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

[Jan Beulich <jbeulich@xxxxxxxx>]

On 08.11.2022 14:55, 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.

I can't find any mention of VFCT in the ACPI 6.3 spec, nor anywhere
under Linux'es include/acpi/. I don't mind the addition that you're
doing, but there needs to be a pointer to a sufficiently "official"
spec.

Jan

> 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.
> ---
>  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