linux-sgx.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [RFC PATCH v5 00/26] KVM SGX virtualization support
@ 2021-02-13 13:28 Kai Huang
  2021-02-13 13:28 ` [RFC PATCH v5 01/26] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
                   ` (26 more replies)
  0 siblings, 27 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:28 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jethro, b.thiel,
	jmattson, joro, vkuznets, wanpengli, corbet

--- Disclaimer ---

These patches were originally written by Sean Christopherson while at Intel.
Now that Sean has left Intel, I (Kai) have taken over getting them upstream.
This series needs more review before it can be merged.  It is being posted
publicly and under RFC so Sean and others can review it. X86 Maintainers are
safe ignoring it for now.

------------------

Hi all,

This series adds KVM SGX virtualization support. The first 14 patches starting
with x86/sgx or x86/cpu.. are necessary changes to x86 and SGX core/driver to
support KVM SGX virtualization, while the rest are patches to KVM subsystem.

Please help to review this series. Any feedback is highly appreciated.
Please let me know if I forgot to CC anyone, or anyone wants to be removed from
CC. Thanks in advance!

This series is based against tip/x86/sgx. You can also get the code from
upstream branch of kvm-sgx repo on github:

        https://github.com/intel/kvm-sgx.git upstream

It also requires Qemu changes to create VM with SGX support. You can find Qemu
repo here:

	https://github.com/intel/qemu-sgx.git upstream

Please refer to README.md of above qemu-sgx repo for detail on how to create
guest with SGX support. At meantime, for your quick reference you can use below
command to create SGX guest:

	#qemu-system-x86_64 -smp 4 -m 2G -drive file=<your_vm_image>,if=virtio \
		-cpu host,+sgx_provisionkey \
		-sgx-epc id=epc1,memdev=mem1 \
		-object memory-backend-epc,id=mem1,size=64M,prealloc

Please note that the SGX relevant part is:

		-cpu host,+sgx_provisionkey \
		-sgx-epc id=epc1,memdev=mem1 \
		-object memory-backend-epc,id=mem1,size=64M,prealloc

And you can change other parameters of your qemu command based on your needs.

=========
Changelog:

(Changelog here is for global changes. Please see each patch's changelog for
 changes made to specific patch.)

v4->v5 (No big update from v4):

 - Updated commit message of patch 4, per Jarkko.
 - Updated comments and commit msg for patch 3, per Dave and Sean.

v3->v4:

 - Removed Jarkko's first patch, which removes WARN() against EPC page's
   SGX_EPC_PAGE_RECLAIMER_TRACKED flag. Dave and Sean were not convinced, and
   Sean "tripped more than once in the past during one of the many rebases of
   the virtual EPC and EPC cgroup branches".
 - Switched the patch to introduce SGX1/SGX2 feature bits, and the patch to move
   SGX_LC to cpuid_deps[] table, per Jarkko. Now SGX_LC patch can be applied to
   existing upstream code directly, if needed.
 - Fixed two problems in one KVM patch (trap ECREATE) after review from Rick and
   Sean.
 - Some other minor changes, i.e. update new file's copyright to 2021.

Hi Dave, Sean, Paolo, Rick, and others,
 
 Btw, in last review, we identified that malicious guest can cause KVM to access
 EPC, which will trigger "page abort", which drops on write, and returns all
 ones on read. If I understand correctly, we agreed that a better option is to
 make memremap() deny EPC. However so far this series doesn't contain this work,
 since looks more discussion is required, and this work can be done
 independently from KVM SGX series.

v2->v3:

 - Split original "x86/cpufeatures: Add SGX1 and SGX2 sub-features" patch into
   two patches, by splitting moving SGX_LC bit also into cpuid-deps table logic
   into a separate patch 2:
       [RFC PATCH v3 01/27] x86/cpufeatures: Add SGX1 and SGX2 sub-features
       [RFC PATCH v3 02/27] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit
 - Changed from /dev/sgx_virt_epc to /dev/sgx_vepc, per Jarkko. And accordingly,
   changed prefix 'sgx_virt_epc_xx' to 'sgx_vepc_xx' in various functions and
   structures.
 - Changed CONFIG_X86_SGX_VIRTUALIZATION to CONFIG_X86_SGX_KVM, per Dave. Couple
   of x86 patches and KVM patches are changed too due to the renaming.

v1->v2:

 - Refined this cover letter by addressing comments from Dave and Jarkko.
 - The original patch which introduced new X86_FEATURE_SGX1/SGX2 were replaced
   by 3 new patches from Sean, following Boris and Sean's discussion.
       [RFC PATCH v2 01/26] x86/cpufeatures: Add SGX1 and SGX2 sub-features
       [RFC PATCH v2 18/26] KVM: x86: Add support for reverse CPUID lookup of scattered features
       [RFC PATCH v2 19/26] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features
 - The original patch 1
       x86/sgx: Split out adding EPC page to free list to separate helper
   was replaced with 2 new patches from Jarkko
       [RFC PATCH v2 02/26] x86/sgx: Remove a warn from sgx_free_epc_page()
       [RFC PATCH v2 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
   addressing Jarkko's comments.
 - Moved modifying sgx_init() to always initialize sgx_virt_epc_init() out of
   patch
       x86/sgx: Introduce virtual EPC for use by KVM guests
   to a separate patch:
       [RFC PATCH v2 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled
   to address Dave's comment that patch ordering can be improved due to before
   patch "Allow SGX virtualization without Launch Control support", all SGX,
   including SGX virtualization, is actually disabled when SGX LC is not
   present.

=========
KVM SGX virtualization Overview

- Virtual EPC

SGX enclave memory is special and is reserved specifically for enclave use.
In bare-metal SGX enclaves, the kernel allocates enclave pages, copies data
into the pages with privileged instructions, then allows the enclave to start.
In this scenario, only initialized pages already assigned to an enclave are
mapped to userspace.

In virtualized environments, the hypervisor still needs to do the physical
enclave page allocation.  The guest kernel is responsible for the data copying
(among other things).  This means that the job of starting an enclave is now
split between hypervisor and guest.

This series introduces a new misc device: /dev/sgx_vepc.  This device allows
the host to map *uninitialized* enclave memory into userspace, which can then
be passed into a guest.

While it might be *possible* to start a host-side enclave with /dev/sgx_enclave
and pass its memory into a guest, it would be wasteful and convoluted.

Implement the *raw* EPC allocation in the x86 core-SGX subsystem via
/dev/sgx_vepc rather than in KVM.  Doing so has two major advantages:

  - Does not require changes to KVM's uAPI, e.g. EPC gets handled as
    just another memory backend for guests.

  - EPC management is wholly contained in the SGX subsystem, e.g. SGX
    does not have to export any symbols, changes to reclaim flows don't
    need to be routed through KVM, SGX's dirty laundry doesn't have to
    get aired out for the world to see, and so on and so forth.

The virtual EPC pages allocated to guests are currently not reclaimable.
Reclaiming EPC page used by enclave requires a special reclaim mechanism
separate from normal page reclaim, and that mechanism is not supported
for virutal EPC pages.  Due to the complications of handling reclaim
conflicts between guest and host, reclaiming virtual EPC pages is 
significantly more complex than basic support for SGX virtualization.

- Support SGX virtualization without SGX Flexible Launch Control

SGX hardware supports two "launch control" modes to limit which enclaves can
run.  In the "locked" mode, the hardware prevents enclaves from running unless
they are blessed by a third party.  In the unlocked mode, the kernel is in
full control of which enclaves can run.  The bare-metal SGX code refuses to
launch enclaves unless it is in the unlocked mode.

This sgx_virt_epc driver does not have such a restriction.  This allows guests
which are OK with the locked mode to use SGX, even if the host kernel refuses
to.

- Support exposing SGX2

Due to the same reason above, SGX2 feature detection is added to core SGX code
to allow KVM to expose SGX2 to guest, even currently SGX driver doesn't support
SGX2, because SGX2 can work just fine in guest w/o any interaction to host SGX
driver.

- Restricit SGX guest access to provisioning key

To grant guest being able to fully use SGX, guest needs to be able to access
provisioning key.  The provisioning key is sensitive, and accessing to it should
be restricted. In bare-metal driver, allowing enclave to access provisioning key
is restricted by being able to open /dev/sgx_provision.

Add a new KVM_CAP_SGX_ATTRIBUTE to KVM uAPI to extend above mechanism to KVM
guests as well.  When userspace hypervisor creates a new VM, the new cap is only
added to VM when userspace hypervisior is able to open /dev/sgx_provision,
following the same role as in bare-metal driver.  KVM then traps ECREATE from
guest, and only allows ECREATE with provisioning key bit to run when guest
supports KVM_CAP_SGX_ATTRIBUTE.


Jarkko Sakkinen (1):
  x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()

Kai Huang (3):
  x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit
  x86/sgx: Initialize virtual EPC driver even when SGX driver is
    disabled
  x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs

Sean Christopherson (22):
  x86/cpufeatures: Add SGX1 and SGX2 sub-features
  x86/sgx: Add SGX_CHILD_PRESENT hardware error code
  x86/sgx: Introduce virtual EPC for use by KVM guests
  x86/cpu/intel: Allow SGX virtualization without Launch Control support
  x86/sgx: Expose SGX architectural definitions to the kernel
  x86/sgx: Move ENCLS leaf definitions to sgx_arch.h
  x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT)
  x86/sgx: Add encls_faulted() helper
  x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  x86/sgx: Move provisioning device creation out of SGX driver
  KVM: VMX: Convert vcpu_vmx.exit_reason to a union
  KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX)
  KVM: x86: Define new #PF SGX error code bit
  KVM: x86: Add support for reverse CPUID lookup of scattered features
  KVM: x86: Add reverse-CPUID lookup support for scattered SGX features
  KVM: VMX: Add basic handling of VM-Exit from SGX enclave
  KVM: VMX: Frame in ENCLS handler for SGX virtualization
  KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions
  KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs
  KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC)
  KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC
  KVM: x86: Add capability to grant VM access to privileged SGX
    attribute

 Documentation/virt/kvm/api.rst                |  23 +
 arch/x86/Kconfig                              |  12 +
 arch/x86/include/asm/cpufeatures.h            |   2 +
 arch/x86/include/asm/kvm_host.h               |   5 +
 arch/x86/include/asm/sgx.h                    |  19 +
 .../cpu/sgx/arch.h => include/asm/sgx_arch.h} |  20 +
 arch/x86/include/asm/vmx.h                    |   1 +
 arch/x86/include/uapi/asm/vmx.h               |   1 +
 arch/x86/kernel/cpu/cpuid-deps.c              |   3 +
 arch/x86/kernel/cpu/feat_ctl.c                |  69 ++-
 arch/x86/kernel/cpu/scattered.c               |   2 +
 arch/x86/kernel/cpu/sgx/Makefile              |   1 +
 arch/x86/kernel/cpu/sgx/driver.c              |  17 -
 arch/x86/kernel/cpu/sgx/encl.c                |  21 +-
 arch/x86/kernel/cpu/sgx/encls.h               |  30 +-
 arch/x86/kernel/cpu/sgx/ioctl.c               |  23 +-
 arch/x86/kernel/cpu/sgx/main.c                |  93 +++-
 arch/x86/kernel/cpu/sgx/sgx.h                 |  13 +-
 arch/x86/kernel/cpu/sgx/virt.c                | 353 +++++++++++++
 arch/x86/kvm/Makefile                         |   2 +
 arch/x86/kvm/cpuid.c                          |  89 +++-
 arch/x86/kvm/cpuid.h                          |  50 +-
 arch/x86/kvm/vmx/nested.c                     |  70 ++-
 arch/x86/kvm/vmx/nested.h                     |   5 +
 arch/x86/kvm/vmx/sgx.c                        | 466 ++++++++++++++++++
 arch/x86/kvm/vmx/sgx.h                        |  34 ++
 arch/x86/kvm/vmx/vmcs12.c                     |   1 +
 arch/x86/kvm/vmx/vmcs12.h                     |   4 +-
 arch/x86/kvm/vmx/vmx.c                        | 171 +++++--
 arch/x86/kvm/vmx/vmx.h                        |  27 +-
 arch/x86/kvm/x86.c                            |  24 +
 include/uapi/linux/kvm.h                      |   1 +
 tools/testing/selftests/sgx/defines.h         |   2 +-
 33 files changed, 1498 insertions(+), 156 deletions(-)
 create mode 100644 arch/x86/include/asm/sgx.h
 rename arch/x86/{kernel/cpu/sgx/arch.h => include/asm/sgx_arch.h} (96%)
 create mode 100644 arch/x86/kernel/cpu/sgx/virt.c
 create mode 100644 arch/x86/kvm/vmx/sgx.c
 create mode 100644 arch/x86/kvm/vmx/sgx.h

-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 01/26] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
@ 2021-02-13 13:28 ` Kai Huang
  2021-02-13 13:28 ` [RFC PATCH v5 02/26] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
                   ` (25 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:28 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

Move SGX_LC feature bit to CPUID dependency table to make clearing all
SGX feature bits easier. Also remove clear_sgx_caps() since it is just
a wrapper of setup_clear_cpu_cap(X86_FEATURE_SGX) now.

Suggested-by: Sean Christopherson <seanjc@google.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - Changed patch order with the patch that introduced new SGX1/SGX2 bits, since
   it is improvement of existing code, per Jarkko.

---
 arch/x86/kernel/cpu/cpuid-deps.c |  1 +
 arch/x86/kernel/cpu/feat_ctl.c   | 12 +++---------
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 42af31b64c2c..d40f8e0a54ce 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -72,6 +72,7 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_AVX512_FP16,		X86_FEATURE_AVX512BW  },
 	{ X86_FEATURE_ENQCMD,			X86_FEATURE_XSAVES    },
 	{ X86_FEATURE_PER_THREAD_MBA,		X86_FEATURE_MBA       },
+	{ X86_FEATURE_SGX_LC,			X86_FEATURE_SGX	      },
 	{}
 };
 
diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index 3b1b01f2b248..27533a6e04fa 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -93,15 +93,9 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
 }
 #endif /* CONFIG_X86_VMX_FEATURE_NAMES */
 
-static void clear_sgx_caps(void)
-{
-	setup_clear_cpu_cap(X86_FEATURE_SGX);
-	setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
-}
-
 static int __init nosgx(char *str)
 {
-	clear_sgx_caps();
+	setup_clear_cpu_cap(X86_FEATURE_SGX);
 
 	return 0;
 }
@@ -116,7 +110,7 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 
 	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
 		clear_cpu_cap(c, X86_FEATURE_VMX);
-		clear_sgx_caps();
+		clear_cpu_cap(c, X86_FEATURE_SGX);
 		return;
 	}
 
@@ -177,6 +171,6 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
 		if (enable_sgx)
 			pr_err_once("SGX disabled by BIOS\n");
-		clear_sgx_caps();
+		clear_cpu_cap(c, X86_FEATURE_SGX);
 	}
 }
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 02/26] x86/cpufeatures: Add SGX1 and SGX2 sub-features
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
  2021-02-13 13:28 ` [RFC PATCH v5 01/26] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
@ 2021-02-13 13:28 ` Kai Huang
  2021-02-13 13:28 ` [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
                   ` (24 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:28 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <seanjc@google.com>

Add SGX1 and SGX2 feature flags, via CPUID.0x12.0x0.EAX, as scattered
features, since adding a new leaf for only two bits would be wasteful.
As part of virtualizing SGX, KVM will expose the SGX CPUID leafs to its
guest, and to do so correctly needs to query hardware and kernel support
for SGX1 and SGX2.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - Added Dave's Acked-by. No code change.

v3->v4:

- Refined the comments of SGX1/SGX2 bits, per comments from Dave, Paolo, Sean
  and Jarkko.
- Moved this patch after the patch which moves SGX_LC to cpuid_deps[] table too.

v2->v3:

- Split moving SGX_LC to cpuid-deps table logic into separate patch.

---
 arch/x86/include/asm/cpufeatures.h | 2 ++
 arch/x86/kernel/cpu/cpuid-deps.c   | 2 ++
 arch/x86/kernel/cpu/scattered.c    | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 84b887825f12..0432e7303996 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -292,6 +292,8 @@
 #define X86_FEATURE_FENCE_SWAPGS_KERNEL	(11*32+ 5) /* "" LFENCE in kernel entry SWAPGS path */
 #define X86_FEATURE_SPLIT_LOCK_DETECT	(11*32+ 6) /* #AC for split lock */
 #define X86_FEATURE_PER_THREAD_MBA	(11*32+ 7) /* "" Per-thread Memory Bandwidth Allocation */
+#define X86_FEATURE_SGX1		(11*32+ 8) /* "" Basic SGX */
+#define X86_FEATURE_SGX2        	(11*32+ 9) /* SGX Enclave Dynamic Memory Management (EDMM) */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
 #define X86_FEATURE_AVX512_BF16		(12*32+ 5) /* AVX512 BFLOAT16 instructions */
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index d40f8e0a54ce..defda61f372d 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -73,6 +73,8 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_ENQCMD,			X86_FEATURE_XSAVES    },
 	{ X86_FEATURE_PER_THREAD_MBA,		X86_FEATURE_MBA       },
 	{ X86_FEATURE_SGX_LC,			X86_FEATURE_SGX	      },
+	{ X86_FEATURE_SGX1,			X86_FEATURE_SGX       },
+	{ X86_FEATURE_SGX2,			X86_FEATURE_SGX1      },
 	{}
 };
 
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index 236924930bf0..fea0df867d18 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -36,6 +36,8 @@ static const struct cpuid_bit cpuid_bits[] = {
 	{ X86_FEATURE_CDP_L2,		CPUID_ECX,  2, 0x00000010, 2 },
 	{ X86_FEATURE_MBA,		CPUID_EBX,  3, 0x00000010, 0 },
 	{ X86_FEATURE_PER_THREAD_MBA,	CPUID_ECX,  0, 0x00000010, 3 },
+	{ X86_FEATURE_SGX1,		CPUID_EAX,  0, 0x00000012, 0 },
+	{ X86_FEATURE_SGX2,		CPUID_EAX,  1, 0x00000012, 0 },
 	{ X86_FEATURE_HW_PSTATE,	CPUID_EDX,  7, 0x80000007, 0 },
 	{ X86_FEATURE_CPB,		CPUID_EDX,  9, 0x80000007, 0 },
 	{ X86_FEATURE_PROC_FEEDBACK,    CPUID_EDX, 11, 0x80000007, 0 },
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
  2021-02-13 13:28 ` [RFC PATCH v5 01/26] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
  2021-02-13 13:28 ` [RFC PATCH v5 02/26] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
@ 2021-02-13 13:28 ` Kai Huang
  2021-02-16 17:04   ` Dave Hansen
  2021-02-13 13:28 ` [RFC PATCH v5 04/26] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
                   ` (23 subsequent siblings)
  26 siblings, 1 reply; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:28 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Jarkko Sakkinen <jarkko@kernel.org>

EREMOVE takes a pages and removes any association between that page and
an enclave.  It must be run on a page before it can be added into
another enclave.  Currently, EREMOVE is run as part of pages being freed
into the SGX page allocator.  It is not expected to fail.

KVM does not track how guest pages are used, which means that SGX
virtualization use of EREMOVE might fail.

Break out the EREMOVE call from the SGX page allocator.  This will allow
the SGX virtualization code to use the allocator directly.  (SGX/KVM
will also introduce a more permissive EREMOVE helper).

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - Refined the comment of sgx_reset_epc_page(), per Dave.
 - Refined the commit msg (which I missed in v4), per Dave.
 - Refined the grammar of the comment of sgx_free_epc_page() (which I missed
   in v4), per Dave.

v3->v4:

 - Moved WARN() on SGX_EPC_PAGE_RECLAIMER_TRACKED flag to sgx_reset_epc_page(),
   since the patch to remove the WARN() in v3 was removed. Dave and Sean were
   not convinced, and Sean "tripped more than once in the past during one of
   the many rebases of the virtual EPC and EPC cgroup branches".
 - Added a comment in sgx_reset_epc_page() to explain sgx_free_epc_page() now
   won't do EREMOVE and is expecting EPC page already in clean slate, per Dave.

---
 arch/x86/kernel/cpu/sgx/encl.c | 19 +++++++++++++++++++
 arch/x86/kernel/cpu/sgx/main.c | 12 ++++--------
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 20a2dd5ba2b4..584fceab6c76 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -381,6 +381,22 @@ const struct vm_operations_struct sgx_vm_ops = {
 	.access = sgx_vma_access,
 };
 
+
+/*
+ * Place the page in uninitialized state.  Only usable by callers that
+ * know the page is in a clean state in which EREMOVE will succeed.
+ */
+static void sgx_reset_epc_page(struct sgx_epc_page *epc_page)
+{
+	int ret;
+
+	WARN_ON_ONCE(epc_page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED);
+
+	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
+	if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
+		return;
+}
+
 /**
  * sgx_encl_release - Destroy an enclave instance
  * @kref:	address of a kref inside &sgx_encl
@@ -404,6 +420,7 @@ void sgx_encl_release(struct kref *ref)
 			if (sgx_unmark_page_reclaimable(entry->epc_page))
 				continue;
 
+			sgx_reset_epc_page(entry->epc_page);
 			sgx_free_epc_page(entry->epc_page);
 			encl->secs_child_cnt--;
 			entry->epc_page = NULL;
@@ -415,6 +432,7 @@ void sgx_encl_release(struct kref *ref)
 	xa_destroy(&encl->page_array);
 
 	if (!encl->secs_child_cnt && encl->secs.epc_page) {
+		sgx_reset_epc_page(encl->secs.epc_page);
 		sgx_free_epc_page(encl->secs.epc_page);
 		encl->secs.epc_page = NULL;
 	}
@@ -423,6 +441,7 @@ void sgx_encl_release(struct kref *ref)
 		va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
 					   list);
 		list_del(&va_page->list);
+		sgx_reset_epc_page(va_page->epc_page);
 		sgx_free_epc_page(va_page->epc_page);
 		kfree(va_page);
 	}
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 8df81a3ed945..44fe91a5bfb3 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -598,18 +598,14 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
  * sgx_free_epc_page() - Free an EPC page
  * @page:	an EPC page
  *
- * Call EREMOVE for an EPC page and insert it back to the list of free pages.
+ * Put the EPC page back to the list of free pages. It's the caller's
+ * responsibility to make sure that the page is in uninitialized state. In other
+ * words, do EREMOVE, EWB or whatever operation is necessary before calling
+ * this function.
  */
 void sgx_free_epc_page(struct sgx_epc_page *page)
 {
 	struct sgx_epc_section *section = &sgx_epc_sections[page->section];
-	int ret;
-
-	WARN_ON_ONCE(page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED);
-
-	ret = __eremove(sgx_get_epc_virt_addr(page));
-	if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
-		return;
 
 	spin_lock(&section->lock);
 	list_add_tail(&page->list, &section->page_list);
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 04/26] x86/sgx: Add SGX_CHILD_PRESENT hardware error code
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (2 preceding siblings ...)
  2021-02-13 13:28 ` [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
@ 2021-02-13 13:28 ` Kai Huang
  2021-02-13 13:28 ` [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
                   ` (22 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:28 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

SGX driver can accurately track how enclave pages are used.  This
enables SECS to be specifically targeted and EREMOVE'd only after all
child pages have been EREMOVE'd.  This ensures that SGX driver will
never encounter SGX_CHILD_PRESENT in normal operation.

Virtual EPC is different.  The host does not track how EPC pages are
used by the guest, so it cannot guarantee EREMOVE success.  It might,
for instance, encounter a SECS with a non-zero child count.

Add a definition of SGX_CHILD_PRESENT.  It will be used exclusively by
the SGX virtualization driver to handle recoverable EREMOVE errors when
saniziting EPC pages after they are freed.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - Refined the last paragraph in commit message, per Dave and Sean.

   (Hi Dave, I assumed I can still have your Acked-by. Let me know I got it
    wrong. Thanks.)

v3->v4:

 - Refined the commit msg, per Dave.

v2->v3:

 - Changed from 'Enclave has child' to 'SECS has child', per Jarkko.

---
 arch/x86/kernel/cpu/sgx/arch.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/cpu/sgx/arch.h b/arch/x86/kernel/cpu/sgx/arch.h
index dd7602c44c72..abf99bb71fdc 100644
--- a/arch/x86/kernel/cpu/sgx/arch.h
+++ b/arch/x86/kernel/cpu/sgx/arch.h
@@ -26,12 +26,14 @@
  * enum sgx_return_code - The return code type for ENCLS, ENCLU and ENCLV
  * %SGX_NOT_TRACKED:		Previous ETRACK's shootdown sequence has not
  *				been completed yet.
+ * %SGX_CHILD_PRESENT		SECS has child pages present in the EPC.
  * %SGX_INVALID_EINITTOKEN:	EINITTOKEN is invalid and enclave signer's
  *				public key does not match IA32_SGXLEPUBKEYHASH.
  * %SGX_UNMASKED_EVENT:		An unmasked event, e.g. INTR, was received
  */
 enum sgx_return_code {
 	SGX_NOT_TRACKED			= 11,
+	SGX_CHILD_PRESENT		= 13,
 	SGX_INVALID_EINITTOKEN		= 16,
 	SGX_UNMASKED_EVENT		= 128,
 };
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (3 preceding siblings ...)
  2021-02-13 13:28 ` [RFC PATCH v5 04/26] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
@ 2021-02-13 13:28 ` Kai Huang
  2021-02-16  2:12   ` Jarkko Sakkinen
  2021-02-16 18:38   ` Dave Hansen
  2021-02-13 13:29 ` [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
                   ` (21 subsequent siblings)
  26 siblings, 2 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:28 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add a misc device /dev/sgx_vepc to allow userspace to allocate "raw" EPC
without an associated enclave.  The intended and only known use case for
raw EPC allocation is to expose EPC to a KVM guest, hence the 'vepc'
moniker, virt.{c,h} files and X86_SGX_KVM Kconfig.

SGX driver uses misc device /dev/sgx_enclave to support userspace to
create enclave.  Each file descriptor from opening /dev/sgx_enclave
represents an enclave.  Unlike SGX driver, KVM doesn't control how guest
uses EPC, therefore EPC allocated to KVM guest is not associated to an
encalve, and /dev/sgx_enclave is not suitable for allocating EPC for KVM
guest.

Having separate device nodes for SGX driver and KVM virtual EPC also
allows separate permission control for running host SGX enclaves and
KVM SGX guests.

More specifically, to allocate a virtual EPC instance with particular
size, the userspace hypervisor opens /dev/sgx_vepc, and uses mmap()
with the intended size to get an address range of virtual EPC.  Then
it may use the address range to create one KVM memory slot as virtual
EPC for guest.

Implement the "raw" EPC allocation in the x86 core-SGX subsystem via
/dev/sgx_vepc rather than in KVM. Doing so has two major advantages:

  - Does not require changes to KVM's uAPI, e.g. EPC gets handled as
    just another memory backend for guests.

  - EPC management is wholly contained in the SGX subsystem, e.g. SGX
    does not have to export any symbols, changes to reclaim flows don't
    need to be routed through KVM, SGX's dirty laundry doesn't have to
    get aired out for the world to see, and so on and so forth.

The virtual EPC pages allocated to guests are currently not reclaimable.
Reclaiming EPC page used by enclave requires a special reclaim mechanism
separate from normal page reclaim, and that mechanism is not supported
for virutal EPC pages.  Due to the complications of handling reclaim
conflicts between guest and host, reclaiming virtual EPC pages is
significantly more complex than basic support for SGX virtualization.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - Added explanation of adding new /dev/sgx_vepc, rather than using existing
   /dev/sgx_enclave in to commit message, per Jarkko. No code change.

v3->v4:

 - Removed #define pr_fmt(fmt), per Dave and Jarkko.
 - Added one line summary next to copyright, and also updated copyright, per
   Dave.
 - Added comment to explain zombie_secs_pages and the lock, per Dave.
 - Removed !IS_ENABLED(CONFIG_KVM_INTEL) in sgx_vepc_init(), per Dave.
 - Removed virt.h, per Dave, and put the declaration of sgx_vepc_init() to
   arch/x86/kernel/cpu/sgx/sgx.h.

v2->v3:

 - Changed from /dev/sgx_virt_epc to /dev/sgx_vepc, per Jarkko. Accordingly,
   renamed 'sgx_virt_epc_xx' to 'sgx_vepc_xx' for various functions and
   structrues.
 - Changed CONFIG_X86_SGX_VIRTUALIZATION to CONFIG_X86_SGX_KVM, per Dave.

v1->v2:

 - Added one paragraph to explain fops of virtual EPC, per Jarkko's suggestion.
 - Moved change to sgx_init() out of this patch to a separate patch, as stated
   in cover letter.
 - In sgx_virt_epc_init(), return error if VMX is not supported, or
   CONFIG_KVM_INTEL is not enabled, because there's no point to create
   /dev/sgx_virt_epc if KVM is not supported.
 - Removed 'struct mm_struct *mm' in 'struct sgx_virt_epc', and related logic in
   sgx_virt_epc_open/release/mmap(), per Dave's comment.
 - Renamed 'virtual_epc_zombie_pages' and 'virt_epc_lock' to 'zombie_secs_pages'
   'zombie_secs_pages_lock', per Dave's suggestion.
 - Changed __sgx_free_epc_page() to sgx_free_epc_page() due to Jarkko's patch
   removes EREMOVE in sgx_free_epc_page().
 - Changed all struct sgx_virt_epc *epc to struct sgx_virt_epc *vepc.
 - In __sgx_virt_epc_fault(), changed comment to use WARN_ON() to make sure
   vepc->lock has already been hold, per Dave's suggestion.
 - In sgx_virt_epc_free_page(), added comments to explain SGX_ENCLAVE_ACT is not
   expected; and changed to use WARN_ONCE() to dump actual error code, per
   Dave's comment.
 - Removed NULL page check in sgx_virt_epc_free_page(), per Dave's comment.

---
 arch/x86/Kconfig                 |  12 ++
 arch/x86/kernel/cpu/sgx/Makefile |   1 +
 arch/x86/kernel/cpu/sgx/sgx.h    |   9 ++
 arch/x86/kernel/cpu/sgx/virt.c   | 259 +++++++++++++++++++++++++++++++
 4 files changed, 281 insertions(+)
 create mode 100644 arch/x86/kernel/cpu/sgx/virt.c

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..ccb35d14c297 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1951,6 +1951,18 @@ config X86_SGX
 
 	  If unsure, say N.
 
