[RFC PATCH V5 00/15] x86/hyperv/sev: Add AMD sev-snp enlightened guest support on hyperv

[RFC PATCH V5 00/15] x86/hyperv/sev: Add AMD sev-snp enlightened guest support on hyperv

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

This patchset is to add AMD sev-snp enlightened guest
support on hyperv. Hyperv uses Linux direct boot mode
to boot up Linux kernel and so it needs to pvalidate
system memory by itself.

In hyperv case, there is no boot loader and so cc blob
is prepared by hypervisor. In this series, hypervisor
set the cc blob address directly into boot parameter
of Linux kernel.

Shared memory between guests and hypervisor should be
decrypted and zero memory after decrypt memory. The data
in the target address. It maybe smearedto avoid smearing
data.

Introduce #HV exception support in AMD sev snp code and
#HV handler.

Change since v4:
       - Use pgcount to free intput arg page.
       - Fix encrypt and free page order.
       - struct_size to calculate array size
       - Share asm code between #HV and #VC exception.

Change since v3:
       - Replace struct sev_es_save_area with struct vmcb_save_area
       - Move smp, cpu and memory enumerating code from mshyperv.c to ivm.c
       - Handle nested entry case of do_exc_hv() case.
       - Check NMI event when irq is disabled

Change since v2:
       - Remove validate kernel memory code at boot stage
       - Split #HV page patch into two parts
       - Remove HV-APIC change due to enable x2apic from
       	 host side
       - Rework vmbus code to handle error of decrypt page
       - Spilt memory and cpu initialization patch. 
Change since v1:
       - Remove boot param changes for cc blob address and
       use setup head to pass cc blob info
       - Remove unnessary WARN and BUG check
       - Add system vector table map in the #HV exception
       - Fix interrupt exit issue when use #HV exception

Ashish Kalra (2):
  x86/sev: optimize system vector processing invoked from #HV exception
  x86/sev: Fix interrupt exit code paths from #HV exception

Tianyu Lan (13):
  x86/hyperv: Add sev-snp enlightened guest static key
  x86/hyperv: Decrypt hv vp assist page in sev-snp enlightened guest
  x86/hyperv: Set Virtual Trust Level in VMBus init message
  x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp
    enlightened guest
  clocksource/drivers/hyper-v: decrypt hyperv tsc page in sev-snp
    enlightened guest
  hv: vmbus: decrypt VMBus pages for sev-snp enlightened guest
  drivers: hv: Decrypt percpu hvcall input arg page in sev-snp
    enlightened guest
  x86/hyperv: Initialize cpu and memory for sev-snp enlightened guest
  x86/hyperv: Add smp support for sev-snp guest
  x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES
  x86/sev: Add a #HV exception handler
  x86/sev: Add Check of #HV event in path
  x86/sev: Add AMD sev-snp enlightened guest support on hyperv

 arch/x86/entry/entry_64.S             |  46 ++-
 arch/x86/hyperv/hv_init.c             |  42 +++
 arch/x86/hyperv/ivm.c                 | 186 ++++++++++++
 arch/x86/include/asm/cpu_entry_area.h |   6 +
 arch/x86/include/asm/hyperv-tlfs.h    |   7 +
 arch/x86/include/asm/idtentry.h       | 106 ++++++-
 arch/x86/include/asm/irqflags.h       |  14 +-
 arch/x86/include/asm/mem_encrypt.h    |   2 +
 arch/x86/include/asm/mshyperv.h       |  82 +++++-
 arch/x86/include/asm/page_64_types.h  |   1 +
 arch/x86/include/asm/sev.h            |  13 +
 arch/x86/include/asm/svm.h            |  15 +-
 arch/x86/include/asm/trapnr.h         |   1 +
 arch/x86/include/asm/traps.h          |   1 +
 arch/x86/include/uapi/asm/svm.h       |   4 +
 arch/x86/kernel/cpu/common.c          |   1 +
 arch/x86/kernel/cpu/mshyperv.c        |  42 ++-
 arch/x86/kernel/dumpstack_64.c        |   9 +-
 arch/x86/kernel/idt.c                 |   1 +
 arch/x86/kernel/sev.c                 | 408 ++++++++++++++++++++++----
 arch/x86/kernel/traps.c               |  42 +++
 arch/x86/kernel/vmlinux.lds.S         |   7 +
 arch/x86/mm/cpu_entry_area.c          |   2 +
 drivers/clocksource/hyperv_timer.c    |   2 +-
 drivers/hv/connection.c               |   1 +
 drivers/hv/hv.c                       |  41 ++-
 drivers/hv/hv_common.c                |  27 +-
 include/asm-generic/hyperv-tlfs.h     |  19 ++
 include/asm-generic/mshyperv.h        |   1 +
 include/linux/hyperv.h                |   4 +-
 30 files changed, 1047 insertions(+), 86 deletions(-)

-- 
2.25.1

[RFC PATCH V5 01/15] x86/hyperv: Add sev-snp enlightened guest static key

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Introduce static key isolation_type_en_snp for enlightened
sev-snp guest check.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC-v3:
	* Remove some Hyper-V specific config setting
---
 arch/x86/hyperv/ivm.c           | 11 +++++++++++
 arch/x86/include/asm/mshyperv.h |  3 +++
 arch/x86/kernel/cpu/mshyperv.c  |  9 +++++++--
 drivers/hv/hv_common.c          |  6 ++++++
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 127d5b7b63de..368b2731950e 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -409,3 +409,14 @@ bool hv_isolation_type_snp(void)
 {
 	return static_branch_unlikely(&isolation_type_snp);
 }
+
+DEFINE_STATIC_KEY_FALSE(isolation_type_en_snp);
+/*
+ * hv_isolation_type_en_snp - Check system runs in the AMD SEV-SNP based
+ * isolation enlightened VM.
+ */
+bool hv_isolation_type_en_snp(void)
+{
+	return static_branch_unlikely(&isolation_type_en_snp);
+}
+
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index b445e252aa83..97d117ec95c4 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -26,6 +26,7 @@
 union hv_ghcb;
 
 DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
+DECLARE_STATIC_KEY_FALSE(isolation_type_en_snp);
 
 typedef int (*hyperv_fill_flush_list_func)(
 		struct hv_guest_mapping_flush_list *flush,
@@ -45,6 +46,8 @@ extern void *hv_hypercall_pg;
 
 extern u64 hv_current_partition_id;
 
+extern bool hv_isolation_type_en_snp(void);
+
 extern union hv_ghcb * __percpu *hv_ghcb_pg;
 
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index c7969e806c64..63a2bfbfe701 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -402,8 +402,12 @@ static void __init ms_hyperv_init_platform(void)
 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
 
-		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
+
+		if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
+			static_branch_enable(&isolation_type_en_snp);
+		} else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
 			static_branch_enable(&isolation_type_snp);
+		}
 	}
 
 	if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
@@ -473,7 +477,8 @@ static void __init ms_hyperv_init_platform(void)
 
 #if IS_ENABLED(CONFIG_HYPERV)
 	if ((hv_get_isolation_type() == HV_ISOLATION_TYPE_VBS) ||
-	    (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP))
+	    (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP
+	     && !cc_platform_has(CC_ATTR_GUEST_SEV_SNP)))
 		hv_vtom_init();
 	/*
 	 * Setup the hook to get control post apic initialization.
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 64f9ceca887b..179bc5f5bf52 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -502,6 +502,12 @@ bool __weak hv_isolation_type_snp(void)
 }
 EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
 
+bool __weak hv_isolation_type_en_snp(void)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_en_snp);
+
 void __weak hv_setup_vmbus_handler(void (*handler)(void))
 {
 }
-- 
2.25.1

[RFC PATCH V5 02/15] x86/hyperv: Decrypt hv vp assist page in sev-snp enlightened guest

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

hv vp assist page is shared between sev snp guest and hyperv. Decrypt
the page when use it.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
 arch/x86/hyperv/hv_init.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index a5f9474f08e1..9f3e2d71d015 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -18,6 +18,7 @@
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
 #include <asm/idtentry.h>
+#include <asm/set_memory.h>
 #include <linux/kexec.h>
 #include <linux/version.h>
 #include <linux/vmalloc.h>
@@ -113,6 +114,11 @@ static int hv_cpu_init(unsigned int cpu)
 
 	}
 	if (!WARN_ON(!(*hvp))) {
+		if (hv_isolation_type_en_snp()) {
+			WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
+			memset(*hvp, 0, PAGE_SIZE);
+		}
+
 		msr.enable = 1;
 		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
 	}
-- 
2.25.1

[RFC PATCH V5 03/15] x86/hyperv: Set Virtual Trust Level in VMBus init message

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

sev-snp guest provides vtl(Virtual Trust Level) and
get it from hyperv hvcall via HVCALL_GET_VP_REGISTERS.
Set target vtl in the VMBus init message.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC v4:
       * Use struct_size to calculate array size.
       * Fix some coding style

Change since RFC v3:
       * Use the standard helper functions to check hypercall result
       * Fix coding style

Change since RFC v2:
       * Rename get_current_vtl() to get_vtl()
       * Fix some coding style issues
---
 arch/x86/hyperv/hv_init.c          | 36 ++++++++++++++++++++++++++++++
 arch/x86/include/asm/hyperv-tlfs.h |  7 ++++++
 drivers/hv/connection.c            |  1 +
 include/asm-generic/mshyperv.h     |  1 +
 include/linux/hyperv.h             |  4 ++--
 5 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 9f3e2d71d015..331b855314b7 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -384,6 +384,40 @@ static void __init hv_get_partition_id(void)
 	local_irq_restore(flags);
 }
 
+static u8 __init get_vtl(void)
+{
+	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
+	struct hv_get_vp_registers_input *input;
+	struct hv_get_vp_registers_output *output;
+	u64 vtl = 0;
+	u64 ret;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	output = (struct hv_get_vp_registers_output *)input;
+	if (!input) {
+		local_irq_restore(flags);
+		goto done;
+	}
+
+	memset(input, 0, struct_size(input, element, 1));
+	input->header.partitionid = HV_PARTITION_ID_SELF;
+	input->header.vpindex = HV_VP_INDEX_SELF;
+	input->header.inputvtl = 0;
+	input->element[0].name0 = HV_X64_REGISTER_VSM_VP_STATUS;
+
+	ret = hv_do_hypercall(control, input, output);
+	if (hv_result_success(ret))
+		vtl = output->as64.low & HV_X64_VTL_MASK;
+	else
+		pr_err("Hyper-V: failed to get VTL! %lld", ret);
+	local_irq_restore(flags);
+
+done:
+	return vtl;
+}
+
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -512,6 +546,8 @@ void __init hyperv_init(void)
 	/* Query the VMs extended capability once, so that it can be cached. */
 	hv_query_ext_cap(0);
 
+	/* Find the VTL */
+	ms_hyperv.vtl = get_vtl();
 	return;
 
 clean_guest_os_id:
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index cea95dcd27c2..4bf0b315b0ce 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -301,6 +301,13 @@ enum hv_isolation_type {
 #define HV_X64_MSR_TIME_REF_COUNT	HV_REGISTER_TIME_REF_COUNT
 #define HV_X64_MSR_REFERENCE_TSC	HV_REGISTER_REFERENCE_TSC
 
+/*
+ * Registers are only accessible via HVCALL_GET_VP_REGISTERS hvcall and
+ * there is not associated MSR address.
+ */
+#define	HV_X64_REGISTER_VSM_VP_STATUS	0x000D0003
+#define	HV_X64_VTL_MASK			GENMASK(3, 0)
+
 /* Hyper-V memory host visibility */
 enum hv_mem_host_visibility {
 	VMBUS_PAGE_NOT_VISIBLE		= 0,
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 5978e9dbc286..02b54f85dc60 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -98,6 +98,7 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
 	 */
 	if (version >= VERSION_WIN10_V5) {
 		msg->msg_sint = VMBUS_MESSAGE_SINT;
+		msg->msg_vtl = ms_hyperv.vtl;
 		vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
 	} else {
 		msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 402a8c1c202d..3052130ba4ef 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -48,6 +48,7 @@ struct ms_hyperv_info {
 		};
 	};
 	u64 shared_gpa_boundary;
+	u8 vtl;
 };
 extern struct ms_hyperv_info ms_hyperv;
 extern bool hv_nested;
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index bfbc37ce223b..1f2bfec4abde 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -665,8 +665,8 @@ struct vmbus_channel_initiate_contact {
 		u64 interrupt_page;
 		struct {
 			u8	msg_sint;
-			u8	padding1[3];
-			u32	padding2;
+			u8	msg_vtl;
+			u8	reserved[6];
 		};
 	};
 	u64 monitor_page1;
-- 
2.25.1

[RFC PATCH V5 04/15] x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

In sev-snp enlightened guest, Hyper-V hypercall needs
to use vmmcall to trigger vmexit and notify hypervisor
to handle hypercall request.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC V2:
       * Fix indentation style
---
 arch/x86/include/asm/mshyperv.h | 44 ++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 97d117ec95c4..939373791249 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -61,16 +61,25 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 	u64 hv_status;
 
 #ifdef CONFIG_X86_64
-	if (!hv_hypercall_pg)
-		return U64_MAX;
+	if (hv_isolation_type_en_snp()) {
+		__asm__ __volatile__("mov %4, %%r8\n"
+				     "vmmcall"
+				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				       "+c" (control), "+d" (input_address)
+				     :  "r" (output_address)
+				     : "cc", "memory", "r8", "r9", "r10", "r11");
+	} else {
+		if (!hv_hypercall_pg)
+			return U64_MAX;
 
-	__asm__ __volatile__("mov %4, %%r8\n"
-			     CALL_NOSPEC
-			     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
-			       "+c" (control), "+d" (input_address)
-			     :  "r" (output_address),
-				THUNK_TARGET(hv_hypercall_pg)
-			     : "cc", "memory", "r8", "r9", "r10", "r11");
+		__asm__ __volatile__("mov %4, %%r8\n"
+				     CALL_NOSPEC
+				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				       "+c" (control), "+d" (input_address)
+				     :  "r" (output_address),
+					THUNK_TARGET(hv_hypercall_pg)
+				     : "cc", "memory", "r8", "r9", "r10", "r11");
+	}
 #else
 	u32 input_address_hi = upper_32_bits(input_address);
 	u32 input_address_lo = lower_32_bits(input_address);
@@ -104,7 +113,13 @@ static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1)
 	u64 hv_status;
 
 #ifdef CONFIG_X86_64
-	{
+	if (hv_isolation_type_en_snp()) {
+		__asm__ __volatile__(
+				"vmmcall"
+				: "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				"+c" (control), "+d" (input1)
+				:: "cc", "r8", "r9", "r10", "r11");
+	} else {
 		__asm__ __volatile__(CALL_NOSPEC
 				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
 				       "+c" (control), "+d" (input1)
@@ -149,7 +164,14 @@ static inline u64 _hv_do_fast_hypercall16(u64 control, u64 input1, u64 input2)
 	u64 hv_status;
 
 #ifdef CONFIG_X86_64
-	{
+	if (hv_isolation_type_en_snp()) {
+		__asm__ __volatile__("mov %4, %%r8\n"
+				     "vmmcall"
+				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				       "+c" (control), "+d" (input1)
+				     : "r" (input2)
+				     : "cc", "r8", "r9", "r10", "r11");
+	} else {
 		__asm__ __volatile__("mov %4, %%r8\n"
 				     CALL_NOSPEC
 				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
-- 
2.25.1

[RFC PATCH V5 05/15] clocksource/drivers/hyper-v: decrypt hyperv tsc page in sev-snp enlightened guest

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Hyper-V tsc page is shared with hypervisor and it should
be decrypted in sev-snp enlightened guest when it's used.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC V2:
       * Change the Subject line prefix
---
 drivers/clocksource/hyperv_timer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index bcd9042a0c9f..66e29a19770b 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -376,7 +376,7 @@ EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
 static union {
 	struct ms_hyperv_tsc_page page;
 	u8 reserved[PAGE_SIZE];
-} tsc_pg __aligned(PAGE_SIZE);
+} tsc_pg __bss_decrypted __aligned(PAGE_SIZE);
 
 static struct ms_hyperv_tsc_page *tsc_page = &tsc_pg.page;
 static unsigned long tsc_pfn;
-- 
2.25.1

[RFC PATCH V5 06/15] hv: vmbus: decrypt VMBus pages for sev-snp enlightened guest

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

VMBus post msg, synic event and message pages are shared
with hypervisor and so decrypt these pages in the sev-snp guest.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change sicne RFC V4:
       * Fix encrypt and free page order.

Change since RFC V3:
       * Set encrypt page back in the hv_synic_free()

Change since RFC V2:
       * Fix error in the error code path and encrypt
       	 pages correctly when decryption failure happens.
---
 drivers/hv/hv.c | 41 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index de6708dbe0df..e0943db51acd 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -20,6 +20,7 @@
 #include <linux/interrupt.h>
 #include <clocksource/hyperv_timer.h>
 #include <asm/mshyperv.h>
+#include <linux/set_memory.h>
 #include "hyperv_vmbus.h"
 
 /* The one and only */
@@ -78,7 +79,7 @@ int hv_post_message(union hv_connection_id connection_id,
 
 int hv_synic_alloc(void)
 {
-	int cpu;
+	int cpu, ret;
 	struct hv_per_cpu_context *hv_cpu;
 
 	/*
@@ -123,9 +124,33 @@ int hv_synic_alloc(void)
 				goto err;
 			}
 		}
+
+		if (hv_isolation_type_en_snp()) {
+			ret = set_memory_decrypted((unsigned long)
+				hv_cpu->synic_message_page, 1);
+			if (ret)
+				goto err;
+
+			ret = set_memory_decrypted((unsigned long)
+				hv_cpu->synic_event_page, 1);
+			if (ret)
+				goto err_decrypt_event_page;
+
+			memset(hv_cpu->synic_message_page, 0, PAGE_SIZE);
+			memset(hv_cpu->synic_event_page, 0, PAGE_SIZE);
+		}
 	}
 
 	return 0;
+
+err_decrypt_msg_page:
+	set_memory_encrypted((unsigned long)
+		hv_cpu->synic_event_page, 1);
+
+err_decrypt_event_page:
+	set_memory_encrypted((unsigned long)
+		hv_cpu->synic_message_page, 1);
+
 err:
 	/*
 	 * Any memory allocations that succeeded will be freed when
@@ -143,8 +168,18 @@ void hv_synic_free(void)
 		struct hv_per_cpu_context *hv_cpu
 			= per_cpu_ptr(hv_context.cpu_context, cpu);
 
-		free_page((unsigned long)hv_cpu->synic_event_page);
-		free_page((unsigned long)hv_cpu->synic_message_page);
+		if (hv_isolation_type_en_snp()) {
+			if (!set_memory_encrypted((unsigned long)
+			    hv_cpu->synic_message_page, 1))
+				free_page((unsigned long)hv_cpu->synic_event_page);
+
+			if (!set_memory_encrypted((unsigned long)
+			    hv_cpu->synic_event_page, 1))
+				free_page((unsigned long)hv_cpu->synic_message_page);
+		} else {
+			free_page((unsigned long)hv_cpu->synic_event_page);
+			free_page((unsigned long)hv_cpu->synic_message_page);
+		}
 	}
 
 	kfree(hv_context.hv_numa_map);
-- 
2.25.1

[RFC PATCH V5 07/15] drivers: hv: Decrypt percpu hvcall input arg page in sev-snp enlightened guest

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Hypervisor needs to access iput arg page and guest should decrypt
the page.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC V4:
        * Use pgcount to free intput arg page

Change since RFC V3:
	* Use pgcount to decrypt memory.

