[PATCH v4 1/5] x86/cpufeatures: Add SNP Secure TSC

Nikunj A Dadhania
2025-03-10T06:44:10Z

The Secure TSC feature for SEV-SNP allows guests to securely use the RDTSC
and RDTSCP instructions, ensuring that the parameters used cannot be
altered by the hypervisor once the guest is launched. For more details,
refer to the AMD64 APM Vol 2, Section "Secure TSC".

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
---
arch/x86/include/asm/cpufeatures.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 8f8aaf94dc00..68a4d6b4cc11 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -449,6 +449,7 @@
#define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* VM Page Flush MSR is supported */
#define X86_FEATURE_SEV_ES (19*32+ 3) /* "sev_es" Secure Encrypted Virtualization - Encrypted State */
#define X86_FEATURE_SEV_SNP (19*32+ 4) /* "sev_snp" Secure Encrypted Virtualization - Secure Nested Paging */
+#define X86_FEATURE_SNP_SECURE_TSC (19*32+ 8) /* SEV-SNP Secure TSC */
#define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* Virtual TSC_AUX */
#define X86_FEATURE_SME_COHERENT (19*32+10) /* hardware-enforced cache coherency */
#define X86_FEATURE_DEBUG_SWAP (19*32+14) /* "debug_swap" SEV-ES full debug state swap support */
--
2.43.0