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* [PATCH v2] OvmfPkg/ResetVector: Removing SEV-ES CPUID bit check
@ 2022-01-13 16:30 Peter Gonda
  2022-01-19 17:03 ` Lendacky, Thomas
  2022-06-01 12:25 ` [PATCH V3] " Ard Biesheuvel
  0 siblings, 2 replies; 4+ messages in thread
From: Peter Gonda @ 2022-01-13 16:30 UTC (permalink / raw)
  To: devel
  Cc: Peter Gonda, James Bottomley, Min Xu, Jiewen Yao, Tom Lendacky,
	Jordan Justen, Ard Biesheuvel, Laszlo Ersek, Erdem Aktas,
	Brijesh Singh, Marc Orr

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)
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Marc Orr <marcorr@google.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
---
 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 1f827da3b9..77692db27e 100644
--- a/OvmfPkg/ResetVector/Ia32/AmdSev.asm
+++ b/OvmfPkg/ResetVector/Ia32/AmdSev.asm
@@ -265,14 +265,6 @@ CheckSevFeatures:
     ; Set the work area header to indicate that the SEV is enabled
     mov     byte[WORK_AREA_GUEST_TYPE], 1
 
-    ; 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
-- 
2.34.1.575.g55b058a8bb-goog


^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-06-01 13:16 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-01-13 16:30 [PATCH v2] OvmfPkg/ResetVector: Removing SEV-ES CPUID bit check Peter Gonda
2022-01-19 17:03 ` Lendacky, Thomas
2022-06-01 12:25 ` [PATCH V3] " Ard Biesheuvel
2022-06-01 13:16   ` Lendacky, Thomas

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