Change since RFC V2:
	* Set inputarg to be zero after kfree()
	* Not free mem when fail to encrypt mem in the hv_common_cpu_die().
---
 drivers/hv/hv_common.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 179bc5f5bf52..15d3054f3440 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -24,6 +24,7 @@
 #include <linux/kmsg_dump.h>
 #include <linux/slab.h>
 #include <linux/dma-map-ops.h>
+#include <linux/set_memory.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
 
@@ -359,6 +360,7 @@ int hv_common_cpu_init(unsigned int cpu)
 	u64 msr_vp_index;
 	gfp_t flags;
 	int pgcount = hv_root_partition ? 2 : 1;
+	int ret;
 
 	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
 	flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
@@ -368,6 +370,17 @@ int hv_common_cpu_init(unsigned int cpu)
 	if (!(*inputarg))
 		return -ENOMEM;
 
+	if (hv_isolation_type_en_snp()) {
+		ret = set_memory_decrypted((unsigned long)*inputarg, pgcount);
+		if (ret) {
+			kfree(*inputarg);
+			*inputarg = NULL;
+			return ret;
+		}
+
+		memset(*inputarg, 0x00, pgcount * PAGE_SIZE);
+	}
+
 	if (hv_root_partition) {
 		outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
 		*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
@@ -387,6 +400,7 @@ int hv_common_cpu_die(unsigned int cpu)
 {
 	unsigned long flags;
 	void **inputarg, **outputarg;
+	int pgcount = hv_root_partition ? 2 : 1;
 	void *mem;
 
 	local_irq_save(flags);
@@ -402,7 +416,12 @@ int hv_common_cpu_die(unsigned int cpu)
 
 	local_irq_restore(flags);
 
-	kfree(mem);
+	if (hv_isolation_type_en_snp()) {
+		if (!set_memory_encrypted((unsigned long)mem, pgcount))
+			kfree(mem);
+	} else {
+		kfree(mem);
+	}
 
 	return 0;
 }
-- 
2.25.1

[RFC PATCH V5 08/15] x86/hyperv: Initialize cpu and memory for sev-snp enlightened guest

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Read processor amd memory info from specific address which are
populated by Hyper-V. Initialize smp cpu related ops, pvalidate
system memory and add it into e820 table.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFCv4:
       * Add mem info addr to get mem layout info
---
 arch/x86/hyperv/ivm.c           | 86 +++++++++++++++++++++++++++++++++
 arch/x86/include/asm/mshyperv.h | 17 +++++++
 arch/x86/kernel/cpu/mshyperv.c  |  3 ++
 3 files changed, 106 insertions(+)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 368b2731950e..522eab55c0dd 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -17,6 +17,11 @@
 #include <asm/mem_encrypt.h>
 #include <asm/mshyperv.h>
 #include <asm/hypervisor.h>
+#include <asm/coco.h>
+#include <asm/io_apic.h>
+#include <asm/sev.h>
+#include <asm/realmode.h>
+#include <asm/e820/api.h>
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 
@@ -57,6 +62,8 @@ union hv_ghcb {
 
 static u16 hv_ghcb_version __ro_after_init;
 
+static u32 processor_count;
+
 u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
 {
 	union hv_ghcb *hv_ghcb;
@@ -356,6 +363,85 @@ static bool hv_is_private_mmio(u64 addr)
 	return false;
 }
 
+static __init void hv_snp_get_smp_config(unsigned int early)
+{
+	if (!early)
+		return;
+	/*
+	 * There is no firmware and ACPI MADT table spport in
+	 * in the Hyper-V SEV-SNP enlightened guest. Set smp
+	 * related config variable during early stage.
+	 */
+	while (num_processors < processor_count) {
+		early_per_cpu(x86_cpu_to_apicid, num_processors) = num_processors;
+		early_per_cpu(x86_bios_cpu_apicid, num_processors) = num_processors;
+		physid_set(num_processors, phys_cpu_present_map);
+		set_cpu_possible(num_processors, true);
+		set_cpu_present(num_processors, true);
+		num_processors++;
+	}
+}
+
+__init void hv_sev_init_mem_and_cpu(void)
+{
+	struct memory_map_entry *entry;
+	struct e820_entry *e820_entry;
+	u64 e820_end;
+	u64 ram_end;
+	u64 page;
+
+	/*
+	 * Hyper-V enlightened snp guest boots kernel
+	 * directly without bootloader and so roms,
+	 * bios regions and reserve resources are not
+	 * available. Set these callback to NULL.
+	 */
+	x86_platform.legacy.rtc			= 0;
+	x86_platform.legacy.reserve_bios_regions = 0;
+	x86_platform.set_wallclock		= set_rtc_noop;
+	x86_platform.get_wallclock		= get_rtc_noop;
+	x86_init.resources.probe_roms		= x86_init_noop;
+	x86_init.resources.reserve_resources	= x86_init_noop;
+	x86_init.mpparse.find_smp_config	= x86_init_noop;
+	x86_init.mpparse.get_smp_config		= hv_snp_get_smp_config;
+
+	/*
+	 * Hyper-V SEV-SNP enlightened guest doesn't support ioapic
+	 * and legacy APIC page read/write. Switch to hv apic here.
+	 */
+	disable_ioapic_support();
+
+	/* Get processor and mem info. */
+	processor_count = *(u32 *)__va(EN_SEV_SNP_PROCESSOR_INFO_ADDR);
+	entry = (struct memory_map_entry *)__va(EN_SEV_SNP_MEM_INFO_ADDR);
+
+	/*
+	 * There is no bootloader/EFI firmware in the SEV SNP guest.
+	 * E820 table in the memory just describes memory for kernel,
+	 * ACPI table, cmdline, boot params and ramdisk. The dynamic
+	 * data(e.g, vcpu nnumber and the rest memory layout) needs to
+	 * be read from EN_SEV_SNP_PROCESSOR_INFO_ADDR.
+	 */
+	for (; entry->numpages != 0; entry++) {
+		e820_entry = &e820_table->entries[
+				e820_table->nr_entries - 1];
+		e820_end = e820_entry->addr + e820_entry->size;
+		ram_end = (entry->starting_gpn +
+			   entry->numpages) * PAGE_SIZE;
+
+		if (e820_end < entry->starting_gpn * PAGE_SIZE)
+			e820_end = entry->starting_gpn * PAGE_SIZE;
+
+		if (e820_end < ram_end) {
+			pr_info("Hyper-V: add e820 entry [mem %#018Lx-%#018Lx]\n", e820_end, ram_end - 1);
+			e820__range_add(e820_end, ram_end - e820_end,
+					E820_TYPE_RAM);
+			for (page = e820_end; page < ram_end; page += PAGE_SIZE)
+				pvalidate((unsigned long)__va(page), RMP_PG_SIZE_4K, true);
+		}
+	}
+}
+
 void __init hv_vtom_init(void)
 {
 	/*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 939373791249..84e024ffacd5 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -50,6 +50,21 @@ extern bool hv_isolation_type_en_snp(void);
 
 extern union hv_ghcb * __percpu *hv_ghcb_pg;
 
+/*
+ * Hyper-V puts processor and memory layout info
+ * to this address in SEV-SNP enlightened guest.
+ */
+#define EN_SEV_SNP_PROCESSOR_INFO_ADDR  0x802000
+#define EN_SEV_SNP_MEM_INFO_ADDR	0x802018
+
+struct memory_map_entry {
+	u64 starting_gpn;
+	u64 numpages;
+	u16 type;
+	u16 flags;
+	u32 reserved;
+};
+
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
@@ -255,12 +270,14 @@ void hv_ghcb_msr_read(u64 msr, u64 *value);
 bool hv_ghcb_negotiate_protocol(void);
 void hv_ghcb_terminate(unsigned int set, unsigned int reason);
 void hv_vtom_init(void);
+void hv_sev_init_mem_and_cpu(void);
 #else
 static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
 static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
 static inline bool hv_ghcb_negotiate_protocol(void) { return false; }
 static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
 static inline void hv_vtom_init(void) {}
+static inline void hv_sev_init_mem_and_cpu(void) {}
 #endif
 
 extern bool hv_isolation_type_snp(void);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 63a2bfbfe701..dea9b881180b 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -529,6 +529,9 @@ static void __init ms_hyperv_init_platform(void)
 	if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
 		mark_tsc_unstable("running on Hyper-V");
 
+	if (hv_isolation_type_en_snp())
+		hv_sev_init_mem_and_cpu();
+
 	hardlockup_detector_disable();
 }
 
-- 
2.25.1

[RFC PATCH V5 09/15] x86/hyperv: Add smp support for sev-snp guest

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

The wakeup_secondary_cpu callback was populated with wakeup_
cpu_via_vmgexit() which doesn't work for Hyper-V and Hyper-V
requires to call Hyper-V specific hvcall to start APs. So override
it with Hyper-V specific hook to start AP sev_es_save_area data
structure.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change sicne RFC v3:
       * Replace struct sev_es_save_area with struct
         vmcb_save_area
       * Move code from mshyperv.c to ivm.c

Change since RFC v2:
       * Add helper function to initialize segment
       * Fix some coding style
---
 arch/x86/hyperv/ivm.c             | 89 +++++++++++++++++++++++++++++++
 arch/x86/include/asm/mshyperv.h   | 18 +++++++
 arch/x86/include/asm/sev.h        | 13 +++++
 arch/x86/include/asm/svm.h        | 15 +++++-
 arch/x86/kernel/cpu/mshyperv.c    | 13 ++++-
 arch/x86/kernel/sev.c             |  4 +-
 include/asm-generic/hyperv-tlfs.h | 19 +++++++
 7 files changed, 166 insertions(+), 5 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 522eab55c0dd..0ef46f1874e6 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -22,11 +22,15 @@
 #include <asm/sev.h>
 #include <asm/realmode.h>
 #include <asm/e820/api.h>
+#include <asm/desc.h>
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 
 #define GHCB_USAGE_HYPERV_CALL	1
 
+static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
+static u8 ap_start_stack[PAGE_SIZE] __aligned(PAGE_SIZE);
+
 union hv_ghcb {
 	struct ghcb ghcb;
 	struct {
@@ -442,6 +446,91 @@ __init void hv_sev_init_mem_and_cpu(void)
 	}
 }
 
+#define hv_populate_vmcb_seg(seg, gdtr_base)			\
+do {								\
+	if (seg.selector) {					\
+		seg.base = 0;					\
+		seg.limit = HV_AP_SEGMENT_LIMIT;		\
+		seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5);	\
+		seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \
+	}							\
+} while (0)							\
+
+int hv_snp_boot_ap(int cpu, unsigned long start_ip)
+{
+	struct sev_es_save_area *vmsa = (struct sev_es_save_area *)
+		__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	struct desc_ptr gdtr;
+	u64 ret, retry = 5;
+	struct hv_start_virtual_processor_input *start_vp_input;
+	union sev_rmp_adjust rmp_adjust;
+	unsigned long flags;
+
+	native_store_gdt(&gdtr);
+
+	vmsa->gdtr.base = gdtr.address;
+	vmsa->gdtr.limit = gdtr.size;
+
+	asm volatile("movl %%es, %%eax;" : "=a" (vmsa->es.selector));
+	hv_populate_vmcb_seg(vmsa->es, vmsa->gdtr.base);
+
+	asm volatile("movl %%cs, %%eax;" : "=a" (vmsa->cs.selector));
+	hv_populate_vmcb_seg(vmsa->cs, vmsa->gdtr.base);
+
+	asm volatile("movl %%ss, %%eax;" : "=a" (vmsa->ss.selector));
+	hv_populate_vmcb_seg(vmsa->ss, vmsa->gdtr.base);
+
+	asm volatile("movl %%ds, %%eax;" : "=a" (vmsa->ds.selector));
+	hv_populate_vmcb_seg(vmsa->ds, vmsa->gdtr.base);
+
+	vmsa->efer = native_read_msr(MSR_EFER);
+
+	asm volatile("movq %%cr4, %%rax;" : "=a" (vmsa->cr4));
+	asm volatile("movq %%cr3, %%rax;" : "=a" (vmsa->cr3));
+	asm volatile("movq %%cr0, %%rax;" : "=a" (vmsa->cr0));
+
+	vmsa->xcr0 = 1;
+	vmsa->g_pat = HV_AP_INIT_GPAT_DEFAULT;
+	vmsa->rip = (u64)secondary_startup_64_no_verify;
+	vmsa->rsp = (u64)&ap_start_stack[PAGE_SIZE];
+
+	vmsa->sev_features.snp = 1;
+	vmsa->sev_features.restrict_injection = 1;
+
+	rmp_adjust.as_uint64 = 0;
+	rmp_adjust.target_vmpl = 1;
+	rmp_adjust.vmsa = 1;
+	ret = rmpadjust((unsigned long)vmsa, RMP_PG_SIZE_4K,
+			rmp_adjust.as_uint64);
+	if (ret != 0) {
+		pr_err("RMPADJUST(%llx) failed: %llx\n", (u64)vmsa, ret);
+		return ret;
+	}
+
+	local_irq_save(flags);
+	start_vp_input =
+		(struct hv_start_virtual_processor_input *)ap_start_input_arg;
+	memset(start_vp_input, 0, sizeof(*start_vp_input));
+	start_vp_input->partitionid = -1;
+	start_vp_input->vpindex = cpu;
+	start_vp_input->targetvtl = ms_hyperv.vtl;
+	*(u64 *)&start_vp_input->context[0] = __pa(vmsa) | 1;
+
+	do {
+		ret = hv_do_hypercall(HVCALL_START_VP,
+				      start_vp_input, NULL);
+	} while (hv_result(ret) == HV_STATUS_TIME_OUT && retry--);
+
+	if (!hv_result_success(ret)) {
+		pr_err("HvCallStartVirtualProcessor failed: %llx\n", ret);
+		goto done;
+	}
+
+done:
+	local_irq_restore(flags);
+	return ret;
+}
+
 void __init hv_vtom_init(void)
 {
 	/*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 84e024ffacd5..5ade250ec771 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -65,6 +65,20 @@ struct memory_map_entry {
 	u32 reserved;
 };
 
+/*
+ * DEFAULT INIT GPAT and SEGMENT LIMIT value in struct VMSA
+ * to start AP in enlightened SEV guest.
+ */
+#define HV_AP_INIT_GPAT_DEFAULT		0x0007040600070406ULL
+#define HV_AP_SEGMENT_LIMIT		0xffffffff
+
+/*
+ * DEFAULT INIT GPAT and SEGMENT LIMIT value in struct VMSA
+ * to start AP in enlightened SEV guest.
+ */
+#define HV_AP_INIT_GPAT_DEFAULT		0x0007040600070406ULL
+#define HV_AP_SEGMENT_LIMIT		0xffffffff
+
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
@@ -263,6 +277,8 @@ struct irq_domain *hv_create_pci_msi_domain(void);
 int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector,
 		struct hv_interrupt_entry *entry);
 int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
+int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible);
+int hv_snp_boot_ap(int cpu, unsigned long start_ip);
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 void hv_ghcb_msr_write(u64 msr, u64 value);
@@ -271,6 +287,7 @@ bool hv_ghcb_negotiate_protocol(void);
 void hv_ghcb_terminate(unsigned int set, unsigned int reason);
 void hv_vtom_init(void);
 void hv_sev_init_mem_and_cpu(void);
+int hv_snp_boot_ap(int cpu, unsigned long start_ip);
 #else
 static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
 static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
@@ -278,6 +295,7 @@ static inline bool hv_ghcb_negotiate_protocol(void) { return false; }
 static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
 static inline void hv_vtom_init(void) {}
 static inline void hv_sev_init_mem_and_cpu(void) {}
+static int hv_snp_boot_ap(int cpu, unsigned long start_ip) {}
 #endif
 
 extern bool hv_isolation_type_snp(void);
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 13dc2a9d23c1..0d57cb1c1bb4 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -88,6 +88,19 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
 
 #define RMPADJUST_VMSA_PAGE_BIT		BIT(16)
 
+union sev_rmp_adjust {
+	u64 as_uint64;
+	struct {
+		unsigned long target_vmpl : 8;
+		unsigned long enable_read : 1;
+		unsigned long enable_write : 1;
+		unsigned long enable_user_execute : 1;
+		unsigned long enable_kernel_execute : 1;
+		unsigned long reserved1 : 4;
+		unsigned long vmsa : 1;
+	};
+};
+
 /* SNP Guest message request */
 struct snp_req_data {
 	unsigned long req_gpa;
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 770dcf75eaa9..cd6bf989d918 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -425,7 +425,20 @@ struct sev_es_save_area {
 	u64 guest_exit_info_2;
 	u64 guest_exit_int_info;
 	u64 guest_nrip;
-	u64 sev_features;
+	union {
+		struct {
+			u64 snp                     : 1;
+			u64 vtom                    : 1;
+			u64 reflectvc               : 1;
+			u64 restrict_injection      : 1;
+			u64 alternate_injection     : 1;
+			u64 full_debug              : 1;
+			u64 reserved1               : 1;
+			u64 snpbtb_isolation        : 1;
+			u64 resrved2                : 56;
+		};
+		u64 val;
+	} sev_features;
 	u64 vintr_ctrl;
 	u64 guest_exit_code;
 	u64 virtual_tom;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index dea9b881180b..0c5f9f7bd7ba 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -295,6 +295,16 @@ static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
 
 	native_smp_prepare_cpus(max_cpus);
 
+	/*
+	 *  Override wakeup_secondary_cpu_64 callback for SEV-SNP
+	 *  enlightened guest.
+	 */
+	if (hv_isolation_type_en_snp())
+		apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap;
+
+	if (!hv_root_partition)
+		return;
+
 #ifdef CONFIG_X86_64
 	for_each_present_cpu(i) {
 		if (i == 0)
@@ -502,8 +512,7 @@ static void __init ms_hyperv_init_platform(void)
 
 # ifdef CONFIG_SMP
 	smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
-	if (hv_root_partition)
-		smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
+	smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
 # endif
 
 	/*
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index b031244d6d2d..20f3fd8ade2f 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1082,7 +1082,7 @@ static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
 	 *   SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
 	 */
 	vmsa->vmpl		= 0;
-	vmsa->sev_features	= sev_status >> 2;
+	vmsa->sev_features.val = sev_status >> 2;
 
 	/* Switch the page over to a VMSA page now that it is initialized */
 	ret = snp_set_vmsa(vmsa, true);
@@ -1099,7 +1099,7 @@ static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
 	ghcb = __sev_get_ghcb(&state);
 
 	vc_ghcb_invalidate(ghcb);
-	ghcb_set_rax(ghcb, vmsa->sev_features);
+	ghcb_set_rax(ghcb, vmsa->sev_features.val);
 	ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION);
 	ghcb_set_sw_exit_info_1(ghcb, ((u64)apic_id << 32) | SVM_VMGEXIT_AP_CREATE);
 	ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa));
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index f4e4cc4f965f..959b075591b2 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -149,6 +149,7 @@ union hv_reference_tsc_msr {
 #define HVCALL_ENABLE_VP_VTL			0x000f
 #define HVCALL_NOTIFY_LONG_SPIN_WAIT		0x0008
 #define HVCALL_SEND_IPI				0x000b
+#define HVCALL_ENABLE_VP_VTL			0x000f
 #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX	0x0013
 #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX	0x0014
 #define HVCALL_SEND_IPI_EX			0x0015
@@ -168,6 +169,7 @@ union hv_reference_tsc_msr {
 #define HVCALL_RETARGET_INTERRUPT		0x007e
 #define HVCALL_START_VP				0x0099
 #define HVCALL_GET_VP_ID_FROM_APIC_ID		0x009a
+#define HVCALL_START_VIRTUAL_PROCESSOR		0x0099
 #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af
 #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0
 #define HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db
@@ -223,6 +225,7 @@ enum HV_GENERIC_SET_FORMAT {
 #define HV_STATUS_INVALID_PORT_ID		17
 #define HV_STATUS_INVALID_CONNECTION_ID		18
 #define HV_STATUS_INSUFFICIENT_BUFFERS		19
+#define HV_STATUS_TIME_OUT                      120
 #define HV_STATUS_VTL_ALREADY_ENABLED		134
 
 /*
@@ -783,6 +786,22 @@ struct hv_input_unmap_device_interrupt {
 	struct hv_interrupt_entry interrupt_entry;
 } __packed;
 
+struct hv_enable_vp_vtl_input {
+	u64 partitionid;
+	u32 vpindex;
+	u8 targetvtl;
+	u8 padding[3];
+	u8 context[0xe0];
+} __packed;
+
+struct hv_start_virtual_processor_input {
+	u64 partitionid;
+	u32 vpindex;
+	u8 targetvtl;
+	u8 padding[3];
+	u8 context[0xe0];
+} __packed;
+
 #define HV_SOURCE_SHADOW_NONE               0x0
 #define HV_SOURCE_SHADOW_BRIDGE_BUS_RANGE   0x1
 
-- 
2.25.1

[RFC PATCH V5 10/15] x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Add Hyperv-specific handling for faults caused by VMMCALL
instructions.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
 arch/x86/kernel/cpu/mshyperv.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 0c5f9f7bd7ba..3469b369e627 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -32,6 +32,7 @@
 #include <asm/nmi.h>
 #include <clocksource/hyperv_timer.h>
 #include <asm/numa.h>
+#include <asm/svm.h>
 
 /* Is Linux running as the root partition? */
 bool hv_root_partition;
@@ -577,6 +578,20 @@ static bool __init ms_hyperv_msi_ext_dest_id(void)
 	return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE;
 }
 
+static void hv_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
+{
+	/* RAX and CPL are already in the GHCB */
+	ghcb_set_rcx(ghcb, regs->cx);
+	ghcb_set_rdx(ghcb, regs->dx);
+	ghcb_set_r8(ghcb, regs->r8);
+}
+
+static bool hv_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
+{
+	/* No checking of the return state needed */
+	return true;
+}
+
 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 	.name			= "Microsoft Hyper-V",
 	.detect			= ms_hyperv_platform,
@@ -584,4 +599,6 @@ const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 	.init.x2apic_available	= ms_hyperv_x2apic_available,
 	.init.msi_ext_dest_id	= ms_hyperv_msi_ext_dest_id,
 	.init.init_platform	= ms_hyperv_init_platform,
+	.runtime.sev_es_hcall_prepare = hv_sev_es_hcall_prepare,
+	.runtime.sev_es_hcall_finish = hv_sev_es_hcall_finish,
 };
-- 
2.25.1

