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audk/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c

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/** @file
AMD SEV helper function.
Copyright (c) 2021 - 2024, AMD Incorporated. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "MpLib.h"
#include <Library/CcExitLib.h>
#include <Library/AmdSvsmLib.h>
#include <Register/Amd/Fam17Msr.h>
#include <Register/Amd/Ghcb.h>
#define _IS_ALIGNED(x, y) (ALIGN_POINTER((x), (y)) == (x))
/**
Perform the requested AP Creation action.
@param[in] SaveArea Pointer to VM save area (VMSA)
@param[in] ApicId APIC ID of the vCPU
@param[in] Action AP action to perform
@retval TRUE Action completed successfully
@retval FALSE Action did not complete successfully
**/
STATIC
BOOLEAN
SevSnpPerformApAction (
IN SEV_ES_SAVE_AREA *SaveArea,
IN UINT32 ApicId,
IN UINTN Action
)
{
MSR_SEV_ES_GHCB_REGISTER Msr;
GHCB *Ghcb;
BOOLEAN InterruptState;
UINT64 ExitInfo1;
UINT64 ExitInfo2;
UINT64 VmgExitStatus;
EFI_STATUS VmsaStatus;
if (Action == SVM_VMGEXIT_SNP_AP_CREATE) {
//
// Turn the page into a recognized VMSA page. When an SVSM is present
// the page following the VMSA is the Calling Area page.
//
VmsaStatus = AmdSvsmSnpVmsaRmpAdjust (SaveArea, ApicId, TRUE);
if (EFI_ERROR (VmsaStatus)) {
DEBUG ((DEBUG_INFO, "SEV-SNP: RMPADJUST failed for VMSA creation\n"));
ASSERT (FALSE);
return FALSE;
}
}
ExitInfo1 = (UINT64)ApicId << 32;
ExitInfo1 |= (UINT64)SaveArea->Vmpl << 16;
ExitInfo1 |= Action;
ExitInfo2 = (UINT64)(UINTN)SaveArea;
Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
Ghcb = Msr.Ghcb;
CcExitVmgInit (Ghcb, &InterruptState);
if (Action == SVM_VMGEXIT_SNP_AP_CREATE) {
Ghcb->SaveArea.Rax = SaveArea->SevFeatures;
CcExitVmgSetOffsetValid (Ghcb, GhcbRax);
}
VmgExitStatus = CcExitVmgExit (
Ghcb,
SVM_EXIT_SNP_AP_CREATION,
ExitInfo1,
ExitInfo2
);
CcExitVmgDone (Ghcb, InterruptState);
if (VmgExitStatus != 0) {
DEBUG ((DEBUG_INFO, "SEV-SNP: AP Destroy failed\n"));
ASSERT (FALSE);
return FALSE;
}
if (Action == SVM_VMGEXIT_SNP_AP_DESTROY) {
//
// Make the current VMSA not runnable and accessible to be reprogrammed.
// When an SVSM is present the page following the VMSA is the Calling Area
// page.
//
VmsaStatus = AmdSvsmSnpVmsaRmpAdjust (SaveArea, ApicId, FALSE);
if (EFI_ERROR (VmsaStatus)) {
DEBUG ((DEBUG_INFO, "SEV-SNP: RMPADJUST failed for VMSA reset\n"));
ASSERT (FALSE);
return FALSE;
}
}
return TRUE;
}
/**
Create an SEV-SNP AP save area (VMSA) for use in running the vCPU.
@param[in] CpuMpData Pointer to CPU MP Data
@param[in] CpuData Pointer to CPU AP Data
@param[in] ApicId APIC ID of the vCPU
**/
VOID
SevSnpCreateSaveArea (
IN CPU_MP_DATA *CpuMpData,
IN CPU_AP_DATA *CpuData,
UINT32 ApicId
)
{
UINTN PageCount;
UINT8 *Pages;
SEV_ES_SAVE_AREA *SaveArea;
IA32_CR0 ApCr0;
IA32_CR0 ResetCr0;
IA32_CR4 ApCr4;
IA32_CR4 ResetCr4;
UINTN StartIp;
UINT8 SipiVector;
//
// When running under an SVSM, a Calling Area page is also needed and is
// always the page following the VMSA.
//
PageCount = AmdSvsmIsSvsmPresent () ? 2 : 1;
if (CpuData->SevEsSaveArea == NULL) {
//
// Allocate a page for the SEV-ES Save Area and initialize it. Due to AMD
// erratum #1467 (VMSA cannot be on a 2MB boundary), allocate an extra page
// to choose from to work around the issue.
//
Pages = AllocateReservedPages (PageCount + 1);
if (!Pages) {
return;
}
//
// Since page allocation works by allocating downward in the address space,
// try to always free the first (lower address) page to limit possible holes
// in the memory map. So, if the address of the second page is 2MB aligned,
// then use the first page and free the last page. Otherwise, free the
// first page and use the second page.