+config X86_SGX_KVM
+	bool "Software Guard eXtensions (SGX) Virtualization"
+	depends on X86_SGX && KVM_INTEL
+	help
+
+	  Enables KVM guests to create SGX enclaves.
+
+	  This includes support to expose "raw" unreclaimable enclave memory to
+	  guests via a device node, e.g. /dev/sgx_vepc.
+
+	  If unsure, say N.
+
 config EFI
 	bool "EFI runtime service support"
 	depends on ACPI
diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
index 91d3dc784a29..9c1656779b2a 100644
--- a/arch/x86/kernel/cpu/sgx/Makefile
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -3,3 +3,4 @@ obj-y += \
 	encl.o \
 	ioctl.o \
 	main.o
+obj-$(CONFIG_X86_SGX_KVM)	+= virt.o
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index 5fa42d143feb..1bff93be7bf4 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -83,4 +83,13 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page);
 int sgx_unmark_page_reclaimable(struct sgx_epc_page *page);
 struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim);
 
+#ifdef CONFIG_X86_SGX_KVM
+int __init sgx_vepc_init(void);
+#else
+static inline int __init sgx_vepc_init(void)
+{
+	return -ENODEV;
+}
+#endif
+
 #endif /* _X86_SGX_H */
diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
new file mode 100644
index 000000000000..47542140f8c1
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/virt.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device driver to expose SGX enclave memory to KVM guests.
+ *
+ * Copyright(c) 2021 Intel Corporation.
+ */
+
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include <linux/xarray.h>
+#include <asm/sgx.h>
+#include <uapi/asm/sgx.h>
+
+#include "encls.h"
+#include "sgx.h"
+
+struct sgx_vepc {
+	struct xarray page_array;
+	struct mutex lock;
+};
+
+/*
+ * Temporary SECS pages that cannot be EREMOVE'd due to having child in other
+ * virtual EPC instances, and the lock to protect it.
+ */
+static struct mutex zombie_secs_pages_lock;
+static struct list_head zombie_secs_pages;
+
+static int __sgx_vepc_fault(struct sgx_vepc *vepc,
+			    struct vm_area_struct *vma, unsigned long addr)
+{
+	struct sgx_epc_page *epc_page;
+	unsigned long index, pfn;
+	int ret;
+
+	WARN_ON(!mutex_is_locked(&vepc->lock));
+
+	/* Calculate index of EPC page in virtual EPC's page_array */
+	index = vma->vm_pgoff + PFN_DOWN(addr - vma->vm_start);
+
+	epc_page = xa_load(&vepc->page_array, index);
+	if (epc_page)
+		return 0;
+
+	epc_page = sgx_alloc_epc_page(vepc, false);
+	if (IS_ERR(epc_page))
+		return PTR_ERR(epc_page);
+
+	ret = xa_err(xa_store(&vepc->page_array, index, epc_page, GFP_KERNEL));
+	if (ret)
+		goto err_free;
+
+	pfn = PFN_DOWN(sgx_get_epc_phys_addr(epc_page));
+
+	ret = vmf_insert_pfn(vma, addr, pfn);
+	if (ret != VM_FAULT_NOPAGE) {
+		ret = -EFAULT;
+		goto err_delete;
+	}
+
+	return 0;
+
+err_delete:
+	xa_erase(&vepc->page_array, index);
+err_free:
+	sgx_free_epc_page(epc_page);
+	return ret;
+}
+
+static vm_fault_t sgx_vepc_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct sgx_vepc *vepc = vma->vm_private_data;
+	int ret;
+
+	mutex_lock(&vepc->lock);
+	ret = __sgx_vepc_fault(vepc, vma, vmf->address);
+	mutex_unlock(&vepc->lock);
+
+	if (!ret)
+		return VM_FAULT_NOPAGE;
+
+	if (ret == -EBUSY && (vmf->flags & FAULT_FLAG_ALLOW_RETRY)) {
+		mmap_read_unlock(vma->vm_mm);
+		return VM_FAULT_RETRY;
+	}
+
+	return VM_FAULT_SIGBUS;
+}
+
+const struct vm_operations_struct sgx_vepc_vm_ops = {
+	.fault = sgx_vepc_fault,
+};
+
+static int sgx_vepc_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct sgx_vepc *vepc = file->private_data;
+
+	if (!(vma->vm_flags & VM_SHARED))
+		return -EINVAL;
+
+	vma->vm_ops = &sgx_vepc_vm_ops;
+	/* Don't copy VMA in fork() */
+	vma->vm_flags |= VM_PFNMAP | VM_IO | VM_DONTDUMP | VM_DONTCOPY;
+	vma->vm_private_data = vepc;
+
+	return 0;
+}
+
+static int sgx_vepc_free_page(struct sgx_epc_page *epc_page)
+{
+	int ret;
+
+	/*
+	 * Take a previously guest-owned EPC page and return it to the
+	 * general EPC page pool.
+	 *
+	 * Guests can not be trusted to have left this page in a good
+	 * state, so run EREMOVE on the page unconditionally.  In the
+	 * case that a guest properly EREMOVE'd this page, a superfluous
+	 * EREMOVE is harmless.
+	 */
+	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
+	if (ret) {
+		/*
+		 * Only SGX_CHILD_PRESENT is expected, which is because of
+		 * EREMOVE'ing an SECS still with child, in which case it can
+		 * be handled by EREMOVE'ing the SECS again after all pages in
+		 * virtual EPC have been EREMOVE'd. See comments in below in
+		 * sgx_vepc_release().
+		 *
+		 * The user of virtual EPC (KVM) needs to guarantee there's no
+		 * logical processor is still running in the enclave in guest,
+		 * otherwise EREMOVE will get SGX_ENCLAVE_ACT which cannot be
+		 * handled here.
+		 */
+		WARN_ONCE(ret != SGX_CHILD_PRESENT,
+			  "EREMOVE (EPC page 0x%lx): unexpected error: %d\n",
+			  sgx_get_epc_phys_addr(epc_page), ret);
+		return ret;
+	}
+
+	sgx_free_epc_page(epc_page);
+	return 0;
+}
+
+static int sgx_vepc_release(struct inode *inode, struct file *file)
+{
+	struct sgx_vepc *vepc = file->private_data;
+	struct sgx_epc_page *epc_page, *tmp, *entry;
+	unsigned long index;
+
+	LIST_HEAD(secs_pages);
+
+	xa_for_each(&vepc->page_array, index, entry) {
+		/*
+		 * Remove all normal, child pages.  sgx_vepc_free_page()
+		 * will fail if EREMOVE fails, but this is OK and expected on
+		 * SECS pages.  Those can only be EREMOVE'd *after* all their
+		 * child pages. Retries below will clean them up.
+		 */
+		if (sgx_vepc_free_page(entry))
+			continue;
+
+		xa_erase(&vepc->page_array, index);
+	}
+
+	/*
+	 * Retry EREMOVE'ing pages.  This will clean up any SECS pages that
+	 * only had children in this 'epc' area.
+	 */
+	xa_for_each(&vepc->page_array, index, entry) {
+		epc_page = entry;
+		/*
+		 * An EREMOVE failure here means that the SECS page still
+		 * has children.  But, since all children in this 'sgx_vepc'
+		 * have been removed, the SECS page must have a child on
+		 * another instance.
+		 */
+		if (sgx_vepc_free_page(epc_page))
+			list_add_tail(&epc_page->list, &secs_pages);
+
+		xa_erase(&vepc->page_array, index);
+	}
+
+	/*
+	 * SECS pages are "pinned" by child pages, an unpinned once all
+	 * children have been EREMOVE'd.  A child page in this instance
+	 * may have pinned an SECS page encountered in an earlier release(),
+	 * creating a zombie.  Since some children were EREMOVE'd above,
+	 * try to EREMOVE all zombies in the hopes that one was unpinned.
+	 */
+	mutex_lock(&zombie_secs_pages_lock);
+	list_for_each_entry_safe(epc_page, tmp, &zombie_secs_pages, list) {
+		/*
+		 * Speculatively remove the page from the list of zombies,
+		 * if the page is successfully EREMOVE it will be added to
+		 * the list of free pages.  If EREMOVE fails, throw the page
+		 * on the local list, which will be spliced on at the end.
+		 */
+		list_del(&epc_page->list);
+
+		if (sgx_vepc_free_page(epc_page))
+			list_add_tail(&epc_page->list, &secs_pages);
+	}
+
+	if (!list_empty(&secs_pages))
+		list_splice_tail(&secs_pages, &zombie_secs_pages);
+	mutex_unlock(&zombie_secs_pages_lock);
+
+	kfree(vepc);
+
+	return 0;
+}
+
+static int sgx_vepc_open(struct inode *inode, struct file *file)
+{
+	struct sgx_vepc *vepc;
+
+	vepc = kzalloc(sizeof(struct sgx_vepc), GFP_KERNEL);
+	if (!vepc)
+		return -ENOMEM;
+	mutex_init(&vepc->lock);
+	xa_init(&vepc->page_array);
+
+	file->private_data = vepc;
+
+	return 0;
+}
+
+static const struct file_operations sgx_vepc_fops = {
+	.owner		= THIS_MODULE,
+	.open		= sgx_vepc_open,
+	.release	= sgx_vepc_release,
+	.mmap		= sgx_vepc_mmap,
+};
+
+static struct miscdevice sgx_vepc_dev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "sgx_vepc",
+	.nodename = "sgx_vepc",
+	.fops = &sgx_vepc_fops,
+};
+
+int __init sgx_vepc_init(void)
+{
+	/* SGX virtualization requires KVM to work */
+	if (!boot_cpu_has(X86_FEATURE_VMX))
+		return -ENODEV;
+
+	INIT_LIST_HEAD(&zombie_secs_pages);
+	mutex_init(&zombie_secs_pages_lock);
+
+	return misc_register(&sgx_vepc_dev);
+}
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (4 preceding siblings ...)
  2021-02-13 13:28 ` [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-16  2:15   ` Jarkko Sakkinen
  2021-02-16 18:40   ` Dave Hansen
  2021-02-13 13:29 ` [RFC PATCH v5 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
                   ` (20 subsequent siblings)
  26 siblings, 2 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jethro, b.thiel,
	Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

The kernel will currently disable all SGX support if the hardware does
not support launch control.  Make it more permissive to allow SGX
virtualization on systems without Launch Control support.  This will
allow KVM to expose SGX to guests that have less-strict requirements on
the availability of flexible launch control.

Improve error message to distinguish between three cases.  There are two
cases where SGX support is completely disabled:
1) SGX has been disabled completely by the BIOS
2) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
   of LC unavailability.  SGX virtualization is unavailable (because of
   Kconfig).
One where it is partially available:
3) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
   of LC unavailability.  SGX virtualization is supported.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - Removed cpu_has(X86_FEATURE_SGX1) check in enable_sgx_any, since it logically
   is not related to KVM SGX series, per Sean.
 - Changed declaration of variables to be in reverse-christmas tree style, per
   Jarkko.

v2->v3:

 - Added to use 'enable_sgx_any', per Dave.
 - Changed to call clear_cpu_cap() directly, rather than using clear_sgx_caps()
   and clear_sgx_lc().
 - Changed to use CONFIG_X86_SGX_KVM, instead of CONFIG_X86_SGX_VIRTUALIZATION.

v1->v2:

 - Refined commit message per Dave's comments.
 - Added check to only enable SGX virtualization when VMX is supported, per
   Dave's comment.
 - Refined error msg print to explicitly call out SGX virtualization will be
   supported when LC is locked by BIOS, per Dave's comment.

---
 arch/x86/kernel/cpu/feat_ctl.c | 57 ++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index 27533a6e04fa..96c370284913 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -105,7 +105,8 @@ early_param("nosgx", nosgx);
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 {
 	bool tboot = tboot_enabled();
-	bool enable_sgx;
+	bool enable_sgx_any, enable_sgx_kvm, enable_sgx_driver;
+	bool enable_vmx;
 	u64 msr;
 
 	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
@@ -114,13 +115,21 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 		return;
 	}
 
+	enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
+		     IS_ENABLED(CONFIG_KVM_INTEL);
+
 	/*
-	 * Enable SGX if and only if the kernel supports SGX and Launch Control
-	 * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
+	 * Separate out SGX driver enabling from KVM.  This allows KVM
+	 * guests to use SGX even if the kernel SGX driver refuses to
+	 * use it.  This happens if flexible Faunch Control is not
+	 * available.
 	 */
-	enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
-		     cpu_has(c, X86_FEATURE_SGX_LC) &&
-		     IS_ENABLED(CONFIG_X86_SGX);
+	enable_sgx_any = cpu_has(c, X86_FEATURE_SGX) &&
+			 IS_ENABLED(CONFIG_X86_SGX);
+	enable_sgx_driver = enable_sgx_any &&
+			    cpu_has(c, X86_FEATURE_SGX_LC);
+	enable_sgx_kvm = enable_sgx_any && enable_vmx &&
+			  IS_ENABLED(CONFIG_X86_SGX_KVM);
 
 	if (msr & FEAT_CTL_LOCKED)
 		goto update_caps;
@@ -136,15 +145,18 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 	 * i.e. KVM is enabled, to avoid unnecessarily adding an attack vector
 	 * for the kernel, e.g. using VMX to hide malicious code.
 	 */
-	if (cpu_has(c, X86_FEATURE_VMX) && IS_ENABLED(CONFIG_KVM_INTEL)) {
+	if (enable_vmx) {
 		msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
 
 		if (tboot)
 			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
 	}
 
-	if (enable_sgx)
-		msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED;
+	if (enable_sgx_kvm || enable_sgx_driver) {
+		msr |= FEAT_CTL_SGX_ENABLED;
+		if (enable_sgx_driver)
+			msr |= FEAT_CTL_SGX_LC_ENABLED;
+	}
 
 	wrmsrl(MSR_IA32_FEAT_CTL, msr);
 
@@ -167,10 +179,29 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 	}
 
 update_sgx:
-	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
-	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
-		if (enable_sgx)
-			pr_err_once("SGX disabled by BIOS\n");
+	if (!(msr & FEAT_CTL_SGX_ENABLED)) {
+		if (enable_sgx_kvm || enable_sgx_driver)
+			pr_err_once("SGX disabled by BIOS.\n");
 		clear_cpu_cap(c, X86_FEATURE_SGX);
+		return;
+	}
+
+	/*
+	 * VMX feature bit may be cleared due to being disabled in BIOS,
+	 * in which case SGX virtualization cannot be supported either.
+	 */
+	if (!cpu_has(c, X86_FEATURE_VMX) && enable_sgx_kvm) {
+		pr_err_once("SGX virtualization disabled due to lack of VMX.\n");
+		enable_sgx_kvm = 0;
+	}
+
+	if (!(msr & FEAT_CTL_SGX_LC_ENABLED) && enable_sgx_driver) {
+		if (!enable_sgx_kvm) {
+			pr_err_once("SGX Launch Control is locked. Disable SGX.\n");
+			clear_cpu_cap(c, X86_FEATURE_SGX);
+		} else {
+			pr_err_once("SGX Launch Control is locked. Support SGX virtualization only.\n");
+			clear_cpu_cap(c, X86_FEATURE_SGX_LC);
+		}
 	}
 }
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (5 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-16 18:41   ` Dave Hansen
  2021-02-13 13:29 ` [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
                   ` (19 subsequent siblings)
  26 siblings, 1 reply; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

Modify sgx_init() to always try to initialize the virtual EPC driver,
even if the SGX driver is disabled.  The SGX driver might be disabled
if SGX Launch Control is in locked mode, or not supported in the
hardware at all.  This allows (non-Linux) guests that support non-LC
configurations to use SGX.

Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - Added comment to explain virtual EPC driver can be supported in both cases
   that SGX driver is not supported, or failed to initialize, per Dave and
   Jarkko.
 - Removed "virt.h" inclusion since it was removed in previous patch, per Dave.

v2->v3:

 - Changed from sgx_virt_epc_init() to sgx_vepc_init().

---
 arch/x86/kernel/cpu/sgx/main.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 44fe91a5bfb3..8c922e68274d 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -712,7 +712,15 @@ static int __init sgx_init(void)
 		goto err_page_cache;
 	}
 
-	ret = sgx_drv_init();
+	/*
+	 * Always try to initialize the native *and* KVM drivers.
+	 * The KVM driver is less picky than the native one and
+	 * can function if the native one is not supported on the
+	 * current system or fails to initialize.
+	 *
+	 * Error out only if both fail to initialize.
+	 */
+	ret = !!sgx_drv_init() & !!sgx_vepc_init();
 	if (ret)
 		goto err_kthread;
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (6 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-16  2:17   ` Jarkko Sakkinen
  2021-02-13 13:29 ` [RFC PATCH v5 09/26] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h Kai Huang
                   ` (18 subsequent siblings)
  26 siblings, 1 reply; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Expose SGX architectural structures, as KVM will use many of the
architectural constants and structs to virtualize SGX.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/{kernel/cpu/sgx/arch.h => include/asm/sgx_arch.h} | 0
 arch/x86/kernel/cpu/sgx/encl.c                             | 2 +-
 arch/x86/kernel/cpu/sgx/sgx.h                              | 2 +-
 tools/testing/selftests/sgx/defines.h                      | 2 +-
 4 files changed, 3 insertions(+), 3 deletions(-)
 rename arch/x86/{kernel/cpu/sgx/arch.h => include/asm/sgx_arch.h} (100%)

diff --git a/arch/x86/kernel/cpu/sgx/arch.h b/arch/x86/include/asm/sgx_arch.h
similarity index 100%
rename from arch/x86/kernel/cpu/sgx/arch.h
rename to arch/x86/include/asm/sgx_arch.h
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 584fceab6c76..0884b9a4e356 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -7,7 +7,7 @@
 #include <linux/shmem_fs.h>
 #include <linux/suspend.h>
 #include <linux/sched/mm.h>
-#include "arch.h"
+#include <asm/sgx_arch.h>
 #include "encl.h"
 #include "encls.h"
 #include "sgx.h"
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index 1bff93be7bf4..161d2d8ac3b6 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -8,7 +8,7 @@
 #include <linux/rwsem.h>
 #include <linux/types.h>
 #include <asm/asm.h>
-#include "arch.h"
+#include <asm/sgx_arch.h>
 
 #undef pr_fmt
 #define pr_fmt(fmt) "sgx: " fmt
diff --git a/tools/testing/selftests/sgx/defines.h b/tools/testing/selftests/sgx/defines.h
index 592c1ccf4576..4dd39a003f40 100644
--- a/tools/testing/selftests/sgx/defines.h
+++ b/tools/testing/selftests/sgx/defines.h
@@ -14,7 +14,7 @@
 #define __aligned(x) __attribute__((__aligned__(x)))
 #define __packed __attribute__((packed))
 
-#include "../../../../arch/x86/kernel/cpu/sgx/arch.h"
+#include "../../../../arch/x86/include/asm/sgx_arch.h"
 #include "../../../../arch/x86/include/asm/enclu.h"
 #include "../../../../arch/x86/include/uapi/asm/sgx.h"
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 09/26] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (7 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 10/26] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
                   ` (17 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Move the ENCLS leaf definitions to sgx_arch.h so that they can be used
by KVM.  And because they're architectural.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/include/asm/sgx_arch.h | 15 +++++++++++++++
 arch/x86/kernel/cpu/sgx/encls.h | 15 ---------------
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/sgx_arch.h b/arch/x86/include/asm/sgx_arch.h
index abf99bb71fdc..3dbe7aacf552 100644
--- a/arch/x86/include/asm/sgx_arch.h
+++ b/arch/x86/include/asm/sgx_arch.h
@@ -22,6 +22,21 @@
 /* The bitmask for the EPC section type. */
 #define SGX_CPUID_EPC_MASK	GENMASK(3, 0)
 
+enum sgx_encls_function {
+	ECREATE	= 0x00,
+	EADD	= 0x01,
+	EINIT	= 0x02,
+	EREMOVE	= 0x03,
+	EDGBRD	= 0x04,
+	EDGBWR	= 0x05,
+	EEXTEND	= 0x06,
+	ELDU	= 0x08,
+	EBLOCK	= 0x09,
+	EPA	= 0x0A,
+	EWB	= 0x0B,
+	ETRACK	= 0x0C,
+};
+
 /**
  * enum sgx_return_code - The return code type for ENCLS, ENCLU and ENCLV
  * %SGX_NOT_TRACKED:		Previous ETRACK's shootdown sequence has not
diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
index 443188fe7e70..be5c49689980 100644
--- a/arch/x86/kernel/cpu/sgx/encls.h
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -11,21 +11,6 @@
 #include <asm/traps.h>
 #include "sgx.h"
 
-enum sgx_encls_function {
-	ECREATE	= 0x00,
-	EADD	= 0x01,
-	EINIT	= 0x02,
-	EREMOVE	= 0x03,
-	EDGBRD	= 0x04,
-	EDGBWR	= 0x05,
-	EEXTEND	= 0x06,
-	ELDU	= 0x08,
-	EBLOCK	= 0x09,
-	EPA	= 0x0A,
-	EWB	= 0x0B,
-	ETRACK	= 0x0C,
-};
-
 /**
  * ENCLS_FAULT_FLAG - flag signifying an ENCLS return code is a trapnr
  *
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 10/26] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT)
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (8 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 09/26] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 11/26] x86/sgx: Add encls_faulted() helper Kai Huang
                   ` (16 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Define the ENCLS leafs that are available with SGX2, also referred to as
Enclave Dynamic Memory Management (EDMM).  The leafs will be used by KVM
to conditionally expose SGX2 capabilities to guests.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/include/asm/sgx_arch.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/include/asm/sgx_arch.h b/arch/x86/include/asm/sgx_arch.h
index 3dbe7aacf552..756c8dacc52a 100644
--- a/arch/x86/include/asm/sgx_arch.h
+++ b/arch/x86/include/asm/sgx_arch.h
@@ -35,6 +35,9 @@ enum sgx_encls_function {
 	EPA	= 0x0A,
 	EWB	= 0x0B,
 	ETRACK	= 0x0C,
+	EAUG	= 0x0D,
+	EMODPR	= 0x0E,
+	EMODT	= 0x0F,
 };
 
 /**
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 11/26] x86/sgx: Add encls_faulted() helper
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (9 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 10/26] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 12/26] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
                   ` (15 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add a helper to extract the fault indicator from an encoded ENCLS return
value.  SGX virtualization will also need to detect ENCLS faults.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - No code change. Added Jarkko's Acked-by.

v2->v3:

 - Changed commenting style for return value, per Jarkko.

---
 arch/x86/kernel/cpu/sgx/encls.h | 15 ++++++++++++++-
 arch/x86/kernel/cpu/sgx/ioctl.c |  2 +-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
index be5c49689980..3219d011ee28 100644
--- a/arch/x86/kernel/cpu/sgx/encls.h
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -40,6 +40,19 @@
 	} while (0);							  \
 }
 
+/*
+ * encls_faulted() - Check if an ENCLS leaf faulted given an error code
+ * @ret 	the return value of an ENCLS leaf function call
+ *
+ * Return:
+ * - true:	ENCLS leaf faulted.
+ * - false:	Otherwise.
+ */
+static inline bool encls_faulted(int ret)
+{
+	return ret & ENCLS_FAULT_FLAG;
+}
+
 /**
  * encls_failed() - Check if an ENCLS function failed
  * @ret:	the return value of an ENCLS function call
@@ -50,7 +63,7 @@
  */
 static inline bool encls_failed(int ret)
 {
-	if (ret & ENCLS_FAULT_FLAG)
+	if (encls_faulted(ret))
 		return ENCLS_TRAPNR(ret) != X86_TRAP_PF;
 
 	return !!ret;
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 90a5caf76939..e5977752c7be 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -568,7 +568,7 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
 		}
 	}
 
-	if (ret & ENCLS_FAULT_FLAG) {
+	if (encls_faulted(ret)) {
 		if (encls_failed(ret))
 			ENCLS_WARN(ret, "EINIT");
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 12/26] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (10 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 11/26] x86/sgx: Add encls_faulted() helper Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
                   ` (14 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

Add a helper to update SGX_LEPUBKEYHASHn MSRs.  SGX virtualization also
needs to update those MSRs based on guest's "virtual" SGX_LEPUBKEYHASHn
before EINIT from guest.

Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - Patch rebase due to sgx/virt.h was removed per Dave, and sgx_vepc_init()
   declaration was moved to sgx/sgx.h.
 - Added Jarkko's Ack-by. Restored Dave's Acked-by.

v2->v3:

 - Added comment for sgx_update_lepubkeyhash(), per Jarkko and Dave.

---
 arch/x86/kernel/cpu/sgx/ioctl.c |  5 ++---
 arch/x86/kernel/cpu/sgx/main.c  | 15 +++++++++++++++
 arch/x86/kernel/cpu/sgx/sgx.h   |  2 ++
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index e5977752c7be..1bae754268d1 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -495,7 +495,7 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
 			 void *token)
 {
 	u64 mrsigner[4];
-	int i, j, k;
+	int i, j;
 	void *addr;
 	int ret;
 
@@ -544,8 +544,7 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
 
 			preempt_disable();
 
-			for (k = 0; k < 4; k++)
-				wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + k, mrsigner[k]);
+			sgx_update_lepubkeyhash(mrsigner);
 
 			ret = __einit(sigstruct, token, addr);
 
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 8c922e68274d..276220d0e4b5 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -696,6 +696,21 @@ static bool __init sgx_page_cache_init(void)
 	return true;
 }
 
+
+/*
+ * Update the SGX_LEPUBKEYHASH MSRs to the values specified by caller.
+ * Bare-metal driver requires to update them to hash of enclave's signer
+ * before EINIT. KVM needs to update them to guest's virtual MSR values
+ * before doing EINIT from guest.
+ */
+void sgx_update_lepubkeyhash(u64 *lepubkeyhash)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
+}
+
 static int __init sgx_init(void)
 {
 	int ret;
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index 161d2d8ac3b6..371fdf3b16a8 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -92,4 +92,6 @@ static inline int __init sgx_vepc_init(void)
 }
 #endif
 
+void sgx_update_lepubkeyhash(u64 *lepubkeyhash);
+
 #endif /* _X86_SGX_H */
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (11 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 12/26] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-16  3:08   ` Jarkko Sakkinen
  2021-02-13 13:29 ` [RFC PATCH v5 14/26] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
                   ` (13 subsequent siblings)
  26 siblings, 1 reply; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

The host kernel must intercept ECREATE to be able to impose policies on
guests.  When it does this, the host kernel runs ECREATE against the
userspace mapping of the virtualized EPC.

Provide wrappers around __ecreate() and __einit() to hide the ugliness
of overloading the ENCLS return value to encode multiple error formats
in a single int.  KVM will trap-and-execute ECREATE and EINIT as part
of SGX virtualization, and on an exception, KVM needs the trapnr so that
it can inject the correct fault into the guest.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - Added one new line before last return in sgx_virt_einit(), per Jarkko.

v2->v3:

 - Added kdoc for sgx_virt_ecreate() and sgx_virt_einit(), per Jarkko.
 - Changed to use CONFIG_X86_SGX_KVM.

---
 arch/x86/include/asm/sgx.h     | 16 ++++++
 arch/x86/kernel/cpu/sgx/virt.c | 94 ++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 arch/x86/include/asm/sgx.h

diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
new file mode 100644
index 000000000000..8a3ea3e1efbe
--- /dev/null
+++ b/arch/x86/include/asm/sgx.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SGX_H
+#define _ASM_X86_SGX_H
+
+#include <linux/types.h>
+
+#ifdef CONFIG_X86_SGX_KVM
+struct sgx_pageinfo;
+
+int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
+		     int *trapnr);
+int sgx_virt_einit(void __user *sigstruct, void __user *token,
+		   void __user *secs, u64 *lepubkeyhash, int *trapnr);
+#endif
+
+#endif /* _ASM_X86_SGX_H */
diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
index 47542140f8c1..016bad7cff8d 100644
--- a/arch/x86/kernel/cpu/sgx/virt.c
+++ b/arch/x86/kernel/cpu/sgx/virt.c
@@ -257,3 +257,97 @@ int __init sgx_vepc_init(void)
 
 	return misc_register(&sgx_vepc_dev);
 }
+
+/**
+ * sgx_virt_ecreate() - Run ECREATE on behalf of guest
+ * @pageinfo:	Pointer to PAGEINFO structure
+ * @secs:	Userspace pointer to SECS page
+ * @trapnr:	trap number injected to guest in case of ECREATE error
+ *
+ * Run ECREATE on behalf of guest after KVM traps ECREATE for the purpose
+ * of enforcing policies of guest's enclaves, and return the trap number
+ * which should be injected to guest in case of any ECREATE error.
+ *
+ * Return:
+ * - 0: 	ECREATE was successful.
+ * - -EFAULT:	ECREATE returned error.
+ */
+int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
+		     int *trapnr)
+{
+	int ret;
+
+	/*
+	 * @secs is userspace address, and it's not guaranteed @secs points at
+	 * an actual EPC page. It's also possible to generate a kernel mapping
+	 * to physical EPC page by resolving PFN but using __uaccess_xx() is
+	 * simpler.
+	 */
+	__uaccess_begin();
+	ret = __ecreate(pageinfo, (void *)secs);
+	__uaccess_end();
+
+	if (encls_faulted(ret)) {
+		*trapnr = ENCLS_TRAPNR(ret);
+		return -EFAULT;
+	}
+
+	/* ECREATE doesn't return an error code, it faults or succeeds. */
+	WARN_ON_ONCE(ret);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sgx_virt_ecreate);
+
+static int __sgx_virt_einit(void __user *sigstruct, void __user *token,
+			    void __user *secs)
+{
+	int ret;
+
+	__uaccess_begin();
+	ret =  __einit((void *)sigstruct, (void *)token, (void *)secs);
+	__uaccess_end();
+	return ret;
+}
+
+/**
+ * sgx_virt_einit() - Run EINIT on behalf of guest
+ * @sigstruct:		Userspace pointer to SIGSTRUCT structure
+ * @token:		Userspace pointer to EINITTOKEN structure
+ * @secs:		Userspace pointer to SECS page
+ * @lepubkeyhash:	Pointer to guest's *virtual* SGX_LEPUBKEYHASH MSR
+ * 			values
+ * @trapnr:		trap number injected to guest in case of EINIT error
+ *
+ * Run EINIT on behalf of guest after KVM traps EINIT. If SGX_LC is available
+ * in host, SGX driver may rewrite the hardware values at wish, therefore KVM
+ * needs to update hardware values to guest's virtual MSR values in order to
+ * ensure EINIT is executed with expected hardware values.
+ *
+ * Return:
+ * - 0: 	EINIT was successful.
+ * - -EFAULT:	EINIT returned error.
+ */
+int sgx_virt_einit(void __user *sigstruct, void __user *token,
+		   void __user *secs, u64 *lepubkeyhash, int *trapnr)
+{
+	int ret;
+
+	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
+		ret = __sgx_virt_einit(sigstruct, token, secs);
+	} else {
+		preempt_disable();
+
+		sgx_update_lepubkeyhash(lepubkeyhash);
+
+		ret = __sgx_virt_einit(sigstruct, token, secs);
+		preempt_enable();
+	}
+
+	if (encls_faulted(ret)) {
+		*trapnr = ENCLS_TRAPNR(ret);
+		return -EFAULT;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sgx_virt_einit);
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 14/26] x86/sgx: Move provisioning device creation out of SGX driver
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (12 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 15/26] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Kai Huang
                   ` (12 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

And extract sgx_set_attribute() out of sgx_ioc_enclave_provision() and
export it as symbol for KVM to use.

Provisioning key is sensitive. SGX driver only allows to create enclave
which can access provisioning key when enclave creator has permission to
open /dev/sgx_provision.  It should apply to VM as well, as provisioning
key is platform specific, thus unrestricted VM can also potentially
compromise provisioning key.

Move provisioning device creation out of sgx_drv_init() to sgx_init() as
preparation for adding SGX virtualization support, so that even SGX
driver is not enabled due to flexible launch control is not available,
SGX virtualization can still be enabled, and use it to restrict VM's
capability of being able to access provisioning key.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - No code change. Added Jarkko's Reviewed-by.

v2->v3:

 - Added kdoc for sgx_set_attribute(), per Jarkko.

---
 arch/x86/include/asm/sgx.h       |  3 ++
 arch/x86/kernel/cpu/sgx/driver.c | 17 ----------
 arch/x86/kernel/cpu/sgx/ioctl.c  | 16 ++-------
 arch/x86/kernel/cpu/sgx/main.c   | 58 +++++++++++++++++++++++++++++++-
 4 files changed, 62 insertions(+), 32 deletions(-)

diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
index 8a3ea3e1efbe..d67afb051db3 100644
--- a/arch/x86/include/asm/sgx.h
+++ b/arch/x86/include/asm/sgx.h
@@ -4,6 +4,9 @@
 
 #include <linux/types.h>
 
+int sgx_set_attribute(unsigned long *allowed_attributes,
+		      unsigned int attribute_fd);
+
 #ifdef CONFIG_X86_SGX_KVM
 struct sgx_pageinfo;
 
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index f2eac41bb4ff..4f3241109bda 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -133,10 +133,6 @@ static const struct file_operations sgx_encl_fops = {
 	.get_unmapped_area	= sgx_get_unmapped_area,
 };
 
-const struct file_operations sgx_provision_fops = {
-	.owner			= THIS_MODULE,
-};
-
 static struct miscdevice sgx_dev_enclave = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "sgx_enclave",
@@ -144,13 +140,6 @@ static struct miscdevice sgx_dev_enclave = {
 	.fops = &sgx_encl_fops,
 };
 
-static struct miscdevice sgx_dev_provision = {
-	.minor = MISC_DYNAMIC_MINOR,
-	.name = "sgx_provision",
-	.nodename = "sgx_provision",
-	.fops = &sgx_provision_fops,
-};
-
 int __init sgx_drv_init(void)
 {
 	unsigned int eax, ebx, ecx, edx;
@@ -184,11 +173,5 @@ int __init sgx_drv_init(void)
 	if (ret)
 		return ret;
 
-	ret = misc_register(&sgx_dev_provision);
-	if (ret) {
-		misc_deregister(&sgx_dev_enclave);
-		return ret;
-	}
-
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 1bae754268d1..4714de12422d 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -2,6 +2,7 @@
 /*  Copyright(c) 2016-20 Intel Corporation. */
 
 #include <asm/mman.h>
+#include <asm/sgx.h>
 #include <linux/mman.h>
 #include <linux/delay.h>
 #include <linux/file.h>
@@ -664,24 +665,11 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
 static long sgx_ioc_enclave_provision(struct sgx_encl *encl, void __user *arg)
 {
 	struct sgx_enclave_provision params;
-	struct file *file;
 
 	if (copy_from_user(&params, arg, sizeof(params)))
 		return -EFAULT;
 
-	file = fget(params.fd);
-	if (!file)
-		return -EINVAL;
-
-	if (file->f_op != &sgx_provision_fops) {
-		fput(file);
-		return -EINVAL;
-	}
-
-	encl->attributes_mask |= SGX_ATTR_PROVISIONKEY;
-
-	fput(file);
-	return 0;
+	return sgx_set_attribute(&encl->attributes_mask, params.fd);
 }
 
 long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 276220d0e4b5..7167f607d92c 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -1,14 +1,18 @@
 // SPDX-License-Identifier: GPL-2.0
 /*  Copyright(c) 2016-20 Intel Corporation. */
 
+#include <linux/file.h>
 #include <linux/freezer.h>
 #include <linux/highmem.h>
 #include <linux/kthread.h>
+#include <linux/miscdevice.h>
 #include <linux/pagemap.h>
 #include <linux/ratelimit.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/signal.h>
 #include <linux/slab.h>
+#include <asm/sgx_arch.h>
+#include <asm/sgx.h>
 #include "driver.h"
 #include "encl.h"
 #include "encls.h"
@@ -711,6 +715,51 @@ void sgx_update_lepubkeyhash(u64 *lepubkeyhash)
 		wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
 }
 
+const struct file_operations sgx_provision_fops = {
+	.owner			= THIS_MODULE,
+};
+
+static struct miscdevice sgx_dev_provision = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "sgx_provision",
+	.nodename = "sgx_provision",
+	.fops = &sgx_provision_fops,
+};
+
+/**
+ * sgx_set_attribute() - Update allowed attributes given file descriptor
+ * @allowed_attributes: 	Pointer to allowed enclave attributes
+ * @attribute_fd:		File descriptor for specific attribute
+ *
+ * Append enclave attribute indicated by file descriptor to allowed
+ * attributes. Currently only SGX_ATTR_PROVISIONKEY indicated by
+ * /dev/sgx_provision is supported.
+ *
+ * Return:
+ * -0:		SGX_ATTR_PROVISIONKEY is appended to allowed_attributes
+ * -EINVAL:	Invalid, or not supported file descriptor
+ */
+int sgx_set_attribute(unsigned long *allowed_attributes,
+		      unsigned int attribute_fd)
+{
+	struct file *file;
+
+	file = fget(attribute_fd);
+	if (!file)
+		return -EINVAL;
+
+	if (file->f_op != &sgx_provision_fops) {
+		fput(file);
+		return -EINVAL;
+	}
+
+	*allowed_attributes |= SGX_ATTR_PROVISIONKEY;
+
+	fput(file);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sgx_set_attribute);
+
 static int __init sgx_init(void)
 {
 	int ret;
@@ -727,6 +776,10 @@ static int __init sgx_init(void)
 		goto err_page_cache;
 	}
 
+	ret = misc_register(&sgx_dev_provision);
+	if (ret)
+		goto err_kthread;
+
 	/*
 	 * Always try to initialize the native *and* KVM drivers.
 	 * The KVM driver is less picky than the native one and
@@ -737,10 +790,13 @@ static int __init sgx_init(void)
 	 */
 	ret = !!sgx_drv_init() & !!sgx_vepc_init();
 	if (ret)
-		goto err_kthread;
+		goto err_provision;
 
 	return 0;
 
+err_provision:
+	misc_deregister(&sgx_dev_provision);
+
 err_kthread:
 	kthread_stop(ksgxd_tsk);
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 15/26] KVM: VMX: Convert vcpu_vmx.exit_reason to a union
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (13 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 14/26] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 16/26] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
                   ` (11 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Convert vcpu_vmx.exit_reason from a u32 to a union (of size u32).  The
full VM_EXIT_REASON field is comprised of a 16-bit basic exit reason in
bits 15:0, and single-bit modifiers in bits 31:16.

Historically, KVM has only had to worry about handling the "failed
VM-Entry" modifier, which could only be set in very specific flows and
required dedicated handling.  I.e. manually stripping the FAILED_VMENTRY
bit was a somewhat viable approach.  But even with only a single bit to
worry about, KVM has had several bugs related to comparing a basic exit
reason against the full exit reason store in vcpu_vmx.