[RFC PATCH V5 11/15] x86/sev: Add a #HV exception handler

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Add a #HV exception handler that uses IST stack.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC V2:
       * Remove unnecessary line in the change log.
---
 arch/x86/entry/entry_64.S             | 22 +++++++----
 arch/x86/include/asm/cpu_entry_area.h |  6 +++
 arch/x86/include/asm/idtentry.h       | 40 +++++++++++++++++++-
 arch/x86/include/asm/page_64_types.h  |  1 +
 arch/x86/include/asm/trapnr.h         |  1 +
 arch/x86/include/asm/traps.h          |  1 +
 arch/x86/kernel/cpu/common.c          |  1 +
 arch/x86/kernel/dumpstack_64.c        |  9 ++++-
 arch/x86/kernel/idt.c                 |  1 +
 arch/x86/kernel/sev.c                 | 53 +++++++++++++++++++++++++++
 arch/x86/kernel/traps.c               | 40 ++++++++++++++++++++
 arch/x86/mm/cpu_entry_area.c          |  2 +
 12 files changed, 165 insertions(+), 12 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index eccc3431e515..653b1f10699b 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -496,7 +496,7 @@ SYM_CODE_END(\asmsym)
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 /**
- * idtentry_vc - Macro to generate entry stub for #VC
+ * idtentry_sev - Macro to generate entry stub for #VC
  * @vector:		Vector number
  * @asmsym:		ASM symbol for the entry point
  * @cfunc:		C function to be called
@@ -515,14 +515,18 @@ SYM_CODE_END(\asmsym)
  *
  * The macro is only used for one vector, but it is planned to be extended in
  * the future for the #HV exception.
- */
-.macro idtentry_vc vector asmsym cfunc
+*/
+.macro idtentry_sev vector asmsym cfunc has_error_code:req
 SYM_CODE_START(\asmsym)
 	UNWIND_HINT_IRET_REGS
 	ENDBR
 	ASM_CLAC
 	cld
 
+	.if \vector == X86_TRAP_HV
+		pushq	$-1			/* ORIG_RAX: no syscall */
+	.endif
+
 	/*
 	 * If the entry is from userspace, switch stacks and treat it as
 	 * a normal entry.
@@ -545,7 +549,12 @@ SYM_CODE_START(\asmsym)
 	 * stack.
 	 */
 	movq	%rsp, %rdi		/* pt_regs pointer */
-	call	vc_switch_off_ist
+	.if \vector == X86_TRAP_VC
+		call	vc_switch_off_ist
+	.else
+		call	hv_switch_off_ist	
+	.endif
+
 	movq	%rax, %rsp		/* Switch to new stack */
 
 	ENCODE_FRAME_POINTER
@@ -568,10 +577,7 @@ SYM_CODE_START(\asmsym)
 
 	/* Switch to the regular task stack */
 .Lfrom_usermode_switch_stack_\@:
-	idtentry_body user_\cfunc, has_error_code=1
-
-_ASM_NOKPROBE(\asmsym)
-SYM_CODE_END(\asmsym)
+	idtentry_body user_\cfunc, \has_error_code
 .endm
 #endif
 
diff --git a/arch/x86/include/asm/cpu_entry_area.h b/arch/x86/include/asm/cpu_entry_area.h
index 462fc34f1317..2186ed601b4a 100644
--- a/arch/x86/include/asm/cpu_entry_area.h
+++ b/arch/x86/include/asm/cpu_entry_area.h
@@ -30,6 +30,10 @@
 	char	VC_stack[optional_stack_size];			\
 	char	VC2_stack_guard[guardsize];			\
 	char	VC2_stack[optional_stack_size];			\
+	char	HV_stack_guard[guardsize];			\
+	char	HV_stack[optional_stack_size];			\
+	char	HV2_stack_guard[guardsize];			\
+	char	HV2_stack[optional_stack_size];			\
 	char	IST_top_guard[guardsize];			\
 
 /* The exception stacks' physical storage. No guard pages required */
@@ -52,6 +56,8 @@ enum exception_stack_ordering {
 	ESTACK_MCE,
 	ESTACK_VC,
 	ESTACK_VC2,
+	ESTACK_HV,
+	ESTACK_HV2,
 	N_EXCEPTION_STACKS
 };
 
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index b241af4ce9b4..b0f3501b2767 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -317,6 +317,19 @@ static __always_inline void __##func(struct pt_regs *regs)
 	__visible noinstr void kernel_##func(struct pt_regs *regs, unsigned long error_code);	\
 	__visible noinstr void   user_##func(struct pt_regs *regs, unsigned long error_code)
 
+
+/**
+ * DECLARE_IDTENTRY_HV - Declare functions for the HV entry point
+ * @vector:	Vector number (ignored for C)
+ * @func:	Function name of the entry point
+ *
+ * Maps to DECLARE_IDTENTRY_RAW, but declares also the user C handler.
+ */
+#define DECLARE_IDTENTRY_HV(vector, func)				\
+	DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func);			\
+	__visible noinstr void kernel_##func(struct pt_regs *regs);	\
+	__visible noinstr void   user_##func(struct pt_regs *regs)
+
 /**
  * DEFINE_IDTENTRY_IST - Emit code for IST entry points
  * @func:	Function name of the entry point
@@ -376,6 +389,26 @@ static __always_inline void __##func(struct pt_regs *regs)
 #define DEFINE_IDTENTRY_VC_USER(func)				\
 	DEFINE_IDTENTRY_RAW_ERRORCODE(user_##func)
 
+/**
+ * DEFINE_IDTENTRY_HV_KERNEL - Emit code for HV injection handler
+ *			       when raised from kernel mode
+ * @func:	Function name of the entry point
+ *
+ * Maps to DEFINE_IDTENTRY_RAW
+ */
+#define DEFINE_IDTENTRY_HV_KERNEL(func)					\
+	DEFINE_IDTENTRY_RAW(kernel_##func)
+
+/**
+ * DEFINE_IDTENTRY_HV_USER - Emit code for HV injection handler
+ *			     when raised from user mode
+ * @func:	Function name of the entry point
+ *
+ * Maps to DEFINE_IDTENTRY_RAW
+ */
+#define DEFINE_IDTENTRY_HV_USER(func)					\
+	DEFINE_IDTENTRY_RAW(user_##func)
+
 #else	/* CONFIG_X86_64 */
 
 /**
@@ -463,8 +496,10 @@ __visible noinstr void func(struct pt_regs *regs,			\
 	DECLARE_IDTENTRY(vector, func)
 
 # define DECLARE_IDTENTRY_VC(vector, func)				\
-	idtentry_vc vector asm_##func func
+	idtentry_sev vector asm_##func func has_error_code=1
 
+# define DECLARE_IDTENTRY_HV(vector, func)				\
+	idtentry_sev vector asm_##func func has_error_code=0
 #else
 # define DECLARE_IDTENTRY_MCE(vector, func)				\
 	DECLARE_IDTENTRY(vector, func)
@@ -618,9 +653,10 @@ DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF,	xenpv_exc_double_fault);
 DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_CP,	exc_control_protection);
 #endif
 
-/* #VC */
+/* #VC & #HV */
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 DECLARE_IDTENTRY_VC(X86_TRAP_VC,	exc_vmm_communication);
+DECLARE_IDTENTRY_HV(X86_TRAP_HV,	exc_hv_injection);
 #endif
 
 #ifdef CONFIG_XEN_PV
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index e9e2c3ba5923..0bd7dab676c5 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -29,6 +29,7 @@
 #define	IST_INDEX_DB		2
 #define	IST_INDEX_MCE		3
 #define	IST_INDEX_VC		4
+#define	IST_INDEX_HV		5
 
 /*
  * Set __PAGE_OFFSET to the most negative possible address +
diff --git a/arch/x86/include/asm/trapnr.h b/arch/x86/include/asm/trapnr.h
index f5d2325aa0b7..c6583631cecb 100644
--- a/arch/x86/include/asm/trapnr.h
+++ b/arch/x86/include/asm/trapnr.h
@@ -26,6 +26,7 @@
 #define X86_TRAP_XF		19	/* SIMD Floating-Point Exception */
 #define X86_TRAP_VE		20	/* Virtualization Exception */
 #define X86_TRAP_CP		21	/* Control Protection Exception */
+#define X86_TRAP_HV		28	/* HV injected exception in SNP restricted mode */
 #define X86_TRAP_VC		29	/* VMM Communication Exception */
 #define X86_TRAP_IRET		32	/* IRET Exception */
 
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 47ecfff2c83d..6795d3e517d6 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -16,6 +16,7 @@ asmlinkage __visible notrace
 struct pt_regs *fixup_bad_iret(struct pt_regs *bad_regs);
 void __init trap_init(void);
 asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs);
+asmlinkage __visible noinstr struct pt_regs *hv_switch_off_ist(struct pt_regs *eregs);
 #endif
 
 extern bool ibt_selftest(void);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8cd4126d8253..5bc44bcf6e48 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2172,6 +2172,7 @@ static inline void tss_setup_ist(struct tss_struct *tss)
 	tss->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE);
 	/* Only mapped when SEV-ES is active */
 	tss->x86_tss.ist[IST_INDEX_VC] = __this_cpu_ist_top_va(VC);
+	tss->x86_tss.ist[IST_INDEX_HV] = __this_cpu_ist_top_va(HV);
 }
 
 #else /* CONFIG_X86_64 */
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index f05339fee778..6d8f8864810c 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -26,11 +26,14 @@ static const char * const exception_stack_names[] = {
 		[ ESTACK_MCE	]	= "#MC",
 		[ ESTACK_VC	]	= "#VC",
 		[ ESTACK_VC2	]	= "#VC2",
+		[ ESTACK_HV	]	= "#HV",
+		[ ESTACK_HV2	]	= "#HV2",
+		
 };
 
 const char *stack_type_name(enum stack_type type)
 {
-	BUILD_BUG_ON(N_EXCEPTION_STACKS != 6);
+	BUILD_BUG_ON(N_EXCEPTION_STACKS != 8);
 
 	if (type == STACK_TYPE_TASK)
 		return "TASK";
@@ -89,6 +92,8 @@ struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {
 	EPAGERANGE(MCE),
 	EPAGERANGE(VC),
 	EPAGERANGE(VC2),
+	EPAGERANGE(HV),
+	EPAGERANGE(HV2),
 };
 
 static __always_inline bool in_exception_stack(unsigned long *stack, struct stack_info *info)
@@ -98,7 +103,7 @@ static __always_inline bool in_exception_stack(unsigned long *stack, struct stac
 	struct pt_regs *regs;
 	unsigned int k;
 
-	BUILD_BUG_ON(N_EXCEPTION_STACKS != 6);
+	BUILD_BUG_ON(N_EXCEPTION_STACKS != 8);
 
 	begin = (unsigned long)__this_cpu_read(cea_exception_stacks);
 	/*
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index a58c6bc1cd68..48c0a7e1dbcb 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -113,6 +113,7 @@ static const __initconst struct idt_data def_idts[] = {
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 	ISTG(X86_TRAP_VC,		asm_exc_vmm_communication, IST_INDEX_VC),
+	ISTG(X86_TRAP_HV,		asm_exc_hv_injection, IST_INDEX_HV),
 #endif
 
 	SYSG(X86_TRAP_OF,		asm_exc_overflow),
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 20f3fd8ade2f..7b06d7c0914f 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2006,6 +2006,59 @@ DEFINE_IDTENTRY_VC_USER(exc_vmm_communication)
 	irqentry_exit_to_user_mode(regs);
 }
 
+static bool hv_raw_handle_exception(struct pt_regs *regs)
+{
+	return false;
+}
+
+static __always_inline bool on_hv_fallback_stack(struct pt_regs *regs)
+{
+	unsigned long sp = (unsigned long)regs;
+
+	return (sp >= __this_cpu_ist_bottom_va(HV2) && sp < __this_cpu_ist_top_va(HV2));
+}
+
+DEFINE_IDTENTRY_HV_USER(exc_hv_injection)
+{
+	irqentry_enter_from_user_mode(regs);
+	instrumentation_begin();
+
+	if (!hv_raw_handle_exception(regs)) {
+		/*
+		 * Do not kill the machine if user-space triggered the
+		 * exception. Send SIGBUS instead and let user-space deal
+		 * with it.
+		 */
+		force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)0);
+	}
+
+	instrumentation_end();
+	irqentry_exit_to_user_mode(regs);
+}
+
+DEFINE_IDTENTRY_HV_KERNEL(exc_hv_injection)
+{
+	irqentry_state_t irq_state;
+
+	irq_state = irqentry_enter(regs);
+	instrumentation_begin();
+
+	if (!hv_raw_handle_exception(regs)) {
+		pr_emerg("PANIC: Unhandled #HV exception in kernel space\n");
+
+		/* Show some debug info */
+		show_regs(regs);
+
+		/* Ask hypervisor to sev_es_terminate */
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
+
+		panic("Returned from Terminate-Request to Hypervisor\n");
+	}
+
+	instrumentation_end();
+	irqentry_exit(regs, irq_state);
+}
+
 bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 {
 	unsigned long exit_code = regs->orig_ax;
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index d317dc3d06a3..d29debec8134 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -905,6 +905,46 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r
 
 	return regs_ret;
 }
+
+asmlinkage __visible noinstr struct pt_regs *hv_switch_off_ist(struct pt_regs *regs)
+{
+	unsigned long sp, *stack;
+	struct stack_info info;
+	struct pt_regs *regs_ret;
+
+	/*
+	 * In the SYSCALL entry path the RSP value comes from user-space - don't
+	 * trust it and switch to the current kernel stack
+	 */
+	if (ip_within_syscall_gap(regs)) {
+		sp = this_cpu_read(pcpu_hot.top_of_stack);
+		goto sync;
+	}
+
+	/*
+	 * From here on the RSP value is trusted. Now check whether entry
+	 * happened from a safe stack. Not safe are the entry or unknown stacks,
+	 * use the fall-back stack instead in this case.
+	 */
+	sp    = regs->sp;
+	stack = (unsigned long *)sp;
+
+	if (!get_stack_info_noinstr(stack, current, &info) || info.type == STACK_TYPE_ENTRY ||
+	    info.type > STACK_TYPE_EXCEPTION_LAST)
+		sp = __this_cpu_ist_top_va(HV2);
+sync:
+	/*
+	 * Found a safe stack - switch to it as if the entry didn't happen via
+	 * IST stack. The code below only copies pt_regs, the real switch happens
+	 * in assembly code.
+	 */
+	sp = ALIGN_DOWN(sp, 8) - sizeof(*regs_ret);
+
+	regs_ret = (struct pt_regs *)sp;
+	*regs_ret = *regs;
+
+	return regs_ret;
+}
 #endif
 
 asmlinkage __visible noinstr struct pt_regs *fixup_bad_iret(struct pt_regs *bad_regs)
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index e91500a80963..97554fa0ff30 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -160,6 +160,8 @@ static void __init percpu_setup_exception_stacks(unsigned int cpu)
 		if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) {
 			cea_map_stack(VC);
 			cea_map_stack(VC2);
+			cea_map_stack(HV);
+			cea_map_stack(HV2);
 		}
 	}
 }
-- 
2.25.1

[RFC PATCH V5 12/15] x86/sev: Add Check of #HV event in path

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Add check_hv_pending() and check_hv_pending_after_irq() to
check queued #HV event when irq is disabled.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
 arch/x86/entry/entry_64.S       | 18 ++++++++++++++++
 arch/x86/include/asm/irqflags.h | 14 +++++++++++-
 arch/x86/kernel/sev.c           | 38 +++++++++++++++++++++++++++++++++
 3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 653b1f10699b..147b850babf6 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1019,6 +1019,15 @@ SYM_CODE_END(paranoid_entry)
  * R15 - old SPEC_CTRL
  */
 SYM_CODE_START_LOCAL(paranoid_exit)
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	/*
+	 * If a #HV was delivered during execution and interrupts were
+	 * disabled, then check if it can be handled before the iret
+	 * (which may re-enable interrupts).
+	 */
+	mov     %rsp, %rdi
+	call    check_hv_pending
+#endif
 	UNWIND_HINT_REGS
 
 	/*
@@ -1143,6 +1152,15 @@ SYM_CODE_START(error_entry)
 SYM_CODE_END(error_entry)
 
 SYM_CODE_START_LOCAL(error_return)
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	/*
+	 * If a #HV was delivered during execution and interrupts were
+	 * disabled, then check if it can be handled before the iret
+	 * (which may re-enable interrupts).
+	 */
+	mov     %rsp, %rdi
+	call    check_hv_pending
+#endif
 	UNWIND_HINT_REGS
 	DEBUG_ENTRY_ASSERT_IRQS_OFF
 	testb	$3, CS(%rsp)
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 8c5ae649d2df..d09ec6d76591 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -11,6 +11,10 @@
 /*
  * Interrupt control:
  */
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+void check_hv_pending(struct pt_regs *regs);
+void check_hv_pending_irq_enable(void);
+#endif
 
 /* Declaration required for gcc < 4.9 to prevent -Werror=missing-prototypes */
 extern inline unsigned long native_save_fl(void);
@@ -40,12 +44,20 @@ static __always_inline void native_irq_disable(void)
 static __always_inline void native_irq_enable(void)
 {
 	asm volatile("sti": : :"memory");
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	check_hv_pending_irq_enable();
+#endif
 }
 
 static __always_inline void native_safe_halt(void)
 {
 	mds_idle_clear_cpu_buffers();
-	asm volatile("sti; hlt": : :"memory");
+	asm volatile("sti": : :"memory");
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	check_hv_pending_irq_enable();
+#endif
+	asm volatile("hlt": : :"memory");
 }
 
 static __always_inline void native_halt(void)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 7b06d7c0914f..e2bb19605a46 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -181,6 +181,44 @@ void noinstr __sev_es_ist_enter(struct pt_regs *regs)
 	this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], new_ist);
 }
 
+static void do_exc_hv(struct pt_regs *regs)
+{
+	/* Handle #HV exception. */
+}
+
+void check_hv_pending(struct pt_regs *regs)
+{
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	if ((regs->flags & X86_EFLAGS_IF) == 0)
+		return;
+
+	do_exc_hv(regs);
+}
+
+void check_hv_pending_irq_enable(void)
+{
+	struct pt_regs regs;
+
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	memset(&regs, 0, sizeof(struct pt_regs));
+	asm volatile("movl %%cs, %%eax;" : "=a" (regs.cs));
+	asm volatile("movl %%ss, %%eax;" : "=a" (regs.ss));
+	regs.orig_ax = 0xffffffff;
+	regs.flags = native_save_fl();
+
+	/*
+	 * Disable irq when handle pending #HV events after
+	 * re-enabling irq.
+	 */
+	asm volatile("cli" : : : "memory");
+	do_exc_hv(&regs);
+	asm volatile("sti" : : : "memory");
+}
+
 void noinstr __sev_es_ist_exit(void)
 {
 	unsigned long ist;
-- 
2.25.1

[RFC PATCH V5 13/15] x86/sev: Add AMD sev-snp enlightened guest support on hyperv

[Tianyu Lan]

From: Tianyu Lan <tiala@microsoft.com>

Enable #HV exception to handle interrupt requests from hypervisor.

