Re: [RFC v2-fix-v2 3/3] x86/tdx: Handle port I/O

From: Dan Williams
Date: Tue Jun 08 2021 - 12:27:44 EST

On Tue, Jun 8, 2021 at 8:40 AM Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> wrote:
> From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> TDX hypervisors cannot emulate instructions directly. This
> includes port IO which is normally emulated in the hypervisor.
> All port IO instructions inside TDX trigger the #VE exception
> in the guest and would be normally emulated there.
> Also string I/O is not supported in TDX guest. So, unroll the
> string I/O operation into a loop operating on one element at
> a time. This method is similar to AMD SEV, so just extend the
> support for TDX guest platform.
> Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> ---
> Changes since RFC v2-fix-v1:
> * Fixed commit log to adapt to decompression support code split.

Looks good to me:

Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>