From: Tom Lendacky <thomas.lenda...@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
Under SEV-ES, a RDTSC intercept generates a #VC exception. VMGEXIT must be
used to allow the hypervisor to handle this intercept.
Cc: Eric Dong <eric.d...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Laszlo Ersek <ler...@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
.../X64/AMDSevVcCommon.c | 30 +++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
index f8966cc3eca0..1f6a1f9a30ce 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
@@ -865,6 +865,32 @@ CpuidExit (
return 0;
}
+STATIC
+UINTN
+RdtscExit (
+ GHCB *Ghcb,
+ EFI_SYSTEM_CONTEXT_X64 *Regs,
+ SEV_ES_INSTRUCTION_DATA *InstructionData
+ )
+{
+ UINTN Status;
+
+ Status = VmgExit (Ghcb, SvmExitRdtsc, 0, 0);
+ if (Status) {
+ return Status;
+ }
+
+ if (!GhcbIsRegValid (Ghcb, GhcbRax) ||
+ !GhcbIsRegValid (Ghcb, GhcbRdx)) {
+ VmgExit (Ghcb, SvmExitUnsupported, SvmExitRdtsc, 0);
+ ASSERT (0);
+ }
+ Regs->Rax = Ghcb->SaveArea.Rax;
+ Regs->Rdx = Ghcb->SaveArea.Rdx;
+
+ return 0;
+}
+
UINTN
DoVcCommon (
GHCB *Ghcb,
@@ -881,6 +907,10 @@ DoVcCommon (
ExitCode = Regs->ExceptionData;
switch (ExitCode) {
+ case SvmExitRdtsc:
+ NaeExit = RdtscExit;
+ break;
+
case SvmExitCpuid:
NaeExit = CpuidExit;
break;
--
2.17.1
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