Co-developed-by: Lendacky Thomas <thomas.lendacky@amd.com>
Co-developed-by: Kalra Ashish <ashish.kalra@amd.com>
Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC V3:
       * Check NMI event when irq is disabled.
       * Remove redundant variable
---
 arch/x86/include/asm/mem_encrypt.h |   2 +
 arch/x86/include/uapi/asm/svm.h    |   4 +
 arch/x86/kernel/sev.c              | 314 ++++++++++++++++++++++++-----
 arch/x86/kernel/traps.c            |   2 +
 4 files changed, 266 insertions(+), 56 deletions(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index b7126701574c..9299caeca69f 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -50,6 +50,7 @@ void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages,
 void __init mem_encrypt_free_decrypted_mem(void);
 
 void __init sev_es_init_vc_handling(void);
+void __init sev_snp_init_hv_handling(void);
 
 #define __bss_decrypted __section(".bss..decrypted")
 
@@ -73,6 +74,7 @@ static inline void __init sme_encrypt_kernel(struct boot_params *bp) { }
 static inline void __init sme_enable(struct boot_params *bp) { }
 
 static inline void sev_es_init_vc_handling(void) { }
+static inline void sev_snp_init_hv_handling(void) { }
 
 static inline int __init
 early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index 80e1df482337..828d624a38cf 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -115,6 +115,10 @@
 #define SVM_VMGEXIT_AP_CREATE_ON_INIT		0
 #define SVM_VMGEXIT_AP_CREATE			1
 #define SVM_VMGEXIT_AP_DESTROY			2
+#define SVM_VMGEXIT_HV_DOORBELL_PAGE		0x80000014
+#define SVM_VMGEXIT_GET_PREFERRED_HV_DOORBELL_PAGE	0
+#define SVM_VMGEXIT_SET_HV_DOORBELL_PAGE		1
+#define SVM_VMGEXIT_QUERY_HV_DOORBELL_PAGE		2
 #define SVM_VMGEXIT_HV_FEATURES			0x8000fffd
 #define SVM_VMGEXIT_TERM_REQUEST		0x8000fffe
 #define SVM_VMGEXIT_TERM_REASON(reason_set, reason_code)	\
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index e2bb19605a46..b6dafeb0edbe 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -124,6 +124,152 @@ struct sev_config {
 
 static struct sev_config sev_cfg __read_mostly;
 
+static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state);
+static noinstr void __sev_put_ghcb(struct ghcb_state *state);
+static int vmgexit_hv_doorbell_page(struct ghcb *ghcb, u64 op, u64 pa);
+static void sev_snp_setup_hv_doorbell_page(struct ghcb *ghcb);
+
+union hv_pending_events {
+	u16 events;
+	struct {
+		u8 vector;
+		u8 nmi : 1;
+		u8 mc : 1;
+		u8 reserved1 : 5;
+		u8 no_further_signal : 1;
+	};
+};
+
+struct sev_hv_doorbell_page {
+	union hv_pending_events pending_events;
+	u8 no_eoi_required;
+	u8 reserved2[61];
+	u8 padding[4032];
+};
+
+struct sev_snp_runtime_data {
+	struct sev_hv_doorbell_page hv_doorbell_page;
+};
+
+static DEFINE_PER_CPU(struct sev_snp_runtime_data*, snp_runtime_data);
+
+static inline u64 sev_es_rd_ghcb_msr(void)
+{
+	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
+}
+
+static __always_inline void sev_es_wr_ghcb_msr(u64 val)
+{
+	u32 low, high;
+
+	low  = (u32)(val);
+	high = (u32)(val >> 32);
+
+	native_wrmsr(MSR_AMD64_SEV_ES_GHCB, low, high);
+}
+
+struct sev_hv_doorbell_page *sev_snp_current_doorbell_page(void)
+{
+	return &this_cpu_read(snp_runtime_data)->hv_doorbell_page;
+}
+
+static u8 sev_hv_pending(void)
+{
+	return sev_snp_current_doorbell_page()->pending_events.events;
+}
+
+#define sev_hv_pending_nmi	\
+		sev_snp_current_doorbell_page()->pending_events.nmi
+
+static void hv_doorbell_apic_eoi_write(u32 reg, u32 val)
+{
+	if (xchg(&sev_snp_current_doorbell_page()->no_eoi_required, 0) & 0x1)
+		return;
+
+	BUG_ON(reg != APIC_EOI);
+	apic->write(reg, val);
+}
+
+static void do_exc_hv(struct pt_regs *regs)
+{
+	union hv_pending_events pending_events;
+
+	while (sev_hv_pending()) {
+		pending_events.events = xchg(
+			&sev_snp_current_doorbell_page()->pending_events.events,
+			0);
+
+		if (pending_events.nmi)
+			exc_nmi(regs);
+
+#ifdef CONFIG_X86_MCE
+		if (pending_events.mc)
+			exc_machine_check(regs);
+#endif
+
+		if (!pending_events.vector)
+			return;
+
+		if (pending_events.vector < FIRST_EXTERNAL_VECTOR) {
+			/* Exception vectors */
+			WARN(1, "exception shouldn't happen\n");
+		} else if (pending_events.vector == FIRST_EXTERNAL_VECTOR) {
+			sysvec_irq_move_cleanup(regs);
+		} else if (pending_events.vector == IA32_SYSCALL_VECTOR) {
+			WARN(1, "syscall shouldn't happen\n");
+		} else if (pending_events.vector >= FIRST_SYSTEM_VECTOR) {
+			switch (pending_events.vector) {
+#if IS_ENABLED(CONFIG_HYPERV)
+			case HYPERV_STIMER0_VECTOR:
+				sysvec_hyperv_stimer0(regs);
+				break;
+			case HYPERVISOR_CALLBACK_VECTOR:
+				sysvec_hyperv_callback(regs);
+				break;
+#endif
+#ifdef CONFIG_SMP
+			case RESCHEDULE_VECTOR:
+				sysvec_reschedule_ipi(regs);
+				break;
+			case IRQ_MOVE_CLEANUP_VECTOR:
+				sysvec_irq_move_cleanup(regs);
+				break;
+			case REBOOT_VECTOR:
+				sysvec_reboot(regs);
+				break;
+			case CALL_FUNCTION_SINGLE_VECTOR:
+				sysvec_call_function_single(regs);
+				break;
+			case CALL_FUNCTION_VECTOR:
+				sysvec_call_function(regs);
+				break;
+#endif
+#ifdef CONFIG_X86_LOCAL_APIC
+			case ERROR_APIC_VECTOR:
+				sysvec_error_interrupt(regs);
+				break;
+			case SPURIOUS_APIC_VECTOR:
+				sysvec_spurious_apic_interrupt(regs);
+				break;
+			case LOCAL_TIMER_VECTOR:
+				sysvec_apic_timer_interrupt(regs);
+				break;
+			case X86_PLATFORM_IPI_VECTOR:
+				sysvec_x86_platform_ipi(regs);
+				break;
+#endif
+			case 0x0:
+				break;
+			default:
+				panic("Unexpected vector %d\n", vector);
+				unreachable();
+			}
+		} else {
+			common_interrupt(regs, pending_events.vector);
+		}
+	}
+}
+
 static __always_inline bool on_vc_stack(struct pt_regs *regs)
 {
 	unsigned long sp = regs->sp;
@@ -181,18 +327,19 @@ void noinstr __sev_es_ist_enter(struct pt_regs *regs)
 	this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], new_ist);
 }
 
-static void do_exc_hv(struct pt_regs *regs)
-{
-	/* Handle #HV exception. */
-}
-
 void check_hv_pending(struct pt_regs *regs)
 {
 	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
 		return;
 
-	if ((regs->flags & X86_EFLAGS_IF) == 0)
+	/* Handle NMI when irq is disabled. */
+	if ((regs->flags & X86_EFLAGS_IF) == 0) {
+		if (sev_hv_pending_nmi) {
+			exc_nmi(regs);
+			sev_hv_pending_nmi = 0;
+		}
 		return;
+	}
 
 	do_exc_hv(regs);
 }
@@ -233,68 +380,35 @@ void noinstr __sev_es_ist_exit(void)
 	this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], *(unsigned long *)ist);
 }
 
-/*
- * Nothing shall interrupt this code path while holding the per-CPU
- * GHCB. The backup GHCB is only for NMIs interrupting this path.
- *
- * Callers must disable local interrupts around it.
- */
-static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state)
+static bool sev_restricted_injection_enabled(void)
+{
+	return sev_status & MSR_AMD64_SNP_RESTRICTED_INJ;
+}
+
+void __init sev_snp_init_hv_handling(void)
 {
 	struct sev_es_runtime_data *data;
+	struct ghcb_state state;
 	struct ghcb *ghcb;
+	unsigned long flags;
 
 	WARN_ON(!irqs_disabled());
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP) || !sev_restricted_injection_enabled())
+		return;
 
 	data = this_cpu_read(runtime_data);
-	ghcb = &data->ghcb_page;
-
-	if (unlikely(data->ghcb_active)) {
-		/* GHCB is already in use - save its contents */
-
-		if (unlikely(data->backup_ghcb_active)) {
-			/*
-			 * Backup-GHCB is also already in use. There is no way
-			 * to continue here so just kill the machine. To make
-			 * panic() work, mark GHCBs inactive so that messages
-			 * can be printed out.
-			 */
-			data->ghcb_active        = false;
-			data->backup_ghcb_active = false;
-
-			instrumentation_begin();
-			panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use");
-			instrumentation_end();
-		}
-
-		/* Mark backup_ghcb active before writing to it */
-		data->backup_ghcb_active = true;
 
-		state->ghcb = &data->backup_ghcb;
+	local_irq_save(flags);
 
-		/* Backup GHCB content */
-		*state->ghcb = *ghcb;
-	} else {
-		state->ghcb = NULL;
-		data->ghcb_active = true;
-	}
+	ghcb = __sev_get_ghcb(&state);
 
-	return ghcb;
-}
+	sev_snp_setup_hv_doorbell_page(ghcb);
 
-static inline u64 sev_es_rd_ghcb_msr(void)
-{
-	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
-}
-
-static __always_inline void sev_es_wr_ghcb_msr(u64 val)
-{
-	u32 low, high;
+	__sev_put_ghcb(&state);
 
-	low  = (u32)(val);
-	high = (u32)(val >> 32);
+	apic_set_eoi_write(hv_doorbell_apic_eoi_write);
 
-	native_wrmsr(MSR_AMD64_SEV_ES_GHCB, low, high);
+	local_irq_restore(flags);
 }
 
 static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt,
@@ -555,6 +669,69 @@ static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt
 /* Include code shared with pre-decompression boot stage */
 #include "sev-shared.c"
 
+/*
+ * Nothing shall interrupt this code path while holding the per-CPU
+ * GHCB. The backup GHCB is only for NMIs interrupting this path.
+ *
+ * Callers must disable local interrupts around it.
+ */
+static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state)
+{
+	struct sev_es_runtime_data *data;
+	struct ghcb *ghcb;
+
+	WARN_ON(!irqs_disabled());
+
+	data = this_cpu_read(runtime_data);
+	ghcb = &data->ghcb_page;
+
+	if (unlikely(data->ghcb_active)) {
+		/* GHCB is already in use - save its contents */
+
+		if (unlikely(data->backup_ghcb_active)) {
+			/*
+			 * Backup-GHCB is also already in use. There is no way
+			 * to continue here so just kill the machine. To make
+			 * panic() work, mark GHCBs inactive so that messages
+			 * can be printed out.
+			 */
+			data->ghcb_active        = false;
+			data->backup_ghcb_active = false;
+
+			instrumentation_begin();
+			panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use");
+			instrumentation_end();
+		}
+
+		/* Mark backup_ghcb active before writing to it */
+		data->backup_ghcb_active = true;
+
+		state->ghcb = &data->backup_ghcb;
+
+		/* Backup GHCB content */
+		*state->ghcb = *ghcb;
+	} else {
+		state->ghcb = NULL;
+		data->ghcb_active = true;
+	}
+
+	return ghcb;
+}
+
+static void sev_snp_setup_hv_doorbell_page(struct ghcb *ghcb)
+{
+	u64 pa;
+	enum es_result ret;
+
+	pa = __pa(sev_snp_current_doorbell_page());
+	vc_ghcb_invalidate(ghcb);
+	ret = vmgexit_hv_doorbell_page(ghcb,
+				       SVM_VMGEXIT_SET_HV_DOORBELL_PAGE,
+				       pa);
+	if (ret != ES_OK)
+		panic("SEV-SNP: failed to set up #HV doorbell page");
+}
+
 static noinstr void __sev_put_ghcb(struct ghcb_state *state)
 {
 	struct sev_es_runtime_data *data;
@@ -1283,6 +1460,7 @@ static void snp_register_per_cpu_ghcb(void)
 	ghcb = &data->ghcb_page;
 
 	snp_register_ghcb_early(__pa(ghcb));
+	sev_snp_setup_hv_doorbell_page(ghcb);
 }
 
 void setup_ghcb(void)
@@ -1322,6 +1500,11 @@ void setup_ghcb(void)
 		snp_register_ghcb_early(__pa(&boot_ghcb_page));
 }
 
+int vmgexit_hv_doorbell_page(struct ghcb *ghcb, u64 op, u64 pa)
+{
+	return sev_es_ghcb_hv_call(ghcb, NULL, SVM_VMGEXIT_HV_DOORBELL_PAGE, op, pa);
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 static void sev_es_ap_hlt_loop(void)
 {
@@ -1395,6 +1578,7 @@ static void __init alloc_runtime_data(int cpu)
 static void __init init_ghcb(int cpu)
 {
 	struct sev_es_runtime_data *data;
+	struct sev_snp_runtime_data *snp_data;
 	int err;
 
 	data = per_cpu(runtime_data, cpu);
@@ -1406,6 +1590,19 @@ static void __init init_ghcb(int cpu)
 
 	memset(&data->ghcb_page, 0, sizeof(data->ghcb_page));
 
+	snp_data = memblock_alloc(sizeof(*snp_data), PAGE_SIZE);
+	if (!snp_data)
+		panic("Can't allocate SEV-SNP runtime data");
+
+	err = early_set_memory_decrypted((unsigned long)&snp_data->hv_doorbell_page,
+					 sizeof(snp_data->hv_doorbell_page));
+	if (err)
+		panic("Can't map #HV doorbell pages unencrypted");
+
+	memset(&snp_data->hv_doorbell_page, 0, sizeof(snp_data->hv_doorbell_page));
+
+	per_cpu(snp_runtime_data, cpu) = snp_data;
+
 	data->ghcb_active = false;
 	data->backup_ghcb_active = false;
 }
@@ -2046,7 +2243,12 @@ DEFINE_IDTENTRY_VC_USER(exc_vmm_communication)
 
 static bool hv_raw_handle_exception(struct pt_regs *regs)
 {
-	return false;
+	/* Clear the no_further_signal bit */
+	sev_snp_current_doorbell_page()->pending_events.events &= 0x7fff;
+
+	check_hv_pending(regs);
+
+	return true;
 }
 
 static __always_inline bool on_hv_fallback_stack(struct pt_regs *regs)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index d29debec8134..1aa6cab2394b 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -1503,5 +1503,7 @@ void __init trap_init(void)
 	cpu_init_exception_handling();
 	/* Setup traps as cpu_init() might #GP */
 	idt_setup_traps();
+	sev_snp_init_hv_handling();
+
 	cpu_init();
 }
-- 
2.25.1

[RFC PATCH V5 14/15] x86/sev: optimize system vector processing invoked from #HV exception

[Tianyu Lan]

From: Ashish Kalra <ashish.kalra@amd.com>

Construct system vector table and dispatch system vector exceptions through
sysvec_table from #HV exception handler instead of explicitly calling each
system vector. The system vector table is created dynamically and is placed
in a new named ELF section.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 arch/x86/entry/entry_64.S     |  6 +++
 arch/x86/kernel/sev.c         | 70 +++++++++++++----------------------
 arch/x86/kernel/vmlinux.lds.S |  7 ++++
 3 files changed, 38 insertions(+), 45 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 147b850babf6..f86b319d0a9e 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -419,6 +419,12 @@ SYM_CODE_START(\asmsym)
 
 _ASM_NOKPROBE(\asmsym)
 SYM_CODE_END(\asmsym)
+	.if \vector >= FIRST_SYSTEM_VECTOR && \vector < NR_VECTORS
+		.section .system_vectors, "aw"
+		.byte \vector
+		.quad \cfunc
+		.previous
+	.endif
 .endm
 
 /*
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index b6dafeb0edbe..b6becf158598 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -153,6 +153,16 @@ struct sev_snp_runtime_data {
 
 static DEFINE_PER_CPU(struct sev_snp_runtime_data*, snp_runtime_data);
 
+static void (*sysvec_table[NR_VECTORS - FIRST_SYSTEM_VECTOR])
+		(struct pt_regs *regs) __ro_after_init;
+
+struct sysvec_entry {
+	unsigned char vector;
+	void (*sysvec_func)(struct pt_regs *regs);
+} __packed;
+
+extern struct sysvec_entry __system_vectors[], __system_vectors_end[];
+
 static inline u64 sev_es_rd_ghcb_msr(void)
 {
 	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
@@ -218,51 +228,11 @@ static void do_exc_hv(struct pt_regs *regs)
 		} else if (pending_events.vector == IA32_SYSCALL_VECTOR) {
 			WARN(1, "syscall shouldn't happen\n");
 		} else if (pending_events.vector >= FIRST_SYSTEM_VECTOR) {
-			switch (pending_events.vector) {
-#if IS_ENABLED(CONFIG_HYPERV)
-			case HYPERV_STIMER0_VECTOR:
-				sysvec_hyperv_stimer0(regs);
-				break;
-			case HYPERVISOR_CALLBACK_VECTOR:
-				sysvec_hyperv_callback(regs);
-				break;
-#endif
-#ifdef CONFIG_SMP
-			case RESCHEDULE_VECTOR:
-				sysvec_reschedule_ipi(regs);
-				break;
-			case IRQ_MOVE_CLEANUP_VECTOR:
-				sysvec_irq_move_cleanup(regs);
-				break;
-			case REBOOT_VECTOR:
-				sysvec_reboot(regs);
-				break;
-			case CALL_FUNCTION_SINGLE_VECTOR:
-				sysvec_call_function_single(regs);
-				break;
-			case CALL_FUNCTION_VECTOR:
-				sysvec_call_function(regs);
-				break;
-#endif
-#ifdef CONFIG_X86_LOCAL_APIC
-			case ERROR_APIC_VECTOR:
-				sysvec_error_interrupt(regs);
-				break;
-			case SPURIOUS_APIC_VECTOR:
-				sysvec_spurious_apic_interrupt(regs);
-				break;
-			case LOCAL_TIMER_VECTOR:
-				sysvec_apic_timer_interrupt(regs);
-				break;
-			case X86_PLATFORM_IPI_VECTOR:
-				sysvec_x86_platform_ipi(regs);
-				break;
-#endif
-			case 0x0:
-				break;
-			default:
-				panic("Unexpected vector %d\n", vector);
-				unreachable();
+			if (!(sysvec_table[pending_events.vector - FIRST_SYSTEM_VECTOR])) {
+				WARN(1, "system vector entry 0x%x is NULL\n",
+				     pending_events.vector);
+			} else {
+				(*sysvec_table[pending_events.vector - FIRST_SYSTEM_VECTOR])(regs);
 			}
 		} else {
 			common_interrupt(regs, pending_events.vector);
@@ -385,6 +355,14 @@ static bool sev_restricted_injection_enabled(void)
 	return sev_status & MSR_AMD64_SNP_RESTRICTED_INJ;
 }
 
+static void __init construct_sysvec_table(void)
+{
+	struct sysvec_entry *p;
+
+	for (p = __system_vectors; p < __system_vectors_end; p++)
+		sysvec_table[p->vector - FIRST_SYSTEM_VECTOR] = p->sysvec_func;
+}
+
 void __init sev_snp_init_hv_handling(void)
 {
 	struct sev_es_runtime_data *data;
@@ -409,6 +387,8 @@ void __init sev_snp_init_hv_handling(void)
 	apic_set_eoi_write(hv_doorbell_apic_eoi_write);
 
 	local_irq_restore(flags);
+
+	construct_sysvec_table();
 }
 
 static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt,
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 25f155205770..c37165d8e877 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -338,6 +338,13 @@ SECTIONS
 		*(.altinstr_replacement)
 	}
 
+	. = ALIGN(8);
+	.system_vectors : AT(ADDR(.system_vectors) - LOAD_OFFSET) {
+		__system_vectors = .;
+		*(.system_vectors)
+		__system_vectors_end = .;
+	}
+
 	. = ALIGN(8);
 	.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
 		__apicdrivers = .;
-- 
2.25.1

[RFC PATCH V5 15/15] x86/sev: Fix interrupt exit code paths from #HV exception

[Tianyu Lan]

From: Ashish Kalra <ashish.kalra@amd.com>

Add checks in interrupt exit code paths in case of returns
to user mode to check if currently executing the #HV handler
then don't follow the irqentry_exit_to_user_mode path as
that can potentially cause the #HV handler to be
preempted and rescheduled on another CPU. Rescheduled #HV
handler on another cpu will cause interrupts to be handled
on a different cpu than the injected one, causing
invalid EOIs and missed/lost guest interrupts and
corresponding hangs and/or per-cpu IRQs handled on
non-intended cpu.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
Change since RFC v3:
       * Add check of hv_handling_events in the do_exc_hv()
       	 to avoid nested entry.
---
 arch/x86/include/asm/idtentry.h | 66 +++++++++++++++++++++++++++++++++
 arch/x86/kernel/sev.c           | 37 +++++++++++++++++-
 2 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index b0f3501b2767..415b7e14c227 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -13,6 +13,10 @@
 
 #include <asm/irq_stack.h>
 
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+noinstr void irqentry_exit_hv_cond(struct pt_regs *regs, irqentry_state_t state);
+#endif
+
 /**
  * DECLARE_IDTENTRY - Declare functions for simple IDT entry points
  *		      No error code pushed by hardware
@@ -176,6 +180,7 @@ __visible noinstr void func(struct pt_regs *regs, unsigned long error_code)
 #define DECLARE_IDTENTRY_IRQ(vector, func)				\
 	DECLARE_IDTENTRY_ERRORCODE(vector, func)
 
