Re: [PATCH edk2-platforms 1/1] Silicon/Qemu: don't advertise GICC legacy mmio interface in SbsaQamu MADT

["Ard Biesheuvel" <ardb@kernel.org>]

On Fri, 8 Oct 2021 at 12:34, Leif Lindholm <leif@nuviainc.com> wrote:
>
> The MADT GICC structure contains the field PhysicalBaseAddress, which
> is needed for a GICv1/v2 implementation, or to indicate legacy
> compatibility in modern GICs.
>
> Linux commit 9739f6ef053f1, included in v5.12, adds a warning message
> when this field is populated but invalid:
>   [Firmware Bug]: CPU interface incapable of MMIO access
>
> As it happens, we currently initialize this to PcdGicDistributorBase
> instead of PcdGicInterruptInterfaceBase, and as a result we now trigger
> this warning.
>
> Since this is an SBSA reference implementation, and legacy GIC support
> has never worked for this port, set the field to 0.
>
> Signed-off-by: Leif Lindholm <leif@nuviainc.com>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Graeme Gregory <graeme@nuviainc.com>
> Cc: Radoslaw Biernacki <rad@semihalf.com>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c b/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c
> index b8901030ecd0..dbc5e9475358 100644
> --- a/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c
> +++ b/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c
> @@ -71,7 +71,7 @@ AddMadtTable (
>      0,                                     /* Mpidr */
>      EFI_ACPI_6_0_GIC_ENABLED,              /* Flags */
>      SBSAQEMU_MADT_GIC_PMU_IRQ,             /* PMU Irq */
> -    FixedPcdGet32 (PcdGicDistributorBase), /* PhysicalBaseAddress */
> +    0,                                     /* PhysicalBaseAddress */
>      SBSAQEMU_MADT_GIC_VBASE,               /* GicVBase */
>      SBSAQEMU_MADT_GIC_HBASE,               /* GicHBase */
>      25,                                    /* GsivId */
> --
> 2.30.2
>