On Tue, 17 May 2022 at 18:26, Tom Lendacky <thomas.lendacky@...> wrote:

On 5/16/22 15:24, Lendacky, Thomas via groups.io wrote:

The BaseMemEncryptSevLib functionality was updated to rely on the use of
the OVMF/SEV workarea to check for SEV guests. However, this area is only
updated when running the X64 OVMF build, not the hybrid Ia32/X64 build.
Base SEV support is allowed under the Ia32/X64 build, but it now fails
to boot as a result of the change.

Update the ResetVector code to check for SEV features when built for
32-bit mode, not just 64-bit mode (requiring updates to both the Ia32
and Ia32X64 fdf files).

So this is a regression and it would be great if it could be applied to
the 202205 release. Can folks take a look and make sure it looks safe to
them for applying during hard feature freeze?

If it's ok to be applied now, is there a particular process for applying
this during hard freeze?

For the change itself:
Acked-by: Ard Biesheuvel <ardb@...>
and I am fine with taking this during hard freeze, but I'll defer to
Liming to make the final call.

Fixes: f1d1c337e7c0575da7fd248b2dd9cffc755940df
Cc: Ard Biesheuvel <ardb+tianocore@...>
Cc: Jiewen Yao <jiewen.yao@...>
Cc: Jordan Justen <jordan.l.justen@...>
Cc: Gerd Hoffmann <kraxel@...>
Cc: Erdem Aktas <erdemaktas@...>
Cc: James Bottomley <jejb@...>
Cc: Michael Roth <michael.roth@...>
Cc: Min Xu <min.m.xu@...>
Signed-off-by: Tom Lendacky <thomas.lendacky@...>
---
OvmfPkg/OvmfPkgIa32.fdf | 11 +++
OvmfPkg/OvmfPkgIa32X64.fdf | 8 +++
OvmfPkg/OvmfPkgX64.fdf | 3 +-
OvmfPkg/ResetVector/Ia32/AmdSev.asm | 4 ++
OvmfPkg/ResetVector/Main.asm | 6 ++
OvmfPkg/ResetVector/ResetVector.nasmb | 72 ++++++++++----------
6 files changed, 67 insertions(+), 37 deletions(-)

diff --git a/OvmfPkg/OvmfPkgIa32.fdf b/OvmfPkg/OvmfPkgIa32.fdf
index 3ab1755749d4..57d13b7130bc 100644
--- a/OvmfPkg/OvmfPkgIa32.fdf
+++ b/OvmfPkg/OvmfPkgIa32.fdf
@@ -76,6 +76,9 @@ [FD.MEMFD]
0x007000|0x001000
gEfiMdePkgTokenSpaceGuid.PcdGuidedExtractHandlerTableAddress|gUefiOvmfPkgTokenSpaceGuid.PcdGuidedExtractHandlerTableSize

+0x008000|0x001000
+gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaSize
+
0x010000|0x010000
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize

@@ -87,6 +90,14 @@ [FD.MEMFD]
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvSize
FV = DXEFV

+##########################################################################################
+# Set the SEV-ES specific work area PCDs (used for all forms of SEV since the
+# the SEV STATUS MSR is now saved in the work area)
+#
+SET gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase = $(MEMFD_BASE_ADDRESS) + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaBase + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfConfidentialComputingWorkAreaHeader
+SET gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize = gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaSize - gUefiOvmfPkgTokenSpaceGuid.PcdOvmfConfidentialComputingWorkAreaHeader
+##########################################################################################
+
################################################################################

[FV.SECFV]
diff --git a/OvmfPkg/OvmfPkgIa32X64.fdf b/OvmfPkg/OvmfPkgIa32X64.fdf
index e1638fa6ea38..ccde366887a9 100644
--- a/OvmfPkg/OvmfPkgIa32X64.fdf
+++ b/OvmfPkg/OvmfPkgIa32X64.fdf
@@ -90,6 +90,14 @@ [FD.MEMFD]
gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDxeMemFvSize
FV = DXEFV

+##########################################################################################
+# Set the SEV-ES specific work area PCDs (used for all forms of SEV since the
+# the SEV STATUS MSR is now saved in the work area)
+#
+SET gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase = $(MEMFD_BASE_ADDRESS) + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaBase + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfConfidentialComputingWorkAreaHeader
+SET gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize = gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaSize - gUefiOvmfPkgTokenSpaceGuid.PcdOvmfConfidentialComputingWorkAreaHeader
+##########################################################################################
+
################################################################################

[FV.SECFV]
diff --git a/OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf
index aa9a83032d9b..438806fba8f1 100644
--- a/OvmfPkg/OvmfPkgX64.fdf
+++ b/OvmfPkg/OvmfPkgX64.fdf
@@ -106,7 +106,8 @@ [FD.MEMFD]
FV = DXEFV