+#ifndef CONFIG_AMD_MEM_ENCRYPT
 /**
  * DEFINE_IDTENTRY_IRQ - Emit code for device interrupt IDT entry points
  * @func:	Function name of the entry point
@@ -205,6 +210,26 @@ __visible noinstr void func(struct pt_regs *regs,			\
 }									\
 									\
 static noinline void __##func(struct pt_regs *regs, u32 vector)
+#else
+
+#define DEFINE_IDTENTRY_IRQ(func)					\
+static void __##func(struct pt_regs *regs, u32 vector);		\
+									\
+__visible noinstr void func(struct pt_regs *regs,			\
+			    unsigned long error_code)			\
+{									\
+	irqentry_state_t state = irqentry_enter(regs);			\
+	u32 vector = (u32)(u8)error_code;				\
+									\
+	instrumentation_begin();					\
+	kvm_set_cpu_l1tf_flush_l1d();					\
+	run_irq_on_irqstack_cond(__##func, regs, vector);		\
+	instrumentation_end();						\
+	irqentry_exit_hv_cond(regs, state);				\
+}									\
+									\
+static noinline void __##func(struct pt_regs *regs, u32 vector)
+#endif
 
 /**
  * DECLARE_IDTENTRY_SYSVEC - Declare functions for system vector entry points
@@ -221,6 +246,7 @@ static noinline void __##func(struct pt_regs *regs, u32 vector)
 #define DECLARE_IDTENTRY_SYSVEC(vector, func)				\
 	DECLARE_IDTENTRY(vector, func)
 
+#ifndef CONFIG_AMD_MEM_ENCRYPT
 /**
  * DEFINE_IDTENTRY_SYSVEC - Emit code for system vector IDT entry points
  * @func:	Function name of the entry point
@@ -245,6 +271,26 @@ __visible noinstr void func(struct pt_regs *regs)			\
 }									\
 									\
 static noinline void __##func(struct pt_regs *regs)
+#else
+
+#define DEFINE_IDTENTRY_SYSVEC(func)					\
+static void __##func(struct pt_regs *regs);				\
+									\
+__visible noinstr void func(struct pt_regs *regs)			\
+{									\
+	irqentry_state_t state = irqentry_enter(regs);			\
+									\
+	instrumentation_begin();					\
+	kvm_set_cpu_l1tf_flush_l1d();					\
+	run_sysvec_on_irqstack_cond(__##func, regs);			\
+	instrumentation_end();						\
+	irqentry_exit_hv_cond(regs, state);				\
+}									\
+									\
+static noinline void __##func(struct pt_regs *regs)
+#endif
+
+#ifndef CONFIG_AMD_MEM_ENCRYPT
 
 /**
  * DEFINE_IDTENTRY_SYSVEC_SIMPLE - Emit code for simple system vector IDT
@@ -274,6 +320,26 @@ __visible noinstr void func(struct pt_regs *regs)			\
 }									\
 									\
 static __always_inline void __##func(struct pt_regs *regs)
+#else
+
+#define DEFINE_IDTENTRY_SYSVEC_SIMPLE(func)				\
+static __always_inline void __##func(struct pt_regs *regs);		\
+									\
+__visible noinstr void func(struct pt_regs *regs)			\
+{									\
+	irqentry_state_t state = irqentry_enter(regs);			\
+									\
+	instrumentation_begin();					\
+	__irq_enter_raw();						\
+	kvm_set_cpu_l1tf_flush_l1d();					\
+	__##func(regs);						\
+	__irq_exit_raw();						\
+	instrumentation_end();						\
+	irqentry_exit_hv_cond(regs, state);				\
+}									\
+									\
+static __always_inline void __##func(struct pt_regs *regs)
+#endif
 
 /**
  * DECLARE_IDTENTRY_XENCB - Declare functions for XEN HV callback entry point
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index b6becf158598..69b55075ddfe 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -149,6 +149,10 @@ struct sev_hv_doorbell_page {
 
 struct sev_snp_runtime_data {
 	struct sev_hv_doorbell_page hv_doorbell_page;
+	/*
+	 * Indication that we are currently handling #HV events.
+	 */
+	bool hv_handling_events;
 };
 
 static DEFINE_PER_CPU(struct sev_snp_runtime_data*, snp_runtime_data);
@@ -204,6 +208,12 @@ static void do_exc_hv(struct pt_regs *regs)
 {
 	union hv_pending_events pending_events;
 
+	/* Avoid nested entry. */
+	if (this_cpu_read(snp_runtime_data)->hv_handling_events)
+		return;
+
+	this_cpu_read(snp_runtime_data)->hv_handling_events = true;
+
 	while (sev_hv_pending()) {
 		pending_events.events = xchg(
 			&sev_snp_current_doorbell_page()->pending_events.events,
@@ -218,7 +228,7 @@ static void do_exc_hv(struct pt_regs *regs)
 #endif
 
 		if (!pending_events.vector)
-			return;
+			goto out;
 
 		if (pending_events.vector < FIRST_EXTERNAL_VECTOR) {
 			/* Exception vectors */
@@ -238,6 +248,9 @@ static void do_exc_hv(struct pt_regs *regs)
 			common_interrupt(regs, pending_events.vector);
 		}
 	}
+
+out:
+	this_cpu_read(snp_runtime_data)->hv_handling_events = false;
 }
 
 static __always_inline bool on_vc_stack(struct pt_regs *regs)
@@ -2542,3 +2555,25 @@ static int __init snp_init_platform_device(void)
 	return 0;
 }
 device_initcall(snp_init_platform_device);
+
+noinstr void irqentry_exit_hv_cond(struct pt_regs *regs, irqentry_state_t state)
+{
+	/*
+	 * Check whether this returns to user mode, if so and if
+	 * we are currently executing the #HV handler then we don't
+	 * want to follow the irqentry_exit_to_user_mode path as
+	 * that can potentially cause the #HV handler to be
+	 * preempted and rescheduled on another CPU. Rescheduled #HV
+	 * handler on another cpu will cause interrupts to be handled
+	 * on a different cpu than the injected one, causing
+	 * invalid EOIs and missed/lost guest interrupts and
+	 * corresponding hangs and/or per-cpu IRQs handled on
+	 * non-intended cpu.
+	 */
+	if (user_mode(regs) &&
+	    this_cpu_read(snp_runtime_data)->hv_handling_events)
+		return;
+
+	/* follow normal interrupt return/exit path */
+	irqentry_exit(regs, state);
+}
-- 
2.25.1

RE: [EXTERNAL] [RFC PATCH V5 09/15] x86/hyperv: Add smp support for sev-snp guest

[Saurabh Singh Sengar]

> -----Original Message-----
> From: Tianyu Lan <ltykernel@gmail.com>
> Sent: Monday, May 1, 2023 2:27 PM
> To: luto@kernel.org; tglx@linutronix.de; mingo@redhat.com; bp@alien8.de;
> dave.hansen@linux.intel.com; x86@kernel.org; hpa@zytor.com;
> seanjc@google.com; pbonzini@redhat.com; jgross@suse.com; Tianyu Lan
> <Tianyu.Lan@microsoft.com>; kirill@shutemov.name;
> jiangshan.ljs@antgroup.com; peterz@infradead.org; ashish.kalra@amd.com;
> srutherford@google.com; akpm@linux-foundation.org;
> anshuman.khandual@arm.com; pawan.kumar.gupta@linux.intel.com;
> adrian.hunter@intel.com; daniel.sneddon@linux.intel.com;
> alexander.shishkin@linux.intel.com; sandipan.das@amd.com;
> ray.huang@amd.com; brijesh.singh@amd.com; michael.roth@amd.com;
> thomas.lendacky@amd.com; venu.busireddy@oracle.com;
> sterritt@google.com; tony.luck@intel.com; samitolvanen@google.com;
> fenghua.yu@intel.com
> Cc: pangupta@amd.com; linux-kernel@vger.kernel.org; kvm@vger.kernel.org;
> linux-hyperv@vger.kernel.org; linux-arch@vger.kernel.org
> Subject: [EXTERNAL] [RFC PATCH V5 09/15] x86/hyperv: Add smp support for
> sev-snp guest
> 
> From: Tianyu Lan <tiala@microsoft.com>
> 
> The wakeup_secondary_cpu callback was populated with wakeup_
> cpu_via_vmgexit() which doesn't work for Hyper-V and Hyper-V requires to
> call Hyper-V specific hvcall to start APs. So override it with Hyper-V specific
> hook to start AP sev_es_save_area data structure.
> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> Change sicne RFC v3:
>        * Replace struct sev_es_save_area with struct
>          vmcb_save_area
>        * Move code from mshyperv.c to ivm.c
> 
> Change since RFC v2:
>        * Add helper function to initialize segment
>        * Fix some coding style
> ---
>  arch/x86/hyperv/ivm.c             | 89 +++++++++++++++++++++++++++++++
>  arch/x86/include/asm/mshyperv.h   | 18 +++++++
>  arch/x86/include/asm/sev.h        | 13 +++++
>  arch/x86/include/asm/svm.h        | 15 +++++-
>  arch/x86/kernel/cpu/mshyperv.c    | 13 ++++-
>  arch/x86/kernel/sev.c             |  4 +-
>  include/asm-generic/hyperv-tlfs.h | 19 +++++++
>  7 files changed, 166 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index
> 522eab55c0dd..0ef46f1874e6 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -22,11 +22,15 @@
>  #include <asm/sev.h>
>  #include <asm/realmode.h>
>  #include <asm/e820/api.h>
> +#include <asm/desc.h>
> 
>  #ifdef CONFIG_AMD_MEM_ENCRYPT
> 
>  #define GHCB_USAGE_HYPERV_CALL	1
> 
> +static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted
> +__aligned(PAGE_SIZE); static u8 ap_start_stack[PAGE_SIZE]
> +__aligned(PAGE_SIZE);
> +
>  union hv_ghcb {
>  	struct ghcb ghcb;
>  	struct {
> @@ -442,6 +446,91 @@ __init void hv_sev_init_mem_and_cpu(void)
>  	}
>  }
> 
> +#define hv_populate_vmcb_seg(seg, gdtr_base)			\
> +do {								\
> +	if (seg.selector) {					\
> +		seg.base = 0;					\
> +		seg.limit = HV_AP_SEGMENT_LIMIT;		\
> +		seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5);	\
> +		seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \
> +	}	
						\

< snip>

>  	ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa)); diff --git a/include/asm-
> generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
> index f4e4cc4f965f..959b075591b2 100644
> --- a/include/asm-generic/hyperv-tlfs.h
> +++ b/include/asm-generic/hyperv-tlfs.h
> @@ -149,6 +149,7 @@ union hv_reference_tsc_msr {
>  #define HVCALL_ENABLE_VP_VTL			0x000f
>  #define HVCALL_NOTIFY_LONG_SPIN_WAIT		0x0008
>  #define HVCALL_SEND_IPI				0x000b
> +#define HVCALL_ENABLE_VP_VTL			0x000f
>  #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX	0x0013
>  #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX	0x0014
>  #define HVCALL_SEND_IPI_EX			0x0015
> @@ -168,6 +169,7 @@ union hv_reference_tsc_msr {
>  #define HVCALL_RETARGET_INTERRUPT		0x007e
>  #define HVCALL_START_VP				0x0099
>  #define HVCALL_GET_VP_ID_FROM_APIC_ID		0x009a
> +#define HVCALL_START_VIRTUAL_PROCESSOR		0x0099
>  #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af  #define
> HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0  #define
> HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db @@ -223,6
> +225,7 @@ enum HV_GENERIC_SET_FORMAT {
>  #define HV_STATUS_INVALID_PORT_ID		17
>  #define HV_STATUS_INVALID_CONNECTION_ID		18
>  #define HV_STATUS_INSUFFICIENT_BUFFERS		19
> +#define HV_STATUS_TIME_OUT                      120
>  #define HV_STATUS_VTL_ALREADY_ENABLED		134
> 
>  /*
> @@ -783,6 +786,22 @@ struct hv_input_unmap_device_interrupt {
>  	struct hv_interrupt_entry interrupt_entry;  } __packed;
> 
> +struct hv_enable_vp_vtl_input {
> +	u64 partitionid;
> +	u32 vpindex;
> +	u8 targetvtl;
> +	u8 padding[3];
> +	u8 context[0xe0];
> +} __packed;
> +
> +struct hv_start_virtual_processor_input {
> +	u64 partitionid;
> +	u32 vpindex;
> +	u8 targetvtl;
> +	u8 padding[3];
> +	u8 context[0xe0];
> +} __packed;

"struct hv_enable_vp_vtl " is defined in arch/x86/include/asm/hyperv-tlfs.h. Please check if that can be reused in place of both the above structs.
- Saurabh

> +
>  #define HV_SOURCE_SHADOW_NONE               0x0
>  #define HV_SOURCE_SHADOW_BRIDGE_BUS_RANGE   0x1
> 
> --
> 2.25.1

RE: [EXTERNAL] [RFC PATCH V5 09/15] x86/hyperv: Add smp support for sev-snp guest

[Saurabh Singh Sengar]

> -----Original Message-----
> From: Tianyu Lan <ltykernel@gmail.com>
> Sent: Monday, May 1, 2023 2:27 PM
> To: luto@kernel.org; tglx@linutronix.de; mingo@redhat.com; bp@alien8.de;
> dave.hansen@linux.intel.com; x86@kernel.org; hpa@zytor.com;
> seanjc@google.com; pbonzini@redhat.com; jgross@suse.com; Tianyu Lan
> <Tianyu.Lan@microsoft.com>; kirill@shutemov.name;
> jiangshan.ljs@antgroup.com; peterz@infradead.org; ashish.kalra@amd.com;
> srutherford@google.com; akpm@linux-foundation.org;
> anshuman.khandual@arm.com; pawan.kumar.gupta@linux.intel.com;
> adrian.hunter@intel.com; daniel.sneddon@linux.intel.com;
> alexander.shishkin@linux.intel.com; sandipan.das@amd.com;
> ray.huang@amd.com; brijesh.singh@amd.com; michael.roth@amd.com;
> thomas.lendacky@amd.com; venu.busireddy@oracle.com;
> sterritt@google.com; tony.luck@intel.com; samitolvanen@google.com;
> fenghua.yu@intel.com
> Cc: pangupta@amd.com; linux-kernel@vger.kernel.org; kvm@vger.kernel.org;
> linux-hyperv@vger.kernel.org; linux-arch@vger.kernel.org
> Subject: [EXTERNAL] [RFC PATCH V5 09/15] x86/hyperv: Add smp support for
> sev-snp guest
> 
> From: Tianyu Lan <tiala@microsoft.com>
> 
> The wakeup_secondary_cpu callback was populated with wakeup_
> cpu_via_vmgexit() which doesn't work for Hyper-V and Hyper-V requires to
> call Hyper-V specific hvcall to start APs. So override it with Hyper-V specific
> hook to start AP sev_es_save_area data structure.
> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> Change sicne RFC v3:
>        * Replace struct sev_es_save_area with struct
>          vmcb_save_area
>        * Move code from mshyperv.c to ivm.c
> 
> Change since RFC v2:
>        * Add helper function to initialize segment
>        * Fix some coding style
> ---
>  arch/x86/hyperv/ivm.c             | 89 +++++++++++++++++++++++++++++++
>  arch/x86/include/asm/mshyperv.h   | 18 +++++++
>  arch/x86/include/asm/sev.h        | 13 +++++
>  arch/x86/include/asm/svm.h        | 15 +++++-
>  arch/x86/kernel/cpu/mshyperv.c    | 13 ++++-
>  arch/x86/kernel/sev.c             |  4 +-
>  include/asm-generic/hyperv-tlfs.h | 19 +++++++
>  7 files changed, 166 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index
> 522eab55c0dd..0ef46f1874e6 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -22,11 +22,15 @@
>  #include <asm/sev.h>
>  #include <asm/realmode.h>
>  #include <asm/e820/api.h>
> +#include <asm/desc.h>
> 
>  #ifdef CONFIG_AMD_MEM_ENCRYPT
> 
>  #define GHCB_USAGE_HYPERV_CALL	1
> 
> +static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted
> +__aligned(PAGE_SIZE); static u8 ap_start_stack[PAGE_SIZE]
> +__aligned(PAGE_SIZE);
> +
>  union hv_ghcb {
>  	struct ghcb ghcb;
>  	struct {
> @@ -442,6 +446,91 @@ __init void hv_sev_init_mem_and_cpu(void)
>  	}
>  }
> 
> +#define hv_populate_vmcb_seg(seg, gdtr_base)			\
> +do {								\
> +	if (seg.selector) {					\
> +		seg.base = 0;					\
> +		seg.limit = HV_AP_SEGMENT_LIMIT;		\
> +		seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5);	\

<snip>

> generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
> index f4e4cc4f965f..959b075591b2 100644
> --- a/include/asm-generic/hyperv-tlfs.h
> +++ b/include/asm-generic/hyperv-tlfs.h
> @@ -149,6 +149,7 @@ union hv_reference_tsc_msr {
>  #define HVCALL_ENABLE_VP_VTL			0x000f
>  #define HVCALL_NOTIFY_LONG_SPIN_WAIT		0x0008
>  #define HVCALL_SEND_IPI				0x000b
> +#define HVCALL_ENABLE_VP_VTL			0x000f

HVCALL_ENABLE_VP_VTL is already defined.

>  #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX	0x0013
>  #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX	0x0014
>  #define HVCALL_SEND_IPI_EX			0x0015
> @@ -168,6 +169,7 @@ union hv_reference_tsc_msr {
>  #define HVCALL_RETARGET_INTERRUPT		0x007e
>  #define HVCALL_START_VP				0x0099
>  #define HVCALL_GET_VP_ID_FROM_APIC_ID		0x009a
> +#define HVCALL_START_VIRTUAL_PROCESSOR		0x0099

We already have HVCALL_START_VP no need of defining HVCALL_START_VIRTUAL_PROCESSOR.
- Saurabh

>  #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af  #define
> HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0  #define
> HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db @@ -223,6
> +225,7 @@ enum HV_GENERIC_SET_FORMAT {
>  #define HV_STATUS_INVALID_PORT_ID		17
>  #define HV_STATUS_INVALID_CONNECTION_ID		18
>  #define HV_STATUS_INSUFFICIENT_BUFFERS		19
> +#define HV_STATUS_TIME_OUT                      120
>  #define HV_STATUS_VTL_ALREADY_ENABLED		134
> 
>  /*
> @@ -783,6 +786,22 @@ struct hv_input_unmap_device_interrupt {
>  	struct hv_interrupt_entry interrupt_entry;  } __packed;
> 
> +struct hv_enable_vp_vtl_input {
> +	u64 partitionid;
> +	u32 vpindex;
> +	u8 targetvtl;
> +	u8 padding[3];
> +	u8 context[0xe0];
> +} __packed;
> +
> +struct hv_start_virtual_processor_input {
> +	u64 partitionid;
> +	u32 vpindex;
> +	u8 targetvtl;
> +	u8 padding[3];
> +	u8 context[0xe0];
> +} __packed;
> +
>  #define HV_SOURCE_SHADOW_NONE               0x0
>  #define HV_SOURCE_SHADOW_BRIDGE_BUS_RANGE   0x1
> 
> --
> 2.25.1

Re: [RFC PATCH V5 02/15] x86/hyperv: Decrypt hv vp assist page in sev-snp enlightened guest

[Tom Lendacky]

On 5/1/23 03:57, Tianyu Lan wrote:
> From: Tianyu Lan <tiala@microsoft.com>
> 
> hv vp assist page is shared between sev snp guest and hyperv. Decrypt
> the page when use it.

You aren't actually decrypting the page, you're changing the mapping from 
private/encrypted to shared/unencrypted (hence the memset that follows to 
clear the page to zeroes).

And please capitalize where necessary, e.g., SEV-SNP, Hyper-V, etc.

