> > +        */
> > +       if (count >= UINT_MAX) {
> > +               pr_err_ratelimited("SNP guest request message sequence counter overflow\n");
> > +               return 0;
> > +       }
> > +
> > +       return count;
> > +}
> > +
> > +static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
> > +{
> > +       /*
> > +        * The counter is also incremented by the PSP, so increment it by 2
> > +        * and save in secrets page.
> > +        */
> > +       *snp_dev->os_area_msg_seqno += 2;
> > +}
> > +
> > +static inline struct snp_guest_dev *to_snp_dev(struct file *file)
> > +{
> > +       struct miscdevice *dev = file->private_data;
> > +
> > +       return container_of(dev, struct snp_guest_dev, misc);
> > +}
> > +
> > +static struct snp_guest_crypto *init_crypto(struct snp_guest_dev *snp_dev, u8 *key, size_t keylen)
> > +{
> > +       struct snp_guest_crypto *crypto;
> > +
> > +       crypto = kzalloc(sizeof(*crypto), GFP_KERNEL_ACCOUNT);
> > +       if (!crypto)
> > +               return NULL;
> > +
> > +       crypto->tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
> > +       if (IS_ERR(crypto->tfm))
> > +               goto e_free;
> > +
> > +       if (crypto_aead_setkey(crypto->tfm, key, keylen))
> > +               goto e_free_crypto;
> > +
> > +       crypto->iv_len = crypto_aead_ivsize(crypto->tfm);
> > +       if (crypto->iv_len < 12) {
> > +               dev_err(snp_dev->dev, "IV length is less than 12.\n");
> > +               goto e_free_crypto;
> > +       }
> > +
> > +       crypto->iv = kmalloc(crypto->iv_len, GFP_KERNEL_ACCOUNT);
> > +       if (!crypto->iv)
> > +               goto e_free_crypto;
> > +
> > +       if (crypto_aead_authsize(crypto->tfm) > MAX_AUTHTAG_LEN) {
> > +               if (crypto_aead_setauthsize(crypto->tfm, MAX_AUTHTAG_LEN)) {
> > +                       dev_err(snp_dev->dev, "failed to set authsize to %d\n", MAX_AUTHTAG_LEN);
> > +                       goto e_free_crypto;
> > +               }
> > +       }
> > +
> > +       crypto->a_len = crypto_aead_authsize(crypto->tfm);
> > +       crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT);
> > +       if (!crypto->authtag)
> > +               goto e_free_crypto;
> > +
> > +       return crypto;
> > +
> > +e_free_crypto:
> > +       crypto_free_aead(crypto->tfm);
> > +e_free:
> > +       kfree(crypto->iv);
> > +       kfree(crypto->authtag);
> > +       kfree(crypto);
> > +
> > +       return NULL;
> > +}
> > +
> > +static void deinit_crypto(struct snp_guest_crypto *crypto)
> > +{
> > +       crypto_free_aead(crypto->tfm);
> > +       kfree(crypto->iv);
> > +       kfree(crypto->authtag);
> > +       kfree(crypto);
> > +}
> > +
> > +static int enc_dec_message(struct snp_guest_crypto *crypto, struct snp_guest_msg *msg,
> > +                          u8 *src_buf, u8 *dst_buf, size_t len, bool enc)
> > +{
> > +       struct snp_guest_msg_hdr *hdr = &msg->hdr;
> > +       struct scatterlist src[3], dst[3];
> > +       DECLARE_CRYPTO_WAIT(wait);
> > +       struct aead_request *req;
> > +       int ret;
> > +
> > +       req = aead_request_alloc(crypto->tfm, GFP_KERNEL);
> > +       if (!req)
> > +               return -ENOMEM;
> > +
> > +       /*
> > +        * AEAD memory operations:
> > +        * +------ AAD -------+------- DATA -----+---- AUTHTAG----+
> > +        * |  msg header      |  plaintext       |  hdr->authtag  |
> > +        * | bytes 30h - 5Fh  |    or            |                |
> > +        * |                  |   cipher         |                |
> > +        * +------------------+------------------+----------------+
> > +        */
> > +       sg_init_table(src, 3);
> > +       sg_set_buf(&src[0], &hdr->algo, AAD_LEN);
> > +       sg_set_buf(&src[1], src_buf, hdr->msg_sz);
> > +       sg_set_buf(&src[2], hdr->authtag, crypto->a_len);
> > +
> > +       sg_init_table(dst, 3);
> > +       sg_set_buf(&dst[0], &hdr->algo, AAD_LEN);
> > +       sg_set_buf(&dst[1], dst_buf, hdr->msg_sz);
> > +       sg_set_buf(&dst[2], hdr->authtag, crypto->a_len);
> > +
> > +       aead_request_set_ad(req, AAD_LEN);
> > +       aead_request_set_tfm(req, crypto->tfm);
> > +       aead_request_set_callback(req, 0, crypto_req_done, &wait);
> > +
> > +       aead_request_set_crypt(req, src, dst, len, crypto->iv);
> > +       ret = crypto_wait_req(enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req), &wait);
> > +
> > +       aead_request_free(req);
> > +       return ret;
> > +}
> > +
> > +static int __enc_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
> > +                        void *plaintext, size_t len)
> > +{
> > +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> > +       struct snp_guest_msg_hdr *hdr = &msg->hdr;
> > +
> > +       memset(crypto->iv, 0, crypto->iv_len);
> > +       memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> > +
> > +       return enc_dec_message(crypto, msg, plaintext, msg->payload, len, true);
> > +}
> > +
> > +static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
> > +                      void *plaintext, size_t len)
> > +{
> > +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> > +       struct snp_guest_msg_hdr *hdr = &msg->hdr;
> > +
> > +       /* Build IV with response buffer sequence number */
> > +       memset(crypto->iv, 0, crypto->iv_len);
> > +       memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> > +
> > +       return enc_dec_message(crypto, msg, msg->payload, plaintext, len, false);
> > +}
> > +
> > +static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
> > +{
> > +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> > +       struct snp_guest_msg *resp = snp_dev->response;
> > +       struct snp_guest_msg *req = snp_dev->request;
> > +       struct snp_guest_msg_hdr *req_hdr = &req->hdr;
> > +       struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
> > +
> > +       dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
> > +               resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
> > +
> > +       /* Verify that the sequence counter is incremented by 1 */
> > +       if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
> > +               return -EBADMSG;
> > +
> > +       /* Verify response message type and version number. */
> > +       if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
> > +           resp_hdr->msg_version != req_hdr->msg_version)
> > +               return -EBADMSG;
> > +
> > +       /*
> > +        * If the message size is greater than our buffer length then return
> > +        * an error.
> > +        */
> > +       if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
> > +               return -EBADMSG;
> > +
> > +       /* Decrypt the payload */
> > +       return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
> > +}
> > +
> > +static bool enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
> > +                       void *payload, size_t sz)
> > +{
> > +       struct snp_guest_msg *req = snp_dev->request;
> > +       struct snp_guest_msg_hdr *hdr = &req->hdr;
> > +
> > +       memset(req, 0, sizeof(*req));
> > +
> > +       hdr->algo = SNP_AEAD_AES_256_GCM;
> > +       hdr->hdr_version = MSG_HDR_VER;
> > +       hdr->hdr_sz = sizeof(*hdr);
> > +       hdr->msg_type = type;
> > +       hdr->msg_version = version;
> > +       hdr->msg_seqno = seqno;
> > +       hdr->msg_vmpck = vmpck_id;
> > +       hdr->msg_sz = sz;
> > +
> > +       /* Verify the sequence number is non-zero */
> > +       if (!hdr->msg_seqno)
> > +               return -ENOSR;
> > +
> > +       dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
> > +               hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
> > +
> > +       return __enc_payload(snp_dev, req, payload, sz);
> > +}
> > +
> > +static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
> > +                               u8 type, void *req_buf, size_t req_sz, void *resp_buf,
> > +                               u32 resp_sz, __u64 *fw_err)
> > +{
> > +       unsigned long err;
> > +       u64 seqno;
> > +       int rc;
> > +
> > +       /* Get message sequence and verify that its a non-zero */
> > +       seqno = snp_get_msg_seqno(snp_dev);
> > +       if (!seqno)
> > +               return -EIO;
> > +
> > +       memset(snp_dev->response, 0, sizeof(*snp_dev->response));
> > +
> > +       /* Encrypt the userspace provided payload */
> > +       rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
> > +       if (rc)
> > +               return rc;
> > +
> > +       /* Call firmware to process the request */
> > +       rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
>
> Isn't everything in the file going to be calling this with
> SVM_VMGEXIT_EXT_GUEST_REQUEST because they are all placing guest
> requests? If so, why not drop the @exit_code parameter and just
> hardcode SVM_VMGEXIT_EXT_GUEST_REQUEST here?

Oops I see we use SVM_VMGEXIT_GUEST_REQUEST and
SVM_VMGEXIT_GUEST_REQUEST, nevermind here.