Upcoming Intel features, e.g. SGX, will add new modifier bits that can
be set on more or less any VM-Exit, as opposed to the significantly more
restricted FAILED_VMENTRY, i.e. correctly handling everything in one-off
flows isn't scalable.  Tracking exit reason in a union forces code to
explicitly choose between consuming the full exit reason and the basic
exit, and is a convenient way to document and access the modifiers.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kvm/vmx/nested.c | 42 +++++++++++++++---------
 arch/x86/kvm/vmx/vmx.c    | 68 ++++++++++++++++++++-------------------
 arch/x86/kvm/vmx/vmx.h    | 25 +++++++++++++-
 3 files changed, 86 insertions(+), 49 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 0fbb46990dfc..f112c2482887 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3311,7 +3311,11 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
 	enum vm_entry_failure_code entry_failure_code;
 	bool evaluate_pending_interrupts;
-	u32 exit_reason, failed_index;
+	u32 failed_index;
+	union vmx_exit_reason exit_reason = {
+		.basic = -1,
+		.failed_vmentry = 1,
+	};
 
 	if (kvm_check_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu))
 		kvm_vcpu_flush_tlb_current(vcpu);
@@ -3363,7 +3367,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 
 		if (nested_vmx_check_guest_state(vcpu, vmcs12,
 						 &entry_failure_code)) {
-			exit_reason = EXIT_REASON_INVALID_STATE;
+			exit_reason.basic = EXIT_REASON_INVALID_STATE;
 			vmcs12->exit_qualification = entry_failure_code;
 			goto vmentry_fail_vmexit;
 		}
@@ -3374,7 +3378,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 		vcpu->arch.tsc_offset += vmcs12->tsc_offset;
 
 	if (prepare_vmcs02(vcpu, vmcs12, &entry_failure_code)) {
-		exit_reason = EXIT_REASON_INVALID_STATE;
+		exit_reason.basic = EXIT_REASON_INVALID_STATE;
 		vmcs12->exit_qualification = entry_failure_code;
 		goto vmentry_fail_vmexit_guest_mode;
 	}
@@ -3384,7 +3388,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 						   vmcs12->vm_entry_msr_load_addr,
 						   vmcs12->vm_entry_msr_load_count);
 		if (failed_index) {
-			exit_reason = EXIT_REASON_MSR_LOAD_FAIL;
+			exit_reason.basic = EXIT_REASON_MSR_LOAD_FAIL;
 			vmcs12->exit_qualification = failed_index;
 			goto vmentry_fail_vmexit_guest_mode;
 		}
@@ -3452,7 +3456,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 		return NVMX_VMENTRY_VMEXIT;
 
 	load_vmcs12_host_state(vcpu, vmcs12);
-	vmcs12->vm_exit_reason = exit_reason | VMX_EXIT_REASONS_FAILED_VMENTRY;
+	vmcs12->vm_exit_reason = exit_reason.full;
 	if (enable_shadow_vmcs || vmx->nested.hv_evmcs)
 		vmx->nested.need_vmcs12_to_shadow_sync = true;
 	return NVMX_VMENTRY_VMEXIT;
@@ -5540,7 +5544,12 @@ static int handle_vmfunc(struct kvm_vcpu *vcpu)
 	return kvm_skip_emulated_instruction(vcpu);
 
 fail:
-	nested_vmx_vmexit(vcpu, vmx->exit_reason,
+	/*
+	 * This is effectively a reflected VM-Exit, as opposed to a synthesized
+	 * nested VM-Exit.  Pass the original exit reason, i.e. don't hardcode
+	 * EXIT_REASON_VMFUNC as the exit reason.
+	 */
+	nested_vmx_vmexit(vcpu, vmx->exit_reason.full,
 			  vmx_get_intr_info(vcpu),
 			  vmx_get_exit_qual(vcpu));
 	return 1;
@@ -5608,7 +5617,8 @@ static bool nested_vmx_exit_handled_io(struct kvm_vcpu *vcpu,
  * MSR bitmap. This may be the case even when L0 doesn't use MSR bitmaps.
  */
 static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu,
-	struct vmcs12 *vmcs12, u32 exit_reason)
+					struct vmcs12 *vmcs12,
+					union vmx_exit_reason exit_reason)
 {
 	u32 msr_index = kvm_rcx_read(vcpu);
 	gpa_t bitmap;
@@ -5622,7 +5632,7 @@ static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu,
 	 * First we need to figure out which of the four to use:
 	 */
 	bitmap = vmcs12->msr_bitmap;
-	if (exit_reason == EXIT_REASON_MSR_WRITE)
+	if (exit_reason.basic == EXIT_REASON_MSR_WRITE)
 		bitmap += 2048;
 	if (msr_index >= 0xc0000000) {
 		msr_index -= 0xc0000000;
@@ -5759,11 +5769,12 @@ static bool nested_vmx_exit_handled_mtf(struct vmcs12 *vmcs12)
  * Return true if L0 wants to handle an exit from L2 regardless of whether or not
  * L1 wants the exit.  Only call this when in is_guest_mode (L2).
  */
-static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason)
+static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu,
+				     union vmx_exit_reason exit_reason)
 {
 	u32 intr_info;
 
-	switch ((u16)exit_reason) {
+	switch (exit_reason.basic) {
 	case EXIT_REASON_EXCEPTION_NMI:
 		intr_info = vmx_get_intr_info(vcpu);
 		if (is_nmi(intr_info))
@@ -5819,12 +5830,13 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason)
  * Return 1 if L1 wants to intercept an exit from L2.  Only call this when in
  * is_guest_mode (L2).
  */
-static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason)
+static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu,
+				     union vmx_exit_reason exit_reason)
 {
 	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
 	u32 intr_info;
 
-	switch ((u16)exit_reason) {
+	switch (exit_reason.basic) {
 	case EXIT_REASON_EXCEPTION_NMI:
 		intr_info = vmx_get_intr_info(vcpu);
 		if (is_nmi(intr_info))
@@ -5943,7 +5955,7 @@ static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason)
 bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	u32 exit_reason = vmx->exit_reason;
+	union vmx_exit_reason exit_reason = vmx->exit_reason;
 	unsigned long exit_qual;
 	u32 exit_intr_info;
 
@@ -5962,7 +5974,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 		goto reflect_vmexit;
 	}
 
-	trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX);
+	trace_kvm_nested_vmexit(exit_reason.full, vcpu, KVM_ISA_VMX);
 
 	/* If L0 (KVM) wants the exit, it trumps L1's desires. */
 	if (nested_vmx_l0_wants_exit(vcpu, exit_reason))
@@ -5988,7 +6000,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 	exit_qual = vmx_get_exit_qual(vcpu);
 
 reflect_vmexit:
-	nested_vmx_vmexit(vcpu, exit_reason, exit_intr_info, exit_qual);
+	nested_vmx_vmexit(vcpu, exit_reason.full, exit_intr_info, exit_qual);
 	return true;
 }
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 2af05d3b0590..746b87375aff 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1577,7 +1577,7 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
 	 * i.e. we end up advancing IP with some random value.
 	 */
 	if (!static_cpu_has(X86_FEATURE_HYPERVISOR) ||
-	    to_vmx(vcpu)->exit_reason != EXIT_REASON_EPT_MISCONFIG) {
+	    to_vmx(vcpu)->exit_reason.basic != EXIT_REASON_EPT_MISCONFIG) {
 		orig_rip = kvm_rip_read(vcpu);
 		rip = orig_rip + vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
 #ifdef CONFIG_X86_64
@@ -5667,7 +5667,7 @@ static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2,
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
 	*info1 = vmx_get_exit_qual(vcpu);
-	if (!(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY)) {
+	if (!vmx->exit_reason.failed_vmentry) {
 		*info2 = vmx->idt_vectoring_info;
 		*intr_info = vmx_get_intr_info(vcpu);
 		if (is_exception_with_error_code(*intr_info))
@@ -5911,8 +5911,9 @@ void dump_vmcs(void)
 static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	u32 exit_reason = vmx->exit_reason;
+	union vmx_exit_reason exit_reason = vmx->exit_reason;
 	u32 vectoring_info = vmx->idt_vectoring_info;
+	u16 exit_handler_index;
 
 	/*
 	 * Flush logged GPAs PML buffer, this will make dirty_bitmap more
@@ -5954,11 +5955,11 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 			return 1;
 	}
 
-	if (exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) {
+	if (exit_reason.failed_vmentry) {
 		dump_vmcs();
 		vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;
 		vcpu->run->fail_entry.hardware_entry_failure_reason
-			= exit_reason;
+			= exit_reason.full;
 		vcpu->run->fail_entry.cpu = vcpu->arch.last_vmentry_cpu;
 		return 0;
 	}
@@ -5980,18 +5981,18 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	 * will cause infinite loop.
 	 */
 	if ((vectoring_info & VECTORING_INFO_VALID_MASK) &&
-			(exit_reason != EXIT_REASON_EXCEPTION_NMI &&
-			exit_reason != EXIT_REASON_EPT_VIOLATION &&
-			exit_reason != EXIT_REASON_PML_FULL &&
-			exit_reason != EXIT_REASON_APIC_ACCESS &&
-			exit_reason != EXIT_REASON_TASK_SWITCH)) {
+	    (exit_reason.basic != EXIT_REASON_EXCEPTION_NMI &&
+	     exit_reason.basic != EXIT_REASON_EPT_VIOLATION &&
+	     exit_reason.basic != EXIT_REASON_PML_FULL &&
+	     exit_reason.basic != EXIT_REASON_APIC_ACCESS &&
+	     exit_reason.basic != EXIT_REASON_TASK_SWITCH)) {
 		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_DELIVERY_EV;
 		vcpu->run->internal.ndata = 3;
 		vcpu->run->internal.data[0] = vectoring_info;
-		vcpu->run->internal.data[1] = exit_reason;
+		vcpu->run->internal.data[1] = exit_reason.full;
 		vcpu->run->internal.data[2] = vcpu->arch.exit_qualification;
-		if (exit_reason == EXIT_REASON_EPT_MISCONFIG) {
+		if (exit_reason.basic == EXIT_REASON_EPT_MISCONFIG) {
 			vcpu->run->internal.ndata++;
 			vcpu->run->internal.data[3] =
 				vmcs_read64(GUEST_PHYSICAL_ADDRESS);
@@ -6023,38 +6024,39 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	if (exit_fastpath != EXIT_FASTPATH_NONE)
 		return 1;
 
-	if (exit_reason >= kvm_vmx_max_exit_handlers)
+	if (exit_reason.basic >= kvm_vmx_max_exit_handlers)
 		goto unexpected_vmexit;
 #ifdef CONFIG_RETPOLINE
-	if (exit_reason == EXIT_REASON_MSR_WRITE)
+	if (exit_reason.basic == EXIT_REASON_MSR_WRITE)
 		return kvm_emulate_wrmsr(vcpu);
-	else if (exit_reason == EXIT_REASON_PREEMPTION_TIMER)
+	else if (exit_reason.basic == EXIT_REASON_PREEMPTION_TIMER)
 		return handle_preemption_timer(vcpu);
-	else if (exit_reason == EXIT_REASON_INTERRUPT_WINDOW)
+	else if (exit_reason.basic == EXIT_REASON_INTERRUPT_WINDOW)
 		return handle_interrupt_window(vcpu);
-	else if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
+	else if (exit_reason.basic == EXIT_REASON_EXTERNAL_INTERRUPT)
 		return handle_external_interrupt(vcpu);
-	else if (exit_reason == EXIT_REASON_HLT)
+	else if (exit_reason.basic == EXIT_REASON_HLT)
 		return kvm_emulate_halt(vcpu);
-	else if (exit_reason == EXIT_REASON_EPT_MISCONFIG)
+	else if (exit_reason.basic == EXIT_REASON_EPT_MISCONFIG)
 		return handle_ept_misconfig(vcpu);
 #endif
 
-	exit_reason = array_index_nospec(exit_reason,
-					 kvm_vmx_max_exit_handlers);
-	if (!kvm_vmx_exit_handlers[exit_reason])
+	exit_handler_index = array_index_nospec((u16)exit_reason.basic,
+						kvm_vmx_max_exit_handlers);
+	if (!kvm_vmx_exit_handlers[exit_handler_index])
 		goto unexpected_vmexit;
 
-	return kvm_vmx_exit_handlers[exit_reason](vcpu);
+	return kvm_vmx_exit_handlers[exit_handler_index](vcpu);
 
 unexpected_vmexit:
-	vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n", exit_reason);
+	vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n",
+		    exit_reason.full);
 	dump_vmcs();
 	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 	vcpu->run->internal.suberror =
 			KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
 	vcpu->run->internal.ndata = 2;
-	vcpu->run->internal.data[0] = exit_reason;
+	vcpu->run->internal.data[0] = exit_reason.full;
 	vcpu->run->internal.data[1] = vcpu->arch.last_vmentry_cpu;
 	return 0;
 }
@@ -6373,9 +6375,9 @@ static void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
-	if (vmx->exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
+	if (vmx->exit_reason.basic == EXIT_REASON_EXTERNAL_INTERRUPT)
 		handle_external_interrupt_irqoff(vcpu);
-	else if (vmx->exit_reason == EXIT_REASON_EXCEPTION_NMI)
+	else if (vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI)
 		handle_exception_nmi_irqoff(vmx);
 }
 
@@ -6567,7 +6569,7 @@ void noinstr vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp)
 
 static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
 {
-	switch (to_vmx(vcpu)->exit_reason) {
+	switch (to_vmx(vcpu)->exit_reason.basic) {
 	case EXIT_REASON_MSR_WRITE:
 		return handle_fastpath_set_msr_irqoff(vcpu);
 	case EXIT_REASON_PREEMPTION_TIMER:
@@ -6766,17 +6768,17 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	vmx->idt_vectoring_info = 0;
 
 	if (unlikely(vmx->fail)) {
-		vmx->exit_reason = 0xdead;
+		vmx->exit_reason.full = 0xdead;
 		return EXIT_FASTPATH_NONE;
 	}
 
-	vmx->exit_reason = vmcs_read32(VM_EXIT_REASON);
-	if (unlikely((u16)vmx->exit_reason == EXIT_REASON_MCE_DURING_VMENTRY))
+	vmx->exit_reason.full = vmcs_read32(VM_EXIT_REASON);
+	if (unlikely(vmx->exit_reason.basic == EXIT_REASON_MCE_DURING_VMENTRY))
 		kvm_machine_check();
 
-	trace_kvm_exit(vmx->exit_reason, vcpu, KVM_ISA_VMX);
+	trace_kvm_exit(vmx->exit_reason.full, vcpu, KVM_ISA_VMX);
 
-	if (unlikely(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY))
+	if (unlikely(vmx->exit_reason.failed_vmentry))
 		return EXIT_FASTPATH_NONE;
 
 	vmx->loaded_vmcs->launched = 1;
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 9d3a557949ac..903f246b5abd 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -70,6 +70,29 @@ struct pt_desc {
 	struct pt_ctx guest;
 };
 
+union vmx_exit_reason {
+	struct {
+		u32	basic			: 16;
+		u32	reserved16		: 1;
+		u32	reserved17		: 1;
+		u32	reserved18		: 1;
+		u32	reserved19		: 1;
+		u32	reserved20		: 1;
+		u32	reserved21		: 1;
+		u32	reserved22		: 1;
+		u32	reserved23		: 1;
+		u32	reserved24		: 1;
+		u32	reserved25		: 1;
+		u32	reserved26		: 1;
+		u32	sgx_enclave_mode	: 1;
+		u32	smi_pending_mtf		: 1;
+		u32	smi_from_vmx_root	: 1;
+		u32	reserved30		: 1;
+		u32	failed_vmentry		: 1;
+	};
+	u32 full;
+};
+
 /*
  * The nested_vmx structure is part of vcpu_vmx, and holds information we need
  * for correct emulation of VMX (i.e., nested VMX) on this vcpu.
@@ -244,7 +267,7 @@ struct vcpu_vmx {
 	int vpid;
 	bool emulation_required;
 
-	u32 exit_reason;
+	union vmx_exit_reason exit_reason;
 
 	/* Posted interrupt descriptor */
 	struct pi_desc pi_desc;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 16/26] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX)
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (14 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 15/26] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 17/26] KVM: x86: Define new #PF SGX error code bit Kai Huang
                   ` (10 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Export the gva_to_gpa() helpers for use by SGX virtualization when
executing ENCLS[ECREATE] and ENCLS[EINIT] on behalf of the guest.
To execute ECREATE and EINIT, KVM must obtain the GPA of the target
Secure Enclave Control Structure (SECS) in order to get its
corresponding HVA.

Because the SECS must reside in the Enclave Page Cache (EPC), copying
the SECS's data to a host-controlled buffer via existing exported
helpers is not a viable option as the EPC is not readable or writable
by the kernel.

SGX virtualization will also use gva_to_gpa() to obtain HVAs for
non-EPC pages in order to pass user pointers directly to ECREATE and
EINIT, which avoids having to copy pages worth of data into the kernel.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kvm/x86.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9a8969a6dd06..5ca7b181a3ae 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5891,6 +5891,7 @@ gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva,
 	u32 access = (kvm_x86_ops.get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
 	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
 }
+EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_read);
 
  gpa_t kvm_mmu_gva_to_gpa_fetch(struct kvm_vcpu *vcpu, gva_t gva,
 				struct x86_exception *exception)
@@ -5907,6 +5908,7 @@ gpa_t kvm_mmu_gva_to_gpa_write(struct kvm_vcpu *vcpu, gva_t gva,
 	access |= PFERR_WRITE_MASK;
 	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);
 }
+EXPORT_SYMBOL_GPL(kvm_mmu_gva_to_gpa_write);
 
 /* uses this to access any guest's mapped memory without checking CPL */
 gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva,
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 17/26] KVM: x86: Define new #PF SGX error code bit
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (15 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 16/26] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 18/26] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
                   ` (9 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Page faults that are signaled by the SGX Enclave Page Cache Map (EPCM),
as opposed to the traditional IA32/EPT page tables, set an SGX bit in
the error code to indicate that the #PF was induced by SGX.  KVM will
need to emulate this behavior as part of its trap-and-execute scheme for
virtualizing SGX Launch Control, e.g. to inject SGX-induced #PFs if
EINIT faults in the host, and to support live migration.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/include/asm/kvm_host.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3d6616f6f6ef..9581f81e62a4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -216,6 +216,7 @@ enum x86_intercept_stage;
 #define PFERR_RSVD_BIT 3
 #define PFERR_FETCH_BIT 4
 #define PFERR_PK_BIT 5
+#define PFERR_SGX_BIT 15
 #define PFERR_GUEST_FINAL_BIT 32
 #define PFERR_GUEST_PAGE_BIT 33
 
@@ -225,6 +226,7 @@ enum x86_intercept_stage;
 #define PFERR_RSVD_MASK (1U << PFERR_RSVD_BIT)
 #define PFERR_FETCH_MASK (1U << PFERR_FETCH_BIT)
 #define PFERR_PK_MASK (1U << PFERR_PK_BIT)
+#define PFERR_SGX_MASK (1U << PFERR_SGX_BIT)
 #define PFERR_GUEST_FINAL_MASK (1ULL << PFERR_GUEST_FINAL_BIT)
 #define PFERR_GUEST_PAGE_MASK (1ULL << PFERR_GUEST_PAGE_BIT)
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 18/26] KVM: x86: Add support for reverse CPUID lookup of scattered features
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (16 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 17/26] KVM: x86: Define new #PF SGX error code bit Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 19/26] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
                   ` (8 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <seanjc@google.com>

Introduce a scheme that allows KVM's CPUID magic to support features
that are scattered in the kernel's feature words.  To advertise and/or
query guest support for CPUID-based features, KVM requires the bit
number of an X86_FEATURE_* to match the bit number in its associated
CPUID entry.  For scattered features, this does not hold true.

Add a framework to allow defining KVM-only words, stored in
kvm_cpu_caps after the shared kernel caps, that can be used to gather
the scattered feature bits by translating X86_FEATURE_* flags into their
KVM-defined feature.

Note, because reverse_cpuid_check() effectively forces kvm_cpu_caps
lookups to be resolved at compile time, there is no runtime cost for
translating from kernel-defined to kvm-defined features.

More details here:  https://lkml.kernel.org/r/X/jxCOLG+HUO4QlZ@google.com

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kvm/cpuid.c | 32 +++++++++++++++++++++++++++-----
 arch/x86/kvm/cpuid.h | 39 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 61 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 13036cf0b912..f8037fab8950 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -28,7 +28,7 @@
  * Unlike "struct cpuinfo_x86.x86_capability", kvm_cpu_caps doesn't need to be
  * aligned to sizeof(unsigned long) because it's not accessed via bitops.
  */
-u32 kvm_cpu_caps[NCAPINTS] __read_mostly;
+u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
 EXPORT_SYMBOL_GPL(kvm_cpu_caps);
 
 static u32 xstate_required_size(u64 xstate_bv, bool compacted)
@@ -53,6 +53,7 @@ static u32 xstate_required_size(u64 xstate_bv, bool compacted)
 }
 
 #define F feature_bit
+#define SF(name) (boot_cpu_has(X86_FEATURE_##name) ? F(name) : 0)
 
 static inline struct kvm_cpuid_entry2 *cpuid_entry2_find(
 	struct kvm_cpuid_entry2 *entries, int nent, u32 function, u32 index)
@@ -331,13 +332,13 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
 	return r;
 }
 
-static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask)
+/* Mask kvm_cpu_caps for @leaf with the raw CPUID capabilities of this CPU. */
+static __always_inline void __kvm_cpu_cap_mask(enum cpuid_leafs leaf)
 {
 	const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32);
 	struct kvm_cpuid_entry2 entry;
 
 	reverse_cpuid_check(leaf);
-	kvm_cpu_caps[leaf] &= mask;
 
 	cpuid_count(cpuid.function, cpuid.index,
 		    &entry.eax, &entry.ebx, &entry.ecx, &entry.edx);
@@ -345,6 +346,26 @@ static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask)
 	kvm_cpu_caps[leaf] &= *__cpuid_entry_get_reg(&entry, cpuid.reg);
 }
 
+static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask)
+{
+	/* Use the "init" variant for scattered leafs. */
+	BUILD_BUG_ON(leaf >= NCAPINTS);
+
+	kvm_cpu_caps[leaf] &= mask;
+
+	__kvm_cpu_cap_mask(leaf);
+}
+
+static __always_inline void kvm_cpu_cap_init(enum cpuid_leafs leaf, u32 mask)
+{
+	/* Use the "mask" variant for hardwared-defined leafs. */
+	BUILD_BUG_ON(leaf < NCAPINTS);
+
+	kvm_cpu_caps[leaf] = mask;
+
+	__kvm_cpu_cap_mask(leaf);
+}
+
 void kvm_set_cpu_caps(void)
 {
 	unsigned int f_nx = is_efer_nx() ? F(NX) : 0;
@@ -355,12 +376,13 @@ void kvm_set_cpu_caps(void)
 	unsigned int f_gbpages = 0;
 	unsigned int f_lm = 0;
 #endif
+	memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps));
 
-	BUILD_BUG_ON(sizeof(kvm_cpu_caps) >
+	BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) >
 		     sizeof(boot_cpu_data.x86_capability));
 
 	memcpy(&kvm_cpu_caps, &boot_cpu_data.x86_capability,
-	       sizeof(kvm_cpu_caps));
+	       sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)));
 
 	kvm_cpu_cap_mask(CPUID_1_ECX,
 		/*
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index dc921d76e42e..2041e2f07347 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -7,7 +7,20 @@
 #include <asm/processor.h>
 #include <uapi/asm/kvm_para.h>
 
-extern u32 kvm_cpu_caps[NCAPINTS] __read_mostly;
+/*
+ * Hardware-defined CPUID leafs that are scattered in the kernel, but need to
+ * be directly used by KVM.  Note, these word values conflict with the kernel's
+ * "bug" caps, but KVM doesn't use those.
+ */
+enum kvm_only_cpuid_leafs {
+	NR_KVM_CPU_CAPS = NCAPINTS,
+
+	NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
+};
+
+#define X86_KVM_FEATURE(w, f)		((w)*32 + (f))
+
+extern u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
 void kvm_set_cpu_caps(void);
 
 void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu);
@@ -83,6 +96,20 @@ static __always_inline void reverse_cpuid_check(unsigned int x86_leaf)
 	BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0);
 }
 
+/*
+ * Translate feature bits that are scattered in the kernel's cpufeatures word
+ * into KVM feature words that align with hardware's definitions.
+ */
+static __always_inline u32 __feature_translate(int x86_feature)
+{
+	return x86_feature;
+}
+
+static __always_inline u32 __feature_leaf(int x86_feature)
+{
+	return __feature_translate(x86_feature) / 32;
+}
+
 /*
  * Retrieve the bit mask from an X86_FEATURE_* definition.  Features contain
  * the hardware defined bit number (stored in bits 4:0) and a software defined
@@ -91,6 +118,8 @@ static __always_inline void reverse_cpuid_check(unsigned int x86_leaf)
  */
 static __always_inline u32 __feature_bit(int x86_feature)
 {
+	x86_feature = __feature_translate(x86_feature);
+
 	reverse_cpuid_check(x86_feature / 32);
 	return 1 << (x86_feature & 31);
 }
@@ -99,7 +128,7 @@ static __always_inline u32 __feature_bit(int x86_feature)
 
 static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned int x86_feature)
 {
-	unsigned int x86_leaf = x86_feature / 32;
+	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
 	reverse_cpuid_check(x86_leaf);
 	return reverse_cpuid[x86_leaf];
@@ -291,7 +320,7 @@ static inline bool cpuid_fault_enabled(struct kvm_vcpu *vcpu)
 
 static __always_inline void kvm_cpu_cap_clear(unsigned int x86_feature)
 {
-	unsigned int x86_leaf = x86_feature / 32;
+	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
 	reverse_cpuid_check(x86_leaf);
 	kvm_cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature);
@@ -299,7 +328,7 @@ static __always_inline void kvm_cpu_cap_clear(unsigned int x86_feature)
 
 static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature)
 {
-	unsigned int x86_leaf = x86_feature / 32;
+	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
 	reverse_cpuid_check(x86_leaf);
 	kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature);
@@ -307,7 +336,7 @@ static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature)
 
 static __always_inline u32 kvm_cpu_cap_get(unsigned int x86_feature)
 {
-	unsigned int x86_leaf = x86_feature / 32;
+	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
 	reverse_cpuid_check(x86_leaf);
 	return kvm_cpu_caps[x86_leaf] & __feature_bit(x86_feature);
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 19/26] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (17 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 18/26] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 20/26] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
                   ` (7 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <seanjc@google.com>

Define a new KVM-only feature word for advertising and querying SGX
sub-features in CPUID.0x12.0x0.EAX.  Because SGX1 and SGX2 are scattered
in the kernel's feature word, they need to be translated so that the
bit numbers match those of hardware.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kvm/cpuid.h | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 2041e2f07347..f55701ef58fc 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -13,13 +13,18 @@
  * "bug" caps, but KVM doesn't use those.
  */
 enum kvm_only_cpuid_leafs {
-	NR_KVM_CPU_CAPS = NCAPINTS,
+	CPUID_12_EAX	 = NCAPINTS,
+	NR_KVM_CPU_CAPS,
 
 	NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
 };
 
 #define X86_KVM_FEATURE(w, f)		((w)*32 + (f))
 
+/* Intel-defined SGX sub-features, CPUID level 0x12 (EAX). */
+#define __X86_FEATURE_SGX1		X86_KVM_FEATURE(CPUID_12_EAX, 0)
+#define __X86_FEATURE_SGX2		X86_KVM_FEATURE(CPUID_12_EAX, 1)
+
 extern u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
 void kvm_set_cpu_caps(void);
 
@@ -76,6 +81,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
 	[CPUID_8000_0007_EBX] = {0x80000007, 0, CPUID_EBX},
 	[CPUID_7_EDX]         = {         7, 0, CPUID_EDX},
 	[CPUID_7_1_EAX]       = {         7, 1, CPUID_EAX},
+	[CPUID_12_EAX]        = {0x00000012, 0, CPUID_EAX},
 };
 
 /*
@@ -102,6 +108,11 @@ static __always_inline void reverse_cpuid_check(unsigned int x86_leaf)
  */
 static __always_inline u32 __feature_translate(int x86_feature)
 {
+	if (x86_feature == X86_FEATURE_SGX1)
+		return __X86_FEATURE_SGX1;
+	else if (x86_feature == X86_FEATURE_SGX2)
+		return __X86_FEATURE_SGX2;
+
 	return x86_feature;
 }
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 20/26] KVM: VMX: Add basic handling of VM-Exit from SGX enclave
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (18 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 19/26] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 21/26] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
                   ` (6 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add support for handling VM-Exits that originate from a guest SGX
enclave.  In SGX, an "enclave" is a new CPL3-only execution environment,
wherein the CPU and memory state is protected by hardware to make the
state inaccesible to code running outside of the enclave.  When exiting
an enclave due to an asynchronous event (from the perspective of the
enclave), e.g. exceptions, interrupts, and VM-Exits, the enclave's state
is automatically saved and scrubbed (the CPU loads synthetic state), and
then reloaded when re-entering the enclave.  E.g. after an instruction
based VM-Exit from an enclave, vmcs.GUEST_RIP will not contain the RIP
of the enclave instruction that trigered VM-Exit, but will instead point
to a RIP in the enclave's untrusted runtime (the guest userspace code
that coordinates entry/exit to/from the enclave).

To help a VMM recognize and handle exits from enclaves, SGX adds bits to
existing VMCS fields, VM_EXIT_REASON.VMX_EXIT_REASON_FROM_ENCLAVE and
GUEST_INTERRUPTIBILITY_INFO.GUEST_INTR_STATE_ENCLAVE_INTR.  Define the
new architectural bits, and add a boolean to struct vcpu_vmx to cache
VMX_EXIT_REASON_FROM_ENCLAVE.  Clear the bit in exit_reason so that
checks against exit_reason do not need to account for SGX, e.g.
"if (exit_reason == EXIT_REASON_EXCEPTION_NMI)" continues to work.

KVM is a largely a passive observer of the new bits, e.g. KVM needs to
account for the bits when propagating information to a nested VMM, but
otherwise doesn't need to act differently for the majority of VM-Exits
from enclaves.

The one scenario that is directly impacted is emulation, which is for
all intents and purposes impossible[1] since KVM does not have access to
the RIP or instruction stream that triggered the VM-Exit.  The inability
to emulate is a non-issue for KVM, as most instructions that might
trigger VM-Exit unconditionally #UD in an enclave (before the VM-Exit
check.  For the few instruction that conditionally #UD, KVM either never
sets the exiting control, e.g. PAUSE_EXITING[2], or sets it if and only
if the feature is not exposed to the guest in order to inject a #UD,
e.g. RDRAND_EXITING.

But, because it is still possible for a guest to trigger emulation,
e.g. MMIO, inject a #UD if KVM ever attempts emulation after a VM-Exit
from an enclave.  This is architecturally accurate for instruction
VM-Exits, and for MMIO it's the least bad choice, e.g. it's preferable
to killing the VM.  In practice, only broken or particularly stupid
guests should ever encounter this behavior.

Add a WARN in skip_emulated_instruction to detect any attempt to
modify the guest's RIP during an SGX enclave VM-Exit as all such flows
should either be unreachable or must handle exits from enclaves before
getting to skip_emulated_instruction.

[1] Impossible for all practical purposes.  Not truly impossible
    since KVM could implement some form of para-virtualization scheme.

