From: Tom Lendacky <thomas.lenda...@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
Under SEV-ES, a RDTSCP intercept generates a #VC exception. VMGEXIT must be
used to allow the hypervisor to handle this intercept.
Cc: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Laszlo Ersek <ler...@redhat.com>
Cc: Ard Biesheuvel <ard.biesheu...@arm.com>
Acked-by: Laszlo Ersek <ler...@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 47 +++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
index 54134f37e614..a1cf792d4d0b 100644
--- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
+++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
@@ -881,6 +881,49 @@ WbinvdExit (
return VmgExit (Ghcb, SVM_EXIT_WBINVD, 0, 0);
}
+/**
+ Handle a RDTSCP event.
+
+ Use the VMGEXIT instruction to handle a RDTSCP event.
+
+ @param[in, out] Ghcb Pointer to the Guest-Hypervisor
Communication
+ Block
+ @param[in, out] Regs x64 processor context
+ @param[in] InstructionData Instruction parsing context
+
+ @retval 0 Event handled successfully
+ @return New exception value to propagate
+
+**/
+STATIC
+UINT64
+RdtscpExit (
+ IN OUT GHCB *Ghcb,
+ IN OUT EFI_SYSTEM_CONTEXT_X64 *Regs,
+ IN SEV_ES_INSTRUCTION_DATA *InstructionData
+ )
+{
+ UINT64 Status;
+
+ DecodeModRm (Regs, InstructionData);
+
+ Status = VmgExit (Ghcb, SVM_EXIT_RDTSCP, 0, 0);
+ if (Status != 0) {
+ return Status;
+ }
+
+ if (!GhcbIsRegValid (Ghcb, GhcbRax) ||
+ !GhcbIsRegValid (Ghcb, GhcbRcx) ||
+ !GhcbIsRegValid (Ghcb, GhcbRdx)) {
+ return UnsupportedExit (Ghcb, Regs, InstructionData);
+ }
+ Regs->Rax = Ghcb->SaveArea.Rax;
+ Regs->Rcx = Ghcb->SaveArea.Rcx;
+ Regs->Rdx = Ghcb->SaveArea.Rdx;
+
+ return 0;
+}
+
/**
Handle a VMMCALL event.
@@ -1443,6 +1486,10 @@ VmgExitHandleVc (
NaeExit = VmmCallExit;
break;
+ case SVM_EXIT_RDTSCP:
+ NaeExit = RdtscpExit;
+ break;
+
case SVM_EXIT_WBINVD:
NaeExit = WbinvdExit;
break;
--
2.27.0
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