>
> > +       if (fw_err)
> > +               *fw_err = err;
> > +
> > +       if (rc)
> > +               return rc;
> > +
> > +       rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
> > +       if (rc) {
> > +               /*
> > +                * The verify_and_dec_payload() will fail only if the hypervisor is
> > +                * actively modifiying the message header or corrupting the encrypted payload.
> modifiying
> > +                * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that
> > +                * the key cannot be used for any communication.
> > +                */
>
> This looks great, thanks for changes Brijesh. Should we mention in
> comment here or at snp_disable_vmpck() the AES-GCM issues with
> continuing to use the key? Or will future updaters to this code
> understand already?
>
>
> > +               dev_alert(snp_dev->dev,
> > +                         "Detected unexpected decode failure, disabling the vmpck_id %d\n", vmpck_id);
> > +               snp_disable_vmpck(snp_dev);
> > +               return rc;
> > +       }
> > +
> > +       /* Increment to new message sequence after payload descryption was successful. */
> > +       snp_inc_msg_seqno(snp_dev);
> > +
> > +       return 0;
> > +}
> > +
> > +static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> > +{
> > +       struct snp_guest_crypto *crypto = snp_dev->crypto;
> > +       struct snp_report_resp *resp;
> > +       struct snp_report_req req;
> > +       int rc, resp_len;
> > +
> > +       if (!arg->req_data || !arg->resp_data)
> > +               return -EINVAL;
> > +
> > +       /* Copy the request payload from userspace */
> > +       if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
> > +               return -EFAULT;
> > +
> > +       /* Message version must be non-zero */
> > +       if (!req.msg_version)
> > +               return -EINVAL;
> > +
> > +       /*
> > +        * The intermediate response buffer is used while decrypting the
> > +        * response payload. Make sure that it has enough space to cover the
> > +        * authtag.
> > +        */
> > +       resp_len = sizeof(resp->data) + crypto->a_len;
> > +       resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
> > +       if (!resp)
> > +               return -ENOMEM;
> > +
> > +       /* Issue the command to get the attestation report */
> > +       rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, req.msg_version,
> > +                                 SNP_MSG_REPORT_REQ, &req.user_data, sizeof(req.user_data),
> > +                                 resp->data, resp_len, &arg->fw_err);
> > +       if (rc)
> > +               goto e_free;
> > +
> > +       /* Copy the response payload to userspace */
> > +       if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
> > +               rc = -EFAULT;
> > +
> > +e_free:
> > +       kfree(resp);
> > +       return rc;
> > +}
> > +
> > +static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
> > +{
> > +       struct snp_guest_dev *snp_dev = to_snp_dev(file);
> > +       void __user *argp = (void __user *)arg;
> > +       struct snp_guest_request_ioctl input;
> > +       int ret = -ENOTTY;
> > +
> > +       if (copy_from_user(&input, argp, sizeof(input)))
> > +               return -EFAULT;
> > +
> > +       input.fw_err = 0;
> > +
> > +       mutex_lock(&snp_cmd_mutex);
> > +
> > +       /* Check if the VMPCK is not empty */
> > +       if (is_vmpck_empty(snp_dev)) {
> > +               dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
> > +               mutex_unlock(&snp_cmd_mutex);
> > +               return -ENOTTY;
> > +       }
> > +
> > +       switch (ioctl) {
> > +       case SNP_GET_REPORT:
> > +               ret = get_report(snp_dev, &input);
> > +               break;
> > +       default:
> > +               break;
> > +       }
> > +
> > +       mutex_unlock(&snp_cmd_mutex);
> > +
> > +       if (input.fw_err && copy_to_user(argp, &input, sizeof(input)))
> > +               return -EFAULT;
> > +
> > +       return ret;
> > +}
> > +
> > +static void free_shared_pages(void *buf, size_t sz)
> > +{
> > +       unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> > +
> > +       if (!buf)
> > +               return;
> > +
> > +       /* If fail to restore the encryption mask then leak it. */
> > +       if (WARN_ONCE(set_memory_encrypted((unsigned long)buf, npages),
> > +                     "Failed to restore encryption mask (leak it)\n"))
> > +               return;
> > +
> > +       __free_pages(virt_to_page(buf), get_order(sz));
> > +}
> > +
> > +static void *alloc_shared_pages(size_t sz)
> > +{
> > +       unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> > +       struct page *page;
> > +       int ret;
> > +
> > +       page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
> > +       if (IS_ERR(page))
> > +               return NULL;
> > +
> > +       ret = set_memory_decrypted((unsigned long)page_address(page), npages);
> > +       if (ret) {
> > +               pr_err("SEV-SNP: failed to mark page shared, ret=%d\n", ret);
> > +               __free_pages(page, get_order(sz));
> > +               return NULL;
> > +       }
>
> No strong preference or anything just curious. Why not allocate from
> SWIOTLB or use the DMA pool that supports decrypted memory:
> https://lkml.org/lkml/2020/4/14/1508.
>
>
> > +
> > +       return page_address(page);
> > +}
> > +
> > +static const struct file_operations snp_guest_fops = {
> > +       .owner  = THIS_MODULE,
> > +       .unlocked_ioctl = snp_guest_ioctl,
> > +};
> > +
> > +static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
> > +{
> > +       u8 *key = NULL;
> > +
> > +       switch (id) {
> > +       case 0:
> > +               *seqno = &layout->os_area.msg_seqno_0;
> > +               key = layout->vmpck0;
> > +               break;
> > +       case 1:
> > +               *seqno = &layout->os_area.msg_seqno_1;
> > +               key = layout->vmpck1;
> > +               break;
> > +       case 2:
> > +               *seqno = &layout->os_area.msg_seqno_2;
> > +               key = layout->vmpck2;
> > +               break;
> > +       case 3:
> > +               *seqno = &layout->os_area.msg_seqno_3;
> > +               key = layout->vmpck3;
> > +               break;
> > +       default:
> > +               break;
> > +       }
> > +
> > +       return key;
> > +}
> > +
> > +static int __init snp_guest_probe(struct platform_device *pdev)
> > +{
> > +       struct snp_secrets_page_layout *layout;
> > +       struct snp_guest_platform_data *data;
> > +       struct device *dev = &pdev->dev;
> > +       struct snp_guest_dev *snp_dev;
> > +       struct miscdevice *misc;
> > +       int ret;
> > +
> > +       if (!dev->platform_data)
> > +               return -ENODEV;
> > +
> > +       data = (struct snp_guest_platform_data *)dev->platform_data;
> > +       layout = (__force void *)ioremap_encrypted(data->secrets_gpa, PAGE_SIZE);
> > +       if (!layout)
> > +               return -ENODEV;
> > +
> > +       ret = -ENOMEM;
> > +       snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
> > +       if (!snp_dev)
> > +               goto e_fail;
> > +
> > +       ret = -EINVAL;
> > +       snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
> > +       if (!snp_dev->vmpck) {
> > +               dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
> > +               goto e_fail;
> > +       }
> > +
> > +       /* Verify that VMPCK is not zero. */
> > +       if (is_vmpck_empty(snp_dev)) {
> > +               dev_err(dev, "vmpck id %d is null\n", vmpck_id);
> > +               goto e_fail;
> > +       }
> > +
> > +       platform_set_drvdata(pdev, snp_dev);
> > +       snp_dev->dev = dev;
> > +       snp_dev->layout = layout;
> > +
> > +       /* Allocate the shared page used for the request and response message. */
> > +       snp_dev->request = alloc_shared_pages(sizeof(struct snp_guest_msg));
> > +       if (!snp_dev->request)
> > +               goto e_fail;
> > +
> > +       snp_dev->response = alloc_shared_pages(sizeof(struct snp_guest_msg));
> > +       if (!snp_dev->response)
> > +               goto e_fail;
> > +
> > +       ret = -EIO;
> > +       snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN);
> > +       if (!snp_dev->crypto)
> > +               goto e_fail;
> > +
> > +       misc = &snp_dev->misc;
> > +       misc->minor = MISC_DYNAMIC_MINOR;
> > +       misc->name = DEVICE_NAME;
> > +       misc->fops = &snp_guest_fops;
> > +
> > +       /* initial the input address for guest request */
> > +       snp_dev->input.req_gpa = __pa(snp_dev->request);
> > +       snp_dev->input.resp_gpa = __pa(snp_dev->response);
> > +
> > +       ret =  misc_register(misc);
> > +       if (ret)
> > +               goto e_fail;
> > +
> > +       dev_info(dev, "Initialized SNP guest driver (using vmpck_id %d)\n", vmpck_id);
> > +       return 0;
> > +
> > +e_fail:
> > +       iounmap(layout);
> > +       free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
> > +       free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
> > +
> > +       return ret;
> > +}
> > +
> > +static int __exit snp_guest_remove(struct platform_device *pdev)
> > +{
> > +       struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev);
> > +
> > +       free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
> > +       free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
> > +       deinit_crypto(snp_dev->crypto);
> > +       misc_deregister(&snp_dev->misc);
> > +
> > +       return 0;
> > +}
> > +
> > +static struct platform_driver snp_guest_driver = {
> > +       .remove         = __exit_p(snp_guest_remove),
> > +       .driver         = {
> > +               .name = "snp-guest",
> > +       },
> > +};
> > +
> > +module_platform_driver_probe(snp_guest_driver, snp_guest_probe);
> > +
> > +MODULE_AUTHOR("Brijesh Singh <brijesh.singh@amd.com>");
> > +MODULE_LICENSE("GPL");
> > +MODULE_VERSION("1.0.0");
> > +MODULE_DESCRIPTION("AMD SNP Guest Driver");
> > diff --git a/drivers/virt/coco/sevguest/sevguest.h b/drivers/virt/coco/sevguest/sevguest.h
> > new file mode 100644
> > index 000000000000..cfa76cf8a21a
> > --- /dev/null
> > +++ b/drivers/virt/coco/sevguest/sevguest.h
> > @@ -0,0 +1,98 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> > + *
> > + * Author: Brijesh Singh <brijesh.singh@amd.com>
> > + *
> > + * SEV-SNP API spec is available at https://developer.amd.com/sev
> > + */
> > +
> > +#ifndef __LINUX_SEVGUEST_H_
> > +#define __LINUX_SEVGUEST_H_
> > +
> > +#include <linux/types.h>
> > +
> > +#define MAX_AUTHTAG_LEN                32
> > +
> > +/* See SNP spec SNP_GUEST_REQUEST section for the structure */
> > +enum msg_type {
> > +       SNP_MSG_TYPE_INVALID = 0,
> > +       SNP_MSG_CPUID_REQ,
> > +       SNP_MSG_CPUID_RSP,
> > +       SNP_MSG_KEY_REQ,
> > +       SNP_MSG_KEY_RSP,
> > +       SNP_MSG_REPORT_REQ,
> > +       SNP_MSG_REPORT_RSP,
> > +       SNP_MSG_EXPORT_REQ,
> > +       SNP_MSG_EXPORT_RSP,
> > +       SNP_MSG_IMPORT_REQ,
> > +       SNP_MSG_IMPORT_RSP,
> > +       SNP_MSG_ABSORB_REQ,
> > +       SNP_MSG_ABSORB_RSP,
> > +       SNP_MSG_VMRK_REQ,
> > +       SNP_MSG_VMRK_RSP,
>
> Did you want to include MSG_ABSORB_NOMA_REQ and MSG_ABSORB_NOMA_RESP here?
>
>
> > +
> > +       SNP_MSG_TYPE_MAX
> > +};
> > +
> > +enum aead_algo {
> > +       SNP_AEAD_INVALID,
> > +       SNP_AEAD_AES_256_GCM,
> > +};
> > +
> > +struct snp_guest_msg_hdr {
> > +       u8 authtag[MAX_AUTHTAG_LEN];
> > +       u64 msg_seqno;
> > +       u8 rsvd1[8];
> > +       u8 algo;
> > +       u8 hdr_version;
> > +       u16 hdr_sz;
> > +       u8 msg_type;
> > +       u8 msg_version;
> > +       u16 msg_sz;
> > +       u32 rsvd2;
> > +       u8 msg_vmpck;
> > +       u8 rsvd3[35];
> > +} __packed;
> > +
> > +struct snp_guest_msg {
> > +       struct snp_guest_msg_hdr hdr;
> > +       u8 payload[4000];
> > +} __packed;
> > +
> > +/*
> > + * The secrets page contains 96-bytes of reserved field that can be used by
> > + * the guest OS. The guest OS uses the area to save the message sequence
> > + * number for each VMPCK.
> > + *
> > + * See the GHCB spec section Secret page layout for the format for this area.
> > + */
> > +struct secrets_os_area {
> > +       u32 msg_seqno_0;
> > +       u32 msg_seqno_1;
> > +       u32 msg_seqno_2;
> > +       u32 msg_seqno_3;
> > +       u64 ap_jump_table_pa;
> > +       u8 rsvd[40];
> > +       u8 guest_usage[32];
> > +} __packed;
> > +
> > +#define VMPCK_KEY_LEN          32
> > +
> > +/* See the SNP spec version 0.9 for secrets page format */
> > +struct snp_secrets_page_layout {
> > +       u32 version;
> > +       u32 imien       : 1,
> > +           rsvd1       : 31;
> > +       u32 fms;
> > +       u32 rsvd2;
> > +       u8 gosvw[16];
> > +       u8 vmpck0[VMPCK_KEY_LEN];
> > +       u8 vmpck1[VMPCK_KEY_LEN];
> > +       u8 vmpck2[VMPCK_KEY_LEN];
> > +       u8 vmpck3[VMPCK_KEY_LEN];
> > +       struct secrets_os_area os_area;
> > +       u8 rsvd3[3840];
> > +} __packed;
> > +
> > +#endif /* __LINUX_SNP_GUEST_H__ */
> > diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h
> > new file mode 100644
> > index 000000000000..eda7edcffda8
> > --- /dev/null
> > +++ b/include/uapi/linux/sev-guest.h
> > @@ -0,0 +1,44 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
> > +/*
> > + * Userspace interface for AMD SEV and SEV-SNP guest driver.
> > + *
> > + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> > + *
> > + * Author: Brijesh Singh <brijesh.singh@amd.com>
> > + *
> > + * SEV API specification is available at: https://developer.amd.com/sev/
> > + */
> > +
> > +#ifndef __UAPI_LINUX_SEV_GUEST_H_
> > +#define __UAPI_LINUX_SEV_GUEST_H_
> > +
> > +#include <linux/types.h>
> > +
> > +struct snp_report_req {
> > +       /* message version number (must be non-zero) */
> > +       __u8 msg_version;
> > +
> > +       /* user data that should be included in the report */
> > +       __u8 user_data[64];
>
> Are we missing the 'vmpl' field here? Does those default all requests
> to be signed with VMPL0? Users might want to change that, they could
> be using a paravisor.
>
> > +};
> > +
> > +struct snp_report_resp {
> > +       /* response data, see SEV-SNP spec for the format */
> > +       __u8 data[4000];
> > +};
> > +
> > +struct snp_guest_request_ioctl {
> > +       /* Request and response structure address */
> > +       __u64 req_data;
> > +       __u64 resp_data;
> > +
> > +       /* firmware error code on failure (see psp-sev.h) */
> > +       __u64 fw_err;
> > +};
> > +
> > +#define SNP_GUEST_REQ_IOC_TYPE 'S'
> > +
> > +/* Get SNP attestation report */
> > +#define SNP_GET_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x0, struct snp_guest_request_ioctl)
> > +
> > +#endif /* __UAPI_LINUX_SEV_GUEST_H_ */
> > --
> > 2.25.1
> >