##########################################################################################
-# Set the SEV-ES specific work area PCDs
+# Set the SEV-ES specific work area PCDs (used for all forms of SEV since the
+# the SEV STATUS MSR is now saved in the work area)
#
SET gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase = $(MEMFD_BASE_ADDRESS) + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaBase + gUefiOvmfPkgTokenSpaceGuid.PcdOvmfConfidentialComputingWorkAreaHeader
SET gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize = gUefiOvmfPkgTokenSpaceGuid.PcdOvmfWorkAreaSize - gUefiOvmfPkgTokenSpaceGuid.PcdOvmfConfidentialComputingWorkAreaHeader
diff --git a/OvmfPkg/ResetVector/Ia32/AmdSev.asm b/OvmfPkg/ResetVector/Ia32/AmdSev.asm
index 864d68385342..9350b0406833 100644
--- a/OvmfPkg/ResetVector/Ia32/AmdSev.asm
+++ b/OvmfPkg/ResetVector/Ia32/AmdSev.asm
@@ -150,6 +150,8 @@ BITS 32
SevEsUnexpectedRespTerminate:
TerminateVmgExit TERM_UNEXPECTED_RESP_CODE

+%ifdef ARCH_X64
+
; If SEV-ES is enabled then initialize and make the GHCB page shared
SevClearPageEncMaskForGhcbPage:
; Check if SEV is enabled
@@ -209,6 +211,8 @@ GetSevCBitMaskAbove31:
GetSevCBitMaskAbove31Exit:
OneTimeCallRet GetSevCBitMaskAbove31

+%endif
+
; Check if Secure Encrypted Virtualization (SEV) features are enabled.
;
; Register usage is tight in this routine, so multiple calls for the
diff --git a/OvmfPkg/ResetVector/Main.asm b/OvmfPkg/ResetVector/Main.asm
index 5cfc0b5c72b1..46cfa87c4c0a 100644
--- a/OvmfPkg/ResetVector/Main.asm
+++ b/OvmfPkg/ResetVector/Main.asm
@@ -75,6 +75,12 @@ SearchBfv:

%ifdef ARCH_IA32

+ ;
+ ; SEV support can be built and run using the Ia32/X64 split environment.
+ ; Set the OVMF/SEV work area as appropriate.
+ ;
+ OneTimeCall CheckSevFeatures
+
;
; Restore initial EAX value into the EAX register
;
diff --git a/OvmfPkg/ResetVector/ResetVector.nasmb b/OvmfPkg/ResetVector/ResetVector.nasmb
index 9421f4818907..94fbb0a87b37 100644
--- a/OvmfPkg/ResetVector/ResetVector.nasmb
+++ b/OvmfPkg/ResetVector/ResetVector.nasmb
@@ -47,7 +47,36 @@
%include "Ia32/SearchForBfvBase.asm"
%include "Ia32/SearchForSecEntry.asm"

-%define WORK_AREA_GUEST_TYPE (FixedPcdGet32 (PcdOvmfWorkAreaBase))
+%define WORK_AREA_GUEST_TYPE (FixedPcdGet32 (PcdOvmfWorkAreaBase))
+%define PT_ADDR(Offset) (FixedPcdGet32 (PcdOvmfSecPageTablesBase) + (Offset))
+
+%define GHCB_PT_ADDR (FixedPcdGet32 (PcdOvmfSecGhcbPageTableBase))
+%define GHCB_BASE (FixedPcdGet32 (PcdOvmfSecGhcbBase))
+%define GHCB_SIZE (FixedPcdGet32 (PcdOvmfSecGhcbSize))
+%define SEV_ES_WORK_AREA (FixedPcdGet32 (PcdSevEsWorkAreaBase))
+%define SEV_ES_WORK_AREA_SIZE 25
+%define SEV_ES_WORK_AREA_STATUS_MSR (FixedPcdGet32 (PcdSevEsWorkAreaBase))
+%define SEV_ES_WORK_AREA_RDRAND (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 8)
+%define SEV_ES_WORK_AREA_ENC_MASK (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 16)
+%define SEV_ES_WORK_AREA_RECEIVED_VC (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 24)
+%define SEV_ES_VC_TOP_OF_STACK (FixedPcdGet32 (PcdOvmfSecPeiTempRamBase) + FixedPcdGet32 (PcdOvmfSecPeiTempRamSize))
+%define SEV_SNP_SECRETS_BASE (FixedPcdGet32 (PcdOvmfSnpSecretsBase))
+%define SEV_SNP_SECRETS_SIZE (FixedPcdGet32 (PcdOvmfSnpSecretsSize))
+%define CPUID_BASE (FixedPcdGet32 (PcdOvmfCpuidBase))
+%define CPUID_SIZE (FixedPcdGet32 (PcdOvmfCpuidSize))
+%define SNP_SEC_MEM_BASE_DESC_1 (FixedPcdGet32 (PcdOvmfSecPageTablesBase))
+%define SNP_SEC_MEM_SIZE_DESC_1 (FixedPcdGet32 (PcdOvmfSecGhcbBase) - SNP_SEC_MEM_BASE_DESC_1)
+;
+; The PcdOvmfSecGhcbBase reserves two GHCB pages. The first page is used
+; as GHCB shared page and second is used for bookkeeping to support the
+; nested GHCB in SEC phase. The bookkeeping page is mapped private. The VMM
+; does not need to validate the shared page but it need to validate the
+; bookkeeping page.
+;
+%define SNP_SEC_MEM_BASE_DESC_2 (GHCB_BASE + 0x1000)
+%define SNP_SEC_MEM_SIZE_DESC_2 (SEV_SNP_SECRETS_BASE - SNP_SEC_MEM_BASE_DESC_2)
+%define SNP_SEC_MEM_BASE_DESC_3 (CPUID_BASE + CPUID_SIZE)
+%define SNP_SEC_MEM_SIZE_DESC_3 (FixedPcdGet32 (PcdOvmfPeiMemFvBase) - SNP_SEC_MEM_BASE_DESC_3)

