On 05/19/20 23:50, Lendacky, Thomas wrote:
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
>
> Under SEV-ES, a MWAIT/MWAITX intercept generates a #VC exception.
> VMGEXIT must be used to allow the hypervisor to handle this intercept.
>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> .../Library/VmgExitLib/X64/VmgExitVcHandler.c | 43 +++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
> index 9b7639069276..b028b20f255a 100644
> --- a/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
> +++ b/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
> @@ -843,6 +843,45 @@ MmioExit (
> return Status;
> }
>
> +/**
> + Handle a MWAIT event.
> +
> + Use the VMGEXIT instruction to handle a MWAIT 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
> + @retval Others New exception value to propagate
> +
> +**/
> +STATIC
> +UINT64
> +MwaitExit (
> + IN OUT GHCB *Ghcb,
> + IN OUT EFI_SYSTEM_CONTEXT_X64 *Regs,
> + IN SEV_ES_INSTRUCTION_DATA *InstructionData
> + )
> +{
> + UINT64 Status;
> +
> + DecodeModRm (Regs, InstructionData);
> +
> + Ghcb->SaveArea.Rax = Regs->Rax;
> + GhcbSetRegValid (Ghcb, GhcbRax);
> + Ghcb->SaveArea.Rcx = Regs->Rcx;
> + GhcbSetRegValid (Ghcb, GhcbRcx);
> +
> + Status = VmgExit (Ghcb, SVM_EXIT_MWAIT, 0, 0);
> + if (Status) {
> + return Status;
> + }
> +
> + return 0;
> +}
> +
(1) Please see my feedback under:
[PATCH v8 18/46] OvmfPkg/VmgExitLib: Add support for WBINVD NAE events
and pick the same approach here that you prefer there.
With that:
Acked-by: Laszlo Ersek <lersek@redhat.com>
Thanks
Laszlo
> /**
> Handle a MONITOR event.
>
> @@ -1539,6 +1578,10 @@ VmgExitHandleVc (
> NaeExit = MonitorExit;
> break;
>
> + case SVM_EXIT_MWAIT:
> + NaeExit = MwaitExit;
> + break;
> +
> case SVM_EXIT_NPF:
> NaeExit = MmioExit;
> break;
>
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