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-17 23:34   ` Peter Gonda
  2021-11-18 17:08     ` Peter Gonda
@ 2021-11-18 17:32     ` Brijesh Singh
  2021-11-19 16:16       ` Peter Gonda
  1 sibling, 1 reply; 80+ messages in thread
From: Brijesh Singh @ 2021-11-18 17:32 UTC (permalink / raw)
  To: Peter Gonda
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Borislav Petkov, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy



On 11/17/21 5:34 PM, Peter Gonda wrote:


>> +The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
>> +The ioctl accepts struct snp_user_guest_request. The input and output structure is
>> +specified through the req_data and resp_data field respectively. If the ioctl fails
>> +to execute due to a firmware error, then fw_err code will be set.
> 
> Should way say what it will be set to? Also Sean pointed out on CCP
> driver that 0 is strange to set the error to, its a uint so we cannot
> do -1 like we did there. What about all FFs?
> 

Sure, all FF's works, I can document and use it.


>> +static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
>> +{
>> +       u64 count;
> 
> I may be overly paranoid here but how about
> `lockdep_assert_held(&snp_cmd_mutex);` when writing or reading
> directly from this data?
> 

Sure, I can do it.

...

>> +
>> +       if (rc)
>> +               return rc;
>> +
>> +       rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
>> +       if (rc) {
>> +               /*
>> +                * The verify_and_dec_payload() will fail only if the hypervisor is
>> +                * actively modifiying the message header or corrupting the encrypted payload.
> modifiying
>> +                * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that
>> +                * the key cannot be used for any communication.
>> +                */
> 
> This looks great, thanks for changes Brijesh. Should we mention in
> comment here or at snp_disable_vmpck() the AES-GCM issues with
> continuing to use the key? Or will future updaters to this code
> understand already?
> 

Sure, I can add comment about the AES-GCM.

...

