Re: [PATCH v2 4/4] OvmfPkg/PciHotPlugInitDxe: reserve more mmio space

["Laszlo Ersek" <lersek@redhat.com>]

On 10/04/22 15:47, Gerd Hoffmann wrote:
> In case the 64-bit pci mmio window is larger than the default size
> of 32G be generous and hand out larger chunks of address space for
> prefetchable mmio bridge windows.
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf |  1 +
>  OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c   | 21 ++++++++++++++++++--
>  2 files changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf b/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf
> index 78b95faa7a7a..f56b1de6fd92 100644
> --- a/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf
> +++ b/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.inf
> @@ -40,6 +40,7 @@ [Protocols]
>  
>  [Pcd]
>    gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId ## CONSUMES
> +  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size          ## CONSUMES
>  
>  [Depex]
>    TRUE
> diff --git a/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c b/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c
> index c122855b735d..3f9c84cf2b54 100644
> --- a/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c
> +++ b/OvmfPkg/PciHotPlugInitDxe/PciHotPlugInit.c
> @@ -556,6 +556,7 @@ GetResourcePadding (
>    EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_PCI_ADDRESS      *Address;
>    BOOLEAN                                          DefaultIo;
>    BOOLEAN                                          DefaultMmio;
> +  BOOLEAN                                          DefaultPrefMmio;
>    RESOURCE_PADDING                                 ReservationRequest;
>    EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR                *FirstResource;
>    EFI_STATUS                                       ReservationHintStatus;
> @@ -588,8 +589,9 @@ GetResourcePadding (
>      return EFI_INVALID_PARAMETER;
>    }
>  
> -  DefaultIo   = TRUE;
> -  DefaultMmio = TRUE;
> +  DefaultIo       = TRUE;
> +  DefaultMmio     = TRUE;
> +  DefaultPrefMmio = TRUE;
>  
>    //
>    // Init ReservationRequest, and point FirstResource one past the last
> @@ -722,6 +724,7 @@ GetResourcePadding (
>        HighBit = HighBitSetRoundUp32 (ReservationHint.Prefetchable32BitMmio);
>        if (HighBit != -1) {
>          SetMmioPadding (--FirstResource, TRUE, TRUE, (UINTN)HighBit);
> +        DefaultPrefMmio = FALSE;
>        }
>      } else if ((ReservationHint.Prefetchable64BitMmio > 0) &&
>                 (ReservationHint.Prefetchable64BitMmio < MAX_UINT64))
> @@ -729,6 +732,7 @@ GetResourcePadding (
>        HighBit = HighBitSetRoundUp64 (ReservationHint.Prefetchable64BitMmio);
>        if (HighBit != -1) {
>          SetMmioPadding (--FirstResource, TRUE, FALSE, (UINTN)HighBit);
> +        DefaultPrefMmio = FALSE;
>        }
>      }
>    }
> @@ -752,6 +756,19 @@ GetResourcePadding (
>        );
>    }
>  
> +  if (DefaultPrefMmio) {
> +    UINT64  Pci64Size = PcdGet64 (PcdPciMmio64Size);
> +
> +    if (Pci64Size > SIZE_32GB) {
> +      SetMmioPadding (
> +        --FirstResource,
> +        TRUE,
> +        FALSE,
> +        (UINTN)HighBitSetRoundUp64 (RShiftU64 (Pci64Size, 8))
> +        );
> +    }
> +  }
> +
>    //
>    // Output a copy of ReservationRequest from the lowest-address populated
>    // entry until the end of the structure (including
> 

Looks good to me, thanks; I'm just missing the rationale on the
RShiftU64() call. Please elaborate.

Laszlo