diff options
12 files changed, 485 insertions, 0 deletions
diff --git a/OvmfPkg/Include/Library/MemEncryptSevLib.h b/OvmfPkg/Include/Library/MemEncryptSevLib.h index 3c77d71df7..4fa9c0d700 100644 --- a/OvmfPkg/Include/Library/MemEncryptSevLib.h +++ b/OvmfPkg/Include/Library/MemEncryptSevLib.h @@ -214,4 +214,18 @@ MemEncryptSevClearMmioPageEncMask ( IN UINTN NumPages
);
+/**
+ Pre-validate the system RAM when SEV-SNP is enabled in the guest VM.
+
+ @param[in] BaseAddress Base address
+ @param[in] NumPages Number of pages starting from the base address
+
+**/
+VOID
+EFIAPI
+MemEncryptSevSnpPreValidateSystemRam (
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ );
+
#endif // _MEM_ENCRYPT_SEV_LIB_H_
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf index f2e162d680..f613bb314f 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf @@ -34,8 +34,10 @@ PeiDxeMemEncryptSevLibInternal.c
[Sources.X64]
+ X64/DxeSnpSystemRamValidate.c
X64/MemEncryptSevLib.c
X64/PeiDxeVirtualMemory.c
+ X64/SnpPageStateChangeInternal.c
X64/VirtualMemory.c
X64/VirtualMemory.h
@@ -49,6 +51,7 @@ DebugLib
MemoryAllocationLib
PcdLib
+ VmgExitLib
[FeaturePcd]
gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c index 9bd66301fc..f92299fc77 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c @@ -136,3 +136,20 @@ MemEncryptSevClearMmioPageEncMask ( //
return RETURN_UNSUPPORTED;
}
+
+/**
+ Pre-validate the system RAM when SEV-SNP is enabled in the guest VM.
+
+ @param[in] BaseAddress Base address
+ @param[in] NumPages Number of pages starting from the base address
+
+**/
+VOID
+EFIAPI
+MemEncryptSevSnpPreValidateSystemRam (
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ )
+{
+ ASSERT (FALSE);
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf index 03a78c32df..0402e49a10 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf @@ -36,6 +36,8 @@ [Sources.X64]
X64/MemEncryptSevLib.c
X64/PeiDxeVirtualMemory.c
+ X64/PeiSnpSystemRamValidate.c
+ X64/SnpPageStateChangeInternal.c
X64/VirtualMemory.c
X64/VirtualMemory.h
@@ -49,6 +51,7 @@ DebugLib
MemoryAllocationLib
PcdLib
+ VmgExitLib
[FeaturePcd]
gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf index 279c38bfbc..939af0a91e 100644 --- a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf @@ -35,6 +35,8 @@ [Sources.X64]
X64/MemEncryptSevLib.c
X64/SecVirtualMemory.c
+ X64/SecSnpSystemRamValidate.c
+ X64/SnpPageStateChangeInternal.c
X64/VirtualMemory.c
X64/VirtualMemory.h
@@ -46,6 +48,7 @@ CpuLib
DebugLib
PcdLib
+ VmgExitLib
[FixedPcd]
gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/DxeSnpSystemRamValidate.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/DxeSnpSystemRamValidate.c new file mode 100644 index 0000000000..d3a95e4913 --- /dev/null +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/DxeSnpSystemRamValidate.c @@ -0,0 +1,40 @@ +/** @file
+
+ SEV-SNP Page Validation functions.
+
+ Copyright (c) 2021 AMD Incorporated. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi/UefiBaseType.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/MemEncryptSevLib.h>
+
+#include "SnpPageStateChange.h"
+
+/**
+ Pre-validate the system RAM when SEV-SNP is enabled in the guest VM.
+
+ @param[in] BaseAddress Base address
+ @param[in] NumPages Number of pages starting from the base address
+
+**/
+VOID
+EFIAPI
+MemEncryptSevSnpPreValidateSystemRam (
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ )
+{
+ if (!MemEncryptSevSnpIsEnabled ()) {
+ return;
+ }
+
+ //
+ // All the pre-validation must be completed in the PEI phase.
+ //
+ ASSERT (FALSE);
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c new file mode 100644 index 0000000000..bc891c2636 --- /dev/null +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c @@ -0,0 +1,36 @@ +/** @file
+
+ SEV-SNP Page Validation functions.