>> +
>> +/* See SNP spec SNP_GUEST_REQUEST section for the structure */
>> +enum msg_type {
>> +       SNP_MSG_TYPE_INVALID = 0,
>> +       SNP_MSG_CPUID_REQ,
>> +       SNP_MSG_CPUID_RSP,
>> +       SNP_MSG_KEY_REQ,
>> +       SNP_MSG_KEY_RSP,
>> +       SNP_MSG_REPORT_REQ,
>> +       SNP_MSG_REPORT_RSP,
>> +       SNP_MSG_EXPORT_REQ,
>> +       SNP_MSG_EXPORT_RSP,
>> +       SNP_MSG_IMPORT_REQ,
>> +       SNP_MSG_IMPORT_RSP,
>> +       SNP_MSG_ABSORB_REQ,
>> +       SNP_MSG_ABSORB_RSP,
>> +       SNP_MSG_VMRK_REQ,
>> +       SNP_MSG_VMRK_RSP,
> 
> Did you want to include MSG_ABSORB_NOMA_REQ and MSG_ABSORB_NOMA_RESP here?
> 

Yes, I can includes those for the completeness.

...

>> +struct snp_report_req {
>> +       /* message version number (must be non-zero) */
>> +       __u8 msg_version;
>> +
>> +       /* user data that should be included in the report */
>> +       __u8 user_data[64];
> 
> Are we missing the 'vmpl' field here? Does those default all requests
> to be signed with VMPL0? Users might want to change that, they could
> be using a paravisor.
> 

Good question, so far I was thinking that guest kernel will provide its 
vmpl level instead of accepted the vmpl level from the userspace. Do you 
see a need for a userspace to provide this information ?


thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 44/45] virt: sevguest: Add support to derive key
  2021-11-18 16:43   ` Peter Gonda
@ 2021-11-18 17:43     ` Brijesh Singh
  0 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-18 17:43 UTC (permalink / raw)
  To: Peter Gonda
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Borislav Petkov, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy



On 11/18/21 10:43 AM, Peter Gonda wrote:
...
>> +       u8 buf[89];
> 
> Could we document this magic number?
> 

Yes, I will document from where this number came.

>> +
>> +       if (!arg->req_data || !arg->resp_data)
>> +               return -EINVAL;
>> +
>> +       /* Copy the request payload from userspace */
>> +       if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
>> +               return -EFAULT;
>> +
>> +       /* Message version must be non-zero */
>> +       if (!req.msg_version)
>> +               return -EINVAL;
>> +
>> +       /*
>> +        * The intermediate response buffer is used while decrypting the
>> +        * response payload. Make sure that it has enough space to cover the
>> +        * authtag.
>> +        */
>> +       resp_len = sizeof(resp.data) + crypto->a_len;
>> +       if (sizeof(buf) < resp_len)
>> +               return -ENOMEM;
>> +
>> +       /* Issue the command to get the attestation report */
>> +       rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, req.msg_version,
>> +                                 SNP_MSG_KEY_REQ, &req.data, sizeof(req.data), buf, resp_len,
>> +                                 &arg->fw_err);
>> +       if (rc)
>> +               goto e_free;
> 
> Should we check the first 32 bits of |data| here since that is a
> status field? If we see 16h here we could return -EINVAL, or better to
> let userspace deal with that error handling?
> 

I was trying to avoid looking into a response structure to keep the 
flexibility; e.g if SNP firmware changes a response format then we don't 
need to have any changes in the driver. The userspace should be able to 
deal with it and it can check the "status" or a new field etc.

thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-18 17:32     ` Brijesh Singh
@ 2021-11-19 16:16       ` Peter Gonda
  2021-11-20  0:28         ` Brijesh Singh
  0 siblings, 1 reply; 80+ messages in thread
From: Peter Gonda @ 2021-11-19 16:16 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Zijlstra,
	Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On Thu, Nov 18, 2021 at 10:32 AM Brijesh Singh <brijesh.singh@amd.com> wrote:
>
>
>
> On 11/17/21 5:34 PM, Peter Gonda wrote:
>
>
> >> +The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
> >> +The ioctl accepts struct snp_user_guest_request. The input and output structure is
> >> +specified through the req_data and resp_data field respectively. If the ioctl fails
> >> +to execute due to a firmware error, then fw_err code will be set.
> >
> > Should way say what it will be set to? Also Sean pointed out on CCP
> > driver that 0 is strange to set the error to, its a uint so we cannot
> > do -1 like we did there. What about all FFs?
> >
>
> Sure, all FF's works, I can document and use it.
>
>
> >> +static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> >> +{
> >> +       u64 count;
> >
> > I may be overly paranoid here but how about
> > `lockdep_assert_held(&snp_cmd_mutex);` when writing or reading
> > directly from this data?
> >
>
> Sure, I can do it.
>
> ...
>
> >> +
> >> +       if (rc)
> >> +               return rc;
> >> +
> >> +       rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
> >> +       if (rc) {
> >> +               /*
> >> +                * The verify_and_dec_payload() will fail only if the hypervisor is
> >> +                * actively modifiying the message header or corrupting the encrypted payload.
> > modifiying
> >> +                * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that
> >> +                * the key cannot be used for any communication.
> >> +                */
> >
> > This looks great, thanks for changes Brijesh. Should we mention in
> > comment here or at snp_disable_vmpck() the AES-GCM issues with
> > continuing to use the key? Or will future updaters to this code
> > understand already?
> >
>
> Sure, I can add comment about the AES-GCM.
>
> ...
>
> >> +
> >> +/* See SNP spec SNP_GUEST_REQUEST section for the structure */
> >> +enum msg_type {
> >> +       SNP_MSG_TYPE_INVALID = 0,
> >> +       SNP_MSG_CPUID_REQ,
> >> +       SNP_MSG_CPUID_RSP,
> >> +       SNP_MSG_KEY_REQ,
> >> +       SNP_MSG_KEY_RSP,
> >> +       SNP_MSG_REPORT_REQ,
> >> +       SNP_MSG_REPORT_RSP,
> >> +       SNP_MSG_EXPORT_REQ,
> >> +       SNP_MSG_EXPORT_RSP,
> >> +       SNP_MSG_IMPORT_REQ,
> >> +       SNP_MSG_IMPORT_RSP,
> >> +       SNP_MSG_ABSORB_REQ,
> >> +       SNP_MSG_ABSORB_RSP,
> >> +       SNP_MSG_VMRK_REQ,
> >> +       SNP_MSG_VMRK_RSP,
> >
> > Did you want to include MSG_ABSORB_NOMA_REQ and MSG_ABSORB_NOMA_RESP here?
> >
>
> Yes, I can includes those for the completeness.
>
> ...
>
> >> +struct snp_report_req {
> >> +       /* message version number (must be non-zero) */
> >> +       __u8 msg_version;
> >> +
> >> +       /* user data that should be included in the report */
> >> +       __u8 user_data[64];
> >
> > Are we missing the 'vmpl' field here? Does those default all requests
> > to be signed with VMPL0? Users might want to change that, they could
> > be using a paravisor.
> >
>
> Good question, so far I was thinking that guest kernel will provide its
> vmpl level instead of accepted the vmpl level from the userspace. Do you
> see a need for a userspace to provide this information ?

That seems fine. I am just confused because we are just encrypting
this struct as the payload for the PSP. Doesn't the message require a
struct that looks like 'snp_report_req_user_data' below?

snp_report_req{
       /* message version number (must be non-zero) */
       __u8 msg_version;

      /* user data that should be included in the report */
       struct snp_report_req_user_data;
};

struct snp_report_req_user_data {
  u8 user_data[64];
  u32 vmpl;
  u32 reserved;
};


>
>
> thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 43/45] virt: Add SEV-SNP guest driver
  2021-11-19 16:16       ` Peter Gonda
@ 2021-11-20  0:28         ` Brijesh Singh
  0 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-11-20  0:28 UTC (permalink / raw)
  To: Peter Gonda
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum,
	Borislav Petkov, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy


On 11/19/21 10:16 AM, Peter Gonda wrote:
> On Thu, Nov 18, 2021 at 10:32 AM Brijesh Singh <brijesh.singh@amd.com> wrote:
>>
>>
>> On 11/17/21 5:34 PM, Peter Gonda wrote:
>>
>>
>>>> +The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
>>>> +The ioctl accepts struct snp_user_guest_request. The input and output structure is
>>>> +specified through the req_data and resp_data field respectively. If the ioctl fails
>>>> +to execute due to a firmware error, then fw_err code will be set.
>>> Should way say what it will be set to? Also Sean pointed out on CCP
>>> driver that 0 is strange to set the error to, its a uint so we cannot
>>> do -1 like we did there. What about all FFs?
>>>
>> Sure, all FF's works, I can document and use it.
>>
>>
>>>> +static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
>>>> +{
>>>> +       u64 count;
>>> I may be overly paranoid here but how about
>>> `lockdep_assert_held(&snp_cmd_mutex);` when writing or reading
>>> directly from this data?
>>>
>> Sure, I can do it.
>>
>> ...
>>
>>>> +
>>>> +       if (rc)
>>>> +               return rc;
>>>> +
>>>> +       rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
>>>> +       if (rc) {
>>>> +               /*
>>>> +                * The verify_and_dec_payload() will fail only if the hypervisor is
>>>> +                * actively modifiying the message header or corrupting the encrypted payload.
>>> modifiying
>>>> +                * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that
>>>> +                * the key cannot be used for any communication.
>>>> +                */
>>> This looks great, thanks for changes Brijesh. Should we mention in
>>> comment here or at snp_disable_vmpck() the AES-GCM issues with
>>> continuing to use the key? Or will future updaters to this code
>>> understand already?
>>>
>> Sure, I can add comment about the AES-GCM.
>>
>> ...
>>
>>>> +
>>>> +/* See SNP spec SNP_GUEST_REQUEST section for the structure */
>>>> +enum msg_type {
>>>> +       SNP_MSG_TYPE_INVALID = 0,
>>>> +       SNP_MSG_CPUID_REQ,
>>>> +       SNP_MSG_CPUID_RSP,
>>>> +       SNP_MSG_KEY_REQ,
>>>> +       SNP_MSG_KEY_RSP,
>>>> +       SNP_MSG_REPORT_REQ,
>>>> +       SNP_MSG_REPORT_RSP,
>>>> +       SNP_MSG_EXPORT_REQ,
>>>> +       SNP_MSG_EXPORT_RSP,
>>>> +       SNP_MSG_IMPORT_REQ,
>>>> +       SNP_MSG_IMPORT_RSP,
>>>> +       SNP_MSG_ABSORB_REQ,
>>>> +       SNP_MSG_ABSORB_RSP,
>>>> +       SNP_MSG_VMRK_REQ,
>>>> +       SNP_MSG_VMRK_RSP,
>>> Did you want to include MSG_ABSORB_NOMA_REQ and MSG_ABSORB_NOMA_RESP here?
>>>
>> Yes, I can includes those for the completeness.
>>
>> ...
>>
>>>> +struct snp_report_req {
>>>> +       /* message version number (must be non-zero) */
>>>> +       __u8 msg_version;
>>>> +
>>>> +       /* user data that should be included in the report */
>>>> +       __u8 user_data[64];
>>> Are we missing the 'vmpl' field here? Does those default all requests
>>> to be signed with VMPL0? Users might want to change that, they could
>>> be using a paravisor.
>>>
>> Good question, so far I was thinking that guest kernel will provide its
>> vmpl level instead of accepted the vmpl level from the userspace. Do you
>> see a need for a userspace to provide this information ?
> That seems fine. I am just confused because we are just encrypting
> this struct as the payload for the PSP. Doesn't the message require a
> struct that looks like 'snp_report_req_user_data' below?
>
> snp_report_req{
>        /* message version number (must be non-zero) */
>        __u8 msg_version;
>
>       /* user data that should be included in the report */
>        struct snp_report_req_user_data;
> };
>
> struct snp_report_req_user_data {
>   u8 user_data[64];
>   u32 vmpl;
>   u32 reserved;
> };
>
The snp_guest_msg structure is zero'ed before building the hdr and
copying the user provided input, see enc_payload. The patch series was
focused on vmpl-0 only I didn't consider anything other than vmpl-. Let
me work to provide the option for userspace to provide the vmpl as an
input during the request so that we give the flexibility to userspace.


>>
>> thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot
  2021-11-12 20:30     ` Michael Roth
@ 2021-11-23 21:55       ` Venu Busireddy
  0 siblings, 0 replies; 80+ messages in thread
From: Venu Busireddy @ 2021-11-23 21:55 UTC (permalink / raw)
  To: Michael Roth
  Cc: Borislav Petkov, Brijesh Singh, x86, linux-kernel, kvm,
	linux-efi, platform-driver-x86, linux-coco, linux-mm,
	Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Vlastimil Babka, Kirill A . Shutemov,
	Andi Kleen, Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On 2021-11-12 14:30:01 -0600, Michael Roth wrote:
> On Fri, Nov 12, 2021 at 05:52:51PM +0100, Borislav Petkov wrote:
> > On Wed, Nov 10, 2021 at 04:06:47PM -0600, Brijesh Singh wrote:
> > > +void sev_enable(struct boot_params *bp)
> > > +{
> > > +	unsigned int eax, ebx, ecx, edx;
> > > +
> > > +	/* Check for the SME/SEV support leaf */
> > > +	eax = 0x80000000;
> > > +	ecx = 0;
> > > +	native_cpuid(&eax, &ebx, &ecx, &edx);
> > > +	if (eax < 0x8000001f)
> > > +		return;
> > > +
> > > +	/*
> > > +	 * Check for the SME/SEV feature:
> > > +	 *   CPUID Fn8000_001F[EAX]
> > > +	 *   - Bit 0 - Secure Memory Encryption support
> > > +	 *   - Bit 1 - Secure Encrypted Virtualization support
> > > +	 *   CPUID Fn8000_001F[EBX]
> > > +	 *   - Bits 5:0 - Pagetable bit position used to indicate encryption
> > > +	 */
> > > +	eax = 0x8000001f;
> > > +	ecx = 0;
> > > +	native_cpuid(&eax, &ebx, &ecx, &edx);
> > > +	/* Check whether SEV is supported */
> > > +	if (!(eax & BIT(1)))
> > > +		return;
> > > +
> > > +	/* Check the SEV MSR whether SEV or SME is enabled */
> > > +	sev_status   = rd_sev_status_msr();
> > > +
> > > +	if (!(sev_status & MSR_AMD64_SEV_ENABLED))
> > > +		error("SEV support indicated by CPUID, but not SEV status MSR.");
> > 
> > What is the practical purpose of this test?
> 
> In the current QEMU/KVM implementation the SEV* CPUID bits are only
> exposed for SEV guests, so this was more of a sanity check on that. But
> looking at things more closely: that's more of a VMM-specific behavior
> and isn't necessarily an invalid guest configuration as far as the spec
> is concerned, so I think this check should be dropped.
> 
> > 
> > > +	sme_me_mask = 1UL << (ebx & 0x3f);
> > 
> > 	sme_me_mask = BIT_ULL(ebx & 0x3f);
> 
> Will do.

Also, could you please remove the references to set_sev_encryption_mask()
at lines 195 and 572? And perhaps reword those comments too?

Thanks,

Venu

> Thanks,
> 
> Mike
> 
> > 
> > Thx.
> > 
> > -- 
> > Regards/Gruss,
> >     Boris.
> > 
> > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpeople.kernel.org%2Ftglx%2Fnotes-about-netiquette&amp;data=04%7C01%7Cmichael.roth%40amd.com%7Ca6bf3479fffa4b5eee8b08d9a5fce2e2%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637723327924654730%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=SRy8YSe8a2njNc6IT8CGKv0hUefSOW55DJV%2Fi2Lhkic%3D&amp;reserved=0

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT
  2021-11-10 22:06 ` [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
@ 2021-12-02 17:52   ` Borislav Petkov
  2021-12-06 15:15     ` Brijesh Singh
  0 siblings, 1 reply; 80+ messages in thread
From: Borislav Petkov @ 2021-12-02 17:52 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 04:06:56PM -0600, Brijesh Singh wrote:
> +/*
> + * The hypervisor features are available from GHCB version 2 onward.
> + */
> +static bool get_hv_features(void)
> +{
> +	u64 val;
> +
> +	sev_hv_features = 0;
> +
> +	if (ghcb_version < 2)
> +		return false;
> +
> +	sev_es_wr_ghcb_msr(GHCB_MSR_HV_FT_REQ);
> +	VMGEXIT();
> +
> +	val = sev_es_rd_ghcb_msr();
> +	if (GHCB_RESP_CODE(val) != GHCB_MSR_HV_FT_RESP)
> +		return false;
> +
> +	sev_hv_features = GHCB_MSR_HV_FT_RESP_VAL(val);
> +
> +	return true;
> +}

I still don't like this.

This is more of that run-me-in-the-exception-handler thing while this is
purely feature detection stuff which needs to be done exactly once on
init.

IOW, that stanza

        if (!sev_es_negotiate_protocol())
                sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED);

should be called once in sev_enable() for the decompressor kernel and
once in sev_es_init_vc_handling() for kernel proper.