[2] PAUSE_LOOP_EXITING only affects CPL0 and enclaves exist only at
    CPL3, so we also don't need to worry about that interaction.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/include/asm/vmx.h      |  1 +
 arch/x86/include/uapi/asm/vmx.h |  1 +
 arch/x86/kvm/vmx/nested.c       |  2 ++
 arch/x86/kvm/vmx/vmx.c          | 38 +++++++++++++++++++++++++++++++--
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 38ca445a8429..e99021a00eb9 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -372,6 +372,7 @@ enum vmcs_field {
 #define GUEST_INTR_STATE_MOV_SS		0x00000002
 #define GUEST_INTR_STATE_SMI		0x00000004
 #define GUEST_INTR_STATE_NMI		0x00000008
+#define GUEST_INTR_STATE_ENCLAVE_INTR	0x00000010
 
 /* GUEST_ACTIVITY_STATE flags */
 #define GUEST_ACTIVITY_ACTIVE		0
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index ada955c5ebb6..c7a18eb2a074 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -27,6 +27,7 @@
 
 
 #define VMX_EXIT_REASONS_FAILED_VMENTRY         0x80000000
+#define VMX_EXIT_REASONS_SGX_ENCLAVE_MODE	0x08000000
 
 #define EXIT_REASON_EXCEPTION_NMI       0
 #define EXIT_REASON_EXTERNAL_INTERRUPT  1
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index f112c2482887..562eab7b0a51 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4126,6 +4126,8 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 {
 	/* update exit information fields: */
 	vmcs12->vm_exit_reason = vm_exit_reason;
+	if (to_vmx(vcpu)->exit_reason.sgx_enclave_mode)
+		vmcs12->vm_exit_reason |= VMX_EXIT_REASONS_SGX_ENCLAVE_MODE;
 	vmcs12->exit_qualification = exit_qualification;
 	vmcs12->vm_exit_intr_info = exit_intr_info;
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 746b87375aff..4cb8a3f1374c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1561,12 +1561,18 @@ static int vmx_rtit_ctl_check(struct kvm_vcpu *vcpu, u64 data)
 
 static bool vmx_can_emulate_instruction(struct kvm_vcpu *vcpu, void *insn, int insn_len)
 {
+	if (to_vmx(vcpu)->exit_reason.sgx_enclave_mode) {
+		kvm_queue_exception(vcpu, UD_VECTOR);
+		return false;
+	}
 	return true;
 }
 
 static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
 {
+	union vmx_exit_reason exit_reason = to_vmx(vcpu)->exit_reason;
 	unsigned long rip, orig_rip;
+	u32 instr_len;
 
 	/*
 	 * Using VMCS.VM_EXIT_INSTRUCTION_LEN on EPT misconfig depends on
@@ -1577,9 +1583,33 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
 	 * i.e. we end up advancing IP with some random value.
 	 */
 	if (!static_cpu_has(X86_FEATURE_HYPERVISOR) ||
-	    to_vmx(vcpu)->exit_reason.basic != EXIT_REASON_EPT_MISCONFIG) {
+	    exit_reason.basic != EXIT_REASON_EPT_MISCONFIG) {
+		instr_len = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
+
+		/*
+		 * Emulating an enclave's instructions isn't supported as KVM
+		 * cannot access the enclave's memory or its true RIP, e.g. the
+		 * vmcs.GUEST_RIP points at the exit point of the enclave, not
+		 * the RIP that actually triggered the VM-Exit.  But, because
+		 * most instructions that cause VM-Exit will #UD in an enclave,
+		 * most instruction-based VM-Exits simply do not occur.
+		 *
+		 * There are a few exceptions, notably the debug instructions
+		 * INT1ICEBRK and INT3, as they are allowed in debug enclaves
+		 * and generate #DB/#BP as expected, which KVM might intercept.
+		 * But again, the CPU does the dirty work and saves an instr
+		 * length of zero so VMMs don't shoot themselves in the foot.
+		 * WARN if KVM tries to skip a non-zero length instruction on
+		 * a VM-Exit from an enclave.
+		 */
+		if (!instr_len)
+			goto rip_updated;
+
+		WARN(exit_reason.sgx_enclave_mode,
+		     "KVM: skipping instruction after SGX enclave VM-Exit");
+
 		orig_rip = kvm_rip_read(vcpu);
-		rip = orig_rip + vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
+		rip = orig_rip + instr_len;
 #ifdef CONFIG_X86_64
 		/*
 		 * We need to mask out the high 32 bits of RIP if not in 64-bit
@@ -1595,6 +1625,7 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
 			return 0;
 	}
 
+rip_updated:
 	/* skipping an emulated instruction also counts */
 	vmx_set_interrupt_shadow(vcpu, 0);
 
@@ -5341,6 +5372,9 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
 {
 	gpa_t gpa;
 
+	if (!vmx_can_emulate_instruction(vcpu, NULL, 0))
+		return 1;
+
 	/*
 	 * A nested guest cannot optimize MMIO vmexits, because we have an
 	 * nGPA here instead of the required GPA.
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 21/26] KVM: VMX: Frame in ENCLS handler for SGX virtualization
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (19 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 20/26] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 22/26] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
                   ` (5 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Introduce sgx.c and sgx.h, along with the framework for handling ENCLS
VM-Exits.  Add a bool, enable_sgx, that will eventually be wired up to a
module param to control whether or not SGX virtualization is enabled at
runtime.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kvm/Makefile  |  2 ++
 arch/x86/kvm/vmx/sgx.c | 51 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/vmx/sgx.h | 15 +++++++++++++
 arch/x86/kvm/vmx/vmx.c |  9 +++++---
 4 files changed, 74 insertions(+), 3 deletions(-)
 create mode 100644 arch/x86/kvm/vmx/sgx.c
 create mode 100644 arch/x86/kvm/vmx/sgx.h

diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 4bd14ab01323..5c86edc73b72 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -21,6 +21,8 @@ kvm-y			+= x86.o emulate.o i8259.o irq.o lapic.o \
 
 kvm-intel-y		+= vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
 			   vmx/evmcs.o vmx/nested.o vmx/posted_intr.o
+kvm-intel-$(CONFIG_X86_SGX_KVM)	+= vmx/sgx.o
+
 kvm-amd-y		+= svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o svm/sev.o
 
 obj-$(CONFIG_KVM)	+= kvm.o
diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
new file mode 100644
index 000000000000..6b3d614d288c
--- /dev/null
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+/*  Copyright(c) 2021 Intel Corporation. */
+
+#include <asm/sgx.h>
+#include <asm/sgx_arch.h>
+
+#include "cpuid.h"
+#include "kvm_cache_regs.h"
+#include "sgx.h"
+#include "vmx.h"
+#include "x86.h"
+
+bool __read_mostly enable_sgx;
+
+static inline bool encls_leaf_enabled_in_guest(struct kvm_vcpu *vcpu, u32 leaf)
+{
+	if (!enable_sgx || !guest_cpuid_has(vcpu, X86_FEATURE_SGX))
+		return false;
+
+	if (leaf >= ECREATE && leaf <= ETRACK)
+		return guest_cpuid_has(vcpu, X86_FEATURE_SGX1);
+
+	if (leaf >= EAUG && leaf <= EMODT)
+		return guest_cpuid_has(vcpu, X86_FEATURE_SGX2);
+
+	return false;
+}
+
+static inline bool sgx_enabled_in_guest_bios(struct kvm_vcpu *vcpu)
+{
+	const u64 bits = FEAT_CTL_SGX_ENABLED | FEAT_CTL_LOCKED;
+
+	return (to_vmx(vcpu)->msr_ia32_feature_control & bits) == bits;
+}
+
+int handle_encls(struct kvm_vcpu *vcpu)
+{
+	u32 leaf = (u32)vcpu->arch.regs[VCPU_REGS_RAX];
+
+	if (!encls_leaf_enabled_in_guest(vcpu, leaf)) {
+		kvm_queue_exception(vcpu, UD_VECTOR);
+	} else if (!sgx_enabled_in_guest_bios(vcpu)) {
+		kvm_inject_gp(vcpu, 0);
+	} else {
+		WARN(1, "KVM: unexpected exit on ENCLS[%u]", leaf);
+		vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
+		vcpu->run->hw.hardware_exit_reason = EXIT_REASON_ENCLS;
+		return 0;
+	}
+	return 1;
+}
diff --git a/arch/x86/kvm/vmx/sgx.h b/arch/x86/kvm/vmx/sgx.h
new file mode 100644
index 000000000000..6e17ecd4aca3
--- /dev/null
+++ b/arch/x86/kvm/vmx/sgx.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_SGX_H
+#define __KVM_X86_SGX_H
+
+#include <linux/kvm_host.h>
+
+#ifdef CONFIG_X86_SGX_KVM
+extern bool __read_mostly enable_sgx;
+
+int handle_encls(struct kvm_vcpu *vcpu);
+#else
+#define enable_sgx 0
+#endif
+
+#endif /* __KVM_X86_SGX_H */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4cb8a3f1374c..dbe585329842 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -56,6 +56,7 @@
 #include "mmu.h"
 #include "nested.h"
 #include "pmu.h"
+#include "sgx.h"
 #include "trace.h"
 #include "vmcs.h"
 #include "vmcs12.h"
@@ -5623,16 +5624,18 @@ static int handle_vmx_instruction(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+#ifndef CONFIG_X86_SGX_KVM
 static int handle_encls(struct kvm_vcpu *vcpu)
 {
 	/*
-	 * SGX virtualization is not yet supported.  There is no software
-	 * enable bit for SGX, so we have to trap ENCLS and inject a #UD
-	 * to prevent the guest from executing ENCLS.
+	 * SGX virtualization is disabled.  There is no software enable bit for
+	 * SGX, so KVM intercepts all ENCLS leafs and injects a #UD to prevent
+	 * the guest from executing ENCLS (when SGX is supported by hardware).
 	 */
 	kvm_queue_exception(vcpu, UD_VECTOR);
 	return 1;
 }
+#endif /* CONFIG_X86_SGX_KVM */
 
 /*
  * The exit handlers return 1 if the exit was handled fully and guest execution
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 22/26] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (20 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 21/26] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 23/26] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
                   ` (4 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add an ECREATE handler that will be used to intercept ECREATE for the
purpose of enforcing and enclave's MISCSELECT, ATTRIBUTES and XFRM, i.e.
to allow userspace to restrict SGX features via CPUID.  ECREATE will be
intercepted when any of the aforementioned masks diverges from hardware
in order to enforce the desired CPUID model, i.e. inject #GP if the
guest attempts to set a bit that hasn't been enumerated as allowed-1 in
CPUID.

Note, access to the PROVISIONKEY is not yet supported.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - No code change.

v3->v4:

 - Added canonical check for guest's PAGEINFO.metadata and PAGEINFO.contents,
   per Rick and Sean.
 - Added deep copy of guest's PAGEINFO.contents to kernel memory to avoid TOCTOU
   attack, per Rick and Sean.

---
 arch/x86/include/asm/kvm_host.h |   3 +
 arch/x86/kvm/vmx/sgx.c          | 247 ++++++++++++++++++++++++++++++++
 2 files changed, 250 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9581f81e62a4..cd71f30fbdd1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1000,6 +1000,9 @@ struct kvm_arch {
 		struct msr_bitmap_range ranges[16];
 	} msr_filter;
 
+	/* Guest can access the SGX PROVISIONKEY. */
+	bool sgx_provisioning_allowed;
+
 	struct kvm_pmu_event_filter *pmu_event_filter;
 	struct task_struct *nx_lpage_recovery_thread;
 
diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index 6b3d614d288c..7bdb125325ef 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -12,6 +12,251 @@
 
 bool __read_mostly enable_sgx;
 
+/*
+ * ENCLS's memory operands use a fixed segment (DS) and a fixed
+ * address size based on the mode.  Related prefixes are ignored.
+ */
+static int sgx_get_encls_gva(struct kvm_vcpu *vcpu, unsigned long offset,
+			     int size, int alignment, gva_t *gva)
+{
+	struct kvm_segment s;
+	bool fault;
+
+	/* Skip vmcs.GUEST_DS retrieval for 64-bit mode to avoid VMREADs. */
+	*gva = offset;
+	if (!is_long_mode(vcpu)) {
+		vmx_get_segment(vcpu, &s, VCPU_SREG_DS);
+		*gva += s.base;
+	}
+
+	if (!IS_ALIGNED(*gva, alignment)) {
+		fault = true;
+	} else if (likely(is_long_mode(vcpu))) {
+		fault = is_noncanonical_address(*gva, vcpu);
+	} else {
+		*gva &= 0xffffffff;
+		fault = (s.unusable) ||
+			(s.type != 2 && s.type != 3) ||
+			(*gva > s.limit) ||
+			((s.base != 0 || s.limit != 0xffffffff) &&
+			(((u64)*gva + size - 1) > s.limit + 1));
+	}
+	if (fault)
+		kvm_inject_gp(vcpu, 0);
+	return fault ? -EINVAL : 0;
+}
+
+static void sgx_handle_emulation_failure(struct kvm_vcpu *vcpu, u64 addr,
+					 unsigned int size)
+{
+	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+	vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
+	vcpu->run->internal.ndata = 2;
+	vcpu->run->internal.data[0] = addr;
+	vcpu->run->internal.data[1] = size;
+}
+
+static int sgx_read_hva(struct kvm_vcpu *vcpu, unsigned long hva, void *data,
+			unsigned int size)
+{
+	if (__copy_from_user(data, (void __user *)hva, size)) {
+		sgx_handle_emulation_failure(vcpu, hva, size);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int sgx_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t gva, bool write,
+			  gpa_t *gpa)
+{
+	struct x86_exception ex;
+
+	if (write)
+		*gpa = kvm_mmu_gva_to_gpa_write(vcpu, gva, &ex);
+	else
+		*gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, &ex);
+
+	if (*gpa == UNMAPPED_GVA) {
+		kvm_inject_emulated_page_fault(vcpu, &ex);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int sgx_gpa_to_hva(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long *hva)
+{
+	*hva = kvm_vcpu_gfn_to_hva(vcpu, PFN_DOWN(gpa));
+	if (kvm_is_error_hva(*hva)) {
+		sgx_handle_emulation_failure(vcpu, gpa, 1);
+		return -EFAULT;
+	}
+
+	*hva |= gpa & ~PAGE_MASK;
+
+	return 0;
+}
+
+static int sgx_inject_fault(struct kvm_vcpu *vcpu, gva_t gva, int trapnr)
+{
+	struct x86_exception ex;
+
+	/*
+	 * A non-EPCM #PF indicates a bad userspace HVA.  This *should* check
+	 * for PFEC.SGX and not assume any #PF on SGX2 originated in the EPC,
+	 * but the error code isn't (yet) plumbed through the ENCLS helpers.
+	 */
+	if (trapnr == PF_VECTOR && !boot_cpu_has(X86_FEATURE_SGX2)) {
+		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
+		vcpu->run->internal.ndata = 0;
+		return 0;
+	}
+
+	/*
+	 * If the guest thinks it's running on SGX2 hardware, inject an SGX
+	 * #PF if the fault matches an EPCM fault signature (#GP on SGX1,
+	 * #PF on SGX2).  The assumption is that EPCM faults are much more
+	 * likely than a bad userspace address.
+	 */
+	if ((trapnr == PF_VECTOR || !boot_cpu_has(X86_FEATURE_SGX2)) &&
+	    guest_cpuid_has(vcpu, X86_FEATURE_SGX2)) {
+		memset(&ex, 0, sizeof(ex));
+		ex.vector = PF_VECTOR;
+		ex.error_code = PFERR_PRESENT_MASK | PFERR_WRITE_MASK |
+				PFERR_SGX_MASK;
+		ex.address = gva;
+		ex.error_code_valid = true;
+		ex.nested_page_fault = false;
+		kvm_inject_page_fault(vcpu, &ex);
+	} else {
+		kvm_inject_gp(vcpu, 0);
+	}
+	return 1;
+}
+
+static int handle_encls_ecreate(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpuid_entry2 *sgx_12_0, *sgx_12_1;
+	gva_t pageinfo_gva, secs_gva;
+	gva_t metadata_gva, contents_gva;
+	gpa_t metadata_gpa, contents_gpa, secs_gpa;
+	unsigned long metadata_hva, contents_hva, secs_hva;
+	struct sgx_pageinfo pageinfo;
+	struct sgx_secs *contents;
+	u64 attributes, xfrm, size;
+	u32 miscselect;
+	struct x86_exception ex;
+	u8 max_size_log2;
+	int trapnr, r;
+
+	sgx_12_0 = kvm_find_cpuid_entry(vcpu, 0x12, 0);
+	sgx_12_1 = kvm_find_cpuid_entry(vcpu, 0x12, 1);
+	if (!sgx_12_0 || !sgx_12_1) {
+		kvm_inject_gp(vcpu, 0);
+		return 1;
+	}
+
+	if (sgx_get_encls_gva(vcpu, kvm_rbx_read(vcpu), 32, 32, &pageinfo_gva) ||
+	    sgx_get_encls_gva(vcpu, kvm_rcx_read(vcpu), 4096, 4096, &secs_gva))
+		return 1;
+
+	/*
+	 * Copy the PAGEINFO to local memory, its pointers need to be
+	 * translated, i.e. we need to do a deep copy/translate.
+	 */
+	r = kvm_read_guest_virt(vcpu, pageinfo_gva, &pageinfo,
+				sizeof(pageinfo), &ex);
+	if (r == X86EMUL_PROPAGATE_FAULT) {
+		kvm_inject_emulated_page_fault(vcpu, &ex);
+		return 1;
+	} else if (r != X86EMUL_CONTINUE) {
+		sgx_handle_emulation_failure(vcpu, pageinfo_gva, size);
+		return 0;
+	}
+
+	if (sgx_get_encls_gva(vcpu, pageinfo.metadata, 64, 64, &metadata_gva) ||
+	    sgx_get_encls_gva(vcpu, pageinfo.contents, 4096, 4096,
+			      &contents_gva))
+		return 1;
+
+	/*
+	 * Translate the SECINFO, SOURCE and SECS pointers from GVA to GPA.
+	 * Resume the guest on failure to inject a #PF.
+	 */
+	if (sgx_gva_to_gpa(vcpu, metadata_gva, false, &metadata_gpa) ||
+	    sgx_gva_to_gpa(vcpu, contents_gva, false, &contents_gpa) ||
+	    sgx_gva_to_gpa(vcpu, secs_gva, true, &secs_gpa))
+		return 1;
+
+	/*
+	 * ...and then to HVA.  The order of accesses isn't architectural, i.e.
+	 * KVM doesn't have to fully process one address at a time.  Exit to
+	 * userspace if a GPA is invalid.
+	 */
+	if (sgx_gpa_to_hva(vcpu, metadata_gpa, &metadata_hva) ||
+	    sgx_gpa_to_hva(vcpu, contents_gpa, &contents_hva) ||
+	    sgx_gpa_to_hva(vcpu, secs_gpa, &secs_hva))
+		return 0;
+
+	/*
+	 * Copy contents into kernel memory to prevent TOCTOU attack. E.g. the
+	 * guest could do ECREATE w/ SECS.SGX_ATTR_PROVISIONKEY=0, and
+	 * simultaneously set SGX_ATTR_PROVISIONKEY to bypass the check to
+	 * enforce restriction of access to the PROVISIONKEY.
+	 */
+	contents = (struct sgx_secs *)__get_free_page(GFP_KERNEL);
+	if (!contents)
+		return -ENOMEM;
+
+	/* Exit to userspace if copying from a host userspace address fails. */
+	if (sgx_read_hva(vcpu, contents_hva, (void *)contents, PAGE_SIZE))
+		return 0;
+
+	miscselect = contents->miscselect;
+	attributes = contents->attributes;
+	xfrm = contents->xfrm;
+	size = contents->size;
+
+	/* Enforce restriction of access to the PROVISIONKEY. */
+	if (!vcpu->kvm->arch.sgx_provisioning_allowed &&
+	    (attributes & SGX_ATTR_PROVISIONKEY)) {
+		if (sgx_12_1->eax & SGX_ATTR_PROVISIONKEY)
+			pr_warn_once("KVM: SGX PROVISIONKEY advertised but not allowed\n");
+		kvm_inject_gp(vcpu, 0);
+		return 1;
+	}
+
+	/* Enforce CPUID restrictions on MISCSELECT, ATTRIBUTES and XFRM. */
+	if ((u32)miscselect & ~sgx_12_0->ebx ||
+	    (u32)attributes & ~sgx_12_1->eax ||
+	    (u32)(attributes >> 32) & ~sgx_12_1->ebx ||
+	    (u32)xfrm & ~sgx_12_1->ecx ||
+	    (u32)(xfrm >> 32) & ~sgx_12_1->edx) {
+		kvm_inject_gp(vcpu, 0);
+		return 1;
+	}
+
+	/* Enforce CPUID restriction on max enclave size. */
+	max_size_log2 = (attributes & SGX_ATTR_MODE64BIT) ? sgx_12_0->edx >> 8 :
+							    sgx_12_0->edx;
+	if (size >= BIT_ULL(max_size_log2))
+		kvm_inject_gp(vcpu, 0);
+
+	pageinfo.metadata = metadata_hva;
+	pageinfo.contents = (u64)contents;
+
+	r = sgx_virt_ecreate(&pageinfo, (void __user *)secs_hva, &trapnr);
+
+	free_page((unsigned long)contents);
+
+	if (r)
+		return sgx_inject_fault(vcpu, secs_gva, trapnr);
+
+	return kvm_skip_emulated_instruction(vcpu);
+}
+
 static inline bool encls_leaf_enabled_in_guest(struct kvm_vcpu *vcpu, u32 leaf)
 {
 	if (!enable_sgx || !guest_cpuid_has(vcpu, X86_FEATURE_SGX))
@@ -42,6 +287,8 @@ int handle_encls(struct kvm_vcpu *vcpu)
 	} else if (!sgx_enabled_in_guest_bios(vcpu)) {
 		kvm_inject_gp(vcpu, 0);
 	} else {
+		if (leaf == ECREATE)
+			return handle_encls_ecreate(vcpu);
 		WARN(1, "KVM: unexpected exit on ENCLS[%u]", leaf);
 		vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
 		vcpu->run->hw.hardware_exit_reason = EXIT_REASON_ENCLS;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 23/26] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (21 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 22/26] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 24/26] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
                   ` (3 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Emulate the four Launch Enclave public key hash MSRs (LE hash MSRs) that
exist on CPUs that support SGX Launch Control (LC).  SGX LC modifies the
behavior of ENCLS[EINIT] to use the LE hash MSRs when verifying the key
used to sign an enclave.  On CPUs without LC support, the LE hash is
hardwired into the CPU to an Intel controlled key (the Intel key is also
the reset value of the LE hash MSRs). Track the guest's desired hash so
that a future patch can stuff the hash into the hardware MSRs when
executing EINIT on behalf of the guest, when those MSRs are writable in
host.

Note, KVM allows writes to the LE hash MSRs if IA32_FEATURE_CONTROL is
unlocked.  This is technically not architectural behavior, but it's
roughly equivalent to the arch behavior of the MSRs being writable prior
to activating SGX[1].  Emulating SGX activation is feasible, but adds no
tangible benefits and would just create extra work for KVM and guest
firmware.

[1] SGX related bits in IA32_FEATURE_CONTROL cannot be set until SGX
    is activated, e.g. by firmware.  SGX activation is triggered by
    setting bit 0 in MSR 0x7a.  Until SGX is activated, the LE hash
    MSRs are writable, e.g. to allow firmware to lock down the LE
    root key with a non-Intel value.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
v4->v5:

 - Fixed a bug in setup_default_sgx_lepubkeyhash(), that when SGX_LC is
   enabled, need to set default value to Intel's hash. 

---
 arch/x86/kvm/vmx/sgx.c | 35 +++++++++++++++++++++++++++++++++++
 arch/x86/kvm/vmx/sgx.h |  6 ++++++
 arch/x86/kvm/vmx/vmx.c | 20 ++++++++++++++++++++
 arch/x86/kvm/vmx/vmx.h |  2 ++
 4 files changed, 63 insertions(+)

diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index 7bdb125325ef..d849629af8e6 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -12,6 +12,9 @@
 
 bool __read_mostly enable_sgx;
 
+/* Initial value of guest's virtual SGX_LEPUBKEYHASHn MSRs */
+static u64 sgx_pubkey_hash[4] __ro_after_init;
+
 /*
  * ENCLS's memory operands use a fixed segment (DS) and a fixed
  * address size based on the mode.  Related prefixes are ignored.
@@ -296,3 +299,35 @@ int handle_encls(struct kvm_vcpu *vcpu)
 	}
 	return 1;
 }
+
+void setup_default_sgx_lepubkeyhash(void)
+{
+	/*
+	 * Use Intel's default value for Skylake hardware if Launch Control is
+	 * not supported, i.e. Intel's hash is hardcoded into silicon, or if
+	 * Launch Control is supported and enabled, i.e. mimic the reset value
+	 * and let the guest write the MSRs at will.  If Launch Control is
+	 * supported but disabled, then use the current MSR values as the hash
+	 * MSRs exist but are read-only (locked and not writable).
+	 */
+	if (!enable_sgx || boot_cpu_has(X86_FEATURE_SGX_LC) ||
+	    rdmsrl_safe(MSR_IA32_SGXLEPUBKEYHASH0, &sgx_pubkey_hash[0])) {
+		sgx_pubkey_hash[0] = 0xa6053e051270b7acULL;
+		sgx_pubkey_hash[1] = 0x6cfbe8ba8b3b413dULL;
+		sgx_pubkey_hash[2] = 0xc4916d99f2b3735dULL;
+		sgx_pubkey_hash[3] = 0xd4f8c05909f9bb3bULL;
+	} else {
+		/* MSR_IA32_SGXLEPUBKEYHASH0 is read above */
+		rdmsrl(MSR_IA32_SGXLEPUBKEYHASH1, sgx_pubkey_hash[1]);
+		rdmsrl(MSR_IA32_SGXLEPUBKEYHASH2, sgx_pubkey_hash[2]);
+		rdmsrl(MSR_IA32_SGXLEPUBKEYHASH3, sgx_pubkey_hash[3]);
+	}
+}
+
+void vcpu_setup_sgx_lepubkeyhash(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+	memcpy(vmx->msr_ia32_sgxlepubkeyhash, sgx_pubkey_hash,
+	       sizeof(sgx_pubkey_hash));
+}
diff --git a/arch/x86/kvm/vmx/sgx.h b/arch/x86/kvm/vmx/sgx.h
index 6e17ecd4aca3..6502fa52c7e9 100644
--- a/arch/x86/kvm/vmx/sgx.h
+++ b/arch/x86/kvm/vmx/sgx.h
@@ -8,8 +8,14 @@
 extern bool __read_mostly enable_sgx;
 
 int handle_encls(struct kvm_vcpu *vcpu);
+
+void setup_default_sgx_lepubkeyhash(void);
+void vcpu_setup_sgx_lepubkeyhash(struct kvm_vcpu *vcpu);
 #else
 #define enable_sgx 0
+
+static inline void setup_default_sgx_lepubkeyhash(void) { }
+static inline void vcpu_setup_sgx_lepubkeyhash(struct kvm_vcpu *vcpu) { }
 #endif
 
 #endif /* __KVM_X86_SGX_H */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index dbe585329842..349585f63c4d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1888,6 +1888,13 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_FEAT_CTL:
 		msr_info->data = vmx->msr_ia32_feature_control;
 		break;
+	case MSR_IA32_SGXLEPUBKEYHASH0 ... MSR_IA32_SGXLEPUBKEYHASH3:
+		if (!msr_info->host_initiated &&
+		    !guest_cpuid_has(vcpu, X86_FEATURE_SGX_LC))
+			return 1;
+		msr_info->data = to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash
+			[msr_info->index - MSR_IA32_SGXLEPUBKEYHASH0];
+		break;
 	case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
 		if (!nested_vmx_allowed(vcpu))
 			return 1;
@@ -2154,6 +2161,15 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (msr_info->host_initiated && data == 0)
 			vmx_leave_nested(vcpu);
 		break;
+	case MSR_IA32_SGXLEPUBKEYHASH0 ... MSR_IA32_SGXLEPUBKEYHASH3:
+		if (!msr_info->host_initiated &&
+		    (!guest_cpuid_has(vcpu, X86_FEATURE_SGX_LC) ||
+		    ((vmx->msr_ia32_feature_control & FEAT_CTL_LOCKED) &&
+		    !(vmx->msr_ia32_feature_control & FEAT_CTL_SGX_LC_ENABLED))))
+			return 1;
+		vmx->msr_ia32_sgxlepubkeyhash
+			[msr_index - MSR_IA32_SGXLEPUBKEYHASH0] = data;
+		break;
 	case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
 		if (!msr_info->host_initiated)
 			return 1; /* they are read-only */
@@ -6957,6 +6973,8 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
 	else
 		memset(&vmx->nested.msrs, 0, sizeof(vmx->nested.msrs));
 
+	vcpu_setup_sgx_lepubkeyhash(vcpu);
+
 	vmx->nested.posted_intr_nv = -1;
 	vmx->nested.current_vmptr = -1ull;
 
@@ -7907,6 +7925,8 @@ static __init int hardware_setup(void)
 	if (!enable_ept || !cpu_has_vmx_intel_pt())
 		pt_mode = PT_MODE_SYSTEM;
 
+	setup_default_sgx_lepubkeyhash();
+
 	if (nested) {
 		nested_vmx_setup_ctls_msrs(&vmcs_config.nested,
 					   vmx_capability.ept);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 903f246b5abd..af4bced6c84b 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -299,6 +299,8 @@ struct vcpu_vmx {
 	 */
 	u64 msr_ia32_feature_control;
 	u64 msr_ia32_feature_control_valid_bits;
+	/* SGX Launch Control public key hash */
+	u64 msr_ia32_sgxlepubkeyhash[4];
 	u64 ept_pointer;
 
 	struct pt_desc pt_desc;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 24/26] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC)
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (22 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 23/26] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:29 ` [RFC PATCH v5 25/26] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
                   ` (2 subsequent siblings)
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add a VM-Exit handler to trap-and-execute EINIT when SGX LC is enabled
in the host.  When SGX LC is enabled, the host kernel may rewrite the
hardware values at will, e.g. to launch enclaves with different signers,
thus KVM needs to intercept EINIT to ensure it is executed with the
correct LE hash (even if the guest sees a hardwired hash).

Switching the LE hash MSRs on VM-Enter/VM-Exit is not a viable option as
writing the MSRs is prohibitively expensive, e.g. on SKL hardware each
WRMSR is ~400 cycles.  And because EINIT takes tens of thousands of
cycles to execute, the ~1500 cycle overhead to trap-and-execute EINIT is
unlikely to be noticed by the guest, let alone impact its overall SGX
performance.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kvm/vmx/sgx.c | 55 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index d849629af8e6..b69a267305c0 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -260,6 +260,59 @@ static int handle_encls_ecreate(struct kvm_vcpu *vcpu)
 	return kvm_skip_emulated_instruction(vcpu);
 }
 
+static int handle_encls_einit(struct kvm_vcpu *vcpu)
+{
+	unsigned long sig_hva, secs_hva, token_hva, rflags;
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	gva_t sig_gva, secs_gva, token_gva;
+	gpa_t sig_gpa, secs_gpa, token_gpa;
+	int ret, trapnr;
+
+	if (sgx_get_encls_gva(vcpu, kvm_rbx_read(vcpu), 1808, 4096, &sig_gva) ||
+	    sgx_get_encls_gva(vcpu, kvm_rcx_read(vcpu), 4096, 4096, &secs_gva) ||
+	    sgx_get_encls_gva(vcpu, kvm_rdx_read(vcpu), 304, 512, &token_gva))
+		return 1;
+
+	/*
+	 * Translate the SIGSTRUCT, SECS and TOKEN pointers from GVA to GPA.
+	 * Resume the guest on failure to inject a #PF.
+	 */
+	if (sgx_gva_to_gpa(vcpu, sig_gva, false, &sig_gpa) ||
+	    sgx_gva_to_gpa(vcpu, secs_gva, true, &secs_gpa) ||
+	    sgx_gva_to_gpa(vcpu, token_gva, false, &token_gpa))
+		return 1;
+
+	/*
+	 * ...and then to HVA.  The order of accesses isn't architectural, i.e.
+	 * KVM doesn't have to fully process one address at a time.  Exit to
+	 * userspace if a GPA is invalid.  Note, all structures are aligned and
+	 * cannot split pages.
+	 */
+	if (sgx_gpa_to_hva(vcpu, sig_gpa, &sig_hva) ||
+	    sgx_gpa_to_hva(vcpu, secs_gpa, &secs_hva) ||
+	    sgx_gpa_to_hva(vcpu, token_gpa, &token_hva))
+		return 0;
+
+	ret = sgx_virt_einit((void __user *)sig_hva, (void __user *)token_hva,
+			     (void __user *)secs_hva,
+			     vmx->msr_ia32_sgxlepubkeyhash, &trapnr);
+
+	if (ret == -EFAULT)
+		return sgx_inject_fault(vcpu, secs_gva, trapnr);
+
+	rflags = vmx_get_rflags(vcpu) & ~(X86_EFLAGS_CF | X86_EFLAGS_PF |
+					  X86_EFLAGS_AF | X86_EFLAGS_SF |
+					  X86_EFLAGS_OF);
+	if (ret)
+		rflags |= X86_EFLAGS_ZF;
+	else
+		rflags &= ~X86_EFLAGS_ZF;
+	vmx_set_rflags(vcpu, rflags);
+
+	kvm_rax_write(vcpu, ret);
+	return kvm_skip_emulated_instruction(vcpu);
+}
+
 static inline bool encls_leaf_enabled_in_guest(struct kvm_vcpu *vcpu, u32 leaf)
 {
 	if (!enable_sgx || !guest_cpuid_has(vcpu, X86_FEATURE_SGX))
@@ -292,6 +345,8 @@ int handle_encls(struct kvm_vcpu *vcpu)
 	} else {
 		if (leaf == ECREATE)
 			return handle_encls_ecreate(vcpu);
+		if (leaf == EINIT)
+			return handle_encls_einit(vcpu);
 		WARN(1, "KVM: unexpected exit on ENCLS[%u]", leaf);
 		vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
 		vcpu->run->hw.hardware_exit_reason = EXIT_REASON_ENCLS;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 25/26] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (23 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 24/26] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
@ 2021-02-13 13:29 ` Kai Huang
  2021-02-13 13:30 ` [RFC PATCH v5 26/26] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
  2021-02-16 18:48 ` [RFC PATCH v5 00/26] KVM SGX virtualization support Dave Hansen
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:29 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Enable SGX virtualization now that KVM has the VM-Exit handlers needed
to trap-and-execute ENCLS to ensure correctness and/or enforce the CPU
model exposed to the guest.  Add a KVM module param, "sgx", to allow an
admin to disable SGX virtualization independent of the kernel.

When supported in hardware and the kernel, advertise SGX1, SGX2 and SGX
LC to userspace via CPUID and wire up the ENCLS_EXITING bitmap based on
the guest's SGX capabilities, i.e. to allow ENCLS to be executed in an
SGX-enabled guest.  With the exception of the provision key, all SGX
attribute bits may be exposed to the guest.  Guest access to the
provision key, which is controlled via securityfs, will be added in a
future patch.

