From 62044aa99bcf0a7b1581b24ad8e8f105e48fa15a Mon Sep 17 00:00:00 2001 From: Peter Gonda Date: Wed, 1 Jun 2022 14:17:45 +0200 Subject: OvmfPkg/ResetVector: Removing SEV-ES CPUID bit check The SEV-ES bit of Fn800-001F[EAX] - Bit 3 is used for a host to determine support for running SEV-ES guests. It should not be checked by a guest to determine if it is running under SEV-ES. The guest should use the SEV_STATUS MSR Bit 1 to determine if SEV-ES is enabled. This check was not part of the original SEV-ES support and was added in a91b700e38. Removing the check makes this code consistent with the Linux kernel Fixes: a91b700e38 ("Ovmf/ResetVector: Simplify and consolidate the SEV features checks") Signed-off-by: Peter Gonda Acked-by: Tom Lendacky --- OvmfPkg/ResetVector/Ia32/AmdSev.asm | 8 -------- 1 file changed, 8 deletions(-) diff --git a/OvmfPkg/ResetVector/Ia32/AmdSev.asm b/OvmfPkg/ResetVector/Ia32/AmdSev.asm index 9350b04..3abc830 100644 --- a/OvmfPkg/ResetVector/Ia32/AmdSev.asm +++ b/OvmfPkg/ResetVector/Ia32/AmdSev.asm @@ -278,14 +278,6 @@ ClearSevEsWorkArea: mov [SEV_ES_WORK_AREA_STATUS_MSR], eax mov [SEV_ES_WORK_AREA_STATUS_MSR + 4], edx - ; Check for SEV-ES memory encryption feature: - ; CPUID Fn8000_001F[EAX] - Bit 3 - ; CPUID raises a #VC exception if running as an SEV-ES guest - mov eax, 0x8000001f - cpuid - bt eax, 3 - jnc GetSevEncBit - ; Check if SEV-ES is enabled ; MSR_0xC0010131 - Bit 1 (SEV-ES enabled) mov ecx, SEV_STATUS_MSR -- cgit v1.1