BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
An SEV-SNP guest requires that the physical address of the GHCB must
be registered with the hypervisor before using it. See the GHCB
specification section 2.3.2 for more details.
Cc: Michael Roth <michael.r...@amd.com>
Cc: Eric Dong <eric.d...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Rahul Kumar <rahul1.ku...@intel.com>
Cc: James Bottomley <j...@linux.ibm.com>
Cc: Min Xu <min.m...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>
Cc: Erdem Aktas <erdemak...@google.com>
Cc: Gerd Hoffmann <kra...@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
---
UefiCpuPkg/Library/MpInitLib/MpLib.h | 2 +
UefiCpuPkg/Library/MpInitLib/MpLib.c | 2 +
UefiCpuPkg/Library/MpInitLib/MpEqu.inc | 1 +
UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm | 54 ++++++++++++++++++++
4 files changed, 59 insertions(+)
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h
b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 2107f3f705a2..45bc1de23e3c 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -222,6 +222,7 @@ typedef struct {
//
BOOLEAN Enable5LevelPaging;
BOOLEAN SevEsIsEnabled;
+ BOOLEAN SevSnpIsEnabled;
UINTN GhcbBase;
} MP_CPU_EXCHANGE_INFO;
@@ -291,6 +292,7 @@ struct _CPU_MP_DATA {
BOOLEAN WakeUpByInitSipiSipi;
BOOLEAN SevEsIsEnabled;
+ BOOLEAN SevSnpIsEnabled;
UINTN SevEsAPBuffer;
UINTN SevEsAPResetStackStart;
CPU_MP_DATA *NewCpuMpData;
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c
b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 16a1602c3079..4dae0974c06a 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -889,6 +889,7 @@ FillExchangeInfoData (
DEBUG ((DEBUG_INFO, "%a: 5-Level Paging = %d\n", gEfiCallerBaseName,
ExchangeInfo->Enable5LevelPaging));
ExchangeInfo->SevEsIsEnabled = CpuMpData->SevEsIsEnabled;
+ ExchangeInfo->SevSnpIsEnabled = CpuMpData->SevSnpIsEnabled;
ExchangeInfo->GhcbBase = (UINTN) CpuMpData->GhcbBase;
//
@@ -1817,6 +1818,7 @@ MpInitLibInitialize (
CpuMpData->CpuInfoInHob = (UINT64) (UINTN) (CpuMpData->CpuData +
MaxLogicalProcessorNumber);
InitializeSpinLock(&CpuMpData->MpLock);
CpuMpData->SevEsIsEnabled = ConfidentialComputingGuestHas (CCAttrAmdSevEs);
+ CpuMpData->SevSnpIsEnabled = ConfidentialComputingGuestHas (CCAttrAmdSevSnp);
CpuMpData->SevEsAPBuffer = (UINTN) -1;
CpuMpData->GhcbBase = PcdGet64 (PcdGhcbBase);
diff --git a/UefiCpuPkg/Library/MpInitLib/MpEqu.inc
b/UefiCpuPkg/Library/MpInitLib/MpEqu.inc
index 2e9368a374a4..01668638f245 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpEqu.inc
+++ b/UefiCpuPkg/Library/MpInitLib/MpEqu.inc
@@ -92,6 +92,7 @@ struc MP_CPU_EXCHANGE_INFO
.ModeHighSegment: CTYPE_UINT16 1
.Enable5LevelPaging: CTYPE_BOOLEAN 1
.SevEsIsEnabled: CTYPE_BOOLEAN 1
+ .SevSnpIsEnabled CTYPE_BOOLEAN 1
.GhcbBase: CTYPE_UINTN 1
endstruc
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm
b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm
index 0ccafe25eca4..0034920b2f6b 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm
@@ -15,6 +15,57 @@
%define SIZE_4KB 0x1000
+RegisterGhcbGpa:
+ ;
+ ; Register GHCB GPA when SEV-SNP is enabled
+ ;
+ lea edi, [esi + MP_CPU_EXCHANGE_INFO_FIELD (SevSnpIsEnabled)]
+ cmp byte [edi], 1 ; SevSnpIsEnabled
+ jne RegisterGhcbGpaDone
+
+ ; Save the rdi and rsi to used for later comparison
+ push rdi
+ push rsi
+ mov edi, eax
+ mov esi, edx
+ or eax, 18 ; Ghcb registration request
+ wrmsr
+ rep vmmcall
+ rdmsr
+ mov r12, rax
+ and r12, 0fffh
+ cmp r12, 19 ; Ghcb registration response
+ jne GhcbGpaRegisterFailure
+
+ ; Verify that GPA is not changed
+ and eax, 0fffff000h
+ cmp edi, eax
+ jne GhcbGpaRegisterFailure
+ cmp esi, edx
+ jne GhcbGpaRegisterFailure
+ pop rsi
+ pop rdi
+ jmp RegisterGhcbGpaDone
+
+ ;
+ ; Request the guest termination
+ ;
+GhcbGpaRegisterFailure:
+ xor edx, edx
+ mov eax, 256 ; GHCB terminate
+ wrmsr
+ rep vmmcall
+
+ ; We should not return from the above terminate request, but if we do
+ ; then enter into the hlt loop.
+DoHltLoop:
+ cli
+ hlt
+ jmp DoHltLoop
+
+RegisterGhcbGpaDone:
+ OneTimeCallRet RegisterGhcbGpa
+
;
; The function checks whether SEV-ES is enabled, if enabled
; then setup the GHCB page.
@@ -39,6 +90,9 @@ SevEsSetupGhcb:
mov rdx, rax
shr rdx, 32
mov rcx, 0xc0010130
+
+ OneTimeCall RegisterGhcbGpa
+
wrmsr
SevEsSetupGhcbExit:
--
2.25.1
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