diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c index 476e94ce5f..f6cfd7fa29 100644 --- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c +++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c @@ -374,6 +374,67 @@ UnsupportedExit ( return Status; } +/** + Handle an MSR event. + + Use the VMGEXIT instruction to handle either a RDMSR or WRMSR 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 +MsrExit ( + IN OUT GHCB *Ghcb, + IN OUT EFI_SYSTEM_CONTEXT_X64 *Regs, + IN SEV_ES_INSTRUCTION_DATA *InstructionData + ) +{ + UINT64 ExitInfo1, Status; + + ExitInfo1 = 0; + + switch (*(InstructionData->OpCodes + 1)) { + case 0x30: // WRMSR + ExitInfo1 = 1; + Ghcb->SaveArea.Rax = Regs->Rax; + GhcbSetRegValid (Ghcb, GhcbRax); + Ghcb->SaveArea.Rdx = Regs->Rdx; + GhcbSetRegValid (Ghcb, GhcbRdx); + // + // fall through + // + case 0x32: // RDMSR + Ghcb->SaveArea.Rcx = Regs->Rcx; + GhcbSetRegValid (Ghcb, GhcbRcx); + break; + default: + return UnsupportedExit (Ghcb, Regs, InstructionData); + } + + Status = VmgExit (Ghcb, SVM_EXIT_MSR, ExitInfo1, 0); + if (Status != 0) { + return Status; + } + + if (ExitInfo1 == 0) { + if (!GhcbIsRegValid (Ghcb, GhcbRax) || + !GhcbIsRegValid (Ghcb, GhcbRdx)) { + return UnsupportedExit (Ghcb, Regs, InstructionData); + } + Regs->Rax = Ghcb->SaveArea.Rax; + Regs->Rdx = Ghcb->SaveArea.Rdx; + } + + return 0; +} + /** Build the IOIO event information. @@ -705,6 +766,10 @@ VmgExitHandleVc ( NaeExit = IoioExit; break; + case SVM_EXIT_MSR: + NaeExit = MsrExit; + break; + default: NaeExit = UnsupportedExit; }