BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654
Currently, the first time an AP is started for an SEV-SNP guest, it relies
on the VMSA as set by the hypervisor. If the list of APIC IDs has been
retrieved, this is not necessary. Instead, use the SEV-SNP AP Create
protocol to start the AP for the first time and thereafter using the VMPL
at which the BSP is running.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf | 1 +
UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf | 3 +-
UefiCpuPkg/Library/MpInitLib/MpLib.h | 13 ++++
UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c | 19 +++++
UefiCpuPkg/Library/MpInitLib/MpLib.c | 7 +-
UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c | 79 +++++++++++++++++++-
6 files changed, 116 insertions(+), 6 deletions(-)
diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
index 55e46d4a1fad..1ec50481f0d4 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
@@ -82,6 +82,7 @@ [Pcd]
gUefiCpuPkgTokenSpaceGuid.PcdGhcbHypervisorFeatures ## CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase ## SOMETIMES_CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdFirstTimeWakeUpAPsBySipi ## CONSUMES
+ gUefiCpuPkgTokenSpaceGuid.PcdSevSnpApicIds ## CONSUMES
gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard ## CONSUMES
gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase ## CONSUMES
gEfiMdePkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr ## CONSUMES
diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
index bc3d716aa951..f0af07d3bdfb 100644
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
@@ -66,7 +66,8 @@ [Pcd]
gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate ## SOMETIMES_CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase ## SOMETIMES_CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdGhcbHypervisorFeatures ## CONSUMES
- gUefiCpuPkgTokenSpaceGuid.PcdFirstTimeWakeUpAPsBySipi ## CONSUMES
+ gUefiCpuPkgTokenSpaceGuid.PcdFirstTimeWakeUpAPsBySipi ## CONSUMES
+ gUefiCpuPkgTokenSpaceGuid.PcdSevSnpApicIds ## CONSUMES
gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase ## CONSUMES
gEfiMdePkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr ## CONSUMES
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 6e2137cb17cd..f1a5fa98d425 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -897,6 +897,19 @@ SevSnpCreateAP (
IN INTN ProcessorNumber
);
+/**
+ Determine if the SEV-SNP AP Create protocol should be used.
+
+ @param[in] CpuMpData Pointer to CPU MP Data
+
+ @retval TRUE Use SEV-SNP AP Create protocol
+ @retval FALSE Do not use SEV-SNP AP Create protocol
+**/
+BOOLEAN
+SevSnpUseCreateAP (
+ IN CPU_MP_DATA *CpuMpData
+ );
+
/**
Get pointer to CPU MP Data structure from GUIDed HOB.
diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
index a2b8a5b3f516..f9f24bee09de 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
@@ -48,3 +48,22 @@ SevSnpCreateAP (
//
ASSERT (FALSE);
}
+
+/**
+ Determine if the SEV-SNP AP Create protocol should be used.
+
+ @param[in] CpuMpData Pointer to CPU MP Data
+
+ @retval TRUE Use SEV-SNP AP Create protocol
+ @retval FALSE Do not use SEV-SNP AP Create protocol
+**/
+BOOLEAN
+SevSnpUseCreateAP (
+ IN CPU_MP_DATA *CpuMpData
+ )
+{
+ //
+ // SEV-SNP is not supported on 32-bit build.
+ //
+ return FALSE;
+}
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index cdfb570e61a0..5e017bcf9018 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -1302,9 +1302,10 @@ WakeUpAP (
//
// Wakeup all APs
// Must use the INIT-SIPI-SIPI method for initial configuration in
- // order to obtain the APIC ID.
+ // order to obtain the APIC ID if not an SEV-SNP guest and the
+ // list of APIC IDs is not available.
