[edk2-devel] [PATCH 2/9] OvmfPkg/VmgExitLib: Set the SW exit fields when performing VMGEXIT
Laszlo Ersek
lersek at redhat.com
Thu Oct 15 08:47:16 UTC 2020
On 10/10/20 18:07, Tom Lendacky wrote:
> From: Tom Lendacky <thomas.lendacky at amd.com>
>
> All fields that are set in the GHCB should have their associated bit in
> the GHCB ValidBitmap field set. Add support to set the bits for the
> software exit information fields when performing a VMGEXIT (SwExitCode,
> SwExitInfo1, SwExitInfo2).
>
> Fixes: 61bacc0fa16f ("OvmfPkg/VmgExitLib: Implement library support for VmgExitLib in OVMF")
> Cc: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Laszlo Ersek <lersek at redhat.com>
> Cc: Ard Biesheuvel <ard.biesheuvel at arm.com>
> Cc: Tom Lendacky <thomas.lendacky at amd.com>
> Cc: Brijesh Singh <brijesh.singh at amd.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
> ---
> OvmfPkg/Library/VmgExitLib/VmgExitLib.c | 30 ++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitLib.c b/OvmfPkg/Library/VmgExitLib/VmgExitLib.c
> index 53040cc6f649..6cf649c6101b 100644
> --- a/OvmfPkg/Library/VmgExitLib/VmgExitLib.c
> +++ b/OvmfPkg/Library/VmgExitLib/VmgExitLib.c
> @@ -78,6 +78,32 @@ VmgExitErrorCheck (
> return Status;
> }
>
> +/**
> + Marks a field at the specified offset as valid in the GHCB.
> +
> + The ValidBitmap area represents the areas of the GHCB that have been marked
> + valid. Set the area of the GHCB at the specified offset as valid.
> +
> + @param[in, out] Ghcb Pointer to the Guest-Hypervisor Communication Block
> + @param[in] Offset Offset in the GHCB to mark valid
> +
> +**/
> +STATIC
> +VOID
> +GhcbSetOffsetValid (
> + IN OUT GHCB *Ghcb,
> + IN GHCB_QWORD_OFFSET Offset
> + )
> +{
> + UINT32 OffsetIndex;
> + UINT32 OffsetBit;
> +
> + OffsetIndex = Offset / 8;
> + OffsetBit = Offset & 0x07;
(1) I suggest improving the consistency of operators -- please either
use division and remainder ("Offset / 8" and "Offset % 8"), or bit shift
and masking ("Offset >> 3" and "Offset & 0x7")
With that:
Acked-by: Laszlo Ersek <lersek at redhat.com>
Thanks
Laszlo
> +
> + Ghcb->SaveArea.ValidBitmap[OffsetIndex] |= (1 << OffsetBit);
> +}
> +
> /**
> Perform VMGEXIT.
>
> @@ -110,6 +136,10 @@ VmgExit (
> Ghcb->SaveArea.SwExitInfo1 = ExitInfo1;
> Ghcb->SaveArea.SwExitInfo2 = ExitInfo2;
>
> + GhcbSetOffsetValid (Ghcb, GhcbSwExitCode);
> + GhcbSetOffsetValid (Ghcb, GhcbSwExitInfo1);
> + GhcbSetOffsetValid (Ghcb, GhcbSwExitInfo2);
> +
> //
> // Guest memory is used for the guest-hypervisor communication, so fence
> // the invocation of the VMGEXIT instruction to ensure GHCB accesses are
>
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