On 05/19/20 23:50, Lendacky, Thomas wrote:
> 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 <[email protected]>
> Cc: Laszlo Ersek <[email protected]>
> Cc: Ard Biesheuvel <[email protected]>
> Signed-off-by: Tom Lendacky <[email protected]>
> ---
> .../Library/VmgExitLib/X64/VmgExitVcHandler.c | 47 +++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
> b/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
> index bf1555234d69..716f21a9ee0e 100644
> --- a/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
> +++ b/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
> @@ -875,6 +875,49 @@ WbinvdExit (
> return 0;
> }
>
> +/**
> + Handle a RDTSCP event.
> +
> + Use the VMGEXIT instruction to handle either a RDTSCP event.
(1) please remove "either"
> +
> + @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
> + @retval Others 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) {
(2) please write (Status != 0) or (Status > 0).
Acked-by: Laszlo Ersek <[email protected]>
Thanks,
Laszlo
> + 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;
>
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