//
if (_IS_ALIGNED (Pages + EFI_PAGE_SIZE, SIZE_2MB)) {
SaveArea = (SEV_ES_SAVE_AREA *)Pages;
FreePages (Pages + (EFI_PAGE_SIZE * PageCount), 1);
} else {
SaveArea = (SEV_ES_SAVE_AREA *)(Pages + EFI_PAGE_SIZE);
FreePages (Pages, 1);
}
CpuData->SevEsSaveArea = SaveArea;
} else {
SaveArea = CpuData->SevEsSaveArea;
//
// Tell the hypervisor to not use the current VMSA
//
if (!SevSnpPerformApAction (SaveArea, ApicId, SVM_VMGEXIT_SNP_AP_DESTROY)) {
return;
}
}
ZeroMem (SaveArea, EFI_PAGE_SIZE * PageCount);
//
// Propogate the CR0.NW and CR0.CD setting to the AP
//
ResetCr0.UintN = 0x00000010;
ApCr0.UintN = CpuData->VolatileRegisters.Cr0;
if (ApCr0.Bits.NW) {
ResetCr0.Bits.NW = 1;
}
if (ApCr0.Bits.CD) {
ResetCr0.Bits.CD = 1;
}
//
// Propagate the CR4.MCE setting to the AP
//
ResetCr4.UintN = 0;
ApCr4.UintN = CpuData->VolatileRegisters.Cr4;
if (ApCr4.Bits.MCE) {
ResetCr4.Bits.MCE = 1;
}
//
// Convert the start IP into a SIPI Vector
//
StartIp = CpuMpData->MpCpuExchangeInfo->BufferStart;
SipiVector = (UINT8)(StartIp >> 12);
//
// Set the CS:RIP value based on the start IP
//
SaveArea->Cs.Base = SipiVector << 12;
SaveArea->Cs.Selector = SipiVector << 8;
SaveArea->Cs.Limit = 0xFFFF;
SaveArea->Cs.Attributes.Bits.Present = 1;
SaveArea->Cs.Attributes.Bits.Sbit = 1;
SaveArea->Cs.Attributes.Bits.Type = SEV_ES_RESET_CODE_SEGMENT_TYPE;
SaveArea->Rip = StartIp & 0xFFF;
//
// Set the remaining values as defined in APM for INIT
//
SaveArea->Ds.Limit = 0xFFFF;
SaveArea->Ds.Attributes.Bits.Present = 1;
SaveArea->Ds.Attributes.Bits.Sbit = 1;
SaveArea->Ds.Attributes.Bits.Type = SEV_ES_RESET_DATA_SEGMENT_TYPE;
SaveArea->Es = SaveArea->Ds;
SaveArea->Fs = SaveArea->Ds;
SaveArea->Gs = SaveArea->Ds;
SaveArea->Ss = SaveArea->Ds;
SaveArea->Gdtr.Limit = 0xFFFF;
SaveArea->Ldtr.Limit = 0xFFFF;
SaveArea->Ldtr.Attributes.Bits.Present = 1;
SaveArea->Ldtr.Attributes.Bits.Type = SEV_ES_RESET_LDT_TYPE;
SaveArea->Idtr.Limit = 0xFFFF;
SaveArea->Tr.Limit = 0xFFFF;
SaveArea->Ldtr.Attributes.Bits.Present = 1;
SaveArea->Ldtr.Attributes.Bits.Type = SEV_ES_RESET_TSS_TYPE;
SaveArea->Efer = 0x1000;
SaveArea->Cr4 = ResetCr4.UintN;
SaveArea->Cr0 = ResetCr0.UintN;
SaveArea->Dr7 = 0x0400;
SaveArea->Dr6 = 0xFFFF0FF0;
SaveArea->Rflags = 0x0002;
SaveArea->GPat = 0x0007040600070406ULL;
SaveArea->XCr0 = 0x0001;
SaveArea->Mxcsr = 0x1F80;
SaveArea->X87Ftw = 0x5555;
SaveArea->X87Fcw = 0x0040;
//
// Set the SEV-SNP specific fields for the save area:
// VMPL - based on current mode
// SEV_FEATURES - equivalent to the SEV_STATUS MSR right shifted 2 bits
//
SaveArea->Vmpl = AmdSvsmSnpGetVmpl ();
SaveArea->SevFeatures = AsmReadMsr64 (MSR_SEV_STATUS) >> 2;
SevSnpPerformApAction (SaveArea, ApicId, SVM_VMGEXIT_SNP_AP_CREATE);
}
/**
Create SEV-SNP APs.
@param[in] CpuMpData Pointer to CPU MP Data
@param[in] ProcessorNumber The handle number of specified processor
(-1 for all APs)
**/
VOID
SevSnpCreateAP (
IN CPU_MP_DATA *CpuMpData,
IN INTN ProcessorNumber
)
{
CPU_INFO_IN_HOB *CpuInfoInHob;
CPU_AP_DATA *CpuData;
UINTN Index;
UINTN MaxIndex;
UINT32 ApicId;
EFI_HOB_GUID_TYPE *GuidHob;
GHCB_APIC_IDS *GhcbApicIds;
ASSERT (CpuMpData->MpCpuExchangeInfo->BufferStart < 0x100000);
CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
if (ProcessorNumber < 0) {
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. CanUseSevSnpCreateAP() guarantees we have a
// HOB when InitFlag is ApInitConfig.
//
GuidHob = GetFirstGuidHob (&gGhcbApicIdsGuid);
GhcbApicIds = (GHCB_APIC_IDS *)(*(UINTN *)GET_GUID_HOB_DATA (GuidHob));
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];
if (CpuMpData->InitFlag == ApInitConfig) {
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);
}
}
} else {
Index = (UINTN)ProcessorNumber;
CpuData = &CpuMpData->CpuData[Index];
ApicId = CpuInfoInHob[ProcessorNumber].ApicId,
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
CanUseSevSnpCreateAP (
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
// - The APIC IDs GUIDed HOB is non-zero.
//
if (!CpuMpData->SevSnpIsEnabled) {
return FALSE;
}
if ((CpuMpData->InitFlag == ApInitConfig) && (GetFirstGuidHob (&gGhcbApicIdsGuid) == NULL)) {
return FALSE;
}
return TRUE;
}
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