tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

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 <pgonda@google.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
This commit is contained in:
Peter Gonda 2022-06-01 14:17:45 +02:00 committed by mergify[bot]
parent df1c7e91b4
commit 62044aa99b
1 changed files with 0 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
OvmfPkg/ResetVector/Ia32/AmdSev.asm
View File

@ -278,14 +278,6 @@ ClearSevEsWorkArea:
mov [SEV_ES_WORK_AREA_STATUS_MSR], eax mov [SEV_ES_WORK_AREA_STATUS_MSR], eax
mov [SEV_ES_WORK_AREA_STATUS_MSR + 4], edx 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 ; Check if SEV-ES is enabled
; MSR_0xC0010131 - Bit 1 (SEV-ES enabled) ; MSR_0xC0010131 - Bit 1 (SEV-ES enabled)
mov ecx, SEV_STATUS_MSR mov ecx, SEV_STATUS_MSR