[PATCH Part2 v6 01/49] x86/cpufeatures: Add SEV-SNP CPU feature

Ashish Kalra
2022-06-20T22:59:19Z

From: Brijesh Singh <brijesh.singh@amd.com>

Add CPU feature detection for Secure Encrypted Virtualization with
Secure Nested Paging. This feature adds a strong memory integrity
protection to help prevent malicious hypervisor-based attacks like
data replay, memory re-mapping, and more.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/amd.c | 3 ++-
tools/arch/x86/include/asm/cpufeatures.h | 1 +
3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 30da1341f226..1cba0217669f 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -407,6 +407,7 @@
#define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */
#define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */
#define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */
+#define X86_FEATURE_SEV_SNP (19*32+4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */
#define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */

/*
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 0c0b09796ced..2e87015a9d69 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -559,7 +559,7 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
* If the kernel has not enabled SME via any means then
* don't advertise the SME feature.
* For SEV: If BIOS has not enabled SEV then don't advertise the
- * SEV and SEV_ES feature (set in scattered.c).
+ * SEV, SEV_ES and SEV_SNP feature.
*
* In all cases, since support for SME and SEV requires long mode,
* don't advertise the feature under CONFIG_X86_32.
@@ -594,6 +594,7 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
clear_sev:
setup_clear_cpu_cap(X86_FEATURE_SEV);
setup_clear_cpu_cap(X86_FEATURE_SEV_ES);
+ setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
}
}

diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index 73e643ae94b6..a636342ecb26 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -405,6 +405,7 @@
#define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */
#define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */
#define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */
+#define X86_FEATURE_SEV_SNP (19*32+4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */
#define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */

/*
--
2.25.1