//
- if (CpuMpData->SevSnpIsEnabled && (CpuMpData->InitFlag != ApInitConfig)) {
+ if (SevSnpUseCreateAP (CpuMpData)) {
SevSnpCreateAP (CpuMpData, -1);
} else {
if ((CpuMpData->InitFlag == ApInitConfig) && FixedPcdGetBool (PcdFirstTimeWakeUpAPsBySipi)) {
@@ -1414,7 +1415,7 @@ WakeUpAP (
SetSevEsJumpTable (ExchangeInfo->BufferStart);
}
- if (CpuMpData->SevSnpIsEnabled && (CpuMpData->InitFlag != ApInitConfig)) {
+ if (SevSnpUseCreateAP (CpuMpData)) {
SevSnpCreateAP (CpuMpData, (INTN)ProcessorNumber);
} else {
SendInitSipiSipi (
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
index db9a37fbbd19..6186a8d71521 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
+++ b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
@@ -263,17 +263,63 @@ SevSnpCreateAP (
CPU_INFO_IN_HOB *CpuInfoInHob;
CPU_AP_DATA *CpuData;
UINTN Index;
+ UINTN MaxIndex;
UINT32 ApicId;
+ GHCB_APIC_IDS *GhcbApicIds;
ASSERT (CpuMpData->MpCpuExchangeInfo->BufferStart < 0x100000);
CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
if (ProcessorNumber < 0) {
- for (Index = 0; Index < CpuMpData->CpuCount; Index++) {
+ GhcbApicIds = (GHCB_APIC_IDS *)(UINTN)PcdGet64 (PcdSevSnpApicIds);
+
+ if (CpuMpData->InitFlag == ApInitConfig) {
+ //
+ // APs have not been started, so CpuCount is not "known" yet.
+ // Use the retrieved APIC IDs to start the APs and fill out the
+ // MpLib CPU information properly.
+ //
+ ASSERT (GhcbApicIds != NULL);
+ if (GhcbApicIds == NULL) {
+ return;
+ }
+
+ MaxIndex = MIN (GhcbApicIds->NumEntries, PcdGet32 (PcdCpuMaxLogicalProcessorNumber));
+ } else {
+ //
+ // APs have been previously started.
+ //
+ MaxIndex = CpuMpData->CpuCount;
+ }
+
+ for (Index = 0; Index < MaxIndex; Index++) {
if (Index != CpuMpData->BspNumber) {
CpuData = &CpuMpData->CpuData[Index];
- ApicId = CpuInfoInHob[Index].ApicId,
+
+ if (CpuMpData->InitFlag == ApInitConfig) {
+ //
+ // CodeQL doesn't understand that a check for NULL was already done
+ // above, so check again.
+ //
+ if (GhcbApicIds == NULL) {
+ return;
+ }
+
+ ApicId = GhcbApicIds->ApicIds[Index];
+
+ //
+ // For the first boot, use the BSP register information.
+ //
+ CopyMem (
+ &CpuData->VolatileRegisters,
+ &CpuMpData->CpuData[0].VolatileRegisters,
+ sizeof (CpuData->VolatileRegisters)
+ );
+ } else {
+ ApicId = CpuInfoInHob[Index].ApicId;
+ }
+
SevSnpCreateSaveArea (CpuMpData, CpuData, ApicId);
}
}
@@ -284,3 +330,32 @@ SevSnpCreateAP (
SevSnpCreateSaveArea (CpuMpData, CpuData, ApicId);
}
}
+
+/**
+ Determine if the SEV-SNP AP Create protocol should be used.
+
+ @param[in] CpuMpData Pointer to CPU MP Data
+
+ @retval TRUE Use SEV-SNP AP Create protocol
+ @retval FALSE Do not use SEV-SNP AP Create protocol
+**/
+BOOLEAN
+SevSnpUseCreateAP (
+ IN CPU_MP_DATA *CpuMpData
+ )
+{
+ //
+ // The AP Create protocol is used for an SEV-SNP guest if
+ // - The initial configuration has been performed already or
+ // - PcdSevSnpApicIds is non-zero.
+ //
+ if (!CpuMpData->SevSnpIsEnabled) {
+ return FALSE;
+ }
+
+ if ((CpuMpData->InitFlag == ApInitConfig) && (PcdGet64 (PcdSevSnpApicIds) == 0)) {
+ return FALSE;
+ }
+
+ return TRUE;
+}
--
2.42.0
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