diff options
Diffstat (limited to 'UefiCpuPkg/Library/MpInitLib/AmdSev.c')
| -rw-r--r-- | UefiCpuPkg/Library/MpInitLib/AmdSev.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/UefiCpuPkg/Library/MpInitLib/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/AmdSev.c new file mode 100644 index 0000000000..0e3c6e2310 --- /dev/null +++ b/UefiCpuPkg/Library/MpInitLib/AmdSev.c @@ -0,0 +1,245 @@ +/** @file
+ CPU MP Initialize helper function for AMD SEV.
+
+ Copyright (c) 2021, AMD Inc. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include "MpLib.h"
+#include <Library/VmgExitLib.h>
+
+/**
+ Get Protected mode code segment with 16-bit default addressing
+ from current GDT table.
+
+ @return Protected mode 16-bit code segment value.
+**/
+STATIC
+UINT16
+GetProtectedMode16CS (
+ VOID
+ )
+{
+ IA32_DESCRIPTOR GdtrDesc;
+ IA32_SEGMENT_DESCRIPTOR *GdtEntry;
+ UINTN GdtEntryCount;
+ UINT16 Index;
+
+ Index = (UINT16)-1;
+ AsmReadGdtr (&GdtrDesc);
+ GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
+ GdtEntry = (IA32_SEGMENT_DESCRIPTOR *)GdtrDesc.Base;
+ for (Index = 0; Index < GdtEntryCount; Index++) {
+ if ((GdtEntry->Bits.L == 0) &&
+ (GdtEntry->Bits.DB == 0) &&
+ (GdtEntry->Bits.Type > 8))
+ {
+ break;
+ }
+
+ GdtEntry++;
+ }
+
+ ASSERT (Index != GdtEntryCount);
+ return Index * 8;
+}
+
+/**
+ Get Protected mode code segment with 32-bit default addressing
+ from current GDT table.
+
+ @return Protected mode 32-bit code segment value.
+**/
+STATIC
+UINT16
+GetProtectedMode32CS (
+ VOID
+ )
+{
+ IA32_DESCRIPTOR GdtrDesc;
+ IA32_SEGMENT_DESCRIPTOR *GdtEntry;
+ UINTN GdtEntryCount;
+ UINT16 Index;
+
+ Index = (UINT16)-1;
+ AsmReadGdtr (&GdtrDesc);
+ GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);
+ GdtEntry = (IA32_SEGMENT_DESCRIPTOR *)GdtrDesc.Base;
+ for (Index = 0; Index < GdtEntryCount; Index++) {
+ if ((GdtEntry->Bits.L == 0) &&
+ (GdtEntry->Bits.DB == 1) &&
+ (GdtEntry->Bits.Type > 8))
+ {
+ break;
+ }
+
+ GdtEntry++;
+ }
+
+ ASSERT (Index != GdtEntryCount);
+ return Index * 8;
+}
+
+/**
+ Reset an AP when in SEV-ES mode.
+
+ If successful, this function never returns.
+
+ @param[in] Ghcb Pointer to the GHCB
+ @param[in] CpuMpData Pointer to CPU MP Data
+
+**/
+VOID
+MpInitLibSevEsAPReset (
+ IN GHCB *Ghcb,
+ IN CPU_MP_DATA *CpuMpData
+ )
+{
+ EFI_STATUS Status;
+ UINTN ProcessorNumber;
+ UINT16 Code16, Code32;
+ AP_RESET *APResetFn;
+ UINTN BufferStart;
+ UINTN StackStart;
+
+ Status = GetProcessorNumber (CpuMpData, &ProcessorNumber);
+ ASSERT_EFI_ERROR (Status);
+
+ Code16 = GetProtectedMode16CS ();
+ Code32 = GetProtectedMode32CS ();
+
+ if (CpuMpData->WakeupBufferHigh != 0) {
+ APResetFn = (AP_RESET *)(CpuMpData->WakeupBufferHigh + CpuMpData->AddressMap.SwitchToRealNoNxOffset);
+ } else {
+ APResetFn = (AP_RESET *)(CpuMpData->MpCpuExchangeInfo->BufferStart + CpuMpData->AddressMap.SwitchToRealOffset);
+ }
+
+ BufferStart = CpuMpData->MpCpuExchangeInfo->BufferStart;
+ StackStart = CpuMpData->SevEsAPResetStackStart -
+ (AP_RESET_STACK_SIZE * ProcessorNumber);
+
+ //
+ // This call never returns.