+
+ Copyright (c) 2021 AMD Incorporated. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi/UefiBaseType.h>
+#include <Library/BaseLib.h>
+#include <Library/MemEncryptSevLib.h>
+
+#include "SnpPageStateChange.h"
+
+/**
+ Pre-validate the system RAM when SEV-SNP is enabled in the guest VM.
+
+ @param[in] BaseAddress Base address
+ @param[in] NumPages Number of pages starting from the base address
+
+**/
+VOID
+EFIAPI
+MemEncryptSevSnpPreValidateSystemRam (
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ )
+{
+ if (!MemEncryptSevSnpIsEnabled ()) {
+ return;
+ }
+
+ InternalSetPageState (BaseAddress, NumPages, SevSnpPagePrivate, TRUE);
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecSnpSystemRamValidate.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecSnpSystemRamValidate.c new file mode 100644 index 0000000000..bc891c2636 --- /dev/null +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecSnpSystemRamValidate.c @@ -0,0 +1,36 @@ +/** @file
+
+ SEV-SNP Page Validation functions.
+
+ Copyright (c) 2021 AMD Incorporated. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi/UefiBaseType.h>
+#include <Library/BaseLib.h>
+#include <Library/MemEncryptSevLib.h>
+
+#include "SnpPageStateChange.h"
+
+/**
+ Pre-validate the system RAM when SEV-SNP is enabled in the guest VM.
+
+ @param[in] BaseAddress Base address
+ @param[in] NumPages Number of pages starting from the base address
+
+**/
+VOID
+EFIAPI
+MemEncryptSevSnpPreValidateSystemRam (
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ )
+{
+ if (!MemEncryptSevSnpIsEnabled ()) {
+ return;
+ }
+
+ InternalSetPageState (BaseAddress, NumPages, SevSnpPagePrivate, TRUE);
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChange.h b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChange.h new file mode 100644 index 0000000000..b396f0ffbd --- /dev/null +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChange.h @@ -0,0 +1,30 @@ +/** @file
+
+ SEV-SNP Page Validation functions.
+
+ Copyright (c) 2021 AMD Incorporated. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef SNP_PAGE_STATE_INTERNAL_H_
+#define SNP_PAGE_STATE_INTERNAL_H_
+
+//
+// SEV-SNP Page states
+//
+typedef enum {
+ SevSnpPagePrivate,
+ SevSnpPageShared,
+} SEV_SNP_PAGE_STATE;
+
+VOID
+InternalSetPageState (
+ IN EFI_PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages,
+ IN SEV_SNP_PAGE_STATE State,
+ IN BOOLEAN UseLargeEntry
+ );
+
+#endif
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c new file mode 100644 index 0000000000..9c552ef5c7 --- /dev/null +++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c @@ -0,0 +1,301 @@ +/** @file
+
+ SEV-SNP Page Validation functions.
+
+ Copyright (c) 2021 AMD Incorporated. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi/UefiBaseType.h>
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/MemEncryptSevLib.h>
+#include <Library/DebugLib.h>
+#include <Library/VmgExitLib.h>
+
+#include <Register/Amd/Ghcb.h>
+#include <Register/Amd/Msr.h>
+
+#include "SnpPageStateChange.h"
+
+#define IS_ALIGNED(x, y) ((((x) & (y - 1)) == 0))
+#define PAGES_PER_LARGE_ENTRY 512
+
+STATIC
+UINTN
+MemoryStateToGhcbOp (
+ IN SEV_SNP_PAGE_STATE State
+ )
+{
+ UINTN Cmd;
+
+ switch (State) {
+ case SevSnpPageShared: Cmd = SNP_PAGE_STATE_SHARED;
+ break;
+ case SevSnpPagePrivate: Cmd = SNP_PAGE_STATE_PRIVATE;
+ break;
+ default: ASSERT (0);
+ }
+
+ return Cmd;
+}
+
+STATIC
+VOID
+SnpPageStateFailureTerminate (
+ VOID
+ )
+{
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+
+ //
+ // Use the GHCB MSR Protocol to request termination by the hypervisor
+ //
+ Msr.GhcbPhysicalAddress = 0;
+ Msr.GhcbTerminate.Function = GHCB_INFO_TERMINATE_REQUEST;
+ Msr.GhcbTerminate.ReasonCodeSet = GHCB_TERMINATE_GHCB;
+ Msr.GhcbTerminate.ReasonCode = GHCB_TERMINATE_GHCB_GENERAL;
+ AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+ AsmVmgExit ();
+
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
+
+/**
+ This function issues the PVALIDATE instruction to validate or invalidate the memory
+ range specified. If PVALIDATE returns size mismatch then it retry validating with
+ smaller page size.