Note, KVM does not yet support exposing ENCLS_C leafs or ENCLV leafs.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kvm/cpuid.c      | 57 +++++++++++++++++++++++++++-
 arch/x86/kvm/vmx/nested.c | 26 +++++++++++--
 arch/x86/kvm/vmx/nested.h |  5 +++
 arch/x86/kvm/vmx/sgx.c    | 80 ++++++++++++++++++++++++++++++++++++++-
 arch/x86/kvm/vmx/sgx.h    | 13 +++++++
 arch/x86/kvm/vmx/vmcs12.c |  1 +
 arch/x86/kvm/vmx/vmcs12.h |  4 +-
 arch/x86/kvm/vmx/vmx.c    | 38 ++++++++++++++++++-
 8 files changed, 215 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index f8037fab8950..04b2f5de2d7b 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -18,6 +18,7 @@
 #include <asm/processor.h>
 #include <asm/user.h>
 #include <asm/fpu/xstate.h>
+#include <asm/sgx_arch.h>
 #include "cpuid.h"
 #include "lapic.h"
 #include "mmu.h"
@@ -171,6 +172,21 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 		vcpu->arch.guest_supported_xcr0 =
 			(best->eax | ((u64)best->edx << 32)) & supported_xcr0;
 
+	/*
+	 * Bits 127:0 of the allowed SECS.ATTRIBUTES (CPUID.0x12.0x1) enumerate
+	 * the supported XSAVE Feature Request Mask (XFRM), i.e. the enclave's
+	 * requested XCR0 value.  The enclave's XFRM must be a subset of XCRO
+	 * at the time of EENTER, thus adjust the allowed XFRM by the guest's
+	 * supported XCR0.  Similar to XCR0 handling, FP and SSE are forced to
+	 * '1' even on CPUs that don't support XSAVE.
+	 */
+	best = kvm_find_cpuid_entry(vcpu, 0x12, 0x1);
+	if (best) {
+		best->ecx &= vcpu->arch.guest_supported_xcr0 & 0xffffffff;
+		best->edx &= vcpu->arch.guest_supported_xcr0 >> 32;
+		best->ecx |= XFEATURE_MASK_FPSSE;
+	}
+
 	kvm_update_pv_runtime(vcpu);
 
 	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
@@ -413,7 +429,7 @@ void kvm_set_cpu_caps(void)
 	);
 
 	kvm_cpu_cap_mask(CPUID_7_0_EBX,
-		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
+		F(FSGSBASE) | F(SGX) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
 		F(BMI2) | F(ERMS) | 0 /*INVPCID*/ | F(RTM) | 0 /*MPX*/ | F(RDSEED) |
 		F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
 		F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
@@ -424,7 +440,8 @@ void kvm_set_cpu_caps(void)
 		F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) |
 		F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
 		F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
-		F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/
+		F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/ |
+		F(SGX_LC)
 	);
 	/* Set LA57 based on hardware capability. */
 	if (cpuid_ecx(7) & F(LA57))
@@ -463,6 +480,10 @@ void kvm_set_cpu_caps(void)
 		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES)
 	);
 
+	kvm_cpu_cap_init(CPUID_12_EAX,
+		SF(SGX1) | SF(SGX2)
+	);
+
 	kvm_cpu_cap_mask(CPUID_8000_0001_ECX,
 		F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
 		F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
@@ -784,6 +805,38 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			entry->edx = 0;
 		}
 		break;
+	case 0x12:
+		/* Intel SGX */
+		if (!kvm_cpu_cap_has(X86_FEATURE_SGX)) {
+			entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
+			break;
+		}
+
+		/*
+		 * Index 0: Sub-features, MISCSELECT (a.k.a extended features)
+		 * and max enclave sizes.   The SGX sub-features and MISCSELECT
+		 * are restricted by kernel and KVM capabilities (like most
+		 * feature flags), while enclave size is unrestricted.
+		 */
+		cpuid_entry_override(entry, CPUID_12_EAX);
+		entry->ebx &= SGX_MISC_EXINFO;
+
+		entry = do_host_cpuid(array, function, 1);
+		if (!entry)
+			goto out;
+
+		/*
+		 * Index 1: SECS.ATTRIBUTES.  ATTRIBUTES are restricted a la
+		 * feature flags.  Advertise all supported flags, including
+		 * privileged attributes that require explicit opt-in from
+		 * userspace.  ATTRIBUTES.XFRM is not adjusted as userspace is
+		 * expected to derive it from supported XCR0.
+		 */
+		entry->eax &= SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT |
+			      /* PROVISIONKEY | */ SGX_ATTR_EINITTOKENKEY |
+			      SGX_ATTR_KSS;
+		entry->ebx &= 0;
+		break;
 	/* Intel PT */
 	case 0x14:
 		if (!kvm_cpu_cap_has(X86_FEATURE_INTEL_PT)) {
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 562eab7b0a51..fca1f4c8cc5b 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -11,6 +11,7 @@
 #include "mmu.h"
 #include "nested.h"
 #include "pmu.h"
+#include "sgx.h"
 #include "trace.h"
 #include "x86.h"
 
@@ -2318,6 +2319,9 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
 		if (!nested_cpu_has2(vmcs12, SECONDARY_EXEC_UNRESTRICTED_GUEST))
 		    exec_control &= ~SECONDARY_EXEC_UNRESTRICTED_GUEST;
 
+		if (exec_control & SECONDARY_EXEC_ENCLS_EXITING)
+			vmx_write_encls_bitmap(&vmx->vcpu, vmcs12);
+
 		secondary_exec_controls_set(vmx, exec_control);
 	}
 
@@ -5726,6 +5730,20 @@ static bool nested_vmx_exit_handled_cr(struct kvm_vcpu *vcpu,
 	return false;
 }
 
+static bool nested_vmx_exit_handled_encls(struct kvm_vcpu *vcpu,
+					  struct vmcs12 *vmcs12)
+{
+	u32 encls_leaf;
+
+	if (!nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENCLS_EXITING))
+		return false;
+
+	encls_leaf = kvm_rax_read(vcpu);
+	if (encls_leaf > 62)
+		encls_leaf = 63;
+	return vmcs12->encls_exiting_bitmap & BIT_ULL(encls_leaf);
+}
+
 static bool nested_vmx_exit_handled_vmcs_access(struct kvm_vcpu *vcpu,
 	struct vmcs12 *vmcs12, gpa_t bitmap)
 {
@@ -5819,9 +5837,6 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu,
 	case EXIT_REASON_VMFUNC:
 		/* VM functions are emulated through L2->L0 vmexits. */
 		return true;
-	case EXIT_REASON_ENCLS:
-		/* SGX is never exposed to L1 */
-		return true;
 	default:
 		break;
 	}
@@ -5945,6 +5960,8 @@ static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu,
 	case EXIT_REASON_TPAUSE:
 		return nested_cpu_has2(vmcs12,
 			SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE);
+	case EXIT_REASON_ENCLS:
+		return nested_vmx_exit_handled_encls(vcpu, vmcs12);
 	default:
 		return true;
 	}
@@ -6517,6 +6534,9 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps)
 		msrs->secondary_ctls_high |=
 			SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
 
+	if (enable_sgx)
+		msrs->secondary_ctls_high |= SECONDARY_EXEC_ENCLS_EXITING;
+
 	/* miscellaneous data */
 	rdmsr(MSR_IA32_VMX_MISC,
 		msrs->misc_low,
diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h
index 197148d76b8f..184418baeb3c 100644
--- a/arch/x86/kvm/vmx/nested.h
+++ b/arch/x86/kvm/vmx/nested.h
@@ -244,6 +244,11 @@ static inline bool nested_exit_on_intr(struct kvm_vcpu *vcpu)
 		PIN_BASED_EXT_INTR_MASK;
 }
 
+static inline bool nested_cpu_has_encls_exit(struct vmcs12 *vmcs12)
+{
+	return nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENCLS_EXITING);
+}
+
 /*
  * if fixed0[i] == 1: val[i] must be 1
  * if fixed1[i] == 0: val[i] must be 0
diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index b69a267305c0..48c46faafff5 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -6,11 +6,13 @@
 
 #include "cpuid.h"
 #include "kvm_cache_regs.h"
+#include "nested.h"
 #include "sgx.h"
 #include "vmx.h"
 #include "x86.h"
 
-bool __read_mostly enable_sgx;
+bool __read_mostly enable_sgx = 1;
+module_param_named(sgx, enable_sgx, bool, 0444);
 
 /* Initial value of guest's virtual SGX_LEPUBKEYHASHn MSRs */
 static u64 sgx_pubkey_hash[4] __ro_after_init;
@@ -386,3 +388,79 @@ void vcpu_setup_sgx_lepubkeyhash(struct kvm_vcpu *vcpu)
 	memcpy(vmx->msr_ia32_sgxlepubkeyhash, sgx_pubkey_hash,
 	       sizeof(sgx_pubkey_hash));
 }
+
+/*
+ * ECREATE must be intercepted to enforce MISCSELECT, ATTRIBUTES and XFRM
+ * restrictions if the guest's allowed-1 settings diverge from hardware.
+ */
+static bool sgx_intercept_encls_ecreate(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpuid_entry2 *guest_cpuid;
+	u32 eax, ebx, ecx, edx;
+
+	if (!vcpu->kvm->arch.sgx_provisioning_allowed)
+		return true;
+
+	guest_cpuid = kvm_find_cpuid_entry(vcpu, 0x12, 0);
+	if (!guest_cpuid)
+		return true;
+
+	cpuid_count(0x12, 0, &eax, &ebx, &ecx, &edx);
+	if (guest_cpuid->ebx != ebx || guest_cpuid->edx != edx)
+		return true;
+
+	guest_cpuid = kvm_find_cpuid_entry(vcpu, 0x12, 1);
+	if (!guest_cpuid)
+		return true;
+
+	cpuid_count(0x12, 1, &eax, &ebx, &ecx, &edx);
+	if (guest_cpuid->eax != eax || guest_cpuid->ebx != ebx ||
+	    guest_cpuid->ecx != ecx || guest_cpuid->edx != edx)
+		return true;
+
+	return false;
+}
+
+void vmx_write_encls_bitmap(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
+{
+	/*
+	 * There is no software enable bit for SGX that is virtualized by
+	 * hardware, e.g. there's no CR4.SGXE, so when SGX is disabled in the
+	 * guest (either by the host or by the guest's BIOS) but enabled in the
+	 * host, trap all ENCLS leafs and inject #UD/#GP as needed to emulate
+	 * the expected system behavior for ENCLS.
+	 */
+	u64 bitmap = -1ull;
+
+	/* Nothing to do if hardware doesn't support SGX */
+	if (!cpu_has_vmx_encls_vmexit())
+		return;
+
+	if (guest_cpuid_has(vcpu, X86_FEATURE_SGX) &&
+	    sgx_enabled_in_guest_bios(vcpu)) {
+		if (guest_cpuid_has(vcpu, X86_FEATURE_SGX1)) {
+			bitmap &= ~GENMASK_ULL(ETRACK, ECREATE);
+			if (sgx_intercept_encls_ecreate(vcpu))
+				bitmap |= (1 << ECREATE);
+		}
+
+		if (guest_cpuid_has(vcpu, X86_FEATURE_SGX2))
+			bitmap &= ~GENMASK_ULL(EMODT, EAUG);
+
+		/*
+		 * Trap and execute EINIT if launch control is enabled in the
+		 * host using the guest's values for launch control MSRs, even
+		 * if the guest's values are fixed to hardware default values.
+		 * The MSRs are not loaded/saved on VM-Enter/VM-Exit as writing
+		 * the MSRs is extraordinarily expensive.
+		 */
+		if (boot_cpu_has(X86_FEATURE_SGX_LC))
+			bitmap |= (1 << EINIT);
+
+		if (!vmcs12 && is_guest_mode(vcpu))
+			vmcs12 = get_vmcs12(vcpu);
+		if (vmcs12 && nested_cpu_has_encls_exit(vmcs12))
+			bitmap |= vmcs12->encls_exiting_bitmap;
+	}
+	vmcs_write64(ENCLS_EXITING_BITMAP, bitmap);
+}
diff --git a/arch/x86/kvm/vmx/sgx.h b/arch/x86/kvm/vmx/sgx.h
index 6502fa52c7e9..a400888b376d 100644
--- a/arch/x86/kvm/vmx/sgx.h
+++ b/arch/x86/kvm/vmx/sgx.h
@@ -4,6 +4,9 @@
 
 #include <linux/kvm_host.h>
 
+#include "capabilities.h"
+#include "vmx_ops.h"
+
 #ifdef CONFIG_X86_SGX_KVM
 extern bool __read_mostly enable_sgx;
 
@@ -11,11 +14,21 @@ int handle_encls(struct kvm_vcpu *vcpu);
 
 void setup_default_sgx_lepubkeyhash(void);
 void vcpu_setup_sgx_lepubkeyhash(struct kvm_vcpu *vcpu);
+
+void vmx_write_encls_bitmap(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12);
 #else
 #define enable_sgx 0
 
 static inline void setup_default_sgx_lepubkeyhash(void) { }
 static inline void vcpu_setup_sgx_lepubkeyhash(struct kvm_vcpu *vcpu) { }
+
+static inline void vmx_write_encls_bitmap(struct kvm_vcpu *vcpu,
+					  struct vmcs12 *vmcs12)
+{
+	/* Nothing to do if hardware doesn't support SGX */
+	if (cpu_has_vmx_encls_vmexit())
+		vmcs_write64(ENCLS_EXITING_BITMAP, -1ull);
+}
 #endif
 
 #endif /* __KVM_X86_SGX_H */
diff --git a/arch/x86/kvm/vmx/vmcs12.c b/arch/x86/kvm/vmx/vmcs12.c
index c8e51c004f78..034adb6404dc 100644
--- a/arch/x86/kvm/vmx/vmcs12.c
+++ b/arch/x86/kvm/vmx/vmcs12.c
@@ -50,6 +50,7 @@ const unsigned short vmcs_field_to_offset_table[] = {
 	FIELD64(VMREAD_BITMAP, vmread_bitmap),
 	FIELD64(VMWRITE_BITMAP, vmwrite_bitmap),
 	FIELD64(XSS_EXIT_BITMAP, xss_exit_bitmap),
+	FIELD64(ENCLS_EXITING_BITMAP, encls_exiting_bitmap),
 	FIELD64(GUEST_PHYSICAL_ADDRESS, guest_physical_address),
 	FIELD64(VMCS_LINK_POINTER, vmcs_link_pointer),
 	FIELD64(GUEST_IA32_DEBUGCTL, guest_ia32_debugctl),
diff --git a/arch/x86/kvm/vmx/vmcs12.h b/arch/x86/kvm/vmx/vmcs12.h
index 80232daf00ff..13494956d0e9 100644
--- a/arch/x86/kvm/vmx/vmcs12.h
+++ b/arch/x86/kvm/vmx/vmcs12.h
@@ -69,7 +69,8 @@ struct __packed vmcs12 {
 	u64 vm_function_control;
 	u64 eptp_list_address;
 	u64 pml_address;
-	u64 padding64[3]; /* room for future expansion */
+	u64 encls_exiting_bitmap;
+	u64 padding64[2]; /* room for future expansion */
 	/*
 	 * To allow migration of L1 (complete with its L2 guests) between
 	 * machines of different natural widths (32 or 64 bit), we cannot have
@@ -256,6 +257,7 @@ static inline void vmx_check_vmcs12_offsets(void)
 	CHECK_OFFSET(vm_function_control, 296);
 	CHECK_OFFSET(eptp_list_address, 304);
 	CHECK_OFFSET(pml_address, 312);
+	CHECK_OFFSET(encls_exiting_bitmap, 320);
 	CHECK_OFFSET(cr0_guest_host_mask, 344);
 	CHECK_OFFSET(cr4_guest_host_mask, 352);
 	CHECK_OFFSET(cr0_read_shadow, 360);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 349585f63c4d..9a2293a39e37 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2160,6 +2160,9 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		vmx->msr_ia32_feature_control = data;
 		if (msr_info->host_initiated && data == 0)
 			vmx_leave_nested(vcpu);
+
+		/* SGX may be enabled/disabled by guest's firmware */
+		vmx_write_encls_bitmap(vcpu, NULL);
 		break;
 	case MSR_IA32_SGXLEPUBKEYHASH0 ... MSR_IA32_SGXLEPUBKEYHASH3:
 		if (!msr_info->host_initiated &&
@@ -4317,6 +4320,15 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
 	vmx_adjust_sec_exec_control(vmx, &exec_control, waitpkg, WAITPKG,
 				    ENABLE_USR_WAIT_PAUSE, false);
 
+	if (cpu_has_vmx_encls_vmexit() && nested) {
+		if (guest_cpuid_has(vcpu, X86_FEATURE_SGX))
+			vmx->nested.msrs.secondary_ctls_high |=
+				SECONDARY_EXEC_ENCLS_EXITING;
+		else
+			vmx->nested.msrs.secondary_ctls_high &=
+				~SECONDARY_EXEC_ENCLS_EXITING;
+	}
+
 	vmx->secondary_exec_control = exec_control;
 }
 
@@ -4416,8 +4428,7 @@ static void init_vmcs(struct vcpu_vmx *vmx)
 		vmcs_write16(GUEST_PML_INDEX, PML_ENTITY_NUM - 1);
 	}
 
-	if (cpu_has_vmx_encls_vmexit())
-		vmcs_write64(ENCLS_EXITING_BITMAP, -1ull);
+	vmx_write_encls_bitmap(&vmx->vcpu, NULL);
 
 	if (vmx_pt_mode_is_host_guest()) {
 		memset(&vmx->pt_desc, 0, sizeof(vmx->pt_desc));
@@ -7301,6 +7312,22 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 
 	set_cr4_guest_host_mask(vmx);
 
+	vmx_write_encls_bitmap(vcpu, NULL);
+	if (guest_cpuid_has(vcpu, X86_FEATURE_SGX))
+		vmx->msr_ia32_feature_control_valid_bits |= FEAT_CTL_SGX_ENABLED;
+	else
+		vmx->msr_ia32_feature_control_valid_bits &= ~FEAT_CTL_SGX_ENABLED;
+	/*
+	 * Only allow guest to write its virtual SGX_LEPUBKEYHASHn MSRs when
+	 * host is writable, otherwise it is meaningless.
+	 */
+	if (guest_cpuid_has(vcpu, X86_FEATURE_SGX_LC))
+		vmx->msr_ia32_feature_control_valid_bits |=
+			FEAT_CTL_SGX_LC_ENABLED;
+	else
+		vmx->msr_ia32_feature_control_valid_bits &=
+			~FEAT_CTL_SGX_LC_ENABLED;
+
 	/* Refresh #PF interception to account for MAXPHYADDR changes. */
 	update_exception_bitmap(vcpu);
 }
@@ -7321,6 +7348,13 @@ static __init void vmx_set_cpu_caps(void)
 	if (vmx_pt_mode_is_host_guest())
 		kvm_cpu_cap_check_and_set(X86_FEATURE_INTEL_PT);
 
+	if (!enable_sgx) {
+		kvm_cpu_cap_clear(X86_FEATURE_SGX);
+		kvm_cpu_cap_clear(X86_FEATURE_SGX_LC);
+		kvm_cpu_cap_clear(X86_FEATURE_SGX1);
+		kvm_cpu_cap_clear(X86_FEATURE_SGX2);
+	}
+
 	if (vmx_umip_emulated())
 		kvm_cpu_cap_set(X86_FEATURE_UMIP);
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* [RFC PATCH v5 26/26] KVM: x86: Add capability to grant VM access to privileged SGX attribute
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (24 preceding siblings ...)
  2021-02-13 13:29 ` [RFC PATCH v5 25/26] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
@ 2021-02-13 13:30 ` Kai Huang
  2021-02-16 18:48 ` [RFC PATCH v5 00/26] KVM SGX virtualization support Dave Hansen
  26 siblings, 0 replies; 64+ messages in thread
From: Kai Huang @ 2021-02-13 13:30 UTC (permalink / raw)
  To: linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jmattson, joro,
	vkuznets, wanpengli, corbet, Andy Lutomirski, Kai Huang

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add a capability, KVM_CAP_SGX_ATTRIBUTE, that can be used by userspace
to grant a VM access to a priveleged attribute, with args[0] holding a
file handle to a valid SGX attribute file.

The SGX subsystem restricts access to a subset of enclave attributes to
provide additional security for an uncompromised kernel, e.g. to prevent
malware from using the PROVISIONKEY to ensure its nodes are running
inside a geniune SGX enclave and/or to obtain a stable fingerprint.

To prevent userspace from circumventing such restrictions by running an
enclave in a VM, KVM restricts guest access to privileged attributes by
default.

Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
 Documentation/virt/kvm/api.rst | 23 +++++++++++++++++++++++
 arch/x86/kvm/cpuid.c           |  2 +-
 arch/x86/kvm/x86.c             | 22 ++++++++++++++++++++++
 include/uapi/linux/kvm.h       |  1 +
 4 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index c136e254b496..47c7c7c33025 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -6037,6 +6037,29 @@ KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications which user space
 can then handle to implement model specific MSR handling and/or user notifications
 to inform a user that an MSR was not handled.
 
+7.22 KVM_CAP_SGX_ATTRIBUTE
+----------------------
+
+:Architectures: x86
+:Target: VM
+:Parameters: args[0] is a file handle of a SGX attribute file in securityfs
+:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested
+          attribute is not supported by KVM.
+
+KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or
+more priveleged enclave attributes.  args[0] must hold a file handle to a valid
+SGX attribute file corresponding to an attribute that is supported/restricted
+by KVM (currently only PROVISIONKEY).
+
+The SGX subsystem restricts access to a subset of enclave attributes to provide
+additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY
+is restricted to deter malware from using the PROVISIONKEY to obtain a stable
+system fingerprint.  To prevent userspace from circumventing such restrictions
+by running an enclave in a VM, KVM prevents access to privileged attributes by
+default.
+
+See Documentation/x86/sgx/2.Kernel-internals.rst for more details.
+
 8. Other capabilities.
 ======================
 
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 04b2f5de2d7b..ad00a1af1545 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -833,7 +833,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		 * expected to derive it from supported XCR0.
 		 */
 		entry->eax &= SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT |
-			      /* PROVISIONKEY | */ SGX_ATTR_EINITTOKENKEY |
+			      SGX_ATTR_PROVISIONKEY | SGX_ATTR_EINITTOKENKEY |
 			      SGX_ATTR_KSS;
 		entry->ebx &= 0;
 		break;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5ca7b181a3ae..3d1b4113a57b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -74,6 +74,8 @@
 #include <asm/tlbflush.h>
 #include <asm/intel_pt.h>
 #include <asm/emulate_prefix.h>
+#include <asm/sgx.h>
+#include <asm/sgx_arch.h>
 #include <clocksource/hyperv_timer.h>
 
 #define CREATE_TRACE_POINTS
@@ -3767,6 +3769,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_X86_USER_SPACE_MSR:
 	case KVM_CAP_X86_MSR_FILTER:
 	case KVM_CAP_ENFORCE_PV_FEATURE_CPUID:
+#ifdef CONFIG_X86_SGX_KVM
+	case KVM_CAP_SGX_ATTRIBUTE:
+#endif
 		r = 1;
 		break;
 	case KVM_CAP_SYNC_REGS:
@@ -5295,6 +5300,23 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		kvm->arch.user_space_msr_mask = cap->args[0];
 		r = 0;
 		break;
+#ifdef CONFIG_X86_SGX_KVM
+	case KVM_CAP_SGX_ATTRIBUTE: {
+		unsigned long allowed_attributes = 0;
+
+		r = sgx_set_attribute(&allowed_attributes, cap->args[0]);
+		if (r)
+			break;
+
+		/* KVM only supports the PROVISIONKEY privileged attribute. */
+		if ((allowed_attributes & SGX_ATTR_PROVISIONKEY) &&
+		    !(allowed_attributes & ~SGX_ATTR_PROVISIONKEY))
+			kvm->arch.sgx_provisioning_allowed = true;
+		else
+			r = -EINVAL;
+		break;
+	}
+#endif
 	default:
 		r = -EINVAL;
 		break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 374c67875cdb..e17bda18a9b4 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1058,6 +1058,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ENFORCE_PV_FEATURE_CPUID 190
 #define KVM_CAP_SYS_HYPERV_CPUID 191
 #define KVM_CAP_DIRTY_LOG_RING 192
+#define KVM_CAP_SGX_ATTRIBUTE 200
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
  2021-02-13 13:28 ` [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
@ 2021-02-16  2:12   ` Jarkko Sakkinen
  2021-02-16 18:38   ` Dave Hansen
  1 sibling, 0 replies; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  2:12 UTC (permalink / raw)
  To: Kai Huang
  Cc: linux-sgx, kvm, x86, seanjc, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa

On Sun, Feb 14, 2021 at 02:28:39AM +1300, Kai Huang wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Add a misc device /dev/sgx_vepc to allow userspace to allocate "raw" EPC
> without an associated enclave.  The intended and only known use case for
> raw EPC allocation is to expose EPC to a KVM guest, hence the 'vepc'
> moniker, virt.{c,h} files and X86_SGX_KVM Kconfig.
> 
> SGX driver uses misc device /dev/sgx_enclave to support userspace to
> create enclave.  Each file descriptor from opening /dev/sgx_enclave
> represents an enclave.  Unlike SGX driver, KVM doesn't control how guest
> uses EPC, therefore EPC allocated to KVM guest is not associated to an
> encalve, and /dev/sgx_enclave is not suitable for allocating EPC for KVM
> guest.
> 
> Having separate device nodes for SGX driver and KVM virtual EPC also
> allows separate permission control for running host SGX enclaves and
> KVM SGX guests.
> 
> More specifically, to allocate a virtual EPC instance with particular
> size, the userspace hypervisor opens /dev/sgx_vepc, and uses mmap()
> with the intended size to get an address range of virtual EPC.  Then
> it may use the address range to create one KVM memory slot as virtual
> EPC for guest.
> 
> Implement the "raw" EPC allocation in the x86 core-SGX subsystem via
> /dev/sgx_vepc rather than in KVM. Doing so has two major advantages:
> 
>   - Does not require changes to KVM's uAPI, e.g. EPC gets handled as
>     just another memory backend for guests.
> 
>   - EPC management is wholly contained in the SGX subsystem, e.g. SGX
>     does not have to export any symbols, changes to reclaim flows don't
>     need to be routed through KVM, SGX's dirty laundry doesn't have to
>     get aired out for the world to see, and so on and so forth.
> 
> The virtual EPC pages allocated to guests are currently not reclaimable.
> Reclaiming EPC page used by enclave requires a special reclaim mechanism
> separate from normal page reclaim, and that mechanism is not supported
> for virutal EPC pages.  Due to the complications of handling reclaim
> conflicts between guest and host, reclaiming virtual EPC pages is
> significantly more complex than basic support for SGX virtualization.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Co-developed-by: Kai Huang <kai.huang@intel.com>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
> v4->v5:
> 
>  - Added explanation of adding new /dev/sgx_vepc, rather than using existing
>    /dev/sgx_enclave in to commit message, per Jarkko. No code change.
> 
> v3->v4:
> 
>  - Removed #define pr_fmt(fmt), per Dave and Jarkko.
>  - Added one line summary next to copyright, and also updated copyright, per
>    Dave.
>  - Added comment to explain zombie_secs_pages and the lock, per Dave.
>  - Removed !IS_ENABLED(CONFIG_KVM_INTEL) in sgx_vepc_init(), per Dave.
>  - Removed virt.h, per Dave, and put the declaration of sgx_vepc_init() to
>    arch/x86/kernel/cpu/sgx/sgx.h.
> 
> v2->v3:
> 
>  - Changed from /dev/sgx_virt_epc to /dev/sgx_vepc, per Jarkko. Accordingly,
>    renamed 'sgx_virt_epc_xx' to 'sgx_vepc_xx' for various functions and
>    structrues.
>  - Changed CONFIG_X86_SGX_VIRTUALIZATION to CONFIG_X86_SGX_KVM, per Dave.
> 
> v1->v2:
> 
>  - Added one paragraph to explain fops of virtual EPC, per Jarkko's suggestion.
>  - Moved change to sgx_init() out of this patch to a separate patch, as stated
>    in cover letter.
>  - In sgx_virt_epc_init(), return error if VMX is not supported, or
>    CONFIG_KVM_INTEL is not enabled, because there's no point to create
>    /dev/sgx_virt_epc if KVM is not supported.
>  - Removed 'struct mm_struct *mm' in 'struct sgx_virt_epc', and related logic in
>    sgx_virt_epc_open/release/mmap(), per Dave's comment.
>  - Renamed 'virtual_epc_zombie_pages' and 'virt_epc_lock' to 'zombie_secs_pages'
>    'zombie_secs_pages_lock', per Dave's suggestion.
>  - Changed __sgx_free_epc_page() to sgx_free_epc_page() due to Jarkko's patch
>    removes EREMOVE in sgx_free_epc_page().
>  - Changed all struct sgx_virt_epc *epc to struct sgx_virt_epc *vepc.
>  - In __sgx_virt_epc_fault(), changed comment to use WARN_ON() to make sure
>    vepc->lock has already been hold, per Dave's suggestion.
>  - In sgx_virt_epc_free_page(), added comments to explain SGX_ENCLAVE_ACT is not
>    expected; and changed to use WARN_ONCE() to dump actual error code, per
>    Dave's comment.
>  - Removed NULL page check in sgx_virt_epc_free_page(), per Dave's comment.
> 
> ---
>  arch/x86/Kconfig                 |  12 ++
>  arch/x86/kernel/cpu/sgx/Makefile |   1 +
>  arch/x86/kernel/cpu/sgx/sgx.h    |   9 ++
>  arch/x86/kernel/cpu/sgx/virt.c   | 259 +++++++++++++++++++++++++++++++
>  4 files changed, 281 insertions(+)
>  create mode 100644 arch/x86/kernel/cpu/sgx/virt.c
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 21f851179ff0..ccb35d14c297 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1951,6 +1951,18 @@ config X86_SGX
>  
>  	  If unsure, say N.
>  
> +config X86_SGX_KVM
> +	bool "Software Guard eXtensions (SGX) Virtualization"
> +	depends on X86_SGX && KVM_INTEL
> +	help
> +
> +	  Enables KVM guests to create SGX enclaves.
> +
> +	  This includes support to expose "raw" unreclaimable enclave memory to
> +	  guests via a device node, e.g. /dev/sgx_vepc.
> +
> +	  If unsure, say N.
> +
>  config EFI
>  	bool "EFI runtime service support"
>  	depends on ACPI
> diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
> index 91d3dc784a29..9c1656779b2a 100644
> --- a/arch/x86/kernel/cpu/sgx/Makefile
> +++ b/arch/x86/kernel/cpu/sgx/Makefile
> @@ -3,3 +3,4 @@ obj-y += \
>  	encl.o \
>  	ioctl.o \
>  	main.o
> +obj-$(CONFIG_X86_SGX_KVM)	+= virt.o
> diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
> index 5fa42d143feb..1bff93be7bf4 100644
> --- a/arch/x86/kernel/cpu/sgx/sgx.h
> +++ b/arch/x86/kernel/cpu/sgx/sgx.h
> @@ -83,4 +83,13 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page);
>  int sgx_unmark_page_reclaimable(struct sgx_epc_page *page);
>  struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim);
>  
> +#ifdef CONFIG_X86_SGX_KVM
> +int __init sgx_vepc_init(void);
> +#else
> +static inline int __init sgx_vepc_init(void)
> +{
> +	return -ENODEV;
> +}
> +#endif
> +
>  #endif /* _X86_SGX_H */
> diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
> new file mode 100644
> index 000000000000..47542140f8c1
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/virt.c
> @@ -0,0 +1,259 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Device driver to expose SGX enclave memory to KVM guests.
> + *
> + * Copyright(c) 2021 Intel Corporation.
> + */
> +
> +#include <linux/miscdevice.h>
> +#include <linux/mm.h>
> +#include <linux/mman.h>
> +#include <linux/sched/mm.h>
> +#include <linux/sched/signal.h>
> +#include <linux/slab.h>
> +#include <linux/xarray.h>
> +#include <asm/sgx.h>
> +#include <uapi/asm/sgx.h>
> +
> +#include "encls.h"
> +#include "sgx.h"
> +
> +struct sgx_vepc {
> +	struct xarray page_array;
> +	struct mutex lock;
> +};
> +
> +/*
> + * Temporary SECS pages that cannot be EREMOVE'd due to having child in other
> + * virtual EPC instances, and the lock to protect it.
> + */
> +static struct mutex zombie_secs_pages_lock;
> +static struct list_head zombie_secs_pages;
> +
> +static int __sgx_vepc_fault(struct sgx_vepc *vepc,
> +			    struct vm_area_struct *vma, unsigned long addr)
> +{
> +	struct sgx_epc_page *epc_page;
> +	unsigned long index, pfn;
> +	int ret;
> +
> +	WARN_ON(!mutex_is_locked(&vepc->lock));
> +
> +	/* Calculate index of EPC page in virtual EPC's page_array */
> +	index = vma->vm_pgoff + PFN_DOWN(addr - vma->vm_start);
> +
> +	epc_page = xa_load(&vepc->page_array, index);
> +	if (epc_page)
> +		return 0;
> +
> +	epc_page = sgx_alloc_epc_page(vepc, false);
> +	if (IS_ERR(epc_page))
> +		return PTR_ERR(epc_page);
> +
> +	ret = xa_err(xa_store(&vepc->page_array, index, epc_page, GFP_KERNEL));
> +	if (ret)
> +		goto err_free;
> +
> +	pfn = PFN_DOWN(sgx_get_epc_phys_addr(epc_page));
> +
> +	ret = vmf_insert_pfn(vma, addr, pfn);
> +	if (ret != VM_FAULT_NOPAGE) {
> +		ret = -EFAULT;
> +		goto err_delete;
> +	}
> +
> +	return 0;
> +
> +err_delete:
> +	xa_erase(&vepc->page_array, index);
> +err_free:
> +	sgx_free_epc_page(epc_page);

Empty line before the return statement.

> +	return ret;
> +}
> +
> +static vm_fault_t sgx_vepc_fault(struct vm_fault *vmf)
> +{
> +	struct vm_area_struct *vma = vmf->vma;
> +	struct sgx_vepc *vepc = vma->vm_private_data;
> +	int ret;
> +
> +	mutex_lock(&vepc->lock);
> +	ret = __sgx_vepc_fault(vepc, vma, vmf->address);
> +	mutex_unlock(&vepc->lock);
> +
> +	if (!ret)
> +		return VM_FAULT_NOPAGE;
> +
> +	if (ret == -EBUSY && (vmf->flags & FAULT_FLAG_ALLOW_RETRY)) {
> +		mmap_read_unlock(vma->vm_mm);
> +		return VM_FAULT_RETRY;
> +	}
> +
> +	return VM_FAULT_SIGBUS;
> +}
> +
> +const struct vm_operations_struct sgx_vepc_vm_ops = {
> +	.fault = sgx_vepc_fault,
> +};
> +
> +static int sgx_vepc_mmap(struct file *file, struct vm_area_struct *vma)
> +{
> +	struct sgx_vepc *vepc = file->private_data;
> +
> +	if (!(vma->vm_flags & VM_SHARED))
> +		return -EINVAL;
> +
> +	vma->vm_ops = &sgx_vepc_vm_ops;
> +	/* Don't copy VMA in fork() */
> +	vma->vm_flags |= VM_PFNMAP | VM_IO | VM_DONTDUMP | VM_DONTCOPY;
> +	vma->vm_private_data = vepc;
> +
> +	return 0;
> +}
> +
> +static int sgx_vepc_free_page(struct sgx_epc_page *epc_page)
> +{
> +	int ret;
> +
> +	/*
> +	 * Take a previously guest-owned EPC page and return it to the
> +	 * general EPC page pool.
> +	 *
> +	 * Guests can not be trusted to have left this page in a good
> +	 * state, so run EREMOVE on the page unconditionally.  In the
> +	 * case that a guest properly EREMOVE'd this page, a superfluous
> +	 * EREMOVE is harmless.
> +	 */
> +	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
> +	if (ret) {
> +		/*
> +		 * Only SGX_CHILD_PRESENT is expected, which is because of
> +		 * EREMOVE'ing an SECS still with child, in which case it can
> +		 * be handled by EREMOVE'ing the SECS again after all pages in
> +		 * virtual EPC have been EREMOVE'd. See comments in below in
> +		 * sgx_vepc_release().
> +		 *
> +		 * The user of virtual EPC (KVM) needs to guarantee there's no
> +		 * logical processor is still running in the enclave in guest,
> +		 * otherwise EREMOVE will get SGX_ENCLAVE_ACT which cannot be
> +		 * handled here.
> +		 */
> +		WARN_ONCE(ret != SGX_CHILD_PRESENT,
> +			  "EREMOVE (EPC page 0x%lx): unexpected error: %d\n",
> +			  sgx_get_epc_phys_addr(epc_page), ret);

Empty line before the return statement.