Thanks,
Tom

> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
>   arch/x86/hyperv/hv_init.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index a5f9474f08e1..9f3e2d71d015 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -18,6 +18,7 @@
>   #include <asm/hyperv-tlfs.h>
>   #include <asm/mshyperv.h>
>   #include <asm/idtentry.h>
> +#include <asm/set_memory.h>
>   #include <linux/kexec.h>
>   #include <linux/version.h>
>   #include <linux/vmalloc.h>
> @@ -113,6 +114,11 @@ static int hv_cpu_init(unsigned int cpu)
>   
>   	}
>   	if (!WARN_ON(!(*hvp))) {
> +		if (hv_isolation_type_en_snp()) {
> +			WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
> +			memset(*hvp, 0, PAGE_SIZE);
> +		}
> +
>   		msr.enable = 1;
>   		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
>   	}

Re: [RFC PATCH V5 09/15] x86/hyperv: Add smp support for sev-snp guest

[Tom Lendacky]

[-- Attachment #1: Type: text/plain, Size: 10986 bytes --]

On 5/1/23 03:57, Tianyu Lan wrote:
> From: Tianyu Lan <tiala@microsoft.com>
> 
> The wakeup_secondary_cpu callback was populated with wakeup_
> cpu_via_vmgexit() which doesn't work for Hyper-V and Hyper-V
> requires to call Hyper-V specific hvcall to start APs. So override
> it with Hyper-V specific hook to start AP sev_es_save_area data
> structure.
> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> Change sicne RFC v3:
>         * Replace struct sev_es_save_area with struct
>           vmcb_save_area
>         * Move code from mshyperv.c to ivm.c
> 
> Change since RFC v2:
>         * Add helper function to initialize segment
>         * Fix some coding style
> ---
>   arch/x86/hyperv/ivm.c             | 89 +++++++++++++++++++++++++++++++
>   arch/x86/include/asm/mshyperv.h   | 18 +++++++
>   arch/x86/include/asm/sev.h        | 13 +++++
>   arch/x86/include/asm/svm.h        | 15 +++++-
>   arch/x86/kernel/cpu/mshyperv.c    | 13 ++++-
>   arch/x86/kernel/sev.c             |  4 +-
>   include/asm-generic/hyperv-tlfs.h | 19 +++++++
>   7 files changed, 166 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> index 522eab55c0dd..0ef46f1874e6 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -22,11 +22,15 @@
>   #include <asm/sev.h>
>   #include <asm/realmode.h>
>   #include <asm/e820/api.h>
> +#include <asm/desc.h>
>   
>   #ifdef CONFIG_AMD_MEM_ENCRYPT
>   
>   #define GHCB_USAGE_HYPERV_CALL	1
>   
> +static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
> +static u8 ap_start_stack[PAGE_SIZE] __aligned(PAGE_SIZE);
> +
>   union hv_ghcb {
>   	struct ghcb ghcb;
>   	struct {
> @@ -442,6 +446,91 @@ __init void hv_sev_init_mem_and_cpu(void)
>   	}
>   }
>   
> +#define hv_populate_vmcb_seg(seg, gdtr_base)			\
> +do {								\
> +	if (seg.selector) {					\
> +		seg.base = 0;					\
> +		seg.limit = HV_AP_SEGMENT_LIMIT;		\
> +		seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5);	\
> +		seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \
> +	}							\
> +} while (0)							\
> +
> +int hv_snp_boot_ap(int cpu, unsigned long start_ip)
> +{
> +	struct sev_es_save_area *vmsa = (struct sev_es_save_area *)
> +		__get_free_page(GFP_KERNEL | __GFP_ZERO);
> +	struct desc_ptr gdtr;
> +	u64 ret, retry = 5;
> +	struct hv_start_virtual_processor_input *start_vp_input;
> +	union sev_rmp_adjust rmp_adjust;
> +	unsigned long flags;
> +
> +	native_store_gdt(&gdtr);
> +
> +	vmsa->gdtr.base = gdtr.address;
> +	vmsa->gdtr.limit = gdtr.size;
> +
> +	asm volatile("movl %%es, %%eax;" : "=a" (vmsa->es.selector));
> +	hv_populate_vmcb_seg(vmsa->es, vmsa->gdtr.base);
> +
> +	asm volatile("movl %%cs, %%eax;" : "=a" (vmsa->cs.selector));
> +	hv_populate_vmcb_seg(vmsa->cs, vmsa->gdtr.base);
> +
> +	asm volatile("movl %%ss, %%eax;" : "=a" (vmsa->ss.selector));
> +	hv_populate_vmcb_seg(vmsa->ss, vmsa->gdtr.base);
> +
> +	asm volatile("movl %%ds, %%eax;" : "=a" (vmsa->ds.selector));
> +	hv_populate_vmcb_seg(vmsa->ds, vmsa->gdtr.base);
> +
> +	vmsa->efer = native_read_msr(MSR_EFER);
> +
> +	asm volatile("movq %%cr4, %%rax;" : "=a" (vmsa->cr4));
> +	asm volatile("movq %%cr3, %%rax;" : "=a" (vmsa->cr3));
> +	asm volatile("movq %%cr0, %%rax;" : "=a" (vmsa->cr0));
> +
> +	vmsa->xcr0 = 1;
> +	vmsa->g_pat = HV_AP_INIT_GPAT_DEFAULT;
> +	vmsa->rip = (u64)secondary_startup_64_no_verify;
> +	vmsa->rsp = (u64)&ap_start_stack[PAGE_SIZE];
> +
> +	vmsa->sev_features.snp = 1;
> +	vmsa->sev_features.restrict_injection = 1;

So this means that any other feature bits set in the BSP won't be set in 
the AP? Shouldn't you be using the BSP value and checking to be sure what 
you really want set is set?

> +
> +	rmp_adjust.as_uint64 = 0;
> +	rmp_adjust.target_vmpl = 1;
> +	rmp_adjust.vmsa = 1;
> +	ret = rmpadjust((unsigned long)vmsa, RMP_PG_SIZE_4K,
> +			rmp_adjust.as_uint64);
> +	if (ret != 0) {
> +		pr_err("RMPADJUST(%llx) failed: %llx\n", (u64)vmsa, ret);
> +		return ret;
> +	}
> +
> +	local_irq_save(flags);
> +	start_vp_input =
> +		(struct hv_start_virtual_processor_input *)ap_start_input_arg;
> +	memset(start_vp_input, 0, sizeof(*start_vp_input));
> +	start_vp_input->partitionid = -1;
> +	start_vp_input->vpindex = cpu;
> +	start_vp_input->targetvtl = ms_hyperv.vtl;
> +	*(u64 *)&start_vp_input->context[0] = __pa(vmsa) | 1;
> +
> +	do {
> +		ret = hv_do_hypercall(HVCALL_START_VP,
> +				      start_vp_input, NULL);
> +	} while (hv_result(ret) == HV_STATUS_TIME_OUT && retry--);
> +
> +	if (!hv_result_success(ret)) {
> +		pr_err("HvCallStartVirtualProcessor failed: %llx\n", ret);
> +		goto done;
> +	}
> +
> +done:
> +	local_irq_restore(flags);
> +	return ret;
> +}
> +
>   void __init hv_vtom_init(void)
>   {
>   	/*


> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
> index 13dc2a9d23c1..0d57cb1c1bb4 100644
> --- a/arch/x86/include/asm/sev.h
> +++ b/arch/x86/include/asm/sev.h
> @@ -88,6 +88,19 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
>   
>   #define RMPADJUST_VMSA_PAGE_BIT		BIT(16)
>   
> +union sev_rmp_adjust {
> +	u64 as_uint64;

Why not "as_u64" or "val" like below ?

> +	struct {
> +		unsigned long target_vmpl : 8;
> +		unsigned long enable_read : 1;
> +		unsigned long enable_write : 1;
> +		unsigned long enable_user_execute : 1;
> +		unsigned long enable_kernel_execute : 1;
> +		unsigned long reserved1 : 4;
> +		unsigned long vmsa : 1;

Please do these as
		u64 target_vmpl		: 8,
		    enable_read		: 1,
		    ...
		    vmsa		: 1;

But why not continue to use the bit definition format that already exists 
in this file (just above what you added)? If you want to do these union 
type changes (here and below), it should be a separate patch that converts 
all the usage sites and then this patch can be purely functional.

> +	};
> +};
> +
>   /* SNP Guest message request */
>   struct snp_req_data {
>   	unsigned long req_gpa;
> diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
> index 770dcf75eaa9..cd6bf989d918 100644
> --- a/arch/x86/include/asm/svm.h
> +++ b/arch/x86/include/asm/svm.h
> @@ -425,7 +425,20 @@ struct sev_es_save_area {
>   	u64 guest_exit_info_2;
>   	u64 guest_exit_int_info;
>   	u64 guest_nrip;
> -	u64 sev_features;
> +	union {
> +		struct {
> +			u64 snp                     : 1;
> +			u64 vtom                    : 1;
> +			u64 reflectvc               : 1;
> +			u64 restrict_injection      : 1;
> +			u64 alternate_injection     : 1;
> +			u64 full_debug              : 1;
> +			u64 reserved1               : 1;
> +			u64 snpbtb_isolation        : 1;
> +			u64 resrved2                : 56;

Ditto here for the bit definitions and fix the spelling of resrved2. 
Although, as above, why aren't you expanding the use of the bit 
definitions that are in here (SVM_SEV_FEAT_SNP_ACTIVE) instead of 
modifying the structure?

> +		};
> +		u64 val;

This should be consistent with what you do above in the rmp_adjust union.

> +	} sev_features;
>   	u64 vintr_ctrl;
>   	u64 guest_exit_code;
>   	u64 virtual_tom;
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index dea9b881180b..0c5f9f7bd7ba 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -295,6 +295,16 @@ static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
>   
>   	native_smp_prepare_cpus(max_cpus);
>   
> +	/*
> +	 *  Override wakeup_secondary_cpu_64 callback for SEV-SNP
> +	 *  enlightened guest.
> +	 */
> +	if (hv_isolation_type_en_snp())
> +		apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap;
> +
> +	if (!hv_root_partition)
> +		return;
> +
>   #ifdef CONFIG_X86_64
>   	for_each_present_cpu(i) {
>   		if (i == 0)
> @@ -502,8 +512,7 @@ static void __init ms_hyperv_init_platform(void)
>   
>   # ifdef CONFIG_SMP
>   	smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
> -	if (hv_root_partition)
> -		smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
> +	smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
>   # endif
>   
>   	/*
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index b031244d6d2d..20f3fd8ade2f 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -1082,7 +1082,7 @@ static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
>   	 *   SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
>   	 */
>   	vmsa->vmpl		= 0;
> -	vmsa->sev_features	= sev_status >> 2;
> +	vmsa->sev_features.val = sev_status >> 2;

Looks like maybe the tab character was lost here between val and the "=" ?

Thanks,
Tom

>   
>   	/* Switch the page over to a VMSA page now that it is initialized */
>   	ret = snp_set_vmsa(vmsa, true);
> @@ -1099,7 +1099,7 @@ static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
>   	ghcb = __sev_get_ghcb(&state);
>   
>   	vc_ghcb_invalidate(ghcb);
> -	ghcb_set_rax(ghcb, vmsa->sev_features);
> +	ghcb_set_rax(ghcb, vmsa->sev_features.val);
>   	ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION);
>   	ghcb_set_sw_exit_info_1(ghcb, ((u64)apic_id << 32) | SVM_VMGEXIT_AP_CREATE);
>   	ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa));
> diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
> index f4e4cc4f965f..959b075591b2 100644
> --- a/include/asm-generic/hyperv-tlfs.h
> +++ b/include/asm-generic/hyperv-tlfs.h
> @@ -149,6 +149,7 @@ union hv_reference_tsc_msr {
>   #define HVCALL_ENABLE_VP_VTL			0x000f
>   #define HVCALL_NOTIFY_LONG_SPIN_WAIT		0x0008
>   #define HVCALL_SEND_IPI				0x000b
> +#define HVCALL_ENABLE_VP_VTL			0x000f
>   #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX	0x0013
>   #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX	0x0014
>   #define HVCALL_SEND_IPI_EX			0x0015
> @@ -168,6 +169,7 @@ union hv_reference_tsc_msr {
>   #define HVCALL_RETARGET_INTERRUPT		0x007e
>   #define HVCALL_START_VP				0x0099
>   #define HVCALL_GET_VP_ID_FROM_APIC_ID		0x009a
> +#define HVCALL_START_VIRTUAL_PROCESSOR		0x0099
>   #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af
>   #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0
>   #define HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db
> @@ -223,6 +225,7 @@ enum HV_GENERIC_SET_FORMAT {
>   #define HV_STATUS_INVALID_PORT_ID		17
>   #define HV_STATUS_INVALID_CONNECTION_ID		18
>   #define HV_STATUS_INSUFFICIENT_BUFFERS		19
> +#define HV_STATUS_TIME_OUT                      120
>   #define HV_STATUS_VTL_ALREADY_ENABLED		134
>   
>   /*
> @@ -783,6 +786,22 @@ struct hv_input_unmap_device_interrupt {
>   	struct hv_interrupt_entry interrupt_entry;
>   } __packed;
>   
> +struct hv_enable_vp_vtl_input {
> +	u64 partitionid;
> +	u32 vpindex;
> +	u8 targetvtl;
> +	u8 padding[3];
> +	u8 context[0xe0];
> +} __packed;
> +
> +struct hv_start_virtual_processor_input {
> +	u64 partitionid;
> +	u32 vpindex;
> +	u8 targetvtl;
> +	u8 padding[3];
> +	u8 context[0xe0];
> +} __packed;
> +
>   #define HV_SOURCE_SHADOW_NONE               0x0
>   #define HV_SOURCE_SHADOW_BRIDGE_BUS_RANGE   0x1
>   

[-- Attachment #2: OpenPGP public key --]
[-- Type: application/pgp-keys, Size: 4881 bytes --]

Re: [RFC PATCH V5 15/15] x86/sev: Fix interrupt exit code paths from #HV exception

[Tom Lendacky]

On 5/1/23 03:57, Tianyu Lan wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
> 
> Add checks in interrupt exit code paths in case of returns
> to user mode to check if currently executing the #HV handler
> then don't follow the irqentry_exit_to_user_mode path as
> that can potentially cause the #HV handler to be
> preempted and rescheduled on another CPU. Rescheduled #HV
> handler on another cpu will cause interrupts to be handled
> on a different cpu than the injected one, causing
> invalid EOIs and missed/lost guest interrupts and
> corresponding hangs and/or per-cpu IRQs handled on
> non-intended cpu.
> 
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>

This should be merged into one of the appropriate #HV patches and just add 
Ashish with a Co-developed-by: tag where appropriate. This would be 
appropriate as a separate only if discovered after the series was merged.

> ---
> Change since RFC v3:
>         * Add check of hv_handling_events in the do_exc_hv()
>         	 to avoid nested entry.
> ---
>   arch/x86/include/asm/idtentry.h | 66 +++++++++++++++++++++++++++++++++
>   arch/x86/kernel/sev.c           | 37 +++++++++++++++++-
>   2 files changed, 102 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index b0f3501b2767..415b7e14c227 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -13,6 +13,10 @@
>   
>   #include <asm/irq_stack.h>
>   
> +#ifdef CONFIG_AMD_MEM_ENCRYPT
> +noinstr void irqentry_exit_hv_cond(struct pt_regs *regs, irqentry_state_t state);
> +#endif
> +
>   /**
>    * DECLARE_IDTENTRY - Declare functions for simple IDT entry points
>    *		      No error code pushed by hardware
> @@ -176,6 +180,7 @@ __visible noinstr void func(struct pt_regs *regs, unsigned long error_code)
>   #define DECLARE_IDTENTRY_IRQ(vector, func)				\
>   	DECLARE_IDTENTRY_ERRORCODE(vector, func)
>   
> +#ifndef CONFIG_AMD_MEM_ENCRYPT
>   /**
>    * DEFINE_IDTENTRY_IRQ - Emit code for device interrupt IDT entry points
>    * @func:	Function name of the entry point
> @@ -205,6 +210,26 @@ __visible noinstr void func(struct pt_regs *regs,			\
>   }									\
>   									\
>   static noinline void __##func(struct pt_regs *regs, u32 vector)
> +#else
> +
> +#define DEFINE_IDTENTRY_IRQ(func)					\
> +static void __##func(struct pt_regs *regs, u32 vector);		\
> +									\
> +__visible noinstr void func(struct pt_regs *regs,			\
> +			    unsigned long error_code)			\
> +{									\
> +	irqentry_state_t state = irqentry_enter(regs);			\
> +	u32 vector = (u32)(u8)error_code;				\
> +									\
> +	instrumentation_begin();					\
> +	kvm_set_cpu_l1tf_flush_l1d();					\
> +	run_irq_on_irqstack_cond(__##func, regs, vector);		\
> +	instrumentation_end();						\
> +	irqentry_exit_hv_cond(regs, state);				\
> +}									\
> +									\
> +static noinline void __##func(struct pt_regs *regs, u32 vector)
> +#endif

This seems like a lot of code duplication. Can't the difference (which is 
the call to irqentry_exit() vs irqentry_exit_hv_cond() be #ifdef'd in the 
current defintion?

Ditto for the changes below, too?

Thanks,
Tom

>   
>   /**
>    * DECLARE_IDTENTRY_SYSVEC - Declare functions for system vector entry points
> @@ -221,6 +246,7 @@ static noinline void __##func(struct pt_regs *regs, u32 vector)
>   #define DECLARE_IDTENTRY_SYSVEC(vector, func)				\
>   	DECLARE_IDTENTRY(vector, func)
>   
> +#ifndef CONFIG_AMD_MEM_ENCRYPT
>   /**
>    * DEFINE_IDTENTRY_SYSVEC - Emit code for system vector IDT entry points
>    * @func:	Function name of the entry point
> @@ -245,6 +271,26 @@ __visible noinstr void func(struct pt_regs *regs)			\
>   }									\
>   									\
>   static noinline void __##func(struct pt_regs *regs)
> +#else
> +
> +#define DEFINE_IDTENTRY_SYSVEC(func)					\
> +static void __##func(struct pt_regs *regs);				\
> +									\
> +__visible noinstr void func(struct pt_regs *regs)			\
> +{									\
> +	irqentry_state_t state = irqentry_enter(regs);			\
> +									\
> +	instrumentation_begin();					\
> +	kvm_set_cpu_l1tf_flush_l1d();					\
> +	run_sysvec_on_irqstack_cond(__##func, regs);			\
> +	instrumentation_end();						\
> +	irqentry_exit_hv_cond(regs, state);				\
> +}									\
> +									\
> +static noinline void __##func(struct pt_regs *regs)
> +#endif
> +
> +#ifndef CONFIG_AMD_MEM_ENCRYPT
>   
>   /**
>    * DEFINE_IDTENTRY_SYSVEC_SIMPLE - Emit code for simple system vector IDT
> @@ -274,6 +320,26 @@ __visible noinstr void func(struct pt_regs *regs)			\
>   }									\
>   									\
>   static __always_inline void __##func(struct pt_regs *regs)
> +#else
> +
> +#define DEFINE_IDTENTRY_SYSVEC_SIMPLE(func)				\
> +static __always_inline void __##func(struct pt_regs *regs);		\
> +									\
> +__visible noinstr void func(struct pt_regs *regs)			\
> +{									\
> +	irqentry_state_t state = irqentry_enter(regs);			\
> +									\
> +	instrumentation_begin();					\
> +	__irq_enter_raw();						\
> +	kvm_set_cpu_l1tf_flush_l1d();					\
> +	__##func(regs);						\
> +	__irq_exit_raw();						\
> +	instrumentation_end();						\
> +	irqentry_exit_hv_cond(regs, state);				\
> +}									\
> +									\
> +static __always_inline void __##func(struct pt_regs *regs)
> +#endif
>   
>   /**
>    * DECLARE_IDTENTRY_XENCB - Declare functions for XEN HV callback entry point
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index b6becf158598..69b55075ddfe 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -149,6 +149,10 @@ struct sev_hv_doorbell_page {
>   
>   struct sev_snp_runtime_data {
>   	struct sev_hv_doorbell_page hv_doorbell_page;
> +	/*
> +	 * Indication that we are currently handling #HV events.
> +	 */
> +	bool hv_handling_events;
>   };
>   
>   static DEFINE_PER_CPU(struct sev_snp_runtime_data*, snp_runtime_data);
> @@ -204,6 +208,12 @@ static void do_exc_hv(struct pt_regs *regs)
>   {
>   	union hv_pending_events pending_events;
>   
> +	/* Avoid nested entry. */
> +	if (this_cpu_read(snp_runtime_data)->hv_handling_events)
> +		return;
> +
> +	this_cpu_read(snp_runtime_data)->hv_handling_events = true;
> +
>   	while (sev_hv_pending()) {
>   		pending_events.events = xchg(
>   			&sev_snp_current_doorbell_page()->pending_events.events,
> @@ -218,7 +228,7 @@ static void do_exc_hv(struct pt_regs *regs)
>   #endif
>   
>   		if (!pending_events.vector)
> -			return;
> +			goto out;
>   
>   		if (pending_events.vector < FIRST_EXTERNAL_VECTOR) {
>   			/* Exception vectors */
> @@ -238,6 +248,9 @@ static void do_exc_hv(struct pt_regs *regs)
>   			common_interrupt(regs, pending_events.vector);
>   		}
>   	}
> +
> +out:
> +	this_cpu_read(snp_runtime_data)->hv_handling_events = false;
>   }
>   
>   static __always_inline bool on_vc_stack(struct pt_regs *regs)
> @@ -2542,3 +2555,25 @@ static int __init snp_init_platform_device(void)
>   	return 0;
>   }
>   device_initcall(snp_init_platform_device);
> +
> +noinstr void irqentry_exit_hv_cond(struct pt_regs *regs, irqentry_state_t state)
> +{
> +	/*
> +	 * Check whether this returns to user mode, if so and if
> +	 * we are currently executing the #HV handler then we don't
> +	 * want to follow the irqentry_exit_to_user_mode path as
> +	 * that can potentially cause the #HV handler to be
> +	 * preempted and rescheduled on another CPU. Rescheduled #HV
> +	 * handler on another cpu will cause interrupts to be handled
> +	 * on a different cpu than the injected one, causing
> +	 * invalid EOIs and missed/lost guest interrupts and
> +	 * corresponding hangs and/or per-cpu IRQs handled on
> +	 * non-intended cpu.
> +	 */
> +	if (user_mode(regs) &&
> +	    this_cpu_read(snp_runtime_data)->hv_handling_events)
> +		return;
> +
> +	/* follow normal interrupt return/exit path */
> +	irqentry_exit(regs, state);
> +}

Re: [RFC PATCH V5 00/15] x86/hyperv/sev: Add AMD sev-snp enlightened guest support on hyperv

[Tom Lendacky]

On 5/1/23 03:57, Tianyu Lan wrote:
> From: Tianyu Lan <tiala@microsoft.com>
> 
> This patchset is to add AMD sev-snp enlightened guest
> support on hyperv. Hyperv uses Linux direct boot mode
> to boot up Linux kernel and so it needs to pvalidate
> system memory by itself.
> 
> In hyperv case, there is no boot loader and so cc blob
> is prepared by hypervisor. In this series, hypervisor
> set the cc blob address directly into boot parameter
> of Linux kernel.
> 
> Shared memory between guests and hypervisor should be
> decrypted and zero memory after decrypt memory. The data
> in the target address. It maybe smearedto avoid smearing
> data.
> 
> Introduce #HV exception support in AMD sev snp code and
> #HV handler.

