diff options
| -rw-r--r-- | OvmfPkg/PlatformPei/AmdSev.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c index 3991edfd1e..f66e0a7f4a 100644 --- a/OvmfPkg/PlatformPei/AmdSev.c +++ b/OvmfPkg/PlatformPei/AmdSev.c @@ -19,10 +19,91 @@ #include <PiPei.h>
#include <Register/Amd/Msr.h>
#include <Register/Intel/SmramSaveStateMap.h>
+#include <Library/VmgExitLib.h>
#include "Platform.h"
/**
+ Handle an SEV-SNP/GHCB protocol check failure.
+
+ Notify the hypervisor using the VMGEXIT instruction that the SEV-SNP guest
+ wishes to be terminated.
+
+ @param[in] ReasonCode Reason code to provide to the hypervisor for the
+ termination request.
+
+**/
+STATIC
+VOID
+SevEsProtocolFailure (
+ IN UINT8 ReasonCode
+ )
+{
+ 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 = ReasonCode;
+ AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+ AsmVmgExit ();
+
+ ASSERT (FALSE);
+ CpuDeadLoop ();
+}
+
+/**
+
+ This function can be used to register the GHCB GPA.
+
+ @param[in] Address The physical address to be registered.
+
+**/
+STATIC
+VOID
+GhcbRegister (
+ IN EFI_PHYSICAL_ADDRESS Address
+ )
+{
+ MSR_SEV_ES_GHCB_REGISTER Msr;
+ MSR_SEV_ES_GHCB_REGISTER CurrentMsr;
+
+ //
+ // Save the current MSR Value
+ //
+ CurrentMsr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+
+ //
+ // Use the GHCB MSR Protocol to request to register the GPA.
+ //
+ Msr.GhcbPhysicalAddress = Address & ~EFI_PAGE_MASK;
+ Msr.GhcbGpaRegister.Function = GHCB_INFO_GHCB_GPA_REGISTER_REQUEST;
+ AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+ AsmVmgExit ();
+
+ Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+
+ //
+ // If hypervisor responded with a different GPA than requested then fail.
+ //
+ if ((Msr.GhcbGpaRegister.Function != GHCB_INFO_GHCB_GPA_REGISTER_RESPONSE) ||
+ ((Msr.GhcbPhysicalAddress & ~EFI_PAGE_MASK) != Address))
+ {
+ SevEsProtocolFailure (GHCB_TERMINATE_GHCB_GENERAL);
+ }
+
+ //
+ // Restore the MSR
+ //
+ AsmWriteMsr64 (MSR_SEV_ES_GHCB, CurrentMsr.GhcbPhysicalAddress);
+}
+
+/**
Initialize SEV-ES support if running as an SEV-ES guest.
@@ -115,6 +196,13 @@ AmdSevEsInitialize ( GhcbBackupBase
));
+ //
+ // SEV-SNP guest requires that GHCB GPA must be registered before using it.
+ //
+ if (MemEncryptSevSnpIsEnabled ()) {
+ GhcbRegister (GhcbBasePa);
+ }
+
AsmWriteMsr64 (MSR_SEV_ES_GHCB, GhcbBasePa);
//
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