tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
audk/OvmfPkg/AmdSevDxe/AmdSevDxe.c

366 lines
11 KiB
C
Raw Blame History

/** @file
AMD Sev Dxe driver. This driver is dispatched early in DXE, due to being list
in APRIORI. It clears C-bit from MMIO and NonExistent Memory space when SEV
is enabled.
Copyright (c) 2017 - 2020, AMD Inc. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <IndustryStandard/Q35MchIch9.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/DxeServicesTableLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Guid/ConfidentialComputingSevSnpBlob.h>
#include <Library/PcdLib.h>
#include <Pi/PrePiDxeCis.h>
#include <Protocol/SevMemoryAcceptance.h>
#include <Protocol/MemoryAccept.h>
#include <Uefi/UefiSpec.h>
// Present, initialized, tested bits defined in MdeModulePkg/Core/Dxe/DxeMain.h
#define EFI_MEMORY_INTERNAL_MASK 0x0700000000000000ULL
STATIC
EFI_STATUS
AllocateConfidentialComputingBlob (
OUT CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION **CcBlobPtr
)
{
EFI_STATUS Status;
CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION *CcBlob;
Status = gBS->AllocatePool (
EfiACPIReclaimMemory,
sizeof (CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION),
(VOID **)&CcBlob
);
if (EFI_ERROR (Status)) {
return Status;
}
CcBlob->Header = SIGNATURE_32 ('A', 'M', 'D', 'E');
CcBlob->Version = 1;
CcBlob->Reserved = 0;
CcBlob->SecretsPhysicalAddress = (UINT64)(UINTN)FixedPcdGet32 (PcdOvmfSnpSecretsBase);
CcBlob->SecretsSize = FixedPcdGet32 (PcdOvmfSnpSecretsSize);
CcBlob->Reserved1 = 0;
CcBlob->CpuidPhysicalAddress = (UINT64)(UINTN)FixedPcdGet32 (PcdOvmfCpuidBase);
CcBlob->CpuidLSize = FixedPcdGet32 (PcdOvmfCpuidSize);
CcBlob->Reserved2 = 0;
*CcBlobPtr = CcBlob;
return EFI_SUCCESS;
}
STATIC EFI_HANDLE mAmdSevDxeHandle = NULL;
STATIC BOOLEAN mAcceptAllMemoryAtEBS = TRUE;
STATIC EFI_EVENT mAcceptAllMemoryEvent = NULL;
STATIC
EFI_STATUS
EFIAPI
AmdSevMemoryAccept (
IN EDKII_MEMORY_ACCEPT_PROTOCOL *This,
IN EFI_PHYSICAL_ADDRESS StartAddress,
IN UINTN Size
)
{
//
// The StartAddress must be page-aligned, and the Size must be a positive
// multiple of SIZE_4KB. Use an assert instead of returning an erros since
// this is an EDK2-internal protocol.
//
ASSERT (IS_ALIGNED (StartAddress, SIZE_4KB));
ASSERT (IS_ALIGNED (Size, SIZE_4KB));
ASSERT (Size != 0);
MemEncryptSevSnpPreValidateSystemRam (
StartAddress,
EFI_SIZE_TO_PAGES (Size)
);
return EFI_SUCCESS;
}
STATIC
EFI_STATUS
AcceptAllMemory (
VOID
)
{
EFI_GCD_MEMORY_SPACE_DESCRIPTOR *AllDescMap;
UINTN NumEntries;
UINTN Index;
EFI_STATUS Status;
DEBUG ((DEBUG_INFO, "Accepting all memory\n"));
/*
* Get a copy of the memory space map to iterate over while
* changing the map.
*/
Status = gDS->GetMemorySpaceMap (&NumEntries, &AllDescMap);
if (EFI_ERROR (Status)) {
return Status;
}
for (Index = 0; Index < NumEntries; Index++) {
CONST EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Desc;
Desc = &AllDescMap[Index];
if (Desc->GcdMemoryType != EFI_GCD_MEMORY_TYPE_UNACCEPTED) {
continue;
}
Status = AmdSevMemoryAccept (
NULL,
Desc->BaseAddress,
Desc->Length
);
if (EFI_ERROR (Status)) {
break;
}
Status = gDS->RemoveMemorySpace (Desc->BaseAddress, Desc->Length);
if (EFI_ERROR (Status)) {
break;
}
Status = gDS->AddMemorySpace (
EfiGcdMemoryTypeSystemMemory,
Desc->BaseAddress,
Desc->Length,
// Allocable system memory resource capabilities as masked
// in MdeModulePkg/Core/Dxe/Mem/Page.c:PromoteMemoryResource
Desc->Capabilities & ~(EFI_MEMORY_INTERNAL_MASK | EFI_MEMORY_RUNTIME)
);
if (EFI_ERROR (Status)) {
break;
}
}
gBS->FreePool (AllDescMap);
gBS->CloseEvent (mAcceptAllMemoryEvent);
return Status;
}
VOID
EFIAPI
ResolveUnacceptedMemory (
IN EFI_EVENT Event,
IN VOID *Context
)
{
EFI_STATUS Status;
if (!mAcceptAllMemoryAtEBS) {
return;
}
Status = AcceptAllMemory ();
ASSERT_EFI_ERROR (Status);
}
STATIC
EFI_STATUS
EFIAPI
AllowUnacceptedMemory (
IN OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL *This
)
{
mAcceptAllMemoryAtEBS = FALSE;
return EFI_SUCCESS;
}
STATIC
OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL
mMemoryAcceptanceProtocol = { AllowUnacceptedMemory };
STATIC EDKII_MEMORY_ACCEPT_PROTOCOL mMemoryAcceptProtocol = {
AmdSevMemoryAccept
};
EFI_STATUS
EFIAPI
AmdSevDxeEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
EFI_GCD_MEMORY_SPACE_DESCRIPTOR *AllDescMap;
UINTN NumEntries;
UINTN Index;
CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION *SnpBootDxeTable;
//
// Do nothing when SEV is not enabled
//
if (!MemEncryptSevIsEnabled ()) {
return EFI_UNSUPPORTED;
}
//
// Iterate through the GCD map and clear the C-bit from MMIO and NonExistent
// memory space. The NonExistent memory space will be used for mapping the
// MMIO space added later (eg PciRootBridge). By clearing both known MMIO and
// NonExistent memory space can gurantee that current and furture MMIO adds
// will have C-bit cleared.
