diff options
Diffstat (limited to 'UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c')
| -rw-r--r-- | UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c new file mode 100644 index 0000000000..a3cd377ef6 --- /dev/null +++ b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c @@ -0,0 +1,263 @@ +/** @file
+
+ AMD SEV helper function.
+
+ Copyright (c) 2021, AMD Incorporated. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include "MpLib.h"
+#include <Library/VmgExitLib.h>
+#include <Register/Amd/Fam17Msr.h>
+#include <Register/Amd/Ghcb.h>
+
+/**
+ 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
+ )
+{
+ SEV_ES_SAVE_AREA *SaveArea;
+ IA32_CR0 ApCr0;
+ IA32_CR0 ResetCr0;
+ IA32_CR4 ApCr4;
+ IA32_CR4 ResetCr4;
+ UINTN StartIp;
+ UINT8 SipiVector;
+ UINT32 RmpAdjustStatus;
+ UINT64 VmgExitStatus;
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+ GHCB *Ghcb;
+ BOOLEAN InterruptState;
+ UINT64 ExitInfo1;
+ UINT64 ExitInfo2;
+
+ //
+ // Allocate a single page for the SEV-ES Save Area and initialize it.
+ //
+ SaveArea = AllocateReservedPages (1);
+ if (!SaveArea) {
+ return;
+ }
+
+ ZeroMem (SaveArea, EFI_PAGE_SIZE);
+
+ //
+ // 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 - always VMPL0
+ // SEV_FEATURES - equivalent to the SEV_STATUS MSR right shifted 2 bits
+ //
+ SaveArea->Vmpl = 0;
+ SaveArea->SevFeatures = AsmReadMsr64 (MSR_SEV_STATUS) >> 2;
+
+ //
+ // To turn the page into a recognized VMSA page, issue RMPADJUST:
+ // Target VMPL but numerically higher than current VMPL
+ // Target PermissionMask is not used
+ //
+ RmpAdjustStatus = SevSnpRmpAdjust (
+ (EFI_PHYSICAL_ADDRESS)(UINTN)SaveArea,
+ TRUE
+ );
+ ASSERT (RmpAdjustStatus == 0);
+
+ ExitInfo1 = (UINT64)ApicId << 32;
+ ExitInfo1 |= SVM_VMGEXIT_SNP_AP_CREATE;
+ ExitInfo2 = (UINT64)(UINTN)SaveArea;
+
+ Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+ Ghcb = Msr.Ghcb;
+
+ VmgInit (Ghcb, &InterruptState);
+ Ghcb->SaveArea.Rax = SaveArea->SevFeatures;
+ VmgSetOffsetValid (Ghcb, GhcbRax);
+ VmgExitStatus = VmgExit (
+ Ghcb,
+ SVM_EXIT_SNP_AP_CREATION,
+ ExitInfo1,
+ ExitInfo2
+ );
+ VmgDone (Ghcb, InterruptState);
+
+ ASSERT (VmgExitStatus == 0);
+ if (VmgExitStatus != 0) {
+ RmpAdjustStatus = SevSnpRmpAdjust (
+ (EFI_PHYSICAL_ADDRESS)(UINTN)SaveArea,
+ FALSE
+ );
+ if (RmpAdjustStatus == 0) {
+ FreePages (SaveArea, 1);
+ } else {
+ DEBUG ((DEBUG_INFO, "SEV-SNP: RMPADJUST failed, leaking VMSA page\n"));
+ }
+
+ SaveArea = NULL;
+ }
+
+ if (CpuData->SevEsSaveArea) {
+ RmpAdjustStatus = SevSnpRmpAdjust (
+ (EFI_PHYSICAL_ADDRESS)(UINTN)CpuData->SevEsSaveArea,
+ FALSE
+ );
+ if (RmpAdjustStatus == 0) {
+ FreePages (CpuData->SevEsSaveArea, 1);
+ } else {
+ DEBUG ((DEBUG_INFO, "SEV-SNP: RMPADJUST failed, leaking VMSA page\n"));
+ }
+ }
+
+ CpuData->SevEsSaveArea = SaveArea;
+}
+
+/**
+ 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;
+ UINT32 ApicId;
+
+ ASSERT (CpuMpData->MpCpuExchangeInfo->BufferStart < 0x100000);
+
+ CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
+
+ if (ProcessorNumber < 0) {
+ for (Index = 0; Index < CpuMpData->CpuCount; Index++) {
+ if (Index != CpuMpData->BspNumber) {
+ CpuData = &CpuMpData->CpuData[Index];
+ ApicId = CpuInfoInHob[Index].ApicId,
+ SevSnpCreateSaveArea (CpuMpData, CpuData, ApicId);
+ }
+ }
+ } else {
+ Index = (UINTN)ProcessorNumber;
+ CpuData = &CpuMpData->CpuData[Index];
+ ApicId = CpuInfoInHob[ProcessorNumber].ApicId,
+ SevSnpCreateSaveArea (CpuMpData, CpuData, ApicId);
+ }
+}
+
+/**
+ Issue RMPADJUST to adjust the VMSA attribute of an SEV-SNP page.
+
+ @param[in] PageAddress
+ @param[in] VmsaPage
+
+ @return RMPADJUST return value
+**/
+UINT32
+SevSnpRmpAdjust (
+ IN EFI_PHYSICAL_ADDRESS PageAddress,
+ IN BOOLEAN VmsaPage
+ )
+{
+ UINT64 Rdx;
+
+ //
+ // The RMPADJUST instruction is used to set or clear the VMSA bit for a
+ // page. The VMSA change is only made when running at VMPL0 and is ignored
+ // otherwise. If too low a target VMPL is specified, the instruction can
+ // succeed without changing the VMSA bit when not running at VMPL0. Using a
+ // target VMPL level of 1, RMPADJUST will return a FAIL_PERMISSION error if
+ // not running at VMPL0, thus ensuring that the VMSA bit is set appropriately
+ // when no error is returned.
+ //
+ Rdx = 1;
+ if (VmsaPage) {
+ Rdx |= RMPADJUST_VMSA_PAGE_BIT;
+ }
+
+ return AsmRmpAdjust ((UINT64)PageAddress, 0, Rdx);
+}
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