+
+ */
+STATIC
+VOID
+PvalidateRange (
+ IN SNP_PAGE_STATE_CHANGE_INFO *Info,
+ IN UINTN StartIndex,
+ IN UINTN EndIndex,
+ IN BOOLEAN Validate
+ )
+{
+ UINTN Address, RmpPageSize, Ret, i;
+
+ for ( ; StartIndex <= EndIndex; StartIndex++) {
+ //
+ // Get the address and the page size from the Info.
+ //
+ Address = Info->Entry[StartIndex].GuestFrameNumber << EFI_PAGE_SHIFT;
+ RmpPageSize = Info->Entry[StartIndex].PageSize;
+
+ Ret = AsmPvalidate (RmpPageSize, Validate, Address);
+
+ //
+ // If we fail to validate due to size mismatch then try with the
+ // smaller page size. This senario will occur if the backing page in
+ // the RMP entry is 4K and we are validating it as a 2MB.
+ //
+ if ((Ret == PVALIDATE_RET_SIZE_MISMATCH) && (RmpPageSize == PvalidatePageSize2MB)) {
+ for (i = 0; i < PAGES_PER_LARGE_ENTRY; i++) {
+ Ret = AsmPvalidate (PvalidatePageSize4K, Validate, Address);
+ if (Ret) {
+ break;
+ }
+
+ Address = Address + EFI_PAGE_SIZE;
+ }
+ }
+
+ //
+ // If validation failed then do not continue.
+ //
+ if (Ret) {
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a:%a: Failed to %a address 0x%Lx Error code %d\n",
+ gEfiCallerBaseName,
+ __FUNCTION__,
+ Validate ? "Validate" : "Invalidate",
+ Address,
+ Ret
+ ));
+ SnpPageStateFailureTerminate ();
+ }
+ }
+}
+
+STATIC
+EFI_PHYSICAL_ADDRESS
+BuildPageStateBuffer (
+ IN EFI_PHYSICAL_ADDRESS BaseAddress,
+ IN EFI_PHYSICAL_ADDRESS EndAddress,
+ IN SEV_SNP_PAGE_STATE State,
+ IN BOOLEAN UseLargeEntry,
+ IN SNP_PAGE_STATE_CHANGE_INFO *Info
+ )
+{
+ EFI_PHYSICAL_ADDRESS NextAddress;
+ UINTN i, RmpPageSize;
+
+ // Clear the page state structure
+ SetMem (Info, sizeof (*Info), 0);
+
+ i = 0;
+ NextAddress = EndAddress;
+
+ //
+ // Populate the page state entry structure
+ //
+ while ((BaseAddress < EndAddress) && (i < SNP_PAGE_STATE_MAX_ENTRY)) {
+ //
+ // Is this a 2MB aligned page? Check if we can use the Large RMP entry.
+ //
+ if (UseLargeEntry && IS_ALIGNED (BaseAddress, SIZE_2MB) &&
+ ((EndAddress - BaseAddress) >= SIZE_2MB))
+ {
+ RmpPageSize = PvalidatePageSize2MB;
+ NextAddress = BaseAddress + SIZE_2MB;
+ } else {
+ RmpPageSize = PvalidatePageSize4K;
+ NextAddress = BaseAddress + EFI_PAGE_SIZE;
+ }
+
+ Info->Entry[i].GuestFrameNumber = BaseAddress >> EFI_PAGE_SHIFT;
+ Info->Entry[i].PageSize = RmpPageSize;
+ Info->Entry[i].Operation = MemoryStateToGhcbOp (State);
+ Info->Entry[i].CurrentPage = 0;
+ Info->Header.EndEntry = (UINT16)i;
+
+ BaseAddress = NextAddress;
+ i++;
+ }
+
+ return NextAddress;
+}
+
+STATIC
+VOID
+PageStateChangeVmgExit (
+ IN GHCB *Ghcb,
+ IN SNP_PAGE_STATE_CHANGE_INFO *Info
+ )
+{
+ EFI_STATUS Status;
+
+ //
+ // As per the GHCB specification, the hypervisor can resume the guest before
+ // processing all the entries. Checks whether all the entries are processed.
+ //
+ // The stragtegy here is to wait for the hypervisor to change the page
+ // state in the RMP table before guest access the memory pages. If the
+ // page state was not successful, then later memory access will result
+ // in the crash.