> +		return ret;
> +	}
> +
> +	sgx_free_epc_page(epc_page);

Ditto.

> +	return 0;
> +}
> +
> +static int sgx_vepc_release(struct inode *inode, struct file *file)
> +{
> +	struct sgx_vepc *vepc = file->private_data;
> +	struct sgx_epc_page *epc_page, *tmp, *entry;
> +	unsigned long index;
> +
> +	LIST_HEAD(secs_pages);
> +
> +	xa_for_each(&vepc->page_array, index, entry) {
> +		/*
> +		 * Remove all normal, child pages.  sgx_vepc_free_page()
> +		 * will fail if EREMOVE fails, but this is OK and expected on
> +		 * SECS pages.  Those can only be EREMOVE'd *after* all their
> +		 * child pages. Retries below will clean them up.
> +		 */
> +		if (sgx_vepc_free_page(entry))
> +			continue;
> +
> +		xa_erase(&vepc->page_array, index);
> +	}
> +
> +	/*
> +	 * Retry EREMOVE'ing pages.  This will clean up any SECS pages that
> +	 * only had children in this 'epc' area.
> +	 */
> +	xa_for_each(&vepc->page_array, index, entry) {
> +		epc_page = entry;
> +		/*
> +		 * An EREMOVE failure here means that the SECS page still
> +		 * has children.  But, since all children in this 'sgx_vepc'
> +		 * have been removed, the SECS page must have a child on
> +		 * another instance.
> +		 */
> +		if (sgx_vepc_free_page(epc_page))
> +			list_add_tail(&epc_page->list, &secs_pages);
> +
> +		xa_erase(&vepc->page_array, index);
> +	}
> +
> +	/*
> +	 * SECS pages are "pinned" by child pages, an unpinned once all
> +	 * children have been EREMOVE'd.  A child page in this instance
> +	 * may have pinned an SECS page encountered in an earlier release(),
> +	 * creating a zombie.  Since some children were EREMOVE'd above,
> +	 * try to EREMOVE all zombies in the hopes that one was unpinned.
> +	 */
> +	mutex_lock(&zombie_secs_pages_lock);
> +	list_for_each_entry_safe(epc_page, tmp, &zombie_secs_pages, list) {
> +		/*
> +		 * Speculatively remove the page from the list of zombies,
> +		 * if the page is successfully EREMOVE it will be added to
> +		 * the list of free pages.  If EREMOVE fails, throw the page
> +		 * on the local list, which will be spliced on at the end.
> +		 */
> +		list_del(&epc_page->list);
> +
> +		if (sgx_vepc_free_page(epc_page))
> +			list_add_tail(&epc_page->list, &secs_pages);
> +	}
> +
> +	if (!list_empty(&secs_pages))
> +		list_splice_tail(&secs_pages, &zombie_secs_pages);
> +	mutex_unlock(&zombie_secs_pages_lock);
> +
> +	kfree(vepc);
> +
> +	return 0;
> +}
> +
> +static int sgx_vepc_open(struct inode *inode, struct file *file)
> +{
> +	struct sgx_vepc *vepc;
> +
> +	vepc = kzalloc(sizeof(struct sgx_vepc), GFP_KERNEL);
> +	if (!vepc)
> +		return -ENOMEM;
> +	mutex_init(&vepc->lock);
> +	xa_init(&vepc->page_array);
> +
> +	file->private_data = vepc;
> +
> +	return 0;
> +}
> +
> +static const struct file_operations sgx_vepc_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= sgx_vepc_open,
> +	.release	= sgx_vepc_release,
> +	.mmap		= sgx_vepc_mmap,
> +};
> +
> +static struct miscdevice sgx_vepc_dev = {
> +	.minor = MISC_DYNAMIC_MINOR,
> +	.name = "sgx_vepc",
> +	.nodename = "sgx_vepc",
> +	.fops = &sgx_vepc_fops,
> +};
> +
> +int __init sgx_vepc_init(void)
> +{
> +	/* SGX virtualization requires KVM to work */
> +	if (!boot_cpu_has(X86_FEATURE_VMX))
> +		return -ENODEV;
> +
> +	INIT_LIST_HEAD(&zombie_secs_pages);
> +	mutex_init(&zombie_secs_pages_lock);
> +
> +	return misc_register(&sgx_vepc_dev);
> +}
> -- 
> 2.29.2
> 
> 

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support
  2021-02-13 13:29 ` [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
@ 2021-02-16  2:15   ` Jarkko Sakkinen
  2021-02-16  5:03     ` Huang, Kai
  2021-02-16 18:40   ` Dave Hansen
  1 sibling, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  2:15 UTC (permalink / raw)
  To: Kai Huang
  Cc: linux-sgx, kvm, x86, seanjc, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jethro, b.thiel

On Sun, Feb 14, 2021 at 02:29:05AM +1300, Kai Huang wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> The kernel will currently disable all SGX support if the hardware does
> not support launch control.  Make it more permissive to allow SGX
> virtualization on systems without Launch Control support.  This will
> allow KVM to expose SGX to guests that have less-strict requirements on
> the availability of flexible launch control.
> 
> Improve error message to distinguish between three cases.  There are two
> cases where SGX support is completely disabled:
> 1) SGX has been disabled completely by the BIOS
> 2) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
>    of LC unavailability.  SGX virtualization is unavailable (because of
>    Kconfig).
> One where it is partially available:
> 3) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
>    of LC unavailability.  SGX virtualization is supported.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Co-developed-by: Kai Huang <kai.huang@intel.com>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
> v4->v5:
> 
>  - No code change.
> 
> v3->v4:
> 
>  - Removed cpu_has(X86_FEATURE_SGX1) check in enable_sgx_any, since it logically
>    is not related to KVM SGX series, per Sean.
>  - Changed declaration of variables to be in reverse-christmas tree style, per
>    Jarkko.
> 
> v2->v3:
> 
>  - Added to use 'enable_sgx_any', per Dave.
>  - Changed to call clear_cpu_cap() directly, rather than using clear_sgx_caps()
>    and clear_sgx_lc().
>  - Changed to use CONFIG_X86_SGX_KVM, instead of CONFIG_X86_SGX_VIRTUALIZATION.
> 
> v1->v2:
> 
>  - Refined commit message per Dave's comments.
>  - Added check to only enable SGX virtualization when VMX is supported, per
>    Dave's comment.
>  - Refined error msg print to explicitly call out SGX virtualization will be
>    supported when LC is locked by BIOS, per Dave's comment.
> 
> ---
>  arch/x86/kernel/cpu/feat_ctl.c | 57 ++++++++++++++++++++++++++--------
>  1 file changed, 44 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
> index 27533a6e04fa..96c370284913 100644
> --- a/arch/x86/kernel/cpu/feat_ctl.c
> +++ b/arch/x86/kernel/cpu/feat_ctl.c
> @@ -105,7 +105,8 @@ early_param("nosgx", nosgx);
>  void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
>  {
>  	bool tboot = tboot_enabled();
> -	bool enable_sgx;
> +	bool enable_sgx_any, enable_sgx_kvm, enable_sgx_driver;
> +	bool enable_vmx;
>  	u64 msr;
>  
>  	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
> @@ -114,13 +115,21 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
>  		return;
>  	}
>  
> +	enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
> +		     IS_ENABLED(CONFIG_KVM_INTEL);

It's less than 100 characters:

        enable_vmx = cpu_has(c, X86_FEATURE_VMX) && IS_ENABLED(CONFIG_KVM_INTEL);

This is better:

        enable_vmx = IS_ENABLED(CONFIG_KVM_INTEL) && cpu_has(c, X86_FEATURE_VMX);

You only want to evaluate cpu_has() if COHNFIG_KVM_INTEL is enabled.

> +
>  	/*
> -	 * Enable SGX if and only if the kernel supports SGX and Launch Control
> -	 * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
> +	 * Separate out SGX driver enabling from KVM.  This allows KVM
> +	 * guests to use SGX even if the kernel SGX driver refuses to
> +	 * use it.  This happens if flexible Faunch Control is not
> +	 * available.
>  	 */
> -	enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
> -		     cpu_has(c, X86_FEATURE_SGX_LC) &&
> -		     IS_ENABLED(CONFIG_X86_SGX);
> +	enable_sgx_any = cpu_has(c, X86_FEATURE_SGX) &&
> +			 IS_ENABLED(CONFIG_X86_SGX);
> +	enable_sgx_driver = enable_sgx_any &&
> +			    cpu_has(c, X86_FEATURE_SGX_LC);
> +	enable_sgx_kvm = enable_sgx_any && enable_vmx &&
> +			  IS_ENABLED(CONFIG_X86_SGX_KVM);
>  
>  	if (msr & FEAT_CTL_LOCKED)
>  		goto update_caps;
> @@ -136,15 +145,18 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
>  	 * i.e. KVM is enabled, to avoid unnecessarily adding an attack vector
>  	 * for the kernel, e.g. using VMX to hide malicious code.
>  	 */
> -	if (cpu_has(c, X86_FEATURE_VMX) && IS_ENABLED(CONFIG_KVM_INTEL)) {
> +	if (enable_vmx) {
>  		msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
>  
>  		if (tboot)
>  			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
>  	}
>  
> -	if (enable_sgx)
> -		msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED;
> +	if (enable_sgx_kvm || enable_sgx_driver) {
> +		msr |= FEAT_CTL_SGX_ENABLED;
> +		if (enable_sgx_driver)
> +			msr |= FEAT_CTL_SGX_LC_ENABLED;
> +	}
>  
>  	wrmsrl(MSR_IA32_FEAT_CTL, msr);
>  
> @@ -167,10 +179,29 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
>  	}
>  
>  update_sgx:
> -	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
> -	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
> -		if (enable_sgx)
> -			pr_err_once("SGX disabled by BIOS\n");
> +	if (!(msr & FEAT_CTL_SGX_ENABLED)) {
> +		if (enable_sgx_kvm || enable_sgx_driver)
> +			pr_err_once("SGX disabled by BIOS.\n");
>  		clear_cpu_cap(c, X86_FEATURE_SGX);

Empty line before return statement.

> +		return;
> +	}
> +
> +	/*
> +	 * VMX feature bit may be cleared due to being disabled in BIOS,
> +	 * in which case SGX virtualization cannot be supported either.
> +	 */
> +	if (!cpu_has(c, X86_FEATURE_VMX) && enable_sgx_kvm) {
> +		pr_err_once("SGX virtualization disabled due to lack of VMX.\n");
> +		enable_sgx_kvm = 0;
> +	}
> +
> +	if (!(msr & FEAT_CTL_SGX_LC_ENABLED) && enable_sgx_driver) {
> +		if (!enable_sgx_kvm) {
> +			pr_err_once("SGX Launch Control is locked. Disable SGX.\n");
> +			clear_cpu_cap(c, X86_FEATURE_SGX);
> +		} else {
> +			pr_err_once("SGX Launch Control is locked. Support SGX virtualization only.\n");
> +			clear_cpu_cap(c, X86_FEATURE_SGX_LC);
> +		}
>  	}
>  }
> -- 
> 2.29.2
> 
> 

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-13 13:29 ` [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
@ 2021-02-16  2:17   ` Jarkko Sakkinen
  2021-02-16 10:30     ` Huang, Kai
  0 siblings, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  2:17 UTC (permalink / raw)
  To: Kai Huang
  Cc: linux-sgx, kvm, x86, seanjc, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa

On Sun, Feb 14, 2021 at 02:29:10AM +1300, Kai Huang wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Expose SGX architectural structures, as KVM will use many of the
> architectural constants and structs to virtualize SGX.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Acked-by: Dave Hansen <dave.hansen@intel.com>
> Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
>  arch/x86/{kernel/cpu/sgx/arch.h => include/asm/sgx_arch.h} | 0
>  arch/x86/kernel/cpu/sgx/encl.c                             | 2 +-
>  arch/x86/kernel/cpu/sgx/sgx.h                              | 2 +-
>  tools/testing/selftests/sgx/defines.h                      | 2 +-
>  4 files changed, 3 insertions(+), 3 deletions(-)
>  rename arch/x86/{kernel/cpu/sgx/arch.h => include/asm/sgx_arch.h} (100%)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/arch.h b/arch/x86/include/asm/sgx_arch.h
> similarity index 100%
> rename from arch/x86/kernel/cpu/sgx/arch.h
> rename to arch/x86/include/asm/sgx_arch.h

Why not just sgx.h? The postfix is useless.

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  2021-02-13 13:29 ` [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
@ 2021-02-16  3:08   ` Jarkko Sakkinen
  2021-02-16  3:09     ` Jarkko Sakkinen
  0 siblings, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  3:08 UTC (permalink / raw)
  To: Kai Huang
  Cc: linux-sgx, kvm, x86, seanjc, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa

On Sun, Feb 14, 2021 at 02:29:15AM +1300, Kai Huang wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> The host kernel must intercept ECREATE to be able to impose policies on
> guests.  When it does this, the host kernel runs ECREATE against the
> userspace mapping of the virtualized EPC.
> 
> Provide wrappers around __ecreate() and __einit() to hide the ugliness
> of overloading the ENCLS return value to encode multiple error formats
> in a single int.  KVM will trap-and-execute ECREATE and EINIT as part
> of SGX virtualization, and on an exception, KVM needs the trapnr so that
> it can inject the correct fault into the guest.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
> v4->v5:
> 
>  - No code change.
> 
> v3->v4:
> 
>  - Added one new line before last return in sgx_virt_einit(), per Jarkko.
> 
> v2->v3:
> 
>  - Added kdoc for sgx_virt_ecreate() and sgx_virt_einit(), per Jarkko.
>  - Changed to use CONFIG_X86_SGX_KVM.
> 
> ---
>  arch/x86/include/asm/sgx.h     | 16 ++++++
>  arch/x86/kernel/cpu/sgx/virt.c | 94 ++++++++++++++++++++++++++++++++++
>  2 files changed, 110 insertions(+)
>  create mode 100644 arch/x86/include/asm/sgx.h
> 
> diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
> new file mode 100644
> index 000000000000..8a3ea3e1efbe
> --- /dev/null
> +++ b/arch/x86/include/asm/sgx.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_X86_SGX_H
> +#define _ASM_X86_SGX_H
> +
> +#include <linux/types.h>
> +
> +#ifdef CONFIG_X86_SGX_KVM
> +struct sgx_pageinfo;
> +
> +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> +		     int *trapnr);
> +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> +		   void __user *secs, u64 *lepubkeyhash, int *trapnr);

s/virt/vepc/g

> +#endif
> +
> +#endif /* _ASM_X86_SGX_H */
> diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
> index 47542140f8c1..016bad7cff8d 100644
> --- a/arch/x86/kernel/cpu/sgx/virt.c
> +++ b/arch/x86/kernel/cpu/sgx/virt.c

Rename as vepc.c.

> @@ -257,3 +257,97 @@ int __init sgx_vepc_init(void)
>  
>  	return misc_register(&sgx_vepc_dev);
>  }
> +
> +/**
> + * sgx_virt_ecreate() - Run ECREATE on behalf of guest
> + * @pageinfo:	Pointer to PAGEINFO structure
> + * @secs:	Userspace pointer to SECS page
> + * @trapnr:	trap number injected to guest in case of ECREATE error
> + *
> + * Run ECREATE on behalf of guest after KVM traps ECREATE for the purpose
> + * of enforcing policies of guest's enclaves, and return the trap number
> + * which should be injected to guest in case of any ECREATE error.
> + *
> + * Return:
> + * - 0: 	ECREATE was successful.
> + * - -EFAULT:	ECREATE returned error.
> + */
> +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> +		     int *trapnr)
> +{
> +	int ret;
> +
> +	/*
> +	 * @secs is userspace address, and it's not guaranteed @secs points at
> +	 * an actual EPC page. It's also possible to generate a kernel mapping
> +	 * to physical EPC page by resolving PFN but using __uaccess_xx() is
> +	 * simpler.
> +	 */
> +	__uaccess_begin();
> +	ret = __ecreate(pageinfo, (void *)secs);
> +	__uaccess_end();
> +
> +	if (encls_faulted(ret)) {
> +		*trapnr = ENCLS_TRAPNR(ret);
> +		return -EFAULT;
> +	}
> +
> +	/* ECREATE doesn't return an error code, it faults or succeeds. */
> +	WARN_ON_ONCE(ret);

Empty line.

> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(sgx_virt_ecreate);
> +
> +static int __sgx_virt_einit(void __user *sigstruct, void __user *token,
> +			    void __user *secs)
> +{
> +	int ret;
> +
> +	__uaccess_begin();
> +	ret =  __einit((void *)sigstruct, (void *)token, (void *)secs);
> +	__uaccess_end();

Ditto.

> +	return ret;
> +}
> +
> +/**
> + * sgx_virt_einit() - Run EINIT on behalf of guest
> + * @sigstruct:		Userspace pointer to SIGSTRUCT structure
> + * @token:		Userspace pointer to EINITTOKEN structure
> + * @secs:		Userspace pointer to SECS page
> + * @lepubkeyhash:	Pointer to guest's *virtual* SGX_LEPUBKEYHASH MSR
> + * 			values
> + * @trapnr:		trap number injected to guest in case of EINIT error
> + *
> + * Run EINIT on behalf of guest after KVM traps EINIT. If SGX_LC is available
> + * in host, SGX driver may rewrite the hardware values at wish, therefore KVM
> + * needs to update hardware values to guest's virtual MSR values in order to
> + * ensure EINIT is executed with expected hardware values.
> + *
> + * Return:
> + * - 0: 	EINIT was successful.
> + * - -EFAULT:	EINIT returned error.
> + */
> +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> +		   void __user *secs, u64 *lepubkeyhash, int *trapnr)
> +{
> +	int ret;
> +
> +	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> +		ret = __sgx_virt_einit(sigstruct, token, secs);
> +	} else {
> +		preempt_disable();
> +
> +		sgx_update_lepubkeyhash(lepubkeyhash);
> +
> +		ret = __sgx_virt_einit(sigstruct, token, secs);
> +		preempt_enable();
> +	}
> +
> +	if (encls_faulted(ret)) {
> +		*trapnr = ENCLS_TRAPNR(ret);
> +		return -EFAULT;
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(sgx_virt_einit);
> -- 
> 2.29.2
> 
> 

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  2021-02-16  3:08   ` Jarkko Sakkinen
@ 2021-02-16  3:09     ` Jarkko Sakkinen
  2021-02-16  4:55       ` Huang, Kai
  0 siblings, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  3:09 UTC (permalink / raw)
  To: Kai Huang
  Cc: linux-sgx, kvm, x86, seanjc, luto, dave.hansen, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 05:08:20AM +0200, Jarkko Sakkinen wrote:
> On Sun, Feb 14, 2021 at 02:29:15AM +1300, Kai Huang wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > The host kernel must intercept ECREATE to be able to impose policies on
> > guests.  When it does this, the host kernel runs ECREATE against the
> > userspace mapping of the virtualized EPC.
> > 
> > Provide wrappers around __ecreate() and __einit() to hide the ugliness
> > of overloading the ENCLS return value to encode multiple error formats
> > in a single int.  KVM will trap-and-execute ECREATE and EINIT as part
> > of SGX virtualization, and on an exception, KVM needs the trapnr so that
> > it can inject the correct fault into the guest.
> > 
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > Signed-off-by: Kai Huang <kai.huang@intel.com>
> > ---
> > v4->v5:
> > 
> >  - No code change.
> > 
> > v3->v4:
> > 
> >  - Added one new line before last return in sgx_virt_einit(), per Jarkko.
> > 
> > v2->v3:
> > 
> >  - Added kdoc for sgx_virt_ecreate() and sgx_virt_einit(), per Jarkko.
> >  - Changed to use CONFIG_X86_SGX_KVM.
> > 
> > ---
> >  arch/x86/include/asm/sgx.h     | 16 ++++++
> >  arch/x86/kernel/cpu/sgx/virt.c | 94 ++++++++++++++++++++++++++++++++++
> >  2 files changed, 110 insertions(+)
> >  create mode 100644 arch/x86/include/asm/sgx.h
> > 
> > diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
> > new file mode 100644
> > index 000000000000..8a3ea3e1efbe
> > --- /dev/null
> > +++ b/arch/x86/include/asm/sgx.h
> > @@ -0,0 +1,16 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_X86_SGX_H
> > +#define _ASM_X86_SGX_H
> > +
> > +#include <linux/types.h>
> > +
> > +#ifdef CONFIG_X86_SGX_KVM
> > +struct sgx_pageinfo;
> > +
> > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > +		     int *trapnr);
> > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr);
> 
> s/virt/vepc/g
> 
> > +#endif
> > +
> > +#endif /* _ASM_X86_SGX_H */
> > diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
> > index 47542140f8c1..016bad7cff8d 100644
> > --- a/arch/x86/kernel/cpu/sgx/virt.c
> > +++ b/arch/x86/kernel/cpu/sgx/virt.c
> 
> Rename as vepc.c.
> 
> > @@ -257,3 +257,97 @@ int __init sgx_vepc_init(void)
> >  
> >  	return misc_register(&sgx_vepc_dev);
> >  }
> > +
> > +/**
> > + * sgx_virt_ecreate() - Run ECREATE on behalf of guest
> > + * @pageinfo:	Pointer to PAGEINFO structure
> > + * @secs:	Userspace pointer to SECS page
> > + * @trapnr:	trap number injected to guest in case of ECREATE error
> > + *
> > + * Run ECREATE on behalf of guest after KVM traps ECREATE for the purpose
> > + * of enforcing policies of guest's enclaves, and return the trap number
> > + * which should be injected to guest in case of any ECREATE error.
> > + *
> > + * Return:
> > + * - 0: 	ECREATE was successful.
> > + * - -EFAULT:	ECREATE returned error.
> > + */
> > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > +		     int *trapnr)
> > +{
> > +	int ret;
> > +
> > +	/*
> > +	 * @secs is userspace address, and it's not guaranteed @secs points at
> > +	 * an actual EPC page. It's also possible to generate a kernel mapping
> > +	 * to physical EPC page by resolving PFN but using __uaccess_xx() is
> > +	 * simpler.
> > +	 */
> > +	__uaccess_begin();
> > +	ret = __ecreate(pageinfo, (void *)secs);
> > +	__uaccess_end();
> > +
> > +	if (encls_faulted(ret)) {
> > +		*trapnr = ENCLS_TRAPNR(ret);
> > +		return -EFAULT;
> > +	}
> > +
> > +	/* ECREATE doesn't return an error code, it faults or succeeds. */
> > +	WARN_ON_ONCE(ret);
> 
> Empty line.
> 
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(sgx_virt_ecreate);
> > +
> > +static int __sgx_virt_einit(void __user *sigstruct, void __user *token,
> > +			    void __user *secs)
> > +{
> > +	int ret;
> > +
> > +	__uaccess_begin();
> > +	ret =  __einit((void *)sigstruct, (void *)token, (void *)secs);
> > +	__uaccess_end();
> 
> Ditto.
> 
> > +	return ret;
> > +}
> > +
> > +/**
> > + * sgx_virt_einit() - Run EINIT on behalf of guest
> > + * @sigstruct:		Userspace pointer to SIGSTRUCT structure
> > + * @token:		Userspace pointer to EINITTOKEN structure
> > + * @secs:		Userspace pointer to SECS page
> > + * @lepubkeyhash:	Pointer to guest's *virtual* SGX_LEPUBKEYHASH MSR
> > + * 			values
> > + * @trapnr:		trap number injected to guest in case of EINIT error
> > + *
> > + * Run EINIT on behalf of guest after KVM traps EINIT. If SGX_LC is available
> > + * in host, SGX driver may rewrite the hardware values at wish, therefore KVM
> > + * needs to update hardware values to guest's virtual MSR values in order to
> > + * ensure EINIT is executed with expected hardware values.
> > + *
> > + * Return:
> > + * - 0: 	EINIT was successful.
> > + * - -EFAULT:	EINIT returned error.
> > + */
> > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr)
> > +{
> > +	int ret;
> > +
> > +	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > +	} else {
> > +		preempt_disable();
> > +
> > +		sgx_update_lepubkeyhash(lepubkeyhash);
> > +
> > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > +		preempt_enable();
> > +	}
> > +
> > +	if (encls_faulted(ret)) {
> > +		*trapnr = ENCLS_TRAPNR(ret);
> > +		return -EFAULT;
> > +	}
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(sgx_virt_einit);

Remove exports.

> > -- 
> > 2.29.2
> > 
> > 
> 
> /Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  2021-02-16  3:09     ` Jarkko Sakkinen
@ 2021-02-16  4:55       ` Huang, Kai
  2021-02-16  8:33         ` Jarkko Sakkinen
  0 siblings, 1 reply; 64+ messages in thread
From: Huang, Kai @ 2021-02-16  4:55 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa

> 
> On Tue, Feb 16, 2021 at 05:08:20AM +0200, Jarkko Sakkinen wrote:
> > On Sun, Feb 14, 2021 at 02:29:15AM +1300, Kai Huang wrote:
> > > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > >
> > > The host kernel must intercept ECREATE to be able to impose policies
> > > on guests.  When it does this, the host kernel runs ECREATE against
> > > the userspace mapping of the virtualized EPC.
> > >
> > > Provide wrappers around __ecreate() and __einit() to hide the
> > > ugliness of overloading the ENCLS return value to encode multiple
> > > error formats in a single int.  KVM will trap-and-execute ECREATE
> > > and EINIT as part of SGX virtualization, and on an exception, KVM
> > > needs the trapnr so that it can inject the correct fault into the guest.
> > >
> > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > > Signed-off-by: Kai Huang <kai.huang@intel.com>
> > > ---
> > > v4->v5:
> > >
> > >  - No code change.
> > >
> > > v3->v4:
> > >
> > >  - Added one new line before last return in sgx_virt_einit(), per Jarkko.
> > >
> > > v2->v3:
> > >
> > >  - Added kdoc for sgx_virt_ecreate() and sgx_virt_einit(), per Jarkko.
> > >  - Changed to use CONFIG_X86_SGX_KVM.
> > >
> > > ---
> > >  arch/x86/include/asm/sgx.h     | 16 ++++++
> > >  arch/x86/kernel/cpu/sgx/virt.c | 94
> > > ++++++++++++++++++++++++++++++++++
> > >  2 files changed, 110 insertions(+)
> > >  create mode 100644 arch/x86/include/asm/sgx.h
> > >
> > > diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
> > > new file mode 100644 index 000000000000..8a3ea3e1efbe
> > > --- /dev/null
> > > +++ b/arch/x86/include/asm/sgx.h
> > > @@ -0,0 +1,16 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_SGX_H
> > > +#define _ASM_X86_SGX_H
> > > +
> > > +#include <linux/types.h>
> > > +
> > > +#ifdef CONFIG_X86_SGX_KVM
> > > +struct sgx_pageinfo;
> > > +
> > > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > > +		     int *trapnr);
> > > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr);
> >
> > s/virt/vepc/g

No. The two are related to enclave construction (from guest), not EPC. 

For instance, what does ECREATE mean for virtual EPC? ECREATE is meaningful for enclave.

> >
> > > +#endif
> > > +
> > > +#endif /* _ASM_X86_SGX_H */
> > > diff --git a/arch/x86/kernel/cpu/sgx/virt.c
> > > b/arch/x86/kernel/cpu/sgx/virt.c index 47542140f8c1..016bad7cff8d
> > > 100644
> > > --- a/arch/x86/kernel/cpu/sgx/virt.c
> > > +++ b/arch/x86/kernel/cpu/sgx/virt.c
> >
> > Rename as vepc.c.

No. This file contains more than virtual EPC implementation, but also other staff like sgx_virt_ecreate()/sgx_virt_einit(), which are used by KVM to run ECREATE/EINIT on behalf of guest.

> >
> > > @@ -257,3 +257,97 @@ int __init sgx_vepc_init(void)
> > >
> > >  	return misc_register(&sgx_vepc_dev);  }
> > > +
> > > +/**
> > > + * sgx_virt_ecreate() - Run ECREATE on behalf of guest
> > > + * @pageinfo:	Pointer to PAGEINFO structure
> > > + * @secs:	Userspace pointer to SECS page
> > > + * @trapnr:	trap number injected to guest in case of ECREATE error
> > > + *
> > > + * Run ECREATE on behalf of guest after KVM traps ECREATE for the
> > > +purpose
> > > + * of enforcing policies of guest's enclaves, and return the trap
> > > +number
> > > + * which should be injected to guest in case of any ECREATE error.
> > > + *
> > > + * Return:
> > > + * - 0: 	ECREATE was successful.
> > > + * - -EFAULT:	ECREATE returned error.
> > > + */
> > > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > > +		     int *trapnr)
> > > +{
> > > +	int ret;
> > > +
> > > +	/*
> > > +	 * @secs is userspace address, and it's not guaranteed @secs points at
> > > +	 * an actual EPC page. It's also possible to generate a kernel mapping
> > > +	 * to physical EPC page by resolving PFN but using __uaccess_xx() is
> > > +	 * simpler.
> > > +	 */
> > > +	__uaccess_begin();
> > > +	ret = __ecreate(pageinfo, (void *)secs);
> > > +	__uaccess_end();
> > > +
> > > +	if (encls_faulted(ret)) {
> > > +		*trapnr = ENCLS_TRAPNR(ret);
> > > +		return -EFAULT;
> > > +	}
> > > +
> > > +	/* ECREATE doesn't return an error code, it faults or succeeds. */
> > > +	WARN_ON_ONCE(ret);
> >
> > Empty line.
> >
> > > +	return 0;
> > > +}
> > > +EXPORT_SYMBOL_GPL(sgx_virt_ecreate);
> > > +
> > > +static int __sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > +			    void __user *secs)
> > > +{
> > > +	int ret;
> > > +
> > > +	__uaccess_begin();
> > > +	ret =  __einit((void *)sigstruct, (void *)token, (void *)secs);
> > > +	__uaccess_end();
> >
> > Ditto.
> >
> > > +	return ret;
> > > +}
> > > +
> > > +/**
> > > + * sgx_virt_einit() - Run EINIT on behalf of guest
> > > + * @sigstruct:		Userspace pointer to SIGSTRUCT structure
> > > + * @token:		Userspace pointer to EINITTOKEN structure
> > > + * @secs:		Userspace pointer to SECS page
> > > + * @lepubkeyhash:	Pointer to guest's *virtual* SGX_LEPUBKEYHASH MSR
> > > + * 			values
> > > + * @trapnr:		trap number injected to guest in case of EINIT error
> > > + *
> > > + * Run EINIT on behalf of guest after KVM traps EINIT. If SGX_LC is
> > > +available
> > > + * in host, SGX driver may rewrite the hardware values at wish,
> > > +therefore KVM
> > > + * needs to update hardware values to guest's virtual MSR values in
> > > +order to
> > > + * ensure EINIT is executed with expected hardware values.
> > > + *
> > > + * Return:
> > > + * - 0: 	EINIT was successful.
> > > + * - -EFAULT:	EINIT returned error.
> > > + */
> > > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr) {
> > > +	int ret;
> > > +
> > > +	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> > > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > > +	} else {
> > > +		preempt_disable();
> > > +
> > > +		sgx_update_lepubkeyhash(lepubkeyhash);
> > > +
> > > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > > +		preempt_enable();
> > > +	}
> > > +
> > > +	if (encls_faulted(ret)) {
> > > +		*trapnr = ENCLS_TRAPNR(ret);
> > > +		return -EFAULT;
> > > +	}
> > > +
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL_GPL(sgx_virt_einit);
> 
> Remove exports.

Why? KVM needs to use them in later patches.

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support
  2021-02-16  2:15   ` Jarkko Sakkinen
@ 2021-02-16  5:03     ` Huang, Kai
  2021-02-16  8:36       ` Jarkko Sakkinen
  0 siblings, 1 reply; 64+ messages in thread
From: Huang, Kai @ 2021-02-16  5:03 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa, jethro,
	b.thiel

> 
> On Sun, Feb 14, 2021 at 02:29:05AM +1300, Kai Huang wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> >
> > The kernel will currently disable all SGX support if the hardware does
> > not support launch control.  Make it more permissive to allow SGX
> > virtualization on systems without Launch Control support.  This will
> > allow KVM to expose SGX to guests that have less-strict requirements
> > on the availability of flexible launch control.
> >
> > Improve error message to distinguish between three cases.  There are
> > two cases where SGX support is completely disabled:
> > 1) SGX has been disabled completely by the BIOS
> > 2) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
> >    of LC unavailability.  SGX virtualization is unavailable (because of
> >    Kconfig).
> > One where it is partially available:
> > 3) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
> >    of LC unavailability.  SGX virtualization is supported.
> >
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > Co-developed-by: Kai Huang <kai.huang@intel.com>
> > Signed-off-by: Kai Huang <kai.huang@intel.com>
> > ---
> > v4->v5:
> >
> >  - No code change.
> >
> > v3->v4:
> >
> >  - Removed cpu_has(X86_FEATURE_SGX1) check in enable_sgx_any, since it
> logically
> >    is not related to KVM SGX series, per Sean.
> >  - Changed declaration of variables to be in reverse-christmas tree style, per
> >    Jarkko.
> >
> > v2->v3:
> >
> >  - Added to use 'enable_sgx_any', per Dave.
> >  - Changed to call clear_cpu_cap() directly, rather than using clear_sgx_caps()
> >    and clear_sgx_lc().
> >  - Changed to use CONFIG_X86_SGX_KVM, instead of
> CONFIG_X86_SGX_VIRTUALIZATION.
> >
> > v1->v2:
> >
> >  - Refined commit message per Dave's comments.
> >  - Added check to only enable SGX virtualization when VMX is supported, per
> >    Dave's comment.
> >  - Refined error msg print to explicitly call out SGX virtualization will be
> >    supported when LC is locked by BIOS, per Dave's comment.
> >
> > ---
> >  arch/x86/kernel/cpu/feat_ctl.c | 57
> > ++++++++++++++++++++++++++--------
> >  1 file changed, 44 insertions(+), 13 deletions(-)
> >
> > diff --git a/arch/x86/kernel/cpu/feat_ctl.c
> > b/arch/x86/kernel/cpu/feat_ctl.c index 27533a6e04fa..96c370284913
> > 100644
> > --- a/arch/x86/kernel/cpu/feat_ctl.c
> > +++ b/arch/x86/kernel/cpu/feat_ctl.c
> > @@ -105,7 +105,8 @@ early_param("nosgx", nosgx);  void
> > init_ia32_feat_ctl(struct cpuinfo_x86 *c)  {
> >  	bool tboot = tboot_enabled();
> > -	bool enable_sgx;
> > +	bool enable_sgx_any, enable_sgx_kvm, enable_sgx_driver;
> > +	bool enable_vmx;
> >  	u64 msr;
> >
> >  	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) { @@ -114,13 +115,21
> @@
> > void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
> >  		return;
> >  	}
> >
> > +	enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
> > +		     IS_ENABLED(CONFIG_KVM_INTEL);
> 
> It's less than 100 characters:

Just carious, shouldn't be 80 characters to wrap a new line, instead of 100?