For bisectability, shouldn't the #HV patches be in place before the 
enlightened SNP support is added, e.g., AP's are launched with the 
restricted injection enabled (even though the BSP will also have that), so 
that things don't crash right away?

Thanks,
Tom

> 
> Change since v4:
>         - Use pgcount to free intput arg page.
>         - Fix encrypt and free page order.
>         - struct_size to calculate array size
>         - Share asm code between #HV and #VC exception.
> 
> Change since v3:
>         - Replace struct sev_es_save_area with struct vmcb_save_area
>         - Move smp, cpu and memory enumerating code from mshyperv.c to ivm.c
>         - Handle nested entry case of do_exc_hv() case.
>         - Check NMI event when irq is disabled
> 
> Change since v2:
>         - Remove validate kernel memory code at boot stage
>         - Split #HV page patch into two parts
>         - Remove HV-APIC change due to enable x2apic from
>         	 host side
>         - Rework vmbus code to handle error of decrypt page
>         - Spilt memory and cpu initialization patch.
> Change since v1:
>         - Remove boot param changes for cc blob address and
>         use setup head to pass cc blob info
>         - Remove unnessary WARN and BUG check
>         - Add system vector table map in the #HV exception
>         - Fix interrupt exit issue when use #HV exception
> 
> Ashish Kalra (2):
>    x86/sev: optimize system vector processing invoked from #HV exception
>    x86/sev: Fix interrupt exit code paths from #HV exception
> 
> Tianyu Lan (13):
>    x86/hyperv: Add sev-snp enlightened guest static key
>    x86/hyperv: Decrypt hv vp assist page in sev-snp enlightened guest
>    x86/hyperv: Set Virtual Trust Level in VMBus init message
>    x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp
>      enlightened guest
>    clocksource/drivers/hyper-v: decrypt hyperv tsc page in sev-snp
>      enlightened guest
>    hv: vmbus: decrypt VMBus pages for sev-snp enlightened guest
>    drivers: hv: Decrypt percpu hvcall input arg page in sev-snp
>      enlightened guest
>    x86/hyperv: Initialize cpu and memory for sev-snp enlightened guest
>    x86/hyperv: Add smp support for sev-snp guest
>    x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES
>    x86/sev: Add a #HV exception handler
>    x86/sev: Add Check of #HV event in path
>    x86/sev: Add AMD sev-snp enlightened guest support on hyperv
> 
>   arch/x86/entry/entry_64.S             |  46 ++-
>   arch/x86/hyperv/hv_init.c             |  42 +++
>   arch/x86/hyperv/ivm.c                 | 186 ++++++++++++
>   arch/x86/include/asm/cpu_entry_area.h |   6 +
>   arch/x86/include/asm/hyperv-tlfs.h    |   7 +
>   arch/x86/include/asm/idtentry.h       | 106 ++++++-
>   arch/x86/include/asm/irqflags.h       |  14 +-
>   arch/x86/include/asm/mem_encrypt.h    |   2 +
>   arch/x86/include/asm/mshyperv.h       |  82 +++++-
>   arch/x86/include/asm/page_64_types.h  |   1 +
>   arch/x86/include/asm/sev.h            |  13 +
>   arch/x86/include/asm/svm.h            |  15 +-
>   arch/x86/include/asm/trapnr.h         |   1 +
>   arch/x86/include/asm/traps.h          |   1 +
>   arch/x86/include/uapi/asm/svm.h       |   4 +
>   arch/x86/kernel/cpu/common.c          |   1 +
>   arch/x86/kernel/cpu/mshyperv.c        |  42 ++-
>   arch/x86/kernel/dumpstack_64.c        |   9 +-
>   arch/x86/kernel/idt.c                 |   1 +
>   arch/x86/kernel/sev.c                 | 408 ++++++++++++++++++++++----
>   arch/x86/kernel/traps.c               |  42 +++
>   arch/x86/kernel/vmlinux.lds.S         |   7 +
>   arch/x86/mm/cpu_entry_area.c          |   2 +
>   drivers/clocksource/hyperv_timer.c    |   2 +-
>   drivers/hv/connection.c               |   1 +
>   drivers/hv/hv.c                       |  41 ++-
>   drivers/hv/hv_common.c                |  27 +-
>   include/asm-generic/hyperv-tlfs.h     |  19 ++
>   include/asm-generic/mshyperv.h        |   1 +
>   include/linux/hyperv.h                |   4 +-
>   30 files changed, 1047 insertions(+), 86 deletions(-)
> 

Re: [RFC PATCH V5 03/15] x86/hyperv: Set Virtual Trust Level in VMBus init message

[Zhi Wang]

On Mon,  1 May 2023 04:57:13 -0400
Tianyu Lan <ltykernel@gmail.com> wrote:

> From: Tianyu Lan <tiala@microsoft.com>
> 
> sev-snp guest provides vtl(Virtual Trust Level) and
> get it from hyperv hvcall via HVCALL_GET_VP_REGISTERS.
> Set target vtl in the VMBus init message.
> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> Change since RFC v4:
>        * Use struct_size to calculate array size.
>        * Fix some coding style
> 
> Change since RFC v3:
>        * Use the standard helper functions to check hypercall result
>        * Fix coding style
> 
> Change since RFC v2:
>        * Rename get_current_vtl() to get_vtl()
>        * Fix some coding style issues
> ---
>  arch/x86/hyperv/hv_init.c          | 36 ++++++++++++++++++++++++++++++
>  arch/x86/include/asm/hyperv-tlfs.h |  7 ++++++
>  drivers/hv/connection.c            |  1 +
>  include/asm-generic/mshyperv.h     |  1 +
>  include/linux/hyperv.h             |  4 ++--
>  5 files changed, 47 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index 9f3e2d71d015..331b855314b7 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -384,6 +384,40 @@ static void __init hv_get_partition_id(void)
>  	local_irq_restore(flags);
>  }
>  
> +static u8 __init get_vtl(void)
> +{
> +	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
> +	struct hv_get_vp_registers_input *input;
> +	struct hv_get_vp_registers_output *output;
> +	u64 vtl = 0;
> +	u64 ret;
> +	unsigned long flags;
> +
> +	local_irq_save(flags);
> +	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
> +	output = (struct hv_get_vp_registers_output *)input;

===
> +	if (!input) {
> +		local_irq_restore(flags);
> +		goto done;
> +	}
> +
===
Is this really necessary?

drivers/hv/hv_common.c:

        hyperv_pcpu_input_arg = alloc_percpu(void  *);
        BUG_ON(!hyperv_pcpu_input_arg);


> +	memset(input, 0, struct_size(input, element, 1));
> +	input->header.partitionid = HV_PARTITION_ID_SELF;
> +	input->header.vpindex = HV_VP_INDEX_SELF;
> +	input->header.inputvtl = 0;
> +	input->element[0].name0 = HV_X64_REGISTER_VSM_VP_STATUS;
> +
> +	ret = hv_do_hypercall(control, input, output);
> +	if (hv_result_success(ret))
> +		vtl = output->as64.low & HV_X64_VTL_MASK;
> +	else
> +		pr_err("Hyper-V: failed to get VTL! %lld", ret);
> +	local_irq_restore(flags);
> +
> +done:
> +	return vtl;
> +}
> +
>  /*
>   * This function is to be invoked early in the boot sequence after the
>   * hypervisor has been detected.
> @@ -512,6 +546,8 @@ void __init hyperv_init(void)
>  	/* Query the VMs extended capability once, so that it can be cached. */
>  	hv_query_ext_cap(0);
>  
> +	/* Find the VTL */
> +	ms_hyperv.vtl = get_vtl();
>  	return;
>  
>  clean_guest_os_id:
> diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
> index cea95dcd27c2..4bf0b315b0ce 100644
> --- a/arch/x86/include/asm/hyperv-tlfs.h
> +++ b/arch/x86/include/asm/hyperv-tlfs.h
> @@ -301,6 +301,13 @@ enum hv_isolation_type {
>  #define HV_X64_MSR_TIME_REF_COUNT	HV_REGISTER_TIME_REF_COUNT
>  #define HV_X64_MSR_REFERENCE_TSC	HV_REGISTER_REFERENCE_TSC
>  
> +/*
> + * Registers are only accessible via HVCALL_GET_VP_REGISTERS hvcall and
> + * there is not associated MSR address.
> + */
> +#define	HV_X64_REGISTER_VSM_VP_STATUS	0x000D0003
> +#define	HV_X64_VTL_MASK			GENMASK(3, 0)
> +
>  /* Hyper-V memory host visibility */
>  enum hv_mem_host_visibility {
>  	VMBUS_PAGE_NOT_VISIBLE		= 0,
> diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
> index 5978e9dbc286..02b54f85dc60 100644
> --- a/drivers/hv/connection.c
> +++ b/drivers/hv/connection.c
> @@ -98,6 +98,7 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
>  	 */
>  	if (version >= VERSION_WIN10_V5) {
>  		msg->msg_sint = VMBUS_MESSAGE_SINT;
> +		msg->msg_vtl = ms_hyperv.vtl;
>  		vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
>  	} else {
>  		msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index 402a8c1c202d..3052130ba4ef 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -48,6 +48,7 @@ struct ms_hyperv_info {
>  		};
>  	};
>  	u64 shared_gpa_boundary;
> +	u8 vtl;
>  };
>  extern struct ms_hyperv_info ms_hyperv;
>  extern bool hv_nested;
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index bfbc37ce223b..1f2bfec4abde 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -665,8 +665,8 @@ struct vmbus_channel_initiate_contact {
>  		u64 interrupt_page;
>  		struct {
>  			u8	msg_sint;
> -			u8	padding1[3];
> -			u32	padding2;
> +			u8	msg_vtl;
> +			u8	reserved[6];
>  		};
>  	};
>  	u64 monitor_page1;

Re: [RFC PATCH V5 03/15] x86/hyperv: Set Virtual Trust Level in VMBus init message

[Tianyu Lan]

On 5/2/2023 12:30 PM, Zhi Wang wrote:
> On Mon,  1 May 2023 04:57:13 -0400
> Tianyu Lan <ltykernel@gmail.com> wrote:
> 
>> From: Tianyu Lan <tiala@microsoft.com>
>>
>> sev-snp guest provides vtl(Virtual Trust Level) and
>> get it from hyperv hvcall via HVCALL_GET_VP_REGISTERS.
>> Set target vtl in the VMBus init message.
>>
>> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
>> ---
>> Change since RFC v4:
>>         * Use struct_size to calculate array size.
>>         * Fix some coding style
>>
>> Change since RFC v3:
>>         * Use the standard helper functions to check hypercall result
>>         * Fix coding style
>>
>> Change since RFC v2:
>>         * Rename get_current_vtl() to get_vtl()
>>         * Fix some coding style issues
>> ---
>>   arch/x86/hyperv/hv_init.c          | 36 ++++++++++++++++++++++++++++++
>>   arch/x86/include/asm/hyperv-tlfs.h |  7 ++++++
>>   drivers/hv/connection.c            |  1 +
>>   include/asm-generic/mshyperv.h     |  1 +
>>   include/linux/hyperv.h             |  4 ++--
>>   5 files changed, 47 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
>> index 9f3e2d71d015..331b855314b7 100644
>> --- a/arch/x86/hyperv/hv_init.c
>> +++ b/arch/x86/hyperv/hv_init.c
>> @@ -384,6 +384,40 @@ static void __init hv_get_partition_id(void)
>>   	local_irq_restore(flags);
>>   }
>>   
>> +static u8 __init get_vtl(void)
>> +{
>> +	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
>> +	struct hv_get_vp_registers_input *input;
>> +	struct hv_get_vp_registers_output *output;
>> +	u64 vtl = 0;
>> +	u64 ret;
>> +	unsigned long flags;
>> +
>> +	local_irq_save(flags);
>> +	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
>> +	output = (struct hv_get_vp_registers_output *)input;
> 
> ===
>> +	if (!input) {
>> +		local_irq_restore(flags);
>> +		goto done;
>> +	}
>> +
> ===
> Is this really necessary?
> 
> drivers/hv/hv_common.c:
> 
>          hyperv_pcpu_input_arg = alloc_percpu(void  *);
>          BUG_ON(!hyperv_pcpu_input_arg);
> 
> 

Hi Zhi:
	The hyperv_pcpu_input_arg is a point to address of input arg
pages and these pages are allocated in the hv_common_cpu_init(). If
it failed to allocate these pages, the value pointed by 
hyperv_pcpu_input_arg will be NULL.
	

Re: [RFC PATCH V5 09/15] x86/hyperv: Add smp support for sev-snp guest

[Tianyu Lan]

On 5/1/2023 8:46 AM, Tom Lendacky wrote:
>> +    vmsa->sev_features.snp = 1;
>> +    vmsa->sev_features.restrict_injection = 1;
> 
> So this means that any other feature bits set in the BSP won't be set in 
> the AP? Shouldn't you be using the BSP value and checking to be sure 
> what you really want set is set?

So far, the snp flag is enough. You are right that we need to keep it as 
same value on the both BSP and APs. will update in the next version.

Re: [EXTERNAL] [RFC PATCH V5 09/15] x86/hyperv: Add smp support for sev-snp guest

[Tianyu Lan]

On 5/1/2023 3:20 AM, Saurabh Singh Sengar wrote:
>> +struct hv_start_virtual_processor_input {
>> +	u64 partitionid;
>> +	u32 vpindex;
>> +	u8 targetvtl;
>> +	u8 padding[3];
>> +	u8 context[0xe0];
>> +} __packed;
> "struct hv_enable_vp_vtl " is defined in arch/x86/include/asm/hyperv-tlfs.h. Please check if that can be reused in place of both the above structs.
> - Saurabh
> 

Yes, these are redundant and will reuse new struct. Thanks.

Re: [RFC PATCH V5 03/15] x86/hyperv: Set Virtual Trust Level in VMBus init message

[Zhi Wang]

On Thu, 4 May 2023 08:38:46 -0700
Tianyu Lan <ltykernel@gmail.com> wrote:

> On 5/2/2023 12:30 PM, Zhi Wang wrote:
> > On Mon,  1 May 2023 04:57:13 -0400
> > Tianyu Lan <ltykernel@gmail.com> wrote:
> > 
> >> From: Tianyu Lan <tiala@microsoft.com>
> >>
> >> sev-snp guest provides vtl(Virtual Trust Level) and
> >> get it from hyperv hvcall via HVCALL_GET_VP_REGISTERS.
> >> Set target vtl in the VMBus init message.
> >>
> >> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> >> ---
> >> Change since RFC v4:
> >>         * Use struct_size to calculate array size.
> >>         * Fix some coding style
> >>
> >> Change since RFC v3:
> >>         * Use the standard helper functions to check hypercall result
> >>         * Fix coding style
> >>
> >> Change since RFC v2:
> >>         * Rename get_current_vtl() to get_vtl()
> >>         * Fix some coding style issues
> >> ---
> >>   arch/x86/hyperv/hv_init.c          | 36 ++++++++++++++++++++++++++++++
> >>   arch/x86/include/asm/hyperv-tlfs.h |  7 ++++++
> >>   drivers/hv/connection.c            |  1 +
> >>   include/asm-generic/mshyperv.h     |  1 +
> >>   include/linux/hyperv.h             |  4 ++--
> >>   5 files changed, 47 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> >> index 9f3e2d71d015..331b855314b7 100644
> >> --- a/arch/x86/hyperv/hv_init.c
> >> +++ b/arch/x86/hyperv/hv_init.c
> >> @@ -384,6 +384,40 @@ static void __init hv_get_partition_id(void)
> >>   	local_irq_restore(flags);
> >>   }
> >>   
> >> +static u8 __init get_vtl(void)
> >> +{
> >> +	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
> >> +	struct hv_get_vp_registers_input *input;
> >> +	struct hv_get_vp_registers_output *output;
> >> +	u64 vtl = 0;
> >> +	u64 ret;
> >> +	unsigned long flags;
> >> +
> >> +	local_irq_save(flags);
> >> +	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
> >> +	output = (struct hv_get_vp_registers_output *)input;
> > 
> > ===
> >> +	if (!input) {
> >> +		local_irq_restore(flags);
> >> +		goto done;
> >> +	}
> >> +
> > ===
> > Is this really necessary?
> > 
> > drivers/hv/hv_common.c:
> > 
> >          hyperv_pcpu_input_arg = alloc_percpu(void  *);
> >          BUG_ON(!hyperv_pcpu_input_arg);
> > 
> > 
> 
> Hi Zhi:
> 	The hyperv_pcpu_input_arg is a point to address of input arg
> pages and these pages are allocated in the hv_common_cpu_init(). If
> it failed to allocate these pages, the value pointed by 
> hyperv_pcpu_input_arg will be NULL.
> 	

Sorry, it seems my email editor dropped some text. I was wondering that
if the check above is necessary as there is a BUG_ON() when allocating
hyperv_pcpu_input_arg.

So when coming to get_vtl(), the hyperv_pcpu_input_arg should not be NULL.
(Guarded by the BUG_ON() in the allocation)?

Re: [RFC PATCH V5 05/15] clocksource/drivers/hyper-v: decrypt hyperv tsc page in sev-snp enlightened guest

[Zhi Wang]

On Mon,  1 May 2023 04:57:15 -0400
Tianyu Lan <ltykernel@gmail.com> wrote:

> From: Tianyu Lan <tiala@microsoft.com>
> 
> Hyper-V tsc page is shared with hypervisor and it should
> be decrypted in sev-snp enlightened guest when it's used.
> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> Change since RFC V2:
>        * Change the Subject line prefix
> ---
>  drivers/clocksource/hyperv_timer.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
> index bcd9042a0c9f..66e29a19770b 100644
> --- a/drivers/clocksource/hyperv_timer.c
> +++ b/drivers/clocksource/hyperv_timer.c
> @@ -376,7 +376,7 @@ EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
>  static union {
>  	struct ms_hyperv_tsc_page page;
>  	u8 reserved[PAGE_SIZE];
> -} tsc_pg __aligned(PAGE_SIZE);
> +} tsc_pg __bss_decrypted __aligned(PAGE_SIZE);
>  

Out of curiosity, this is not a on/off for VM with paravisor and full-enlightened VM, how
does change affect the case of VM with paravisor? I assume the VM with paravisor works fine
without this previously.

>  static struct ms_hyperv_tsc_page *tsc_page = &tsc_pg.page;
>  static unsigned long tsc_pfn;

Re: [RFC PATCH V5 15/15] x86/sev: Fix interrupt exit code paths from #HV exception

[Tianyu Lan]

On 5/1/2023 9:02 AM, Tom Lendacky wrote:
>> From: Ashish Kalra <ashish.kalra@amd.com>
>>
>> Add checks in interrupt exit code paths in case of returns
>> to user mode to check if currently executing the #HV handler
>> then don't follow the irqentry_exit_to_user_mode path as
>> that can potentially cause the #HV handler to be
>> preempted and rescheduled on another CPU. Rescheduled #HV
>> handler on another cpu will cause interrupts to be handled
>> on a different cpu than the injected one, causing
>> invalid EOIs and missed/lost guest interrupts and
>> corresponding hangs and/or per-cpu IRQs handled on
>> non-intended cpu.
>>
>> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> 
> This should be merged into one of the appropriate #HV patches and just 
> add Ashish with a Co-developed-by: tag where appropriate. This would be 
> appropriate as a separate only if discovered after the series was merged.

Sure. Will update in the next version.

Re: [RFC PATCH V5 11/15] x86/sev: Add a #HV exception handler

[Gupta, Pankaj]

Hi Tianyu,

I tried to understand some details of this patch. Please find below
some comments/questions.