//
Status = gDS->GetMemorySpaceMap (&NumEntries, &AllDescMap);
if (!EFI_ERROR (Status)) {
for (Index = 0; Index < NumEntries; Index++) {
CONST EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Desc;
Desc = &AllDescMap[Index];
if ((Desc->GcdMemoryType == EfiGcdMemoryTypeMemoryMappedIo) ||
(Desc->GcdMemoryType == EfiGcdMemoryTypeNonExistent))
{
Status = MemEncryptSevClearMmioPageEncMask (
0,
Desc->BaseAddress,
EFI_SIZE_TO_PAGES (Desc->Length)
);
ASSERT_EFI_ERROR (Status);
}
}
FreePool (AllDescMap);
}
//
// If PCI Express is enabled, the MMCONFIG area has been reserved, rather
// than marked as MMIO, and so the C-bit won't be cleared by the above walk
// through the GCD map. Check for the MMCONFIG area and clear the C-bit for
// the range.
//
if (PcdGet16 (PcdOvmfHostBridgePciDevId) == INTEL_Q35_MCH_DEVICE_ID) {
Status = MemEncryptSevClearMmioPageEncMask (
0,
FixedPcdGet64 (PcdPciExpressBaseAddress),
EFI_SIZE_TO_PAGES (SIZE_256MB)
);
ASSERT_EFI_ERROR (Status);
}
//
// When SMM is enabled, clear the C-bit from SMM Saved State Area
//
// NOTES: The SavedStateArea address cleared here is before SMBASE
// relocation. Currently, we do not clear the SavedStateArea address after
// SMBASE is relocated due to the following reasons:
//
// 1) Guest BIOS never access the relocated SavedStateArea.
//
// 2) The C-bit works on page-aligned address, but the SavedStateArea
// address is not a page-aligned. Theoretically, we could roundup the address
// and clear the C-bit of aligned address but looking carefully we found
// that some portion of the page contains code -- which will causes a bigger
// issues for SEV guest. When SEV is enabled, all the code must be encrypted
// otherwise hardware will cause trap.
//
// We restore the C-bit for this SMM Saved State Area after SMBASE relocation
// is completed (See OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c).
//
if (FeaturePcdGet (PcdSmmSmramRequire)) {
UINTN MapPagesBase;
UINTN MapPagesCount;
Status = MemEncryptSevLocateInitialSmramSaveStateMapPages (
&MapPagesBase,
&MapPagesCount
);
ASSERT_EFI_ERROR (Status);
//
// Although these pages were set aside (i.e., allocated) by PlatformPei, we
// could be after a warm reboot from the OS. Don't leak any stale OS data
// to the hypervisor.
//
ZeroMem ((VOID *)MapPagesBase, EFI_PAGES_TO_SIZE (MapPagesCount));
Status = MemEncryptSevClearPageEncMask (
0, // Cr3BaseAddress -- use current CR3
MapPagesBase, // BaseAddress
MapPagesCount // NumPages
);
if (EFI_ERROR (Status)) {
DEBUG ((
DEBUG_ERROR,
"%a: MemEncryptSevClearPageEncMask(): %r\n",
__func__,
Status
));
ASSERT (FALSE);
CpuDeadLoop ();
}
}
Status = AllocateConfidentialComputingBlob (&SnpBootDxeTable);
if (EFI_ERROR (Status)) {
DEBUG ((
DEBUG_ERROR,
"%a: AllocateConfidentialComputingBlob(): %r\n",
__func__,
Status
));
ASSERT (FALSE);
CpuDeadLoop ();
}
if (MemEncryptSevSnpIsEnabled ()) {
//
// Memory acceptance began being required in SEV-SNP, so install the
// memory accept protocol implementation for a SEV-SNP active guest.
//
Status = gBS->InstallMultipleProtocolInterfaces (
&mAmdSevDxeHandle,
&gEdkiiMemoryAcceptProtocolGuid,
&mMemoryAcceptProtocol,
&gOvmfSevMemoryAcceptanceProtocolGuid,
&mMemoryAcceptanceProtocol,
NULL
);
ASSERT_EFI_ERROR (Status);
// SEV-SNP support does not automatically imply unaccepted memory support,
// so make ExitBootServices accept all unaccepted memory if support is
// not communicated.
Status = gBS->CreateEventEx (
EVT_NOTIFY_SIGNAL,
TPL_CALLBACK,
ResolveUnacceptedMemory,
NULL,
&gEfiEventBeforeExitBootServicesGuid,
&mAcceptAllMemoryEvent
);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_ERROR, "AllowUnacceptedMemory event creation for EventBeforeExitBootServices failed.\n"));
}
//
// If its SEV-SNP active guest then install the CONFIDENTIAL_COMPUTING_SEV_SNP_BLOB.
// It contains the location for both the Secrets and CPUID page.
//
return gBS->InstallConfigurationTable (
&gConfidentialComputingSevSnpBlobGuid,
SnpBootDxeTable
);
}
return EFI_SUCCESS;
}
Reference in New Issue View Git Blame Copy Permalink