> 
>         enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
> IS_ENABLED(CONFIG_KVM_INTEL);
> 
> This is better:
> 
>         enable_vmx = IS_ENABLED(CONFIG_KVM_INTEL) && cpu_has(c,
> X86_FEATURE_VMX);
> 
> You only want to evaluate cpu_has() if COHNFIG_KVM_INTEL is enabled.

If you look at the original code, cpu_has() comes first. It's just one-time booting time code, and I don't think it matters.

Btw, are you also suggesting IS_ENABLED(CONFIG_X86_SGX) should come before cpu_has() for SGX in below code? 

That being said, cpu_has() comes first for both VMX and SGX in the original code. I don't know why I need to change the sequence in this patch.

> 
> > +
> >  	/*
> > -	 * Enable SGX if and only if the kernel supports SGX and Launch Control
> > -	 * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
> > +	 * Separate out SGX driver enabling from KVM.  This allows KVM
> > +	 * guests to use SGX even if the kernel SGX driver refuses to
> > +	 * use it.  This happens if flexible Faunch Control is not
> > +	 * available.
> >  	 */
> > -	enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
> > -		     cpu_has(c, X86_FEATURE_SGX_LC) &&
> > -		     IS_ENABLED(CONFIG_X86_SGX);
> > +	enable_sgx_any = cpu_has(c, X86_FEATURE_SGX) &&
> > +			 IS_ENABLED(CONFIG_X86_SGX);
> > +	enable_sgx_driver = enable_sgx_any &&
> > +			    cpu_has(c, X86_FEATURE_SGX_LC);
> > +	enable_sgx_kvm = enable_sgx_any && enable_vmx &&
> > +			  IS_ENABLED(CONFIG_X86_SGX_KVM);
> >
> >  	if (msr & FEAT_CTL_LOCKED)
> >  		goto update_caps;
> > @@ -136,15 +145,18 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
> >  	 * i.e. KVM is enabled, to avoid unnecessarily adding an attack vector
> >  	 * for the kernel, e.g. using VMX to hide malicious code.
> >  	 */
> > -	if (cpu_has(c, X86_FEATURE_VMX) &&
> IS_ENABLED(CONFIG_KVM_INTEL)) {
> > +	if (enable_vmx) {
> >  		msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
> >
> >  		if (tboot)
> >  			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
> >  	}
> >
> > -	if (enable_sgx)
> > -		msr |= FEAT_CTL_SGX_ENABLED |
> FEAT_CTL_SGX_LC_ENABLED;
> > +	if (enable_sgx_kvm || enable_sgx_driver) {
> > +		msr |= FEAT_CTL_SGX_ENABLED;
> > +		if (enable_sgx_driver)
> > +			msr |= FEAT_CTL_SGX_LC_ENABLED;
> > +	}
> >
> >  	wrmsrl(MSR_IA32_FEAT_CTL, msr);
> >
> > @@ -167,10 +179,29 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
> >  	}
> >
> >  update_sgx:
> > -	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
> > -	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
> > -		if (enable_sgx)
> > -			pr_err_once("SGX disabled by BIOS\n");
> > +	if (!(msr & FEAT_CTL_SGX_ENABLED)) {
> > +		if (enable_sgx_kvm || enable_sgx_driver)
> > +			pr_err_once("SGX disabled by BIOS.\n");
> >  		clear_cpu_cap(c, X86_FEATURE_SGX);
> 
> Empty line before return statement.

It's just two statements inside the if() {} statement. Putting a new line here is too sparse IMHO.

I'd like to hear more.

Dave, do you have any comment?

> 
> > +		return;
> > +	}
> > +
> > +	/*
> > +	 * VMX feature bit may be cleared due to being disabled in BIOS,
> > +	 * in which case SGX virtualization cannot be supported either.
> > +	 */
> > +	if (!cpu_has(c, X86_FEATURE_VMX) && enable_sgx_kvm) {
> > +		pr_err_once("SGX virtualization disabled due to lack of VMX.\n");
> > +		enable_sgx_kvm = 0;
> > +	}
> > +
> > +	if (!(msr & FEAT_CTL_SGX_LC_ENABLED) && enable_sgx_driver) {
> > +		if (!enable_sgx_kvm) {
> > +			pr_err_once("SGX Launch Control is locked. Disable
> SGX.\n");
> > +			clear_cpu_cap(c, X86_FEATURE_SGX);
> > +		} else {
> > +			pr_err_once("SGX Launch Control is locked. Support
> SGX virtualization only.\n");
> > +			clear_cpu_cap(c, X86_FEATURE_SGX_LC);
> > +		}
> >  	}
> >  }
> > --
> > 2.29.2
> >
> >
> 
> /Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  2021-02-16  4:55       ` Huang, Kai
@ 2021-02-16  8:33         ` Jarkko Sakkinen
  2021-02-16  8:35           ` Jarkko Sakkinen
  0 siblings, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  8:33 UTC (permalink / raw)
  To: Huang, Kai
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 04:55:49AM +0000, Huang, Kai wrote:
> > 
> > On Tue, Feb 16, 2021 at 05:08:20AM +0200, Jarkko Sakkinen wrote:
> > > On Sun, Feb 14, 2021 at 02:29:15AM +1300, Kai Huang wrote:
> > > > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > > >
> > > > The host kernel must intercept ECREATE to be able to impose policies
> > > > on guests.  When it does this, the host kernel runs ECREATE against
> > > > the userspace mapping of the virtualized EPC.
> > > >
> > > > Provide wrappers around __ecreate() and __einit() to hide the
> > > > ugliness of overloading the ENCLS return value to encode multiple
> > > > error formats in a single int.  KVM will trap-and-execute ECREATE
> > > > and EINIT as part of SGX virtualization, and on an exception, KVM
> > > > needs the trapnr so that it can inject the correct fault into the guest.
> > > >
> > > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > > > Signed-off-by: Kai Huang <kai.huang@intel.com>
> > > > ---
> > > > v4->v5:
> > > >
> > > >  - No code change.
> > > >
> > > > v3->v4:
> > > >
> > > >  - Added one new line before last return in sgx_virt_einit(), per Jarkko.
> > > >
> > > > v2->v3:
> > > >
> > > >  - Added kdoc for sgx_virt_ecreate() and sgx_virt_einit(), per Jarkko.
> > > >  - Changed to use CONFIG_X86_SGX_KVM.
> > > >
> > > > ---
> > > >  arch/x86/include/asm/sgx.h     | 16 ++++++
> > > >  arch/x86/kernel/cpu/sgx/virt.c | 94
> > > > ++++++++++++++++++++++++++++++++++
> > > >  2 files changed, 110 insertions(+)
> > > >  create mode 100644 arch/x86/include/asm/sgx.h
> > > >
> > > > diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
> > > > new file mode 100644 index 000000000000..8a3ea3e1efbe
> > > > --- /dev/null
> > > > +++ b/arch/x86/include/asm/sgx.h
> > > > @@ -0,0 +1,16 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_SGX_H
> > > > +#define _ASM_X86_SGX_H
> > > > +
> > > > +#include <linux/types.h>
> > > > +
> > > > +#ifdef CONFIG_X86_SGX_KVM
> > > > +struct sgx_pageinfo;
> > > > +
> > > > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > > > +		     int *trapnr);
> > > > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr);
> > >
> > > s/virt/vepc/g
> 
> No. The two are related to enclave construction (from guest), not EPC. 
> 
> For instance, what does ECREATE mean for virtual EPC? ECREATE is meaningful for enclave.
> 
> > >
> > > > +#endif
> > > > +
> > > > +#endif /* _ASM_X86_SGX_H */
> > > > diff --git a/arch/x86/kernel/cpu/sgx/virt.c
> > > > b/arch/x86/kernel/cpu/sgx/virt.c index 47542140f8c1..016bad7cff8d
> > > > 100644
> > > > --- a/arch/x86/kernel/cpu/sgx/virt.c
> > > > +++ b/arch/x86/kernel/cpu/sgx/virt.c
> > >
> > > Rename as vepc.c.
> 
> No. This file contains more than virtual EPC implementation, but also other staff like sgx_virt_ecreate()/sgx_virt_einit(), which are used by KVM to run ECREATE/EINIT on behalf of guest.
> 
> > >
> > > > @@ -257,3 +257,97 @@ int __init sgx_vepc_init(void)
> > > >
> > > >  	return misc_register(&sgx_vepc_dev);  }
> > > > +
> > > > +/**
> > > > + * sgx_virt_ecreate() - Run ECREATE on behalf of guest
> > > > + * @pageinfo:	Pointer to PAGEINFO structure
> > > > + * @secs:	Userspace pointer to SECS page
> > > > + * @trapnr:	trap number injected to guest in case of ECREATE error
> > > > + *
> > > > + * Run ECREATE on behalf of guest after KVM traps ECREATE for the
> > > > +purpose
> > > > + * of enforcing policies of guest's enclaves, and return the trap
> > > > +number
> > > > + * which should be injected to guest in case of any ECREATE error.
> > > > + *
> > > > + * Return:
> > > > + * - 0: 	ECREATE was successful.
> > > > + * - -EFAULT:	ECREATE returned error.
> > > > + */
> > > > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > > > +		     int *trapnr)
> > > > +{
> > > > +	int ret;
> > > > +
> > > > +	/*
> > > > +	 * @secs is userspace address, and it's not guaranteed @secs points at
> > > > +	 * an actual EPC page. It's also possible to generate a kernel mapping
> > > > +	 * to physical EPC page by resolving PFN but using __uaccess_xx() is
> > > > +	 * simpler.
> > > > +	 */
> > > > +	__uaccess_begin();
> > > > +	ret = __ecreate(pageinfo, (void *)secs);
> > > > +	__uaccess_end();
> > > > +
> > > > +	if (encls_faulted(ret)) {
> > > > +		*trapnr = ENCLS_TRAPNR(ret);
> > > > +		return -EFAULT;
> > > > +	}
> > > > +
> > > > +	/* ECREATE doesn't return an error code, it faults or succeeds. */
> > > > +	WARN_ON_ONCE(ret);
> > >
> > > Empty line.
> > >
> > > > +	return 0;
> > > > +}
> > > > +EXPORT_SYMBOL_GPL(sgx_virt_ecreate);
> > > > +
> > > > +static int __sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > > +			    void __user *secs)
> > > > +{
> > > > +	int ret;
> > > > +
> > > > +	__uaccess_begin();
> > > > +	ret =  __einit((void *)sigstruct, (void *)token, (void *)secs);
> > > > +	__uaccess_end();
> > >
> > > Ditto.
> > >
> > > > +	return ret;
> > > > +}
> > > > +
> > > > +/**
> > > > + * sgx_virt_einit() - Run EINIT on behalf of guest
> > > > + * @sigstruct:		Userspace pointer to SIGSTRUCT structure
> > > > + * @token:		Userspace pointer to EINITTOKEN structure
> > > > + * @secs:		Userspace pointer to SECS page
> > > > + * @lepubkeyhash:	Pointer to guest's *virtual* SGX_LEPUBKEYHASH MSR
> > > > + * 			values
> > > > + * @trapnr:		trap number injected to guest in case of EINIT error
> > > > + *
> > > > + * Run EINIT on behalf of guest after KVM traps EINIT. If SGX_LC is
> > > > +available
> > > > + * in host, SGX driver may rewrite the hardware values at wish,
> > > > +therefore KVM
> > > > + * needs to update hardware values to guest's virtual MSR values in
> > > > +order to
> > > > + * ensure EINIT is executed with expected hardware values.
> > > > + *
> > > > + * Return:
> > > > + * - 0: 	EINIT was successful.
> > > > + * - -EFAULT:	EINIT returned error.
> > > > + */
> > > > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr) {
> > > > +	int ret;
> > > > +
> > > > +	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> > > > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > > > +	} else {
> > > > +		preempt_disable();
> > > > +
> > > > +		sgx_update_lepubkeyhash(lepubkeyhash);
> > > > +
> > > > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > > > +		preempt_enable();
> > > > +	}
> > > > +
> > > > +	if (encls_faulted(ret)) {
> > > > +		*trapnr = ENCLS_TRAPNR(ret);
> > > > +		return -EFAULT;
> > > > +	}
> > > > +
> > > > +	return ret;
> > > > +}
> > > > +EXPORT_SYMBOL_GPL(sgx_virt_einit);
> > 
> > Remove exports.
> 
> Why? KVM needs to use them in later patches.

Because they are only required for LKM's.

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  2021-02-16  8:33         ` Jarkko Sakkinen
@ 2021-02-16  8:35           ` Jarkko Sakkinen
  2021-02-16  9:33             ` Huang, Kai
  0 siblings, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  8:35 UTC (permalink / raw)
  To: Huang, Kai
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 10:33:17AM +0200, Jarkko Sakkinen wrote:
> On Tue, Feb 16, 2021 at 04:55:49AM +0000, Huang, Kai wrote:
> > > 
> > > On Tue, Feb 16, 2021 at 05:08:20AM +0200, Jarkko Sakkinen wrote:
> > > > On Sun, Feb 14, 2021 at 02:29:15AM +1300, Kai Huang wrote:
> > > > > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > > > >
> > > > > The host kernel must intercept ECREATE to be able to impose policies
> > > > > on guests.  When it does this, the host kernel runs ECREATE against
> > > > > the userspace mapping of the virtualized EPC.
> > > > >
> > > > > Provide wrappers around __ecreate() and __einit() to hide the
> > > > > ugliness of overloading the ENCLS return value to encode multiple
> > > > > error formats in a single int.  KVM will trap-and-execute ECREATE
> > > > > and EINIT as part of SGX virtualization, and on an exception, KVM
> > > > > needs the trapnr so that it can inject the correct fault into the guest.
> > > > >
> > > > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > > > > Signed-off-by: Kai Huang <kai.huang@intel.com>
> > > > > ---
> > > > > v4->v5:
> > > > >
> > > > >  - No code change.
> > > > >
> > > > > v3->v4:
> > > > >
> > > > >  - Added one new line before last return in sgx_virt_einit(), per Jarkko.
> > > > >
> > > > > v2->v3:
> > > > >
> > > > >  - Added kdoc for sgx_virt_ecreate() and sgx_virt_einit(), per Jarkko.
> > > > >  - Changed to use CONFIG_X86_SGX_KVM.
> > > > >
> > > > > ---
> > > > >  arch/x86/include/asm/sgx.h     | 16 ++++++
> > > > >  arch/x86/kernel/cpu/sgx/virt.c | 94
> > > > > ++++++++++++++++++++++++++++++++++
> > > > >  2 files changed, 110 insertions(+)
> > > > >  create mode 100644 arch/x86/include/asm/sgx.h
> > > > >
> > > > > diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
> > > > > new file mode 100644 index 000000000000..8a3ea3e1efbe
> > > > > --- /dev/null
> > > > > +++ b/arch/x86/include/asm/sgx.h
> > > > > @@ -0,0 +1,16 @@
> > > > > +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_SGX_H
> > > > > +#define _ASM_X86_SGX_H
> > > > > +
> > > > > +#include <linux/types.h>
> > > > > +
> > > > > +#ifdef CONFIG_X86_SGX_KVM
> > > > > +struct sgx_pageinfo;
> > > > > +
> > > > > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > > > > +		     int *trapnr);
> > > > > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > > > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr);
> > > >
> > > > s/virt/vepc/g
> > 
> > No. The two are related to enclave construction (from guest), not EPC. 
> > 
> > For instance, what does ECREATE mean for virtual EPC? ECREATE is meaningful for enclave.
> > 
> > > >
> > > > > +#endif
> > > > > +
> > > > > +#endif /* _ASM_X86_SGX_H */
> > > > > diff --git a/arch/x86/kernel/cpu/sgx/virt.c
> > > > > b/arch/x86/kernel/cpu/sgx/virt.c index 47542140f8c1..016bad7cff8d
> > > > > 100644
> > > > > --- a/arch/x86/kernel/cpu/sgx/virt.c
> > > > > +++ b/arch/x86/kernel/cpu/sgx/virt.c
> > > >
> > > > Rename as vepc.c.
> > 
> > No. This file contains more than virtual EPC implementation, but also other staff like sgx_virt_ecreate()/sgx_virt_einit(), which are used by KVM to run ECREATE/EINIT on behalf of guest.
> > 
> > > >
> > > > > @@ -257,3 +257,97 @@ int __init sgx_vepc_init(void)
> > > > >
> > > > >  	return misc_register(&sgx_vepc_dev);  }
> > > > > +
> > > > > +/**
> > > > > + * sgx_virt_ecreate() - Run ECREATE on behalf of guest
> > > > > + * @pageinfo:	Pointer to PAGEINFO structure
> > > > > + * @secs:	Userspace pointer to SECS page
> > > > > + * @trapnr:	trap number injected to guest in case of ECREATE error
> > > > > + *
> > > > > + * Run ECREATE on behalf of guest after KVM traps ECREATE for the
> > > > > +purpose
> > > > > + * of enforcing policies of guest's enclaves, and return the trap
> > > > > +number
> > > > > + * which should be injected to guest in case of any ECREATE error.
> > > > > + *
> > > > > + * Return:
> > > > > + * - 0: 	ECREATE was successful.
> > > > > + * - -EFAULT:	ECREATE returned error.
> > > > > + */
> > > > > +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs,
> > > > > +		     int *trapnr)
> > > > > +{
> > > > > +	int ret;
> > > > > +
> > > > > +	/*
> > > > > +	 * @secs is userspace address, and it's not guaranteed @secs points at
> > > > > +	 * an actual EPC page. It's also possible to generate a kernel mapping
> > > > > +	 * to physical EPC page by resolving PFN but using __uaccess_xx() is
> > > > > +	 * simpler.
> > > > > +	 */
> > > > > +	__uaccess_begin();
> > > > > +	ret = __ecreate(pageinfo, (void *)secs);
> > > > > +	__uaccess_end();
> > > > > +
> > > > > +	if (encls_faulted(ret)) {
> > > > > +		*trapnr = ENCLS_TRAPNR(ret);
> > > > > +		return -EFAULT;
> > > > > +	}
> > > > > +
> > > > > +	/* ECREATE doesn't return an error code, it faults or succeeds. */
> > > > > +	WARN_ON_ONCE(ret);
> > > >
> > > > Empty line.
> > > >
> > > > > +	return 0;
> > > > > +}
> > > > > +EXPORT_SYMBOL_GPL(sgx_virt_ecreate);
> > > > > +
> > > > > +static int __sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > > > +			    void __user *secs)
> > > > > +{
> > > > > +	int ret;
> > > > > +
> > > > > +	__uaccess_begin();
> > > > > +	ret =  __einit((void *)sigstruct, (void *)token, (void *)secs);
> > > > > +	__uaccess_end();
> > > >
> > > > Ditto.
> > > >
> > > > > +	return ret;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * sgx_virt_einit() - Run EINIT on behalf of guest
> > > > > + * @sigstruct:		Userspace pointer to SIGSTRUCT structure
> > > > > + * @token:		Userspace pointer to EINITTOKEN structure
> > > > > + * @secs:		Userspace pointer to SECS page
> > > > > + * @lepubkeyhash:	Pointer to guest's *virtual* SGX_LEPUBKEYHASH MSR
> > > > > + * 			values
> > > > > + * @trapnr:		trap number injected to guest in case of EINIT error
> > > > > + *
> > > > > + * Run EINIT on behalf of guest after KVM traps EINIT. If SGX_LC is
> > > > > +available
> > > > > + * in host, SGX driver may rewrite the hardware values at wish,
> > > > > +therefore KVM
> > > > > + * needs to update hardware values to guest's virtual MSR values in
> > > > > +order to
> > > > > + * ensure EINIT is executed with expected hardware values.
> > > > > + *
> > > > > + * Return:
> > > > > + * - 0: 	EINIT was successful.
> > > > > + * - -EFAULT:	EINIT returned error.
> > > > > + */
> > > > > +int sgx_virt_einit(void __user *sigstruct, void __user *token,
> > > > > +		   void __user *secs, u64 *lepubkeyhash, int *trapnr) {
> > > > > +	int ret;
> > > > > +
> > > > > +	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> > > > > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > > > > +	} else {
> > > > > +		preempt_disable();
> > > > > +
> > > > > +		sgx_update_lepubkeyhash(lepubkeyhash);
> > > > > +
> > > > > +		ret = __sgx_virt_einit(sigstruct, token, secs);
> > > > > +		preempt_enable();
> > > > > +	}
> > > > > +
> > > > > +	if (encls_faulted(ret)) {
> > > > > +		*trapnr = ENCLS_TRAPNR(ret);
> > > > > +		return -EFAULT;
> > > > > +	}
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +EXPORT_SYMBOL_GPL(sgx_virt_einit);
> > > 
> > > Remove exports.
> > 
> > Why? KVM needs to use them in later patches.
> 
> Because they are only required for LKM's.

I mean when LKM needs to call kernel functions.

Right, KVM can be compiled as LKM.

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support
  2021-02-16  5:03     ` Huang, Kai
@ 2021-02-16  8:36       ` Jarkko Sakkinen
  2021-02-16 10:24         ` Huang, Kai
  0 siblings, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16  8:36 UTC (permalink / raw)
  To: Huang, Kai
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa, jethro,
	b.thiel

On Tue, Feb 16, 2021 at 05:03:26AM +0000, Huang, Kai wrote:
> > 
> > On Sun, Feb 14, 2021 at 02:29:05AM +1300, Kai Huang wrote:
> > > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > >
> > > The kernel will currently disable all SGX support if the hardware does
> > > not support launch control.  Make it more permissive to allow SGX
> > > virtualization on systems without Launch Control support.  This will
> > > allow KVM to expose SGX to guests that have less-strict requirements
> > > on the availability of flexible launch control.
> > >
> > > Improve error message to distinguish between three cases.  There are
> > > two cases where SGX support is completely disabled:
> > > 1) SGX has been disabled completely by the BIOS
> > > 2) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
> > >    of LC unavailability.  SGX virtualization is unavailable (because of
> > >    Kconfig).
> > > One where it is partially available:
> > > 3) SGX LC is locked by the BIOS.  Bare-metal support is disabled because
> > >    of LC unavailability.  SGX virtualization is supported.
> > >
> > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > > Co-developed-by: Kai Huang <kai.huang@intel.com>
> > > Signed-off-by: Kai Huang <kai.huang@intel.com>
> > > ---
> > > v4->v5:
> > >
> > >  - No code change.
> > >
> > > v3->v4:
> > >
> > >  - Removed cpu_has(X86_FEATURE_SGX1) check in enable_sgx_any, since it
> > logically
> > >    is not related to KVM SGX series, per Sean.
> > >  - Changed declaration of variables to be in reverse-christmas tree style, per
> > >    Jarkko.
> > >
> > > v2->v3:
> > >
> > >  - Added to use 'enable_sgx_any', per Dave.
> > >  - Changed to call clear_cpu_cap() directly, rather than using clear_sgx_caps()
> > >    and clear_sgx_lc().
> > >  - Changed to use CONFIG_X86_SGX_KVM, instead of
> > CONFIG_X86_SGX_VIRTUALIZATION.
> > >
> > > v1->v2:
> > >
> > >  - Refined commit message per Dave's comments.
> > >  - Added check to only enable SGX virtualization when VMX is supported, per
> > >    Dave's comment.
> > >  - Refined error msg print to explicitly call out SGX virtualization will be
> > >    supported when LC is locked by BIOS, per Dave's comment.
> > >
> > > ---
> > >  arch/x86/kernel/cpu/feat_ctl.c | 57
> > > ++++++++++++++++++++++++++--------
> > >  1 file changed, 44 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/arch/x86/kernel/cpu/feat_ctl.c
> > > b/arch/x86/kernel/cpu/feat_ctl.c index 27533a6e04fa..96c370284913
> > > 100644
> > > --- a/arch/x86/kernel/cpu/feat_ctl.c
> > > +++ b/arch/x86/kernel/cpu/feat_ctl.c
> > > @@ -105,7 +105,8 @@ early_param("nosgx", nosgx);  void
> > > init_ia32_feat_ctl(struct cpuinfo_x86 *c)  {
> > >  	bool tboot = tboot_enabled();
> > > -	bool enable_sgx;
> > > +	bool enable_sgx_any, enable_sgx_kvm, enable_sgx_driver;
> > > +	bool enable_vmx;
> > >  	u64 msr;
> > >
> > >  	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) { @@ -114,13 +115,21
> > @@
> > > void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
> > >  		return;
> > >  	}
> > >
> > > +	enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
> > > +		     IS_ENABLED(CONFIG_KVM_INTEL);
> > 
> > It's less than 100 characters:
> 
> Just carious, shouldn't be 80 characters to wrap a new line, instead of 100?

Try with checkpatch.pl.

> 
> > 
> >         enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
> > IS_ENABLED(CONFIG_KVM_INTEL);
> > 
> > This is better:
> > 
> >         enable_vmx = IS_ENABLED(CONFIG_KVM_INTEL) && cpu_has(c,
> > X86_FEATURE_VMX);
> > 
> > You only want to evaluate cpu_has() if COHNFIG_KVM_INTEL is enabled.
> 
> If you look at the original code, cpu_has() comes first. It's just one-time booting time code, and I don't think it matters.
> 
> Btw, are you also suggesting IS_ENABLED(CONFIG_X86_SGX) should come before cpu_has() for SGX in below code? 
> 
> That being said, cpu_has() comes first for both VMX and SGX in the original code. I don't know why I need to change the sequence in this patch.
> 
> > 
> > > +
> > >  	/*
> > > -	 * Enable SGX if and only if the kernel supports SGX and Launch Control
> > > -	 * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
> > > +	 * Separate out SGX driver enabling from KVM.  This allows KVM
> > > +	 * guests to use SGX even if the kernel SGX driver refuses to
> > > +	 * use it.  This happens if flexible Faunch Control is not
> > > +	 * available.
> > >  	 */
> > > -	enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
> > > -		     cpu_has(c, X86_FEATURE_SGX_LC) &&
> > > -		     IS_ENABLED(CONFIG_X86_SGX);
> > > +	enable_sgx_any = cpu_has(c, X86_FEATURE_SGX) &&
> > > +			 IS_ENABLED(CONFIG_X86_SGX);
> > > +	enable_sgx_driver = enable_sgx_any &&
> > > +			    cpu_has(c, X86_FEATURE_SGX_LC);
> > > +	enable_sgx_kvm = enable_sgx_any && enable_vmx &&
> > > +			  IS_ENABLED(CONFIG_X86_SGX_KVM);
> > >
> > >  	if (msr & FEAT_CTL_LOCKED)
> > >  		goto update_caps;
> > > @@ -136,15 +145,18 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
> > >  	 * i.e. KVM is enabled, to avoid unnecessarily adding an attack vector
> > >  	 * for the kernel, e.g. using VMX to hide malicious code.
> > >  	 */
> > > -	if (cpu_has(c, X86_FEATURE_VMX) &&
> > IS_ENABLED(CONFIG_KVM_INTEL)) {
> > > +	if (enable_vmx) {
> > >  		msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
> > >
> > >  		if (tboot)
> > >  			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
> > >  	}
> > >
> > > -	if (enable_sgx)
> > > -		msr |= FEAT_CTL_SGX_ENABLED |
> > FEAT_CTL_SGX_LC_ENABLED;
> > > +	if (enable_sgx_kvm || enable_sgx_driver) {
> > > +		msr |= FEAT_CTL_SGX_ENABLED;
> > > +		if (enable_sgx_driver)
> > > +			msr |= FEAT_CTL_SGX_LC_ENABLED;
> > > +	}
> > >
> > >  	wrmsrl(MSR_IA32_FEAT_CTL, msr);
> > >
> > > @@ -167,10 +179,29 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
> > >  	}
> > >
> > >  update_sgx:
> > > -	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
> > > -	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
> > > -		if (enable_sgx)
> > > -			pr_err_once("SGX disabled by BIOS\n");
> > > +	if (!(msr & FEAT_CTL_SGX_ENABLED)) {
> > > +		if (enable_sgx_kvm || enable_sgx_driver)
> > > +			pr_err_once("SGX disabled by BIOS.\n");
> > >  		clear_cpu_cap(c, X86_FEATURE_SGX);
> > 
> > Empty line before return statement.
> 
> It's just two statements inside the if() {} statement. Putting a new line here is too sparse IMHO.
> 
> I'd like to hear more.

This was a common review comment in original SGX series, so I'm
sticking to the pattern.

> 
> Dave, do you have any comment?
> 
> > 
> > > +		return;
> > > +	}
> > > +
> > > +	/*
> > > +	 * VMX feature bit may be cleared due to being disabled in BIOS,
> > > +	 * in which case SGX virtualization cannot be supported either.
> > > +	 */
> > > +	if (!cpu_has(c, X86_FEATURE_VMX) && enable_sgx_kvm) {
> > > +		pr_err_once("SGX virtualization disabled due to lack of VMX.\n");
> > > +		enable_sgx_kvm = 0;
> > > +	}
> > > +
> > > +	if (!(msr & FEAT_CTL_SGX_LC_ENABLED) && enable_sgx_driver) {
> > > +		if (!enable_sgx_kvm) {
> > > +			pr_err_once("SGX Launch Control is locked. Disable
> > SGX.\n");
> > > +			clear_cpu_cap(c, X86_FEATURE_SGX);
> > > +		} else {
> > > +			pr_err_once("SGX Launch Control is locked. Support
> > SGX virtualization only.\n");
> > > +			clear_cpu_cap(c, X86_FEATURE_SGX_LC);
> > > +		}
> > >  	}
> > >  }
> > > --
> > > 2.29.2
> > >
> > >
> > 
> > /Jarkko
> 

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM
  2021-02-16  8:35           ` Jarkko Sakkinen
@ 2021-02-16  9:33             ` Huang, Kai
  0 siblings, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16  9:33 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa

> > > > > > +EXPORT_SYMBOL_GPL(sgx_virt_einit);
> > > >
> > > > Remove exports.
> > >
> > > Why? KVM needs to use them in later patches.
> >
> > Because they are only required for LKM's.
> 
> I mean when LKM needs to call kernel functions.
> 
> Right, KVM can be compiled as LKM.

Just to confirm, you are OK with exposing them as symbol, since KVM (as a module) needs to use them, right?

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support
  2021-02-16  8:36       ` Jarkko Sakkinen
@ 2021-02-16 10:24         ` Huang, Kai
  0 siblings, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 10:24 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa, jethro,
	b.thiel

> > > >
> > > > +	enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
> > > > +		     IS_ENABLED(CONFIG_KVM_INTEL);
> > >
> > > It's less than 100 characters:
> >
> > Just carious, shouldn't be 80 characters to wrap a new line, instead of 100?
> 
> Try with checkpatch.pl.

Checkpatch.pl has default value 100, but it can be overwritten. I found below document explicitly said 80 should be the length:

https://www.kernel.org/doc/html/v5.11-rc7/process/coding-style.html

2) Breaking long lines and strings

Coding style is all about readability and maintainability using commonly available tools.

The preferred limit on the length of a single line is 80 columns.

Statements longer than 80 columns should be broken into sensible chunks, unless exceeding 80 columns significantly increases readability and does not hide information.

[...]

> > > >  update_sgx:
> > > > -	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
> > > > -	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
> > > > -		if (enable_sgx)
> > > > -			pr_err_once("SGX disabled by BIOS\n");
> > > > +	if (!(msr & FEAT_CTL_SGX_ENABLED)) {
> > > > +		if (enable_sgx_kvm || enable_sgx_driver)
> > > > +			pr_err_once("SGX disabled by BIOS.\n");
> > > >  		clear_cpu_cap(c, X86_FEATURE_SGX);
> > >
> > > Empty line before return statement.
> >
> > It's just two statements inside the if() {} statement. Putting a new line here is
> too sparse IMHO.
> >
> > I'd like to hear more.
> 
> This was a common review comment in original SGX series, so I'm sticking to the
> pattern.

Well if you insist, I can do that. 

But I am not that convinced. In fact, I also believe that in most cases, having empty line before 'return' is good practice, for instance, when 'return' is the very last statement in the function.

I am also glad to do it if it is a x86 patch convention that we even need to put a new empty line when there are only very few statements inside if() {}. However it seems it is not the case.

For example, I just did a search in SGX driver code, and below examples all DONOT have empty line before return (and I don't think I captured them all):

sgx/driver.c:

static int sgx_release(struct inode *inode, struct file *file)
{
        ......
        kref_put(&encl->refcount, sgx_encl_release);
        return 0;
}

sgx/ioctl.c: 

static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
{
        ......
                va_page->epc_page = sgx_alloc_va_page();
                if (IS_ERR(va_page->epc_page)) {
                        err = ERR_CAST(va_page->epc_page);
                        kfree(va_page);
                        return err;
                }

                WARN_ON_ONCE(encl->page_cnt % SGX_VA_SLOT_COUNT);
        }
        encl->page_cnt++;
        return va_page;
}

static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
{
        ......
        kfree(secs);
        return ret;
}

static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
                             unsigned long offset, struct sgx_secinfo *secinfo,
                             unsigned long flags)
{
        ......
        epc_page = sgx_alloc_epc_page(encl_page, true);
        if (IS_ERR(epc_page)) {
                kfree(encl_page);
                return PTR_ERR(epc_page);
        }
        ......
        sgx_mark_page_reclaimable(encl_page->epc_page);
        mutex_unlock(&encl->lock);
        mmap_read_unlock(current->mm);
        return ret;

        ......
}

And in cpu/feat_ctl.c:

void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
{
        ......
        if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
                clear_cpu_cap(c, X86_FEATURE_VMX);
                clear_sgx_caps();
                return;
        }
        ......
}

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16  2:17   ` Jarkko Sakkinen
@ 2021-02-16 10:30     ` Huang, Kai
  2021-02-16 10:32       ` Borislav Petkov
  0 siblings, 1 reply; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 10:30 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, bp, tglx, mingo, hpa

> 
> On Sun, Feb 14, 2021 at 02:29:10AM +1300, Kai Huang wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> >
> > Expose SGX architectural structures, as KVM will use many of the
> > architectural constants and structs to virtualize SGX.
> >
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > Acked-by: Dave Hansen <dave.hansen@intel.com>
> > Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
> > Signed-off-by: Kai Huang <kai.huang@intel.com>
> > ---
> >  arch/x86/{kernel/cpu/sgx/arch.h => include/asm/sgx_arch.h} | 0
> >  arch/x86/kernel/cpu/sgx/encl.c                             | 2 +-
> >  arch/x86/kernel/cpu/sgx/sgx.h                              | 2 +-
> >  tools/testing/selftests/sgx/defines.h                      | 2 +-
> >  4 files changed, 3 insertions(+), 3 deletions(-)  rename
> > arch/x86/{kernel/cpu/sgx/arch.h => include/asm/sgx_arch.h} (100%)
> >
> > diff --git a/arch/x86/kernel/cpu/sgx/arch.h
> > b/arch/x86/include/asm/sgx_arch.h similarity index 100% rename from
> > arch/x86/kernel/cpu/sgx/arch.h rename to
> > arch/x86/include/asm/sgx_arch.h
> 
> Why not just sgx.h? The postfix is useless.