%ifdef ARCH_X64
#include <AutoGen.h>
@@ -94,43 +123,14 @@
%define TDX_WORK_AREA_PGTBL_READY (FixedPcdGet32 (PcdOvmfWorkAreaBase) + 4)
%define TDX_WORK_AREA_GPAW (FixedPcdGet32 (PcdOvmfWorkAreaBase) + 8)

- %define PT_ADDR(Offset) (FixedPcdGet32 (PcdOvmfSecPageTablesBase) + (Offset))
+ %include "X64/IntelTdxMetadata.asm"
+ %include "Ia32/Flat32ToFlat64.asm"
+ %include "Ia32/PageTables64.asm"
+ %include "Ia32/IntelTdx.asm"
+ %include "X64/OvmfSevMetadata.asm"
+%endif

- %define GHCB_PT_ADDR (FixedPcdGet32 (PcdOvmfSecGhcbPageTableBase))
- %define GHCB_BASE (FixedPcdGet32 (PcdOvmfSecGhcbBase))
- %define GHCB_SIZE (FixedPcdGet32 (PcdOvmfSecGhcbSize))
- %define SEV_ES_WORK_AREA (FixedPcdGet32 (PcdSevEsWorkAreaBase))
- %define SEV_ES_WORK_AREA_SIZE 25
- %define SEV_ES_WORK_AREA_STATUS_MSR (FixedPcdGet32 (PcdSevEsWorkAreaBase))
- %define SEV_ES_WORK_AREA_RDRAND (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 8)
- %define SEV_ES_WORK_AREA_ENC_MASK (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 16)
- %define SEV_ES_WORK_AREA_RECEIVED_VC (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 24)
- %define SEV_ES_VC_TOP_OF_STACK (FixedPcdGet32 (PcdOvmfSecPeiTempRamBase) + FixedPcdGet32 (PcdOvmfSecPeiTempRamSize))
- %define SEV_SNP_SECRETS_BASE (FixedPcdGet32 (PcdOvmfSnpSecretsBase))
- %define SEV_SNP_SECRETS_SIZE (FixedPcdGet32 (PcdOvmfSnpSecretsSize))
- %define CPUID_BASE (FixedPcdGet32 (PcdOvmfCpuidBase))
- %define CPUID_SIZE (FixedPcdGet32 (PcdOvmfCpuidSize))
- %define SNP_SEC_MEM_BASE_DESC_1 (FixedPcdGet32 (PcdOvmfSecPageTablesBase))
- %define SNP_SEC_MEM_SIZE_DESC_1 (FixedPcdGet32 (PcdOvmfSecGhcbBase) - SNP_SEC_MEM_BASE_DESC_1)
- ;
- ; The PcdOvmfSecGhcbBase reserves two GHCB pages. The first page is used
- ; as GHCB shared page and second is used for bookkeeping to support the
- ; nested GHCB in SEC phase. The bookkeeping page is mapped private. The VMM
- ; does not need to validate the shared page but it need to validate the
- ; bookkeeping page.
- ;
- %define SNP_SEC_MEM_BASE_DESC_2 (GHCB_BASE + 0x1000)
- %define SNP_SEC_MEM_SIZE_DESC_2 (SEV_SNP_SECRETS_BASE - SNP_SEC_MEM_BASE_DESC_2)
- %define SNP_SEC_MEM_BASE_DESC_3 (CPUID_BASE + CPUID_SIZE)
- %define SNP_SEC_MEM_SIZE_DESC_3 (FixedPcdGet32 (PcdOvmfPeiMemFvBase) - SNP_SEC_MEM_BASE_DESC_3)
-
-%include "X64/IntelTdxMetadata.asm"
-%include "Ia32/Flat32ToFlat64.asm"
%include "Ia32/AmdSev.asm"
-%include "Ia32/PageTables64.asm"
-%include "Ia32/IntelTdx.asm"
-%include "X64/OvmfSevMetadata.asm"
-%endif

%include "Ia16/Real16ToFlat32.asm"
%include "Ia16/Init16.asm"