Re: [PATCH for-4.17?] x86/pvh: report ACPI VFCT table to dom0 if present

[Huang Rui <ray.huang@xxxxxxx>]

On Tue, Nov 08, 2022 at 09:55:16PM +0800, Roger Pau Monne wrote:
> The VFCT ACPI table is used by AMD GPUs to expose the vbios ROM image
> from the firmware instead of doing it on the PCI ROM on the physical
> device.
> 
> As such, this needs to be available for PVH dom0 to access, or else
> the GPU won't work.
> 
> Reported-by: Huang Rui <ray.huang@xxxxxxx>
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
> This is a bugfix, but given PVH dom0 is still experimental I'm not
> sure it would qualify for the release.  OTOH being experimental means
> there are no guarantees it will work, so the change is unlikely to
> make this any worse.


Yes, thanks Roger! AMD GPU needs a Video BIOS which needs to do the
initialization for hardware. We use ACPI VFCT table to expose the VBIOS rom
image even on the Xen PVH dom0, so we need to add the related signature in
Xen as well.

Acked-and-Tested-by: Huang Rui <ray.huang@xxxxxxx>

> ---
>  xen/arch/x86/hvm/dom0_build.c | 1 +
>  xen/include/acpi/actbl3.h     | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
> index 1864d048a1..307edc6a8c 100644
> --- a/xen/arch/x86/hvm/dom0_build.c
> +++ b/xen/arch/x86/hvm/dom0_build.c
> @@ -924,6 +924,7 @@ static bool __init pvh_acpi_table_allowed(const char *sig,
>          ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_FACS, ACPI_SIG_PSDT,
>          ACPI_SIG_SSDT, ACPI_SIG_SBST, ACPI_SIG_MCFG, ACPI_SIG_SLIC,
>          ACPI_SIG_MSDM, ACPI_SIG_WDAT, ACPI_SIG_FPDT, ACPI_SIG_S3PT,
> +        ACPI_SIG_VFCT,
>      };
>      unsigned int i;
>  
> diff --git a/xen/include/acpi/actbl3.h b/xen/include/acpi/actbl3.h
> index 0a6778421f..6858d3e60f 100644
> --- a/xen/include/acpi/actbl3.h
> +++ b/xen/include/acpi/actbl3.h
> @@ -79,6 +79,7 @@
>  #define ACPI_SIG_MATR           "MATR"       /* Memory Address Translation 
> Table */
>  #define ACPI_SIG_MSDM           "MSDM"       /* Microsoft Data Management 
> Table */
>  #define ACPI_SIG_WPBT           "WPBT"       /* Windows Platform Binary 
> Table */
> +#define ACPI_SIG_VFCT           "VFCT"       /* AMD Video BIOS */
>  
>  /*
>   * All tables must be byte-packed to match the ACPI specification, since
> -- 
> 2.37.3
>