Thanks,


> Add a #HV exception handler that uses IST stack.
> 
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> Change since RFC V2:
>         * Remove unnecessary line in the change log.
> ---
>   arch/x86/entry/entry_64.S             | 22 +++++++----
>   arch/x86/include/asm/cpu_entry_area.h |  6 +++
>   arch/x86/include/asm/idtentry.h       | 40 +++++++++++++++++++-
>   arch/x86/include/asm/page_64_types.h  |  1 +
>   arch/x86/include/asm/trapnr.h         |  1 +
>   arch/x86/include/asm/traps.h          |  1 +
>   arch/x86/kernel/cpu/common.c          |  1 +
>   arch/x86/kernel/dumpstack_64.c        |  9 ++++-
>   arch/x86/kernel/idt.c                 |  1 +
>   arch/x86/kernel/sev.c                 | 53 +++++++++++++++++++++++++++
>   arch/x86/kernel/traps.c               | 40 ++++++++++++++++++++
>   arch/x86/mm/cpu_entry_area.c          |  2 +
>   12 files changed, 165 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
> index eccc3431e515..653b1f10699b 100644
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -496,7 +496,7 @@ SYM_CODE_END(\asmsym)
>   
>   #ifdef CONFIG_AMD_MEM_ENCRYPT
>   /**
> - * idtentry_vc - Macro to generate entry stub for #VC
> + * idtentry_sev - Macro to generate entry stub for #VC
>    * @vector:		Vector number
>    * @asmsym:		ASM symbol for the entry point
>    * @cfunc:		C function to be called
> @@ -515,14 +515,18 @@ SYM_CODE_END(\asmsym)
>    *
>    * The macro is only used for one vector, but it is planned to be extended in
>    * the future for the #HV exception.
> - */
> -.macro idtentry_vc vector asmsym cfunc
> +*/
> +.macro idtentry_sev vector asmsym cfunc has_error_code:req
>   SYM_CODE_START(\asmsym)
>   	UNWIND_HINT_IRET_REGS
>   	ENDBR
>   	ASM_CLAC
>   	cld
>   
> +	.if \vector == X86_TRAP_HV
> +		pushq	$-1			/* ORIG_RAX: no syscall */
> +	.endif
> +
>   	/*
>   	 * If the entry is from userspace, switch stacks and treat it as
>   	 * a normal entry.
> @@ -545,7 +549,12 @@ SYM_CODE_START(\asmsym)
>   	 * stack.
>   	 */
>   	movq	%rsp, %rdi		/* pt_regs pointer */
> -	call	vc_switch_off_ist
> +	.if \vector == X86_TRAP_VC
> +		call	vc_switch_off_ist

I think the stack switching logic is similar for #VC & #HV.
So, we can use common function. Just the corresponding fallback
stack switching is different. Maybe we can pass the hint as an
argument (%rsi?) to something like "sev_switch_off_ist()", and use
the corresponding (#HV or #VC) fallbacks stack?

> +	.else
> +		call	hv_switch_off_ist	
> +	.endif
> +
>   	movq	%rax, %rsp		/* Switch to new stack */
>   
>   	ENCODE_FRAME_POINTER
> @@ -568,10 +577,7 @@ SYM_CODE_START(\asmsym)
>   
>   	/* Switch to the regular task stack */
>   .Lfrom_usermode_switch_stack_\@:
> -	idtentry_body user_\cfunc, has_error_code=1
> -
> -_ASM_NOKPROBE(\asmsym)
> -SYM_CODE_END(\asmsym)
> +	idtentry_body user_\cfunc, \has_error_code
>   .endm
>   #endif
>   
> diff --git a/arch/x86/include/asm/cpu_entry_area.h b/arch/x86/include/asm/cpu_entry_area.h
> index 462fc34f1317..2186ed601b4a 100644
> --- a/arch/x86/include/asm/cpu_entry_area.h
> +++ b/arch/x86/include/asm/cpu_entry_area.h
> @@ -30,6 +30,10 @@
>   	char	VC_stack[optional_stack_size];			\
>   	char	VC2_stack_guard[guardsize];			\
>   	char	VC2_stack[optional_stack_size];			\
> +	char	HV_stack_guard[guardsize];			\
> +	char	HV_stack[optional_stack_size];			\
> +	char	HV2_stack_guard[guardsize];			\
> +	char	HV2_stack[optional_stack_size];			\
>   	char	IST_top_guard[guardsize];			\
>   
>   /* The exception stacks' physical storage. No guard pages required */
> @@ -52,6 +56,8 @@ enum exception_stack_ordering {
>   	ESTACK_MCE,
>   	ESTACK_VC,
>   	ESTACK_VC2,
> +	ESTACK_HV,
> +	ESTACK_HV2,
>   	N_EXCEPTION_STACKS
>   };
>   
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index b241af4ce9b4..b0f3501b2767 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -317,6 +317,19 @@ static __always_inline void __##func(struct pt_regs *regs)
>   	__visible noinstr void kernel_##func(struct pt_regs *regs, unsigned long error_code);	\
>   	__visible noinstr void   user_##func(struct pt_regs *regs, unsigned long error_code)
>   
> +
> +/**
> + * DECLARE_IDTENTRY_HV - Declare functions for the HV entry point
> + * @vector:	Vector number (ignored for C)
> + * @func:	Function name of the entry point
> + *
> + * Maps to DECLARE_IDTENTRY_RAW, but declares also the user C handler.
> + */
> +#define DECLARE_IDTENTRY_HV(vector, func)				\
> +	DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func);			\
> +	__visible noinstr void kernel_##func(struct pt_regs *regs);	\
> +	__visible noinstr void   user_##func(struct pt_regs *regs)
> +
>   /**
>    * DEFINE_IDTENTRY_IST - Emit code for IST entry points
>    * @func:	Function name of the entry point
> @@ -376,6 +389,26 @@ static __always_inline void __##func(struct pt_regs *regs)
>   #define DEFINE_IDTENTRY_VC_USER(func)				\
>   	DEFINE_IDTENTRY_RAW_ERRORCODE(user_##func)
>   
> +/**
> + * DEFINE_IDTENTRY_HV_KERNEL - Emit code for HV injection handler
> + *			       when raised from kernel mode
> + * @func:	Function name of the entry point
> + *
> + * Maps to DEFINE_IDTENTRY_RAW
> + */
> +#define DEFINE_IDTENTRY_HV_KERNEL(func)					\
> +	DEFINE_IDTENTRY_RAW(kernel_##func)
> +
> +/**
> + * DEFINE_IDTENTRY_HV_USER - Emit code for HV injection handler
> + *			     when raised from user mode
> + * @func:	Function name of the entry point
> + *
> + * Maps to DEFINE_IDTENTRY_RAW
> + */
> +#define DEFINE_IDTENTRY_HV_USER(func)					\
> +	DEFINE_IDTENTRY_RAW(user_##func)
> +
>   #else	/* CONFIG_X86_64 */
>   
>   /**
> @@ -463,8 +496,10 @@ __visible noinstr void func(struct pt_regs *regs,			\
>   	DECLARE_IDTENTRY(vector, func)
>   
>   # define DECLARE_IDTENTRY_VC(vector, func)				\
> -	idtentry_vc vector asm_##func func
> +	idtentry_sev vector asm_##func func has_error_code=1
>   
> +# define DECLARE_IDTENTRY_HV(vector, func)				\
> +	idtentry_sev vector asm_##func func has_error_code=0
>   #else
>   # define DECLARE_IDTENTRY_MCE(vector, func)				\
>   	DECLARE_IDTENTRY(vector, func)
> @@ -618,9 +653,10 @@ DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF,	xenpv_exc_double_fault);
>   DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_CP,	exc_control_protection);
>   #endif
>   
> -/* #VC */
> +/* #VC & #HV */
>   #ifdef CONFIG_AMD_MEM_ENCRYPT
>   DECLARE_IDTENTRY_VC(X86_TRAP_VC,	exc_vmm_communication);
> +DECLARE_IDTENTRY_HV(X86_TRAP_HV,	exc_hv_injection);
>   #endif
>   
>   #ifdef CONFIG_XEN_PV
> diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
> index e9e2c3ba5923..0bd7dab676c5 100644
> --- a/arch/x86/include/asm/page_64_types.h
> +++ b/arch/x86/include/asm/page_64_types.h
> @@ -29,6 +29,7 @@
>   #define	IST_INDEX_DB		2
>   #define	IST_INDEX_MCE		3
>   #define	IST_INDEX_VC		4
> +#define	IST_INDEX_HV		5
>   
>   /*
>    * Set __PAGE_OFFSET to the most negative possible address +
> diff --git a/arch/x86/include/asm/trapnr.h b/arch/x86/include/asm/trapnr.h
> index f5d2325aa0b7..c6583631cecb 100644
> --- a/arch/x86/include/asm/trapnr.h
> +++ b/arch/x86/include/asm/trapnr.h
> @@ -26,6 +26,7 @@
>   #define X86_TRAP_XF		19	/* SIMD Floating-Point Exception */
>   #define X86_TRAP_VE		20	/* Virtualization Exception */
>   #define X86_TRAP_CP		21	/* Control Protection Exception */
> +#define X86_TRAP_HV		28	/* HV injected exception in SNP restricted mode */
>   #define X86_TRAP_VC		29	/* VMM Communication Exception */
>   #define X86_TRAP_IRET		32	/* IRET Exception */
>   
> diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
> index 47ecfff2c83d..6795d3e517d6 100644
> --- a/arch/x86/include/asm/traps.h
> +++ b/arch/x86/include/asm/traps.h
> @@ -16,6 +16,7 @@ asmlinkage __visible notrace
>   struct pt_regs *fixup_bad_iret(struct pt_regs *bad_regs);
>   void __init trap_init(void);
>   asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs);
> +asmlinkage __visible noinstr struct pt_regs *hv_switch_off_ist(struct pt_regs *eregs);
>   #endif
>   
>   extern bool ibt_selftest(void);
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 8cd4126d8253..5bc44bcf6e48 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -2172,6 +2172,7 @@ static inline void tss_setup_ist(struct tss_struct *tss)
>   	tss->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE);
>   	/* Only mapped when SEV-ES is active */
>   	tss->x86_tss.ist[IST_INDEX_VC] = __this_cpu_ist_top_va(VC);
> +	tss->x86_tss.ist[IST_INDEX_HV] = __this_cpu_ist_top_va(HV);
>   }
>   
>   #else /* CONFIG_X86_64 */
> diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
> index f05339fee778..6d8f8864810c 100644
> --- a/arch/x86/kernel/dumpstack_64.c
> +++ b/arch/x86/kernel/dumpstack_64.c
> @@ -26,11 +26,14 @@ static const char * const exception_stack_names[] = {
>   		[ ESTACK_MCE	]	= "#MC",
>   		[ ESTACK_VC	]	= "#VC",
>   		[ ESTACK_VC2	]	= "#VC2",
> +		[ ESTACK_HV	]	= "#HV",
> +		[ ESTACK_HV2	]	= "#HV2",
> +		
>   };
>   
>   const char *stack_type_name(enum stack_type type)
>   {
> -	BUILD_BUG_ON(N_EXCEPTION_STACKS != 6);
> +	BUILD_BUG_ON(N_EXCEPTION_STACKS != 8);
>   
>   	if (type == STACK_TYPE_TASK)
>   		return "TASK";
> @@ -89,6 +92,8 @@ struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {
>   	EPAGERANGE(MCE),
>   	EPAGERANGE(VC),
>   	EPAGERANGE(VC2),
> +	EPAGERANGE(HV),
> +	EPAGERANGE(HV2),
>   };
>   
>   static __always_inline bool in_exception_stack(unsigned long *stack, struct stack_info *info)
> @@ -98,7 +103,7 @@ static __always_inline bool in_exception_stack(unsigned long *stack, struct stac
>   	struct pt_regs *regs;
>   	unsigned int k;
>   
> -	BUILD_BUG_ON(N_EXCEPTION_STACKS != 6);
> +	BUILD_BUG_ON(N_EXCEPTION_STACKS != 8);
>   
>   	begin = (unsigned long)__this_cpu_read(cea_exception_stacks);
>   	/*
> diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
> index a58c6bc1cd68..48c0a7e1dbcb 100644
> --- a/arch/x86/kernel/idt.c
> +++ b/arch/x86/kernel/idt.c
> @@ -113,6 +113,7 @@ static const __initconst struct idt_data def_idts[] = {
>   
>   #ifdef CONFIG_AMD_MEM_ENCRYPT
>   	ISTG(X86_TRAP_VC,		asm_exc_vmm_communication, IST_INDEX_VC),
> +	ISTG(X86_TRAP_HV,		asm_exc_hv_injection, IST_INDEX_HV),
>   #endif
>   
>   	SYSG(X86_TRAP_OF,		asm_exc_overflow),
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index 20f3fd8ade2f..7b06d7c0914f 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -2006,6 +2006,59 @@ DEFINE_IDTENTRY_VC_USER(exc_vmm_communication)
>   	irqentry_exit_to_user_mode(regs);
>   }
>   
> +static bool hv_raw_handle_exception(struct pt_regs *regs)
> +{
> +	return false;
> +}
> +
> +static __always_inline bool on_hv_fallback_stack(struct pt_regs *regs)
> +{

Don't see this functioned used yet?

> +	unsigned long sp = (unsigned long)regs;
> +
> +	return (sp >= __this_cpu_ist_bottom_va(HV2) && sp < __this_cpu_ist_top_va(HV2));
> +}
> +
> +DEFINE_IDTENTRY_HV_USER(exc_hv_injection)
> +{
> +	irqentry_enter_from_user_mode(regs);
> +	instrumentation_begin();
> +
> +	if (!hv_raw_handle_exception(regs)) {
> +		/*
> +		 * Do not kill the machine if user-space triggered the
> +		 * exception. Send SIGBUS instead and let user-space deal
> +		 * with it.
> +		 */
> +		force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)0);
> +	}
> +
> +	instrumentation_end();
> +	irqentry_exit_to_user_mode(regs);
> +}
> +
> +DEFINE_IDTENTRY_HV_KERNEL(exc_hv_injection)
> +{
> +	irqentry_state_t irq_state;
> +
> +	irq_state = irqentry_enter(regs);

Any reason for not using "irqentry_nmi_enter" here?
We are dispatching both irqs & NMI's right?

Thanks,
Pankaj
> +	instrumentation_begin();
> +
> +	if (!hv_raw_handle_exception(regs)) {
> +		pr_emerg("PANIC: Unhandled #HV exception in kernel space\n");
> +
> +		/* Show some debug info */
> +		show_regs(regs);
> +
> +		/* Ask hypervisor to sev_es_terminate */
> +		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
> +
> +		panic("Returned from Terminate-Request to Hypervisor\n");
> +	}
> +
> +	instrumentation_end();
> +	irqentry_exit(regs, irq_state);
> +}
> +
>   bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
>   {
>   	unsigned long exit_code = regs->orig_ax;
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index d317dc3d06a3..d29debec8134 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -905,6 +905,46 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r
>   
>   	return regs_ret;
>   }
> +
> +asmlinkage __visible noinstr struct pt_regs *hv_switch_off_ist(struct pt_regs *regs) > +{
> +	unsigned long sp, *stack;
> +	struct stack_info info;
> +	struct pt_regs *regs_ret;
> +
> +	/*
> +	 * In the SYSCALL entry path the RSP value comes from user-space - don't
> +	 * trust it and switch to the current kernel stack
> +	 */
> +	if (ip_within_syscall_gap(regs)) {
> +		sp = this_cpu_read(pcpu_hot.top_of_stack);
> +		goto sync;
> +	}
> +
> +	/*
> +	 * From here on the RSP value is trusted. Now check whether entry
> +	 * happened from a safe stack. Not safe are the entry or unknown stacks,
> +	 * use the fall-back stack instead in this case.
> +	 */
> +	sp    = regs->sp;
> +	stack = (unsigned long *)sp;
> +
> +	if (!get_stack_info_noinstr(stack, current, &info) || info.type == STACK_TYPE_ENTRY ||
> +	    info.type > STACK_TYPE_EXCEPTION_LAST)
> +		sp = __this_cpu_ist_top_va(HV2);
> +sync:
> +	/*
> +	 * Found a safe stack - switch to it as if the entry didn't happen via
> +	 * IST stack. The code below only copies pt_regs, the real switch happens
> +	 * in assembly code.
> +	 */
> +	sp = ALIGN_DOWN(sp, 8) - sizeof(*regs_ret);
> +
> +	regs_ret = (struct pt_regs *)sp;
> +	*regs_ret = *regs;
> +
> +	return regs_ret;
> +}
>   #endif
>   
>   asmlinkage __visible noinstr struct pt_regs *fixup_bad_iret(struct pt_regs *bad_regs)
> diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
> index e91500a80963..97554fa0ff30 100644
> --- a/arch/x86/mm/cpu_entry_area.c
> +++ b/arch/x86/mm/cpu_entry_area.c
> @@ -160,6 +160,8 @@ static void __init percpu_setup_exception_stacks(unsigned int cpu)
>   		if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) {
>   			cea_map_stack(VC);
>   			cea_map_stack(VC2);
> +			cea_map_stack(HV);
> +			cea_map_stack(HV2);
>   		}
>   	}
>   }

Re: [RFC PATCH V5 11/15] x86/sev: Add a #HV exception handler

[Gupta, Pankaj]

On 5/5/2023 12:59 PM, Gupta, Pankaj wrote:
> Hi Tianyu,
> 
> I tried to understand some details of this patch. Please find below
> some comments/questions.
> 
> Thanks,
> 
> 
>> Add a #HV exception handler that uses IST stack.
>>
>> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
>> ---
>> Change since RFC V2:
>>         * Remove unnecessary line in the change log.
>> ---
>>   arch/x86/entry/entry_64.S             | 22 +++++++----
>>   arch/x86/include/asm/cpu_entry_area.h |  6 +++
>>   arch/x86/include/asm/idtentry.h       | 40 +++++++++++++++++++-
>>   arch/x86/include/asm/page_64_types.h  |  1 +
>>   arch/x86/include/asm/trapnr.h         |  1 +
>>   arch/x86/include/asm/traps.h          |  1 +
>>   arch/x86/kernel/cpu/common.c          |  1 +
>>   arch/x86/kernel/dumpstack_64.c        |  9 ++++-
>>   arch/x86/kernel/idt.c                 |  1 +
>>   arch/x86/kernel/sev.c                 | 53 +++++++++++++++++++++++++++
>>   arch/x86/kernel/traps.c               | 40 ++++++++++++++++++++
>>   arch/x86/mm/cpu_entry_area.c          |  2 +
>>   12 files changed, 165 insertions(+), 12 deletions(-)
>>
>> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
>> index eccc3431e515..653b1f10699b 100644
>> --- a/arch/x86/entry/entry_64.S
>> +++ b/arch/x86/entry/entry_64.S
>> @@ -496,7 +496,7 @@ SYM_CODE_END(\asmsym)
>>   #ifdef CONFIG_AMD_MEM_ENCRYPT
>>   /**
>> - * idtentry_vc - Macro to generate entry stub for #VC
>> + * idtentry_sev - Macro to generate entry stub for #VC
>>    * @vector:        Vector number
>>    * @asmsym:        ASM symbol for the entry point
>>    * @cfunc:        C function to be called
>> @@ -515,14 +515,18 @@ SYM_CODE_END(\asmsym)
>>    *
>>    * The macro is only used for one vector, but it is planned to be 
>> extended in
>>    * the future for the #HV exception.
>> - */
>> -.macro idtentry_vc vector asmsym cfunc
>> +*/
>> +.macro idtentry_sev vector asmsym cfunc has_error_code:req
>>   SYM_CODE_START(\asmsym)
>>       UNWIND_HINT_IRET_REGS
>>       ENDBR
>>       ASM_CLAC
>>       cld
>> +    .if \vector == X86_TRAP_HV
>> +        pushq    $-1            /* ORIG_RAX: no syscall */
>> +    .endif
>> +
>>       /*
>>        * If the entry is from userspace, switch stacks and treat it as
>>        * a normal entry.
>> @@ -545,7 +549,12 @@ SYM_CODE_START(\asmsym)
>>        * stack.
>>        */
>>       movq    %rsp, %rdi        /* pt_regs pointer */
>> -    call    vc_switch_off_ist
>> +    .if \vector == X86_TRAP_VC
>> +        call    vc_switch_off_ist
> 
> I think the stack switching logic is similar for #VC & #HV.
> So, we can use common function. Just the corresponding fallback
> stack switching is different. Maybe we can pass the hint as an
> argument (%rsi?) to something like "sev_switch_off_ist()", and use
> the corresponding (#HV or #VC) fallbacks stack?

Also, Please include the below patch from Ashish for #HV
reentrancy check.

https://github.com/ashkalra/linux/commit/6975484094b7cb8d703c45066780dd85043cd040

Thanks,
Pankaj