Because those contents are *architectural*. They are defined in SDM.

And patch 13 (x86/sgx: Add helpers to expose ECREATE and EINIT to KVM) will introduce arch/x86/include/asm/sgx.h, where non-architectural functions will be declared.


^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 10:30     ` Huang, Kai
@ 2021-02-16 10:32       ` Borislav Petkov
  2021-02-16 11:15         ` Huang, Kai
  2021-02-16 16:28         ` Jarkko Sakkinen
  0 siblings, 2 replies; 64+ messages in thread
From: Borislav Petkov @ 2021-02-16 10:32 UTC (permalink / raw)
  To: Huang, Kai
  Cc: Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 10:30:03AM +0000, Huang, Kai wrote:
> Because those contents are *architectural*. They are defined in SDM.
>
> And patch 13 (x86/sgx: Add helpers to expose ECREATE and EINIT to KVM)
> will introduce arch/x86/include/asm/sgx.h, where non-architectural
> functions will be declared.

Who cares about the SDM?

-- 
Regards/Gruss,
    Boris.

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

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 10:32       ` Borislav Petkov
@ 2021-02-16 11:15         ` Huang, Kai
  2021-02-16 11:48           ` Borislav Petkov
  2021-02-16 16:28         ` Jarkko Sakkinen
  1 sibling, 1 reply; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 11:15 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

> 
> On Tue, Feb 16, 2021 at 10:30:03AM +0000, Huang, Kai wrote:
> > Because those contents are *architectural*. They are defined in SDM.
> >
> > And patch 13 (x86/sgx: Add helpers to expose ECREATE and EINIT to KVM)
> > will introduce arch/x86/include/asm/sgx.h, where non-architectural
> > functions will be declared.
> 
> Who cares about the SDM?

Sorry I am not sure I understand your question. Could you elaborate?

IMHO it's better to put architectural staff (such as data structures defined in SDM and used by hardware) into one header, and other non-architectural staff into another header, so that the user can include the one that is actually required, but doesn't have to include one big header which includes all SGX related data structures and functions.


^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 11:15         ` Huang, Kai
@ 2021-02-16 11:48           ` Borislav Petkov
  2021-02-16 11:56             ` Huang, Kai
  2021-02-16 15:18             ` Dave Hansen
  0 siblings, 2 replies; 64+ messages in thread
From: Borislav Petkov @ 2021-02-16 11:48 UTC (permalink / raw)
  To: Huang, Kai
  Cc: Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 11:15:35AM +0000, Huang, Kai wrote:
> Sorry I am not sure I understand your question. Could you elaborate?
>
> IMHO it's better to put architectural staff (such as data structures
> defined in SDM and used by hardware) into one header, and other
> non-architectural staff into another header, so that the user can
> include the one that is actually required, but doesn't have to include
> one big header which includes all SGX related data structures and
> functions.

And including one big - (not sure about "big" - we have a lot bigger) -
header is an actual problem because?

What I'm trying to point you at is, to not give some artificial reasons
why the headers should be separate - artificial as the SDM says it
is architectural and so on - but give a reason from software design
perspective why the separation is needed: better build times, less
symbols exposed to modules, blabla and so on.

If you don't have such reasons, then it all is just unnecessary and
not needed churn. And in that case, keeping it simple is the proper
approach.

Those headers can always be split later, when really needed.

HTH.

-- 
Regards/Gruss,
    Boris.

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

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 11:48           ` Borislav Petkov
@ 2021-02-16 11:56             ` Huang, Kai
  2021-02-16 15:18             ` Dave Hansen
  1 sibling, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 11:56 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

> 
> On Tue, Feb 16, 2021 at 11:15:35AM +0000, Huang, Kai wrote:
> > Sorry I am not sure I understand your question. Could you elaborate?
> >
> > IMHO it's better to put architectural staff (such as data structures
> > defined in SDM and used by hardware) into one header, and other
> > non-architectural staff into another header, so that the user can
> > include the one that is actually required, but doesn't have to include
> > one big header which includes all SGX related data structures and
> > functions.
> 
> And including one big - (not sure about "big" - we have a lot bigger) - header is
> an actual problem because?
> 
> What I'm trying to point you at is, to not give some artificial reasons why the
> headers should be separate - artificial as the SDM says it is architectural and so
> on - but give a reason from software design perspective why the separation is
> needed: better build times, less symbols exposed to modules, blabla and so on.
> 
> If you don't have such reasons, then it all is just unnecessary and not needed
> churn. And in that case, keeping it simple is the proper approach.
> 
> Those headers can always be split later, when really needed.
> 
> HTH.

Thanks for feedback! I'll take a deeper look at the code and give feedback (too late for me today).

> 
> --
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 11:48           ` Borislav Petkov
  2021-02-16 11:56             ` Huang, Kai
@ 2021-02-16 15:18             ` Dave Hansen
  2021-02-16 18:47               ` Borislav Petkov
  2021-02-17 22:20               ` Jarkko Sakkinen
  1 sibling, 2 replies; 64+ messages in thread
From: Dave Hansen @ 2021-02-16 15:18 UTC (permalink / raw)
  To: Borislav Petkov, Huang, Kai
  Cc: Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On 2/16/21 3:48 AM, Borislav Petkov wrote:
> What I'm trying to point you at is, to not give some artificial reasons
> why the headers should be separate - artificial as the SDM says it
> is architectural and so on - but give a reason from software design
> perspective why the separation is needed: better build times, less
> symbols exposed to modules, blabla and so on.

I think I actually suggested this sgx_arch.h split for SGX in the first
place.

I was reading the patches and I had a really hard time separating the
hardware and software structures.  There would be a 'struct sgx_foo {}'
and some chit chat about what it did...  and I still had no idea if it
was an architectural structure or not.

This way, it's 100% crystal clear what Linux is defining and what the
hardware defines from the diff context.

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 10:32       ` Borislav Petkov
  2021-02-16 11:15         ` Huang, Kai
@ 2021-02-16 16:28         ` Jarkko Sakkinen
  1 sibling, 0 replies; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-16 16:28 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Huang, Kai, linux-sgx, kvm, x86, seanjc, luto, Hansen, Dave,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 11:32:18AM +0100, Borislav Petkov wrote:
> On Tue, Feb 16, 2021 at 10:30:03AM +0000, Huang, Kai wrote:
> > Because those contents are *architectural*. They are defined in SDM.
> >
> > And patch 13 (x86/sgx: Add helpers to expose ECREATE and EINIT to KVM)
> > will introduce arch/x86/include/asm/sgx.h, where non-architectural
> > functions will be declared.
> 
> Who cares about the SDM?

I don't.

> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
  2021-02-13 13:28 ` [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
@ 2021-02-16 17:04   ` Dave Hansen
  2021-02-16 20:42     ` Huang, Kai
  0 siblings, 1 reply; 64+ messages in thread
From: Dave Hansen @ 2021-02-16 17:04 UTC (permalink / raw)
  To: Kai Huang, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, rick.p.edgecombe, haitao.huang, pbonzini,
	bp, tglx, mingo, hpa

> +/*
> + * Place the page in uninitialized state.  Only usable by callers that
> + * know the page is in a clean state in which EREMOVE will succeed.
> + */
> +static void sgx_reset_epc_page(struct sgx_epc_page *epc_page)
> +{
> +	int ret;
> +
> +	WARN_ON_ONCE(epc_page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED);
> +
> +	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
> +	if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
> +		return;
> +}

Shouldn't this just be:

...
	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
	WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret);
}

Sometimes, you actually need to look at the code that you cut and paste. ;)

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
  2021-02-13 13:28 ` [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
  2021-02-16  2:12   ` Jarkko Sakkinen
@ 2021-02-16 18:38   ` Dave Hansen
  2021-02-16 19:25     ` Sean Christopherson
                       ` (2 more replies)
  1 sibling, 3 replies; 64+ messages in thread
From: Dave Hansen @ 2021-02-16 18:38 UTC (permalink / raw)
  To: Kai Huang, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, rick.p.edgecombe, haitao.huang, pbonzini,
	bp, tglx, mingo, hpa

On 2/13/21 5:28 AM, Kai Huang wrote:
> SGX driver uses misc device /dev/sgx_enclave to support userspace to
> create enclave.  Each file descriptor from opening /dev/sgx_enclave
> represents an enclave.  

Is this strictly true?  Does dup(2) create a new enclave?

> Unlike SGX driver, KVM doesn't control how guest
> uses EPC, therefore EPC allocated to KVM guest is not associated to an
> encalve, and /dev/sgx_enclave is not suitable for allocating EPC for KVM

  ^ enclave

> guest.


> Having separate device nodes for SGX driver and KVM virtual EPC also
> allows separate permission control for running host SGX enclaves and
> KVM SGX guests.

Specifically, 'sgx_vepc' is a less restrictive interface.  It would make
a lot of sense to more tightly control access compared to 'sgx_enclave'.

> More specifically, to allocate a virtual EPC instance with particular
> size, the userspace hypervisor opens /dev/sgx_vepc, and uses mmap()
> with the intended size to get an address range of virtual EPC.  Then
> it may use the address range to create one KVM memory slot as virtual
> EPC for guest.

This paragraph doesn't really explain anything important to me.  Both
devices require using mmap().

With typos in the changelog fixed, I'm OK with the rest:

Acked-by: Dave Hansen <dave.hansen@intel.com>

BTW...  A lot of this patch is just a skeletal device driver.  I'm a
horrible device driver writer, so take this ack as "everything seems
explained well" versus "I promise this will pass muster with the guys
who review device drivers all day long."

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support
  2021-02-13 13:29 ` [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
  2021-02-16  2:15   ` Jarkko Sakkinen
@ 2021-02-16 18:40   ` Dave Hansen
  2021-02-16 20:42     ` Huang, Kai
  1 sibling, 1 reply; 64+ messages in thread
From: Dave Hansen @ 2021-02-16 18:40 UTC (permalink / raw)
  To: Kai Huang, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, rick.p.edgecombe, haitao.huang, pbonzini,
	bp, tglx, mingo, hpa, jethro, b.thiel

On 2/13/21 5:29 AM, Kai Huang wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> The kernel will currently disable all SGX support if the hardware does
> not support launch control.  Make it more permissive to allow SGX
> virtualization on systems without Launch Control support.  This will
> allow KVM to expose SGX to guests that have less-strict requirements on
> the availability of flexible launch control.
...

Acked-by: Dave Hansen <dave.hansen@intel.com>

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled
  2021-02-13 13:29 ` [RFC PATCH v5 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
@ 2021-02-16 18:41   ` Dave Hansen
  0 siblings, 0 replies; 64+ messages in thread
From: Dave Hansen @ 2021-02-16 18:41 UTC (permalink / raw)
  To: Kai Huang, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, rick.p.edgecombe, haitao.huang, pbonzini,
	bp, tglx, mingo, hpa

On 2/13/21 5:29 AM, Kai Huang wrote:
> Modify sgx_init() to always try to initialize the virtual EPC driver,
> even if the SGX driver is disabled.  The SGX driver might be disabled
> if SGX Launch Control is in locked mode, or not supported in the
> hardware at all.  This allows (non-Linux) guests that support non-LC
> configurations to use SGX.
> 
> Signed-off-by: Kai Huang <kai.huang@intel.com>
...
> +	ret = !!sgx_drv_init() & !!sgx_vepc_init();

That little nugget is starting to grow on me.

Acked-by: Dave Hansen <dave.hansen@intel.com>

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 15:18             ` Dave Hansen
@ 2021-02-16 18:47               ` Borislav Petkov
  2021-02-16 18:53                 ` Dave Hansen
  2021-02-17 22:20               ` Jarkko Sakkinen
  1 sibling, 1 reply; 64+ messages in thread
From: Borislav Petkov @ 2021-02-16 18:47 UTC (permalink / raw)
  To: Dave Hansen
  Cc: Huang, Kai, Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 07:18:27AM -0800, Dave Hansen wrote:
> On 2/16/21 3:48 AM, Borislav Petkov wrote:
> > What I'm trying to point you at is, to not give some artificial reasons
> > why the headers should be separate - artificial as the SDM says it
> > is architectural and so on - but give a reason from software design
> > perspective why the separation is needed: better build times, less
> > symbols exposed to modules, blabla and so on.
> 
> I think I actually suggested this sgx_arch.h split for SGX in the first
> place.
> 
> I was reading the patches and I had a really hard time separating the
> hardware and software structures.  There would be a 'struct sgx_foo {}'
> and some chit chat about what it did...  and I still had no idea if it
> was an architectural structure or not.
> 
> This way, it's 100% crystal clear what Linux is defining and what the
> hardware defines from the diff context.

Yap, that's a valid reason in my book. And arch.h has at the top:

 * Contains data structures defined by the SGX architecture.  Data structures
 * defined by the Linux software stack should not be placed here.

and by now we already have:

$ git ls-files | grep \/sgx.h
arch/x86/include/uapi/asm/sgx.h
arch/x86/kernel/cpu/sgx/sgx.h

two sgx.h headers.

So how about we have a single

  arch/x86/include/asm/sgx.h

header which contains the architectural definitions at the *top* and at
their end, there'll be a:

/* Do not put any hardware-defined SGX structure representations below this line! */

and after that line begin the other, software definitions?

Then that arch/x86/kernel/cpu/sgx/sgx.h can be renamed to private.h
because it is included only there so you'll have:

arch/x86/include/uapi/asm/sgx.h	- user API crap
arch/x86/include/asm/sgx.h - shared with other kernel facilities
arch/x86/kernel/cpu/sgx/internal.h - SGX-internal definitions

How does that look?

And we do have similar header structure with other features...

Thx.

-- 
Regards/Gruss,
    Boris.

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

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 00/26] KVM SGX virtualization support
  2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
                   ` (25 preceding siblings ...)
  2021-02-13 13:30 ` [RFC PATCH v5 26/26] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
@ 2021-02-16 18:48 ` Dave Hansen
  2021-02-16 19:15   ` Sean Christopherson
  2021-02-16 20:58   ` Huang, Kai
  26 siblings, 2 replies; 64+ messages in thread
From: Dave Hansen @ 2021-02-16 18:48 UTC (permalink / raw)
  To: Kai Huang, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, rick.p.edgecombe, haitao.huang, pbonzini,
	bp, tglx, mingo, hpa, jethro, b.thiel, jmattson, joro, vkuznets,
	wanpengli, corbet

On 2/13/21 5:28 AM, Kai Huang wrote:
>  arch/x86/kvm/vmx/sgx.c                        | 466 ++++++++++++++++++
>  arch/x86/kvm/vmx/sgx.h                        |  34 ++

Changes to these files won't hit the SGX MAINTAINERS entry if you run
get_maintainer.pl.  That means Jarkko (and me, and the SGX mailing list)
probably won't get cc'd on changes here.

Is that a bug or a feature? :)

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 18:47               ` Borislav Petkov
@ 2021-02-16 18:53                 ` Dave Hansen
  2021-02-16 19:18                   ` Borislav Petkov
  0 siblings, 1 reply; 64+ messages in thread
From: Dave Hansen @ 2021-02-16 18:53 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Huang, Kai, Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On 2/16/21 10:47 AM, Borislav Petkov wrote:
> header which contains the architectural definitions at the *top* and at
> their end, there'll be a:
> 
> /* Do not put any hardware-defined SGX structure representations below this line! */
> 
> and after that line begin the other, software definitions?

Fine with me.  It's just as easy to miss this comment as is would be to
miss the comment at the top of sgx_arch.h. :)

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 00/26] KVM SGX virtualization support
  2021-02-16 18:48 ` [RFC PATCH v5 00/26] KVM SGX virtualization support Dave Hansen
@ 2021-02-16 19:15   ` Sean Christopherson
  2021-02-16 20:58   ` Huang, Kai
  1 sibling, 0 replies; 64+ messages in thread
From: Sean Christopherson @ 2021-02-16 19:15 UTC (permalink / raw)
  To: Dave Hansen
  Cc: Kai Huang, linux-sgx, kvm, x86, jarkko, luto, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa, jethro, b.thiel,
	jmattson, joro, vkuznets, wanpengli, corbet

On Tue, Feb 16, 2021, Dave Hansen wrote:
> On 2/13/21 5:28 AM, Kai Huang wrote:
> >  arch/x86/kvm/vmx/sgx.c                        | 466 ++++++++++++++++++
> >  arch/x86/kvm/vmx/sgx.h                        |  34 ++
> 
> Changes to these files won't hit the SGX MAINTAINERS entry if you run
> get_maintainer.pl.  That means Jarkko (and me, and the SGX mailing list)
> probably won't get cc'd on changes here.
> 
> Is that a bug or a feature? :)

Feature.  The stuff in those files is pure KVM, there's nothing interesting from
an SGX subsystem persective.  That's another reason to have sgx/virt.c, the
stuff that does impact SGX can all go in there.

The KVM SGX code is in split out because virtualizing ENCLS leafs takes a
painful amount of code, and because SGX already has a separate Kconfig.
Association with the SGX subsystem was a non-factor in that choice.

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 18:53                 ` Dave Hansen
@ 2021-02-16 19:18                   ` Borislav Petkov
  0 siblings, 0 replies; 64+ messages in thread
From: Borislav Petkov @ 2021-02-16 19:18 UTC (permalink / raw)
  To: Dave Hansen
  Cc: Huang, Kai, Jarkko Sakkinen, linux-sgx, kvm, x86, seanjc, luto,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 10:53:03AM -0800, Dave Hansen wrote:
> Fine with me. It's just as easy to miss this comment as is would be to
> miss the comment at the top of sgx_arch.h. :)

Sure but SGX should try to keep it together and not plant headers
everywhere. :-)

-- 
Regards/Gruss,
    Boris.

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

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
  2021-02-16 18:38   ` Dave Hansen
@ 2021-02-16 19:25     ` Sean Christopherson
  2021-02-16 21:33       ` Huang, Kai
  2021-02-16 21:34     ` Huang, Kai
  2021-02-17 22:22     ` Jarkko Sakkinen
  2 siblings, 1 reply; 64+ messages in thread
From: Sean Christopherson @ 2021-02-16 19:25 UTC (permalink / raw)
  To: Dave Hansen
  Cc: Kai Huang, linux-sgx, kvm, x86, jarkko, luto, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa

On Tue, Feb 16, 2021, Dave Hansen wrote:
> > Having separate device nodes for SGX driver and KVM virtual EPC also
> > allows separate permission control for running host SGX enclaves and
> > KVM SGX guests.
> 
> Specifically, 'sgx_vepc' is a less restrictive interface.  It would make
> a lot of sense to more tightly control access compared to 'sgx_enclave'.

The opposite is just as likely, i.e. exposing SGX to a guest but not allowing
enclaves in the host.  Not from a "sgx_enclave is easier to abuse" perspective,
but from a "enclaves should never be runnable in the host in our environment".

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
  2021-02-16 17:04   ` Dave Hansen
@ 2021-02-16 20:42     ` Huang, Kai
  0 siblings, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 20:42 UTC (permalink / raw)
  To: Hansen, Dave, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, Edgecombe, Rick P, Huang, Haitao, pbonzini,
	bp, tglx, mingo, hpa

> > +/*
> > + * Place the page in uninitialized state.  Only usable by callers
> > +that
> > + * know the page is in a clean state in which EREMOVE will succeed.
> > + */
> > +static void sgx_reset_epc_page(struct sgx_epc_page *epc_page) {
> > +	int ret;
> > +
> > +	WARN_ON_ONCE(epc_page->flags &
> SGX_EPC_PAGE_RECLAIMER_TRACKED);
> > +
> > +	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
> > +	if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
> > +		return;
> > +}
> 
> Shouldn't this just be:
> 
> ...
> 	ret = __eremove(sgx_get_epc_virt_addr(epc_page));
> 	WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret); }
> 
> Sometimes, you actually need to look at the code that you cut and paste. ;)

Correct! Thanks for catching. I'll remove this useless 'return' in next version.


^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support
  2021-02-16 18:40   ` Dave Hansen
@ 2021-02-16 20:42     ` Huang, Kai
  0 siblings, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 20:42 UTC (permalink / raw)
  To: Hansen, Dave, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, Edgecombe, Rick P, Huang, Haitao, pbonzini,
	bp, tglx, mingo, hpa, jethro, b.thiel

> 
> On 2/13/21 5:29 AM, Kai Huang wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> >
> > The kernel will currently disable all SGX support if the hardware does
> > not support launch control.  Make it more permissive to allow SGX
> > virtualization on systems without Launch Control support.  This will
> > allow KVM to expose SGX to guests that have less-strict requirements
> > on the availability of flexible launch control.
> ...
> 
> Acked-by: Dave Hansen <dave.hansen@intel.com>

Thanks!

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 00/26] KVM SGX virtualization support
  2021-02-16 18:48 ` [RFC PATCH v5 00/26] KVM SGX virtualization support Dave Hansen
  2021-02-16 19:15   ` Sean Christopherson
@ 2021-02-16 20:58   ` Huang, Kai
  1 sibling, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 20:58 UTC (permalink / raw)
  To: Hansen, Dave, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, Edgecombe, Rick P, Huang, Haitao, pbonzini,
	bp, tglx, mingo, hpa, jethro, b.thiel, jmattson, joro, vkuznets,
	wanpengli, corbet

> On 2/13/21 5:28 AM, Kai Huang wrote:
> >  arch/x86/kvm/vmx/sgx.c                        | 466 ++++++++++++++++++
> >  arch/x86/kvm/vmx/sgx.h                        |  34 ++
> 
> Changes to these files won't hit the SGX MAINTAINERS entry if you run
> get_maintainer.pl.  That means Jarkko (and me, and the SGX mailing list)
> probably won't get cc'd on changes here.
> 
> Is that a bug or a feature? :)

The two files only contains staff to virtualize SGX, for instance, initializing virtual SGX_LEPUBKEYHASH MSRs, how to trap and run ENCLS[ECREATE/EINIT], etc.

Sean, Paolo,

What's your comments?

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
  2021-02-16 19:25     ` Sean Christopherson
@ 2021-02-16 21:33       ` Huang, Kai
  0 siblings, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 21:33 UTC (permalink / raw)
  To: Sean Christopherson, Hansen, Dave
  Cc: linux-sgx, kvm, x86, jarkko, luto, Edgecombe, Rick P, Huang,
	Haitao, pbonzini, bp, tglx, mingo, hpa

> 
> On Tue, Feb 16, 2021, Dave Hansen wrote:
> > > Having separate device nodes for SGX driver and KVM virtual EPC also
> > > allows separate permission control for running host SGX enclaves and
> > > KVM SGX guests.
> >
> > Specifically, 'sgx_vepc' is a less restrictive interface.  It would
> > make a lot of sense to more tightly control access compared to 'sgx_enclave'.
> 
> The opposite is just as likely, i.e. exposing SGX to a guest but not allowing
> enclaves in the host.  Not from a "sgx_enclave is easier to abuse" perspective,
> but from a "enclaves should never be runnable in the host in our environment".

Agreed. CSP may want to provide SGX service in VMs, but not to run SGX app in host. 

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
  2021-02-16 18:38   ` Dave Hansen
  2021-02-16 19:25     ` Sean Christopherson
@ 2021-02-16 21:34     ` Huang, Kai
  2021-02-17 22:22     ` Jarkko Sakkinen
  2 siblings, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-16 21:34 UTC (permalink / raw)
  To: Hansen, Dave, linux-sgx, kvm, x86
  Cc: seanjc, jarkko, luto, Edgecombe, Rick P, Huang, Haitao, pbonzini,
	bp, tglx, mingo, hpa

> On 2/13/21 5:28 AM, Kai Huang wrote:
> > SGX driver uses misc device /dev/sgx_enclave to support userspace to
> > create enclave.  Each file descriptor from opening /dev/sgx_enclave
> > represents an enclave.
> 
> Is this strictly true?  Does dup(2) create a new enclave?

I don't think dup() will create a new enclave. Enclave data structure is kept in filep->private_data, and only 'open' will create a new one.

> 
> > Unlike SGX driver, KVM doesn't control how guest uses EPC, therefore
> > EPC allocated to KVM guest is not associated to an encalve, and
> > /dev/sgx_enclave is not suitable for allocating EPC for KVM
> 
>   ^ enclave

Ops. Thanks.

> 
> > guest.
> 
> 
> > Having separate device nodes for SGX driver and KVM virtual EPC also
> > allows separate permission control for running host SGX enclaves and
> > KVM SGX guests.
> 
> Specifically, 'sgx_vepc' is a less restrictive interface.  It would make a lot of
> sense to more tightly control access compared to 'sgx_enclave'.

Sean mentioned the opposite is also likely, and I agree. Please see my reply to Sean's.

> 
> > More specifically, to allocate a virtual EPC instance with particular
> > size, the userspace hypervisor opens /dev/sgx_vepc, and uses mmap()
> > with the intended size to get an address range of virtual EPC.  Then
> > it may use the address range to create one KVM memory slot as virtual
> > EPC for guest.
> 
> This paragraph doesn't really explain anything important to me.  Both devices
> require using mmap().

This paragraph was requested by Jarkko to explain how to use this /dev/sgx_vepc. 

Perhaps I can remove it?

Or perhaps I can refine to "To use /dev/sgx_vepc to allocate a virtual EPC instance with particular size, the userspace hypervisor..."?

> 
> With typos in the changelog fixed, I'm OK with the rest:
> 
> Acked-by: Dave Hansen <dave.hansen@intel.com>
> 
> BTW...  A lot of this patch is just a skeletal device driver.  I'm a horrible device
> driver writer, so take this ack as "everything seems explained well" versus "I
> promise this will pass muster with the guys who review device drivers all day
> long."

Thanks. 

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-16 15:18             ` Dave Hansen
  2021-02-16 18:47               ` Borislav Petkov
@ 2021-02-17 22:20               ` Jarkko Sakkinen
  2021-02-18  9:09                 ` Huang, Kai
  1 sibling, 1 reply; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-17 22:20 UTC (permalink / raw)
  To: Dave Hansen
  Cc: Borislav Petkov, Huang, Kai, linux-sgx, kvm, x86, seanjc, luto,
	Edgecombe, Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 07:18:27AM -0800, Dave Hansen wrote:
> On 2/16/21 3:48 AM, Borislav Petkov wrote:
> > What I'm trying to point you at is, to not give some artificial reasons
> > why the headers should be separate - artificial as the SDM says it
> > is architectural and so on - but give a reason from software design
> > perspective why the separation is needed: better build times, less
> > symbols exposed to modules, blabla and so on.
> 
> I think I actually suggested this sgx_arch.h split for SGX in the first
> place.
> 
> I was reading the patches and I had a really hard time separating the
> hardware and software structures.  There would be a 'struct sgx_foo {}'
> and some chit chat about what it did...  and I still had no idea if it
> was an architectural structure or not.
> 
> This way, it's 100% crystal clear what Linux is defining and what the
> hardware defines from the diff context.

Let's worry about split later on when we add "big" SGX specific
features like EDMM, and consider this more like "move and rename".

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* Re: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
  2021-02-16 18:38   ` Dave Hansen
  2021-02-16 19:25     ` Sean Christopherson
  2021-02-16 21:34     ` Huang, Kai
@ 2021-02-17 22:22     ` Jarkko Sakkinen
  2 siblings, 0 replies; 64+ messages in thread
From: Jarkko Sakkinen @ 2021-02-17 22:22 UTC (permalink / raw)
  To: Dave Hansen
  Cc: Kai Huang, linux-sgx, kvm, x86, seanjc, luto, rick.p.edgecombe,
	haitao.huang, pbonzini, bp, tglx, mingo, hpa

On Tue, Feb 16, 2021 at 10:38:42AM -0800, Dave Hansen wrote:
> On 2/13/21 5:28 AM, Kai Huang wrote:
> > SGX driver uses misc device /dev/sgx_enclave to support userspace to
> > create enclave.  Each file descriptor from opening /dev/sgx_enclave
> > represents an enclave.  
> 
> Is this strictly true?  Does dup(2) create a new enclave?

No.

> > Unlike SGX driver, KVM doesn't control how guest
> > uses EPC, therefore EPC allocated to KVM guest is not associated to an
> > encalve, and /dev/sgx_enclave is not suitable for allocating EPC for KVM
> 
>   ^ enclave
> 
> > guest.
> 
> 
> > Having separate device nodes for SGX driver and KVM virtual EPC also
> > allows separate permission control for running host SGX enclaves and
> > KVM SGX guests.
> 
> Specifically, 'sgx_vepc' is a less restrictive interface.  It would make
> a lot of sense to more tightly control access compared to 'sgx_enclave'.
> 
> > More specifically, to allocate a virtual EPC instance with particular
> > size, the userspace hypervisor opens /dev/sgx_vepc, and uses mmap()
> > with the intended size to get an address range of virtual EPC.  Then
> > it may use the address range to create one KVM memory slot as virtual
> > EPC for guest.
> 
> This paragraph doesn't really explain anything important to me.  Both
> devices require using mmap().
> 
> With typos in the changelog fixed, I'm OK with the rest:
> 
> Acked-by: Dave Hansen <dave.hansen@intel.com>
> 
> BTW...  A lot of this patch is just a skeletal device driver.  I'm a
> horrible device driver writer, so take this ack as "everything seems
> explained well" versus "I promise this will pass muster with the guys
> who review device drivers all day long."
> 

/Jarkko

^ permalink raw reply	[flat|nested] 64+ messages in thread

* RE: [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel
  2021-02-17 22:20               ` Jarkko Sakkinen
@ 2021-02-18  9:09                 ` Huang, Kai
  0 siblings, 0 replies; 64+ messages in thread
From: Huang, Kai @ 2021-02-18  9:09 UTC (permalink / raw)
  To: Jarkko Sakkinen, Hansen, Dave
  Cc: Borislav Petkov, linux-sgx, kvm, x86, seanjc, luto, Edgecombe,
	Rick P, Huang, Haitao, pbonzini, tglx, mingo, hpa

> 
> On Tue, Feb 16, 2021 at 07:18:27AM -0800, Dave Hansen wrote:
> > On 2/16/21 3:48 AM, Borislav Petkov wrote:
> > > What I'm trying to point you at is, to not give some artificial
> > > reasons why the headers should be separate - artificial as the SDM
> > > says it is architectural and so on - but give a reason from software
> > > design perspective why the separation is needed: better build times,
> > > less symbols exposed to modules, blabla and so on.
> >
> > I think I actually suggested this sgx_arch.h split for SGX in the
> > first place.
> >
> > I was reading the patches and I had a really hard time separating the
> > hardware and software structures.  There would be a 'struct sgx_foo {}'
> > and some chit chat about what it did...  and I still had no idea if it
> > was an architectural structure or not.
> >
> > This way, it's 100% crystal clear what Linux is defining and what the
> > hardware defines from the diff context.
> 
> Let's worry about split later on when we add "big" SGX specific features like
> EDMM, and consider this more like "move and rename".

If we need to worry about split when we add EDMM, why we are merging to one single asm/sgx.h in this KVM SGX series?

EDMM is a feature we definitely need to support, right?

^ permalink raw reply	[flat|nested] 64+ messages in thread

end of thread, other threads:[~2021-02-18 10:19 UTC | newest]

Thread overview: 64+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 01/26] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 02/26] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
2021-02-16 17:04   ` Dave Hansen
2021-02-16 20:42     ` Huang, Kai
2021-02-13 13:28 ` [RFC PATCH v5 04/26] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-02-16  2:12   ` Jarkko Sakkinen
2021-02-16 18:38   ` Dave Hansen
2021-02-16 19:25     ` Sean Christopherson
2021-02-16 21:33       ` Huang, Kai
2021-02-16 21:34     ` Huang, Kai
2021-02-17 22:22     ` Jarkko Sakkinen
2021-02-13 13:29 ` [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-02-16  2:15   ` Jarkko Sakkinen
2021-02-16  5:03     ` Huang, Kai
2021-02-16  8:36       ` Jarkko Sakkinen
2021-02-16 10:24         ` Huang, Kai
2021-02-16 18:40   ` Dave Hansen
2021-02-16 20:42     ` Huang, Kai
2021-02-13 13:29 ` [RFC PATCH v5 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
2021-02-16 18:41   ` Dave Hansen
2021-02-13 13:29 ` [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-02-16  2:17   ` Jarkko Sakkinen
2021-02-16 10:30     ` Huang, Kai
2021-02-16 10:32       ` Borislav Petkov
2021-02-16 11:15         ` Huang, Kai
2021-02-16 11:48           ` Borislav Petkov
2021-02-16 11:56             ` Huang, Kai
2021-02-16 15:18             ` Dave Hansen
2021-02-16 18:47               ` Borislav Petkov
2021-02-16 18:53                 ` Dave Hansen
2021-02-16 19:18                   ` Borislav Petkov
2021-02-17 22:20               ` Jarkko Sakkinen
2021-02-18  9:09                 ` Huang, Kai
2021-02-16 16:28         ` Jarkko Sakkinen
2021-02-13 13:29 ` [RFC PATCH v5 09/26] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 10/26] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 11/26] x86/sgx: Add encls_faulted() helper Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 12/26] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-02-16  3:08   ` Jarkko Sakkinen
2021-02-16  3:09     ` Jarkko Sakkinen
2021-02-16  4:55       ` Huang, Kai
2021-02-16  8:33         ` Jarkko Sakkinen
2021-02-16  8:35           ` Jarkko Sakkinen
2021-02-16  9:33             ` Huang, Kai
2021-02-13 13:29 ` [RFC PATCH v5 14/26] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 15/26] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 16/26] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 17/26] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 18/26] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 19/26] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 20/26] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 21/26] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 22/26] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 23/26] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 24/26] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 25/26] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-02-13 13:30 ` [RFC PATCH v5 26/26] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-02-16 18:48 ` [RFC PATCH v5 00/26] KVM SGX virtualization support Dave Hansen
2021-02-16 19:15   ` Sean Christopherson
2021-02-16 20:58   ` Huang, Kai

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).