+ //
+ APResetFn (BufferStart, Code16, Code32, StackStart);
+}
+
+/**
+ Allocate the SEV-ES AP jump table buffer.
+
+ @param[in, out] CpuMpData The pointer to CPU MP Data structure.
+**/
+VOID
+AllocateSevEsAPMemory (
+ IN OUT CPU_MP_DATA *CpuMpData
+ )
+{
+ if (CpuMpData->SevEsAPBuffer == (UINTN)-1) {
+ CpuMpData->SevEsAPBuffer =
+ CpuMpData->SevEsIsEnabled ? GetSevEsAPMemory () : 0;
+ }
+}
+
+/**
+ Program the SEV-ES AP jump table buffer.
+
+ @param[in] SipiVector The SIPI vector used for the AP Reset
+**/
+VOID
+SetSevEsJumpTable (
+ IN UINTN SipiVector
+ )
+{
+ SEV_ES_AP_JMP_FAR *JmpFar;
+ UINT32 Offset, InsnByte;
+ UINT8 LoNib, HiNib;
+
+ JmpFar = (SEV_ES_AP_JMP_FAR *)(UINTN)FixedPcdGet32 (PcdSevEsWorkAreaBase);
+ ASSERT (JmpFar != NULL);
+
+ //
+ // Obtain the address of the Segment/Rip location in the workarea.
+ // This will be set to a value derived from the SIPI vector and will
+ // be the memory address used for the far jump below.
+ //
+ Offset = FixedPcdGet32 (PcdSevEsWorkAreaBase);
+ Offset += sizeof (JmpFar->InsnBuffer);
+ LoNib = (UINT8)Offset;
+ HiNib = (UINT8)(Offset >> 8);
+
+ //
+ // Program the workarea (which is the initial AP boot address) with
+ // far jump to the SIPI vector (where XX and YY represent the
+ // address of where the SIPI vector is stored.
+ //
+ // JMP FAR [CS:XXYY] => 2E FF 2E YY XX
+ //
+ InsnByte = 0;
+ JmpFar->InsnBuffer[InsnByte++] = 0x2E; // CS override prefix
+ JmpFar->InsnBuffer[InsnByte++] = 0xFF; // JMP (FAR)
+ JmpFar->InsnBuffer[InsnByte++] = 0x2E; // ModRM (JMP memory location)
+ JmpFar->InsnBuffer[InsnByte++] = LoNib; // YY offset ...
+ JmpFar->InsnBuffer[InsnByte++] = HiNib; // XX offset ...
+
+ //
+ // Program the Segment/Rip based on the SIPI vector (always at least
+ // 16-byte aligned, so Rip is set to 0).
+ //
+ JmpFar->Rip = 0;
+ JmpFar->Segment = (UINT16)(SipiVector >> 4);
+}
+
+/**
+ The function puts the AP in halt loop.
+
+ @param[in] CpuMpData The pointer to CPU MP Data structure.
+**/
+VOID
+SevEsPlaceApHlt (
+ CPU_MP_DATA *CpuMpData
+ )
+{
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+ GHCB *Ghcb;
+ UINT64 Status;
+ BOOLEAN DoDecrement;
+ BOOLEAN InterruptState;
+
+ DoDecrement = (BOOLEAN)(CpuMpData->InitFlag == ApInitConfig);
+
+ while (TRUE) {
+ Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+ Ghcb = Msr.Ghcb;
+
+ VmgInit (Ghcb, &InterruptState);
+
+ if (DoDecrement) {
+ DoDecrement = FALSE;
+
+ //
+ // Perform the delayed decrement just before issuing the first
+ // VMGEXIT with AP_RESET_HOLD.
+ //
+ InterlockedDecrement ((UINT32 *)&CpuMpData->MpCpuExchangeInfo->NumApsExecuting);
+ }
+
+ Status = VmgExit (Ghcb, SVM_EXIT_AP_RESET_HOLD, 0, 0);
+ if ((Status == 0) && (Ghcb->SaveArea.SwExitInfo2 != 0)) {
+ VmgDone (Ghcb, InterruptState);
+ break;
+ }
+
+ VmgDone (Ghcb, InterruptState);
+ }
+
+ //
+ // Awakened in a new phase? Use the new CpuMpData
+ //
+ if (CpuMpData->NewCpuMpData != NULL) {
+ CpuMpData = CpuMpData->NewCpuMpData;
+ }
+
+ MpInitLibSevEsAPReset (Ghcb, CpuMpData);
+}
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