Then you don't need to do any of that sev_hv_features = 0 thing but
detect them exactly once and query them as much as you can.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT
  2021-12-02 17:52   ` Borislav Petkov
@ 2021-12-06 15:15     ` Brijesh Singh
  0 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-12-06 15:15 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy



On 12/2/21 11:52 AM, Borislav Petkov wrote:
> On Wed, Nov 10, 2021 at 04:06:56PM -0600, Brijesh Singh wrote:
>> +/*
>> + * The hypervisor features are available from GHCB version 2 onward.
>> + */
>> +static bool get_hv_features(void)
>> +{
>> +	u64 val;
>> +
>> +	sev_hv_features = 0;
>> +
>> +	if (ghcb_version < 2)
>> +		return false;
>> +
>> +	sev_es_wr_ghcb_msr(GHCB_MSR_HV_FT_REQ);
>> +	VMGEXIT();
>> +
>> +	val = sev_es_rd_ghcb_msr();
>> +	if (GHCB_RESP_CODE(val) != GHCB_MSR_HV_FT_RESP)
>> +		return false;
>> +
>> +	sev_hv_features = GHCB_MSR_HV_FT_RESP_VAL(val);
>> +
>> +	return true;
>> +}
> 
> I still don't like this.
> 
> This is more of that run-me-in-the-exception-handler thing while this is
> purely feature detection stuff which needs to be done exactly once on
> init.
> 
> IOW, that stanza
> 
>          if (!sev_es_negotiate_protocol())
>                  sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED);
> 
> should be called once in sev_enable() for the decompressor kernel and
> once in sev_es_init_vc_handling() for kernel proper.
> 

I will look into it, I will improve the sev_enable() to call GHCB MSR 
protocol query the version and feature.


> Then you don't need to do any of that sev_hv_features = 0 thing but
> detect them exactly once and query them as much as you can.
> 
> Thx.
> 

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 13/45] x86/sev: Check the vmpl level
  2021-11-10 22:06 ` [PATCH v7 13/45] x86/sev: Check the vmpl level Brijesh Singh
@ 2021-12-06 18:25   ` Borislav Petkov
  0 siblings, 0 replies; 80+ messages in thread
From: Borislav Petkov @ 2021-12-06 18:25 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 04:06:59PM -0600, Brijesh Singh wrote:
> Virtual Machine Privilege Level (VMPL) is an optional feature in the
> SEV-SNP architecture, which allows a guest VM to divide its address space
> into four levels. The level can be used to provide the hardware isolated
> abstraction layers with a VM.

That sentence needs improving.

> The VMPL0 is the highest privilege, and
> VMPL3 is the least privilege. Certain operations must be done by the VMPL0
> software, such as:
> 
> * Validate or invalidate memory range (PVALIDATE instruction)
> * Allocate VMSA page (RMPADJUST instruction when VMSA=1)
> 
> The initial SEV-SNP support assumes that the guest kernel is running on

assumes? I think it is "requires".

> VMPL0. Let's add a check to make sure that kernel is running at VMPL0

s/Let's //

> before continuing the boot. There is no easy method to query the current
> VMPL level, so use the RMPADJUST instruction to determine whether its

"... whether the guest is running at VMPL0."

> booted at the VMPL0.
> 
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  arch/x86/boot/compressed/sev.c    | 34 ++++++++++++++++++++++++++++---
>  arch/x86/include/asm/sev-common.h |  1 +
>  arch/x86/include/asm/sev.h        | 16 +++++++++++++++
>  3 files changed, 48 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
> index e525fa74a551..21feb7f4f76f 100644
> --- a/arch/x86/boot/compressed/sev.c
> +++ b/arch/x86/boot/compressed/sev.c
> @@ -124,6 +124,29 @@ static inline bool sev_snp_enabled(void)
>  	return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
>  }
>  
> +static bool is_vmpl0(void)
> +{
> +	u64 attrs;
> +	int err;
> +
> +	/*
> +	 * There is no straightforward way to query the current VMPL level. The
> +	 * simplest method is to use the RMPADJUST instruction to change a page
> +	 * permission to a VMPL level-1, and if the guest kernel is launched at
> +	 * a level <= 1, then RMPADJUST instruction will return an error.
> +	 */

So I was wondering what this is changing because if the change you do is
relevant, you'd have to undo it.

But looking at RMPADJUST, TARGET_PERM_MASK is 0 for target VMPL1 so
you're basically clearing all permissions for boot_ghcb_page on VMPL1.
Which is fine currently as we do only VMPL0 but pls write that out
explicitly what you're doing here and why it is ok to use RMPADJUST
without having to restore any changes it has done to the RMP table.

> +	attrs = 1;
> +
> +	/*
> +	 * Any page-aligned virtual address is sufficient to test the VMPL level.
> +	 * The boot_ghcb_page is page aligned memory, so lets use for the test.
> +	 */
> +	if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, attrs))
> +		return false;
> +
> +	return true;
> +}
> +
>  static bool do_early_sev_setup(void)
>  {
>  	if (!sev_es_negotiate_protocol())
> @@ -132,10 +155,15 @@ static bool do_early_sev_setup(void)
>  	/*
>  	 * SNP is supported in v2 of the GHCB spec which mandates support for HV
>  	 * features. If SEV-SNP is enabled, then check if the hypervisor supports
> -	 * the SEV-SNP features.
> +	 * the SEV-SNP features and is launched at VMPL-0 level.

"VMPL0" - no hyphen - like in the APM. Below too.

>  	 */
> -	if (sev_snp_enabled() && !(sev_hv_features & GHCB_HV_FT_SNP))
> -		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
> +	if (sev_snp_enabled()) {
> +		if (!(sev_hv_features & GHCB_HV_FT_SNP))
> +			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
> +
> +		if (!is_vmpl0())
> +			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
> +	}
>  
>  	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
>  		return false;

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 02/45] x86/sev: detect/setup SEV/SME features earlier in boot
  2021-11-10 22:06 ` [PATCH v7 02/45] x86/sev: " Brijesh Singh
  2021-11-15 19:12   ` Borislav Petkov
@ 2021-12-06 23:47   ` Venu Busireddy
  1 sibling, 0 replies; 80+ messages in thread
From: Venu Busireddy @ 2021-12-06 23:47 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

On 2021-11-10 16:06:48 -0600, Brijesh Singh wrote:
> From: Michael Roth <michael.roth@amd.com>
> 
> sme_enable() handles feature detection for both SEV and SME. Future
> patches will also use it for SEV-SNP feature detection/setup, which
> will need to be done immediately after the first #VC handler is set up.
> Move it now in preparation.

The previous patch added the function sev_enable(), which has most of its
code duplicated in sme_enable(). Can sme_enable() be changed (and maybe
sev_enable() a bit) to call sev_enable() and avoid all the duplicate code?

Venu

> 
> Signed-off-by: Michael Roth <michael.roth@amd.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  arch/x86/include/asm/setup.h | 2 +-
>  arch/x86/kernel/head64.c     | 8 ++++----
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
> index a12458a7a8d4..cee1e816fdcd 100644
> --- a/arch/x86/include/asm/setup.h
> +++ b/arch/x86/include/asm/setup.h
> @@ -50,7 +50,7 @@ extern void reserve_standard_io_resources(void);
>  extern void i386_reserve_resources(void);
>  extern unsigned long __startup_64(unsigned long physaddr, struct boot_params *bp);
>  extern unsigned long __startup_secondary_64(void);
> -extern void startup_64_setup_env(unsigned long physbase);
> +extern void startup_64_setup_env(unsigned long physbase, struct boot_params *bp);
>  extern void early_setup_idt(void);
>  extern void __init do_early_exception(struct pt_regs *regs, int trapnr);
>  
> diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
> index fc5371a7e9d1..4eb83ae7ceb8 100644
> --- a/arch/x86/kernel/head64.c
> +++ b/arch/x86/kernel/head64.c
> @@ -163,9 +163,6 @@ unsigned long __head __startup_64(unsigned long physaddr,
>  	if (load_delta & ~PMD_PAGE_MASK)
>  		for (;;);
>  
> -	/* Activate Secure Memory Encryption (SME) if supported and enabled */
> -	sme_enable(bp);
> -
>  	/* Include the SME encryption mask in the fixup value */
>  	load_delta += sme_get_me_mask();
>  
> @@ -594,7 +591,7 @@ void early_setup_idt(void)
>  /*
>   * Setup boot CPU state needed before kernel switches to virtual addresses.
>   */
> -void __head startup_64_setup_env(unsigned long physbase)
> +void __head startup_64_setup_env(unsigned long physbase, struct boot_params *bp)
>  {
>  	/* Load GDT */
>  	startup_gdt_descr.address = (unsigned long)fixup_pointer(startup_gdt, physbase);
> @@ -606,4 +603,7 @@ void __head startup_64_setup_env(unsigned long physbase)
>  		     "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory");
>  
>  	startup_64_load_idt(physbase);
> +
> +	/* Activate SEV/SME memory encryption if supported/enabled. */
> +	sme_enable(bp);
>  }
> -- 
> 2.25.1
> 

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage
  2021-11-10 22:07 ` [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
@ 2021-12-07 11:48   ` Borislav Petkov
  2021-12-07 19:21     ` Brijesh Singh
  0 siblings, 1 reply; 80+ messages in thread
From: Borislav Petkov @ 2021-12-07 11:48 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 04:07:00PM -0600, Brijesh Singh wrote:
> diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
> index f7213d0943b8..3cf7a7575f5c 100644
> --- a/arch/x86/boot/compressed/ident_map_64.c
> +++ b/arch/x86/boot/compressed/ident_map_64.c
> @@ -275,15 +275,31 @@ static int set_clr_page_flags(struct x86_mapping_info *info,
>  	 * Changing encryption attributes of a page requires to flush it from
>  	 * the caches.
>  	 */
> -	if ((set | clr) & _PAGE_ENC)
> +	if ((set | clr) & _PAGE_ENC) {
>  		clflush_page(address);
>  
> +		/*
> +		 * If the encryption attribute is being cleared, then change
> +		 * the page state to shared in the RMP table.
> +		 */
> +		if (clr)
> +			snp_set_page_shared(pte_pfn(*ptep) << PAGE_SHIFT);

So I'm wondering: __page_state_change() wants a physical address and
you're reading it out from the PTE here.

