diff options
Diffstat (limited to 'OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c')
| -rw-r--r-- | OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c b/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c new file mode 100644 index 0000000000..861bf9591a --- /dev/null +++ b/OvmfPkg/Library/AmdSvsmLib/AmdSvsmLib.c @@ -0,0 +1,267 @@ +/** @file
+ SVSM Support Library.
+
+ Copyright (C) 2024, Advanced Micro Devices, Inc. All rights reserved.<BR>
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Base.h>
+#include <Uefi.h>
+#include <Library/AmdSvsmLib.h>
+#include <Register/Amd/Msr.h>
+#include <Register/Amd/Svsm.h>
+
+#define PAGES_PER_2MB_ENTRY 512
+
+/**
+ Issue a GHCB termination request for termination.
+
+ Request termination using the GHCB MSR protocol.
+
+**/
+STATIC
+VOID
+SnpTerminate (
+ VOID
+ )
+{
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+
+ //
+ // Use the GHCB MSR Protocol to request termination by the hypervisor
+ //
+ Msr.Uint64 = 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.Uint64);
+
+ AsmVmgExit ();
+
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
+
+/**
+ Report the presence of an Secure Virtual Services Module (SVSM).
+
+ Determines the presence of an SVSM.
+
+ @retval TRUE An SVSM is present
+ @retval FALSE An SVSM is not present
+
+**/
+BOOLEAN
+EFIAPI
+AmdSvsmIsSvsmPresent (
+ VOID
+ )
+{
+ SVSM_INFORMATION *SvsmInfo;
+
+ SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+ return (SvsmInfo != NULL && SvsmInfo->SvsmSize != 0);
+}
+
+/**
+ Report the VMPL level at which the SEV-SNP guest is running.
+
+ Determines the VMPL level at which the guest is running. If an SVSM is
+ not present, then it must be VMPL0, otherwise return what is reported
+ by the SVSM.
+
+ @return The VMPL level
+
+**/
+UINT8
+EFIAPI
+AmdSvsmSnpGetVmpl (
+ VOID
+ )
+{
+ SVSM_INFORMATION *SvsmInfo;
+
+ SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+ return AmdSvsmIsSvsmPresent () ? SvsmInfo->SvsmGuestVmpl : 0;
+}
+
+/**
+ Report the Calling Area address (CAA) for the BSP of the SEV-SNP guest.
+
+ If an SVSM is present, the CAA for the BSP is returned.
+
+ @return The CAA
+
+**/
+UINT64
+EFIAPI
+AmdSvsmSnpGetCaa (
+ VOID
+ )
+{
+ SVSM_INFORMATION *SvsmInfo;
+
+ SvsmInfo = (SVSM_INFORMATION *)(UINTN)PcdGet32 (PcdOvmfSnpSecretsBase);
+
+ return AmdSvsmIsSvsmPresent () ? SvsmInfo->SvsmCaa : 0;
+}
+
+/**
+ Perform a native PVALIDATE operation for the page ranges specified.
+
+ Validate or rescind the validation of the specified pages.
+
+ @param[in] Info Pointer to a page state change structure
+
+**/
+STATIC
+VOID
+BasePvalidate (
+ IN SNP_PAGE_STATE_CHANGE_INFO *Info
+ )
+{
+ UINTN RmpPageSize;
+ UINTN StartIndex;
+ UINTN EndIndex;
+ UINTN Index;
+ UINTN Ret;
+ EFI_PHYSICAL_ADDRESS Address;
+ BOOLEAN Validate;
+
+ StartIndex = Info->Header.CurrentEntry;
+ EndIndex = Info->Header.EndEntry;
+
+ for ( ; StartIndex <= EndIndex; StartIndex++) {
+ //
+ // Get the address and the page size from the Info.
+ //
+ Address = ((EFI_PHYSICAL_ADDRESS)Info->Entry[StartIndex].GuestFrameNumber) << EFI_PAGE_SHIFT;
+ RmpPageSize = Info->Entry[StartIndex].PageSize;
+ Validate = Info->Entry[StartIndex].Operation == SNP_PAGE_STATE_PRIVATE;
+
+ 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 (Index = 0; Index < PAGES_PER_2MB_ENTRY; Index++) {
+ 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,
+ __func__,
+ Validate ? "Validate" : "Invalidate",
+ Address,
+ Ret
+ ));
+
+ SnpTerminate ();
+ }
+ }
+}
+
+/**
+ Perform a PVALIDATE operation for the page ranges specified.
+
+ Validate or rescind the validation of the specified pages.
+
+ @param[in] Info Pointer to a page state change structure
+
+**/
+VOID
+EFIAPI
+AmdSvsmSnpPvalidate (
+ IN SNP_PAGE_STATE_CHANGE_INFO *Info
+ )
+{
+ BasePvalidate (Info);
+}
+
+/**
+ Perform a native RMPADJUST operation to alter the VMSA setting of a page.
+
+ Add or remove the VMSA attribute for a page.
+
+ @param[in] Vmsa Pointer to an SEV-ES save area page
+ @param[in] SetVmsa Boolean indicator as to whether to set or
+ or clear the VMSA setting for the page
+
+ @retval EFI_SUCCESS RMPADJUST operation successful
+ @retval EFI_INVALID_PARAMETER RMPADJUST operation failed, an invalid
+ parameter was supplied
+
+**/
+STATIC
+EFI_STATUS
+BaseVmsaRmpAdjust (
+ IN SEV_ES_SAVE_AREA *Vmsa,
+ IN BOOLEAN SetVmsa
+ )
+{
+ UINT64 Rdx;
+ UINT32 Ret;
+
+ //
+ // 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 (SetVmsa) {
+ Rdx |= RMPADJUST_VMSA_PAGE_BIT;
+ }
+
+ Ret = AsmRmpAdjust ((UINT64)(UINTN)Vmsa, 0, Rdx);
+
+ return (Ret == 0) ? EFI_SUCCESS : EFI_INVALID_PARAMETER;
+}
+
+/**
+ Perform an RMPADJUST operation to alter the VMSA setting of a page.
+
+ Add or remove the VMSA attribute for a page.
+
+ @param[in] Vmsa Pointer to an SEV-ES save area page
+ @param[in] ApicId APIC ID associated with the VMSA
+ @param[in] SetVmsa Boolean indicator as to whether to set or
+ or clear the VMSA setting for the page
+
+ @retval EFI_SUCCESS RMPADJUST operation successful
+ @retval EFI_UNSUPPORTED Operation is not supported
+ @retval EFI_INVALID_PARAMETER RMPADJUST operation failed, an invalid
+ parameter was supplied
+
+**/
+EFI_STATUS
+EFIAPI
+AmdSvsmSnpVmsaRmpAdjust (
+ IN SEV_ES_SAVE_AREA *Vmsa,
+ IN UINT32 ApicId,
+ IN BOOLEAN SetVmsa
+ )
+{
+ return BaseVmsaRmpAdjust (Vmsa, SetVmsa);
+}
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