+ //
+ while (Info->Header.CurrentEntry <= Info->Header.EndEntry) {
+ Ghcb->SaveArea.SwScratch = (UINT64)Ghcb->SharedBuffer;
+ VmgSetOffsetValid (Ghcb, GhcbSwScratch);
+
+ Status = VmgExit (Ghcb, SVM_EXIT_SNP_PAGE_STATE_CHANGE, 0, 0);
+
+ //
+ // The Page State Change VMGEXIT can pass the failure through the
+ // ExitInfo2. Lets check both the return value as well as ExitInfo2.
+ //
+ if ((Status != 0) || (Ghcb->SaveArea.SwExitInfo2)) {
+ SnpPageStateFailureTerminate ();
+ }
+ }
+}
+
+/**
+ The function is used to set the page state when SEV-SNP is active. The page state
+ transition consist of changing the page ownership in the RMP table, and using the
+ PVALIDATE instruction to update the Validated bit in RMP table.
+
+ When the UseLargeEntry is set to TRUE, then function will try to use the large RMP
+ entry (whevever possible).
+ */
+VOID
+InternalSetPageState (
+ IN EFI_PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages,
+ IN SEV_SNP_PAGE_STATE State,
+ IN BOOLEAN UseLargeEntry
+ )
+{
+ GHCB *Ghcb;
+ EFI_PHYSICAL_ADDRESS NextAddress, EndAddress;
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+ BOOLEAN InterruptState;
+ SNP_PAGE_STATE_CHANGE_INFO *Info;
+
+ Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+ Ghcb = Msr.Ghcb;
+
+ EndAddress = BaseAddress + EFI_PAGES_TO_SIZE (NumPages);
+
+ DEBUG ((
+ DEBUG_VERBOSE,
+ "%a:%a Address 0x%Lx - 0x%Lx State = %a LargeEntry = %d\n",
+ gEfiCallerBaseName,
+ __FUNCTION__,
+ BaseAddress,
+ EndAddress,
+ State == SevSnpPageShared ? "Shared" : "Private",
+ UseLargeEntry
+ ));
+
+ while (BaseAddress < EndAddress) {
+ UINTN CurrentEntry, EndEntry;
+
+ //
+ // Initialize the GHCB
+ //
+ VmgInit (Ghcb, &InterruptState);
+
+ //
+ // Build the page state structure
+ //
+ Info = (SNP_PAGE_STATE_CHANGE_INFO *)Ghcb->SharedBuffer;
+ NextAddress = BuildPageStateBuffer (
+ BaseAddress,
+ EndAddress,
+ State,
+ UseLargeEntry,
+ Info
+ );
+
+ //
+ // Save the current and end entry from the page state structure. We need
+ // it later.
+ //
+ CurrentEntry = Info->Header.CurrentEntry;
+ EndEntry = Info->Header.EndEntry;
+
+ //
+ // If the caller requested to change the page state to shared then
+ // invalidate the pages before making the page shared in the RMP table.
+ //
+ if (State == SevSnpPageShared) {
+ PvalidateRange (Info, CurrentEntry, EndEntry, FALSE);
+ }
+
+ //
+ // Invoke the page state change VMGEXIT.
+ //
+ PageStateChangeVmgExit (Ghcb, Info);
+
+ //
+ // If the caller requested to change the page state to private then
+ // validate the pages after it has been added in the RMP table.
+ //
+ if (State == SevSnpPagePrivate) {
+ PvalidateRange (Info, CurrentEntry, EndEntry, TRUE);
+ }
+
+ VmgDone (Ghcb, InterruptState);
+
+ BaseAddress = NextAddress;
+ }
+}
diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc index 6a5be97c05..1dc069e424 100644 --- a/OvmfPkg/OvmfPkgIa32.dsc +++ b/OvmfPkg/OvmfPkgIa32.dsc @@ -266,6 +266,7 @@ !else
CpuExceptionHandlerLib|UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
!endif
+ MemEncryptSevLib|OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
[LibraryClasses.common.PEI_CORE]
HobLib|MdePkg/Library/PeiHobLib/PeiHobLib.inf
diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc index 13d9a1f111..a766457e6b 100644 --- a/OvmfPkg/OvmfPkgIa32X64.dsc +++ b/OvmfPkg/OvmfPkgIa32X64.dsc @@ -270,6 +270,7 @@ !else
CpuExceptionHandlerLib|UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuExceptionHandlerLib.inf
!endif
+ MemEncryptSevLib|OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
[LibraryClasses.common.PEI_CORE]
HobLib|MdePkg/Library/PeiHobLib/PeiHobLib.inf
|