Why not do

	__pa(address & PAGE_MASK);

like it is usually done?

And those macros are right there at the top of ident_map_64.c with an
explanation that we're ident-mapped here so pa == va...

> +	}
> +
>  	/* Update PTE */
>  	pte = *ptep;
>  	pte = pte_set_flags(pte, set);
>  	pte = pte_clear_flags(pte, clr);
>  	set_pte(ptep, pte);
>  
> +	/*
> +	 * If the encryption attribute is being set, then change the page state to
> +	 * private in the RMP entry. The page state must be done after the PTE
						   ^
						 change

> +	 * is updated.
> +	 */
> +	if (set & _PAGE_ENC)
> +		snp_set_page_private(pte_pfn(*ptep) << PAGE_SHIFT);
> +
>  	/* Flush TLB after changing encryption attribute */
>  	write_cr3(top_level_pgt);
>  
-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version
  2021-11-10 22:06 ` [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version Brijesh Singh
@ 2021-12-07 12:51   ` Tianyu Lan
  2021-12-07 13:17     ` Borislav Petkov
  0 siblings, 1 reply; 80+ messages in thread
From: Tianyu Lan @ 2021-12-07 12:51 UTC (permalink / raw)
  To: Brijesh Singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Michael Kelley,
	Andrea Parri (Microsoft)
  Cc: Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Borislav Petkov, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy

Hi Brijesh:
      We find this patch breaks AMD SEV support in the Hyper-V Isolation
VM. Hyper-V code also uses sev_es_ghcb_hv_call() to read or write msr
value. The sev_es_check_cpu_features() isn't called in the Hyper-V code
and so the ghcb_version is always 0. Could you add a new parameter 
ghcb_version for sev_es_ghcb_hv_call() and then caller may input 
ghcb_version?

Thanks.

On 11/11/2021 6:06 AM, Brijesh Singh wrote:
> The SEV-ES guest calls the sev_es_negotiate_protocol() to negotiate the
> GHCB protocol version before establishing the GHCB. Cache the negotiated
> GHCB version so that it can be used later.
> 
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>   arch/x86/include/asm/sev.h   |  2 +-
>   arch/x86/kernel/sev-shared.c | 17 ++++++++++++++---
>   2 files changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
> index ec060c433589..9b9c190e8c3b 100644
> --- a/arch/x86/include/asm/sev.h
> +++ b/arch/x86/include/asm/sev.h
> @@ -12,7 +12,7 @@
>   #include <asm/insn.h>
>   #include <asm/sev-common.h>
>   
> -#define GHCB_PROTO_OUR		0x0001UL
> +#define GHCB_PROTOCOL_MIN	1ULL
>   #define GHCB_PROTOCOL_MAX	1ULL
>   #define GHCB_DEFAULT_USAGE	0ULL
>   
> diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> index 2abf8a7d75e5..91105f5a02a8 100644
> --- a/arch/x86/kernel/sev-shared.c
> +++ b/arch/x86/kernel/sev-shared.c
> @@ -14,6 +14,15 @@
>   #define has_cpuflag(f)	boot_cpu_has(f)
>   #endif
>   
> +/*
> + * Since feature negotiation related variables are set early in the boot
> + * process they must reside in the .data section so as not to be zeroed
> + * out when the .bss section is later cleared.
> + *
> + * GHCB protocol version negotiated with the hypervisor.
> + */
> +static u16 ghcb_version __ro_after_init;
> +
>   static bool __init sev_es_check_cpu_features(void)
>   {
>   	if (!has_cpuflag(X86_FEATURE_RDRAND)) {
> @@ -51,10 +60,12 @@ static bool sev_es_negotiate_protocol(void)
>   	if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP)
>   		return false;
>   
> -	if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTO_OUR ||
> -	    GHCB_MSR_PROTO_MIN(val) > GHCB_PROTO_OUR)
> +	if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN ||
> +	    GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX)
>   		return false;
>   
> +	ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val), GHCB_PROTOCOL_MAX);
> +
>   	return true;
>   }
>   
> @@ -127,7 +138,7 @@ enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr,
>   				   u64 exit_info_1, u64 exit_info_2)
>   {
>   	/* Fill in protocol and format specifiers */
> -	ghcb->protocol_version = GHCB_PROTOCOL_MAX;
> +	ghcb->protocol_version = ghcb_version;
>   	ghcb->ghcb_usage       = GHCB_DEFAULT_USAGE;
>   
>   	ghcb_set_sw_exit_code(ghcb, exit_code);
> 

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version
  2021-12-07 12:51   ` Tianyu Lan
@ 2021-12-07 13:17     ` Borislav Petkov
  2021-12-07 16:58       ` Brijesh Singh
  0 siblings, 1 reply; 80+ messages in thread
From: Borislav Petkov @ 2021-12-07 13:17 UTC (permalink / raw)
  To: Tianyu Lan
  Cc: Brijesh Singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Michael Kelley,
	Andrea Parri (Microsoft),
	Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy

On Tue, Dec 07, 2021 at 08:51:53PM +0800, Tianyu Lan wrote:
> Hi Brijesh:

Do me a favor please and learn not to top-post on a public mailing list.
Also, take the time to read Documentation/process/ before you send
upstream patches and how to work with the community in general.

> We find this patch breaks AMD SEV support in the Hyper-V Isolation
> VM. Hyper-V code also uses sev_es_ghcb_hv_call() to read or write msr
> value. The sev_es_check_cpu_features() isn't called in the Hyper-V
> code and so the ghcb_version is always 0.

If hyperv is going to expose hypervisor features, then it better report
GHCB v2. If not, then I guess < 2 or 1 or so, depending on how this is
defined.

> Could you add a new parameter ghcb_version for sev_es_ghcb_hv_call()
> and then caller may input ghcb_version?

No, your hypervisor needs to adhere to the spec and report proper ghcb
version. We won't be doing any accomodate-hyperv hacks.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version
  2021-12-07 13:17     ` Borislav Petkov
@ 2021-12-07 16:58       ` Brijesh Singh
  0 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-12-07 16:58 UTC (permalink / raw)
  To: Borislav Petkov, Tianyu Lan
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Michael Kelley,
	Andrea Parri (Microsoft),
	Thomas Gleixner, Ingo Molnar, Joerg Roedel, Tom Lendacky,
	H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy



On 12/7/21 7:17 AM, Borislav Petkov wrote:
> On Tue, Dec 07, 2021 at 08:51:53PM +0800, Tianyu Lan wrote:
>> Hi Brijesh:
> 
> Do me a favor please and learn not to top-post on a public mailing list.
> Also, take the time to read Documentation/process/ before you send
> upstream patches and how to work with the community in general.
> 
>> We find this patch breaks AMD SEV support in the Hyper-V Isolation
>> VM. Hyper-V code also uses sev_es_ghcb_hv_call() to read or write msr
>> value. The sev_es_check_cpu_features() isn't called in the Hyper-V
>> code and so the ghcb_version is always 0.
> 
> If hyperv is going to expose hypervisor features, then it better report
> GHCB v2. If not, then I guess < 2 or 1 or so, depending on how this is
> defined.
> 
>> Could you add a new parameter ghcb_version for sev_es_ghcb_hv_call()
>> and then caller may input ghcb_version?
> 
> No, your hypervisor needs to adhere to the spec and report proper ghcb
> version. We won't be doing any accomodate-hyperv hacks.
> 


Agreed, the HyperV support need to negotiate the GHCB version before 
making those HC. In the current patch, the sev_es_negotiate_protocol() 
will save the ghcb_version in global variable and the saved value is 
used during the HC. Just make sure that initial HyperV support is 
adhering to the specification.

thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage
  2021-12-07 11:48   ` Borislav Petkov
@ 2021-12-07 19:21     ` Brijesh Singh
  0 siblings, 0 replies; 80+ messages in thread
From: Brijesh Singh @ 2021-12-07 19:21 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: brijesh.singh, x86, linux-kernel, kvm, linux-efi,
	platform-driver-x86, linux-coco, linux-mm, Thomas Gleixner,
	Ingo Molnar, Joerg Roedel, Tom Lendacky, H. Peter Anvin,
	Ard Biesheuvel, Paolo Bonzini, Sean Christopherson,
	Vitaly Kuznetsov, Jim Mattson, Andy Lutomirski, Dave Hansen,
	Sergio Lopez, Peter Gonda, Peter Zijlstra, Srinivas Pandruvada,
	David Rientjes, Dov Murik, Tobin Feldman-Fitzthum, Michael Roth,
	Vlastimil Babka, Kirill A . Shutemov, Andi Kleen,
	Dr . David Alan Gilbert, tony.luck, marcorr,
	sathyanarayanan.kuppuswamy



On 12/7/21 5:48 AM, Borislav Petkov wrote:
> On Wed, Nov 10, 2021 at 04:07:00PM -0600, Brijesh Singh wrote:
>> diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
>> index f7213d0943b8..3cf7a7575f5c 100644
>> --- a/arch/x86/boot/compressed/ident_map_64.c
>> +++ b/arch/x86/boot/compressed/ident_map_64.c
>> @@ -275,15 +275,31 @@ static int set_clr_page_flags(struct x86_mapping_info *info,
>>   	 * Changing encryption attributes of a page requires to flush it from
>>   	 * the caches.
>>   	 */
>> -	if ((set | clr) & _PAGE_ENC)
>> +	if ((set | clr) & _PAGE_ENC) {
>>   		clflush_page(address);
>>   
>> +		/*
>> +		 * If the encryption attribute is being cleared, then change
>> +		 * the page state to shared in the RMP table.
>> +		 */
>> +		if (clr)
>> +			snp_set_page_shared(pte_pfn(*ptep) << PAGE_SHIFT);
> 
> So I'm wondering: __page_state_change() wants a physical address and
> you're reading it out from the PTE here.
> 
> Why not do
> 
> 	__pa(address & PAGE_MASK);
> 
> like it is usually done?

I am okay to use __pa().

thanks

^ permalink raw reply	[flat|nested] 80+ messages in thread

* Re: [PATCH v7 16/45] x86/sev: Register GHCB memory when SEV-SNP is active
  2021-11-10 22:07 ` [PATCH v7 16/45] x86/sev: " Brijesh Singh
@ 2021-12-08 17:41   ` Borislav Petkov
  0 siblings, 0 replies; 80+ messages in thread
From: Borislav Petkov @ 2021-12-08 17:41 UTC (permalink / raw)
  To: Brijesh Singh
  Cc: x86, linux-kernel, kvm, linux-efi, platform-driver-x86,
	linux-coco, linux-mm, Thomas Gleixner, Ingo Molnar, Joerg Roedel,
	Tom Lendacky, H. Peter Anvin, Ard Biesheuvel, Paolo Bonzini,
	Sean Christopherson, Vitaly Kuznetsov, Jim Mattson,
	Andy Lutomirski, Dave Hansen, Sergio Lopez, Peter Gonda,
	Peter Zijlstra, Srinivas Pandruvada, David Rientjes, Dov Murik,
	Tobin Feldman-Fitzthum, Michael Roth, Vlastimil Babka,
	Kirill A . Shutemov, Andi Kleen, Dr . David Alan Gilbert,
	tony.luck, marcorr, sathyanarayanan.kuppuswamy

On Wed, Nov 10, 2021 at 04:07:02PM -0600, Brijesh Singh wrote:
> The SEV-SNP guest is required to perform GHCB GPA registration. This is
> because the hypervisor may prefer that a guest use a consistent and/or
> specific GPA for the GHCB associated with a vCPU. For more information,
> see the GHCB specification section GHCB GPA Registration.
> 
> During the boot, init_ghcb() allocates a per-cpu GHCB page. On very first
> VC exception,

That is not true anymore - you're doing proper init at init time - no
more #VC hackery.

> @@ -1977,6 +1978,10 @@ void cpu_init_exception_handling(void)
>  
>  	load_TR_desc();
>  
> +	/* Register the GHCB before taking any VC exception */
> +	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))

No need for that if branch - sev_snp_register_ghcb() already has an
empty stub for the !CONFIG_AMD_MEM_ENCRYPT case so you can simply call
it unconditionally.

> +		sev_snp_register_ghcb();
> +
>  	/* Finally load the IDT */
>  	load_current_idt();
>  }
> diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
> index 54bf0603002f..968105cec364 100644
> --- a/arch/x86/kernel/head64.c
> +++ b/arch/x86/kernel/head64.c
> @@ -588,6 +588,9 @@ void early_setup_idt(void)
>  
>  	bringup_idt_descr.address = (unsigned long)bringup_idt_table;
>  	native_load_idt(&bringup_idt_descr);
> +
> +	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
> +		sev_snp_register_ghcb();

Ditto.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 80+ messages in thread

end of thread, other threads:[~2021-12-08 17:41 UTC | newest]

Thread overview: 80+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-10 22:06 [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 01/45] x86/compressed/64: detect/setup SEV/SME features earlier in boot Brijesh Singh
2021-11-12 16:52   ` Borislav Petkov
2021-11-12 20:30     ` Michael Roth
2021-11-23 21:55       ` Venu Busireddy
2021-11-10 22:06 ` [PATCH v7 02/45] x86/sev: " Brijesh Singh
2021-11-15 19:12   ` Borislav Petkov
2021-11-15 20:17     ` Michael Roth
2021-11-17 13:11       ` Borislav Petkov
2021-12-06 23:47   ` Venu Busireddy
2021-11-10 22:06 ` [PATCH v7 03/45] x86/mm: Extend cc_attr to include AMD SEV-SNP Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 04/45] x86/sev: Shorten GHCB terminate macro names Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 05/45] x86/sev: Get rid of excessive use of defines Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 06/45] x86/head64: Carve out the guest encryption postprocessing into a helper Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 07/45] x86/sev: Remove do_early_exception() forward declarations Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 08/45] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version Brijesh Singh
2021-12-07 12:51   ` Tianyu Lan
2021-12-07 13:17     ` Borislav Petkov
2021-12-07 16:58       ` Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 10/45] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
2021-12-02 17:52   ` Borislav Petkov
2021-12-06 15:15     ` Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 11/45] x86/sev: Check SEV-SNP features support Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 12/45] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2021-11-10 22:06 ` [PATCH v7 13/45] x86/sev: Check the vmpl level Brijesh Singh
2021-12-06 18:25   ` Borislav Petkov
2021-11-10 22:07 ` [PATCH v7 14/45] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2021-12-07 11:48   ` Borislav Petkov
2021-12-07 19:21     ` Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 15/45] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2021-11-15 14:05   ` Jörg Rödel
2021-11-10 22:07 ` [PATCH v7 16/45] x86/sev: " Brijesh Singh
2021-12-08 17:41   ` Borislav Petkov
2021-11-10 22:07 ` [PATCH v7 17/45] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 18/45] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 19/45] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 20/45] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 21/45] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 22/45] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 23/45] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 24/45] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 25/45] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 26/45] x86/head: re-enable stack protection for 32/64-bit builds Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 27/45] x86/sev: move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 28/45] KVM: x86: move lookup of indexed CPUID leafs " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 29/45] x86/compressed/acpi: move EFI system table lookup " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 30/45] x86/compressed/acpi: move EFI config " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 31/45] x86/compressed/acpi: move EFI vendor " Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 32/45] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 33/45] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 34/45] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 35/45] x86/boot: add a pointer to Confidential Computing blob in bootparams Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 36/45] x86/compressed: add SEV-SNP feature detection/setup Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 37/45] x86/compressed: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 38/45] x86/compressed/64: add identity mapping for Confidential Computing blob Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 39/45] x86/sev: add SEV-SNP feature detection/setup Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 40/45] x86/sev: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 41/45] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 42/45] x86/sev: Register SNP guest request platform device Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 43/45] virt: Add SEV-SNP guest driver Brijesh Singh
2021-11-10 22:27   ` Randy Dunlap
2021-11-11 19:27     ` Brijesh Singh
2021-11-11 22:57       ` Randy Dunlap
2021-11-17 23:34   ` Peter Gonda
2021-11-18 17:08     ` Peter Gonda
2021-11-18 17:32     ` Brijesh Singh
2021-11-19 16:16       ` Peter Gonda
2021-11-20  0:28         ` Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 44/45] virt: sevguest: Add support to derive key Brijesh Singh
2021-11-18 16:43   ` Peter Gonda
2021-11-18 17:43     ` Brijesh Singh
2021-11-10 22:07 ` [PATCH v7 45/45] virt: sevguest: Add support to get extended report Brijesh Singh
2021-11-15 15:56 ` [PATCH v7 00/45] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Venu Busireddy
2021-11-15 16:02   ` Brijesh Singh
2021-11-15 16:37     ` Venu Busireddy
2021-11-15 16:45       ` Brijesh Singh
2021-11-15 16:55         ` Venu Busireddy
2021-11-16 15:45           ` Venu Busireddy
2021-11-16 16:03             ` Brijesh Singh

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