Re: [PATCH v4 4/5] OvmfPkg/PlatformInitLib: Add PlatformReservationConflictCB

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

On 1/17/23 13:16, Gerd Hoffmann wrote:
> Add PlatformReservationConflictCB() callback function for use with
> PlatformScanE820().  It checks whenever the 64bit PCI MMIO window
> overlaps with a reservation from qemu.  If so move down the MMIO window
> to resolve the conflict.
> 
> Write any actions done (moving mmio window) to the firmware log with
> INFO loglevel.
> 
> This happens on (virtual) AMD machines with 1TB address space,
> because the AMD IOMMU uses an address window just below 1TB.
> 
> Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=4251
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  OvmfPkg/Library/PlatformInitLib/MemDetect.c | 45 +++++++++++++++++++++
>  1 file changed, 45 insertions(+)
> 
> diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
> index c626fc49cf6c..1ce692e77ecb 100644
> --- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c
> +++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
> @@ -213,6 +213,50 @@ PlatformAddHobCB (
>    }
>  }
>  
> +/**
> +  Check whenever the 64bit PCI MMIO window overlaps with a reservation
> +  from qemu.  If so move down the MMIO window to resolve the conflict.
> +
> +  This happens on (virtual) AMD machines with 1TB address space,
> +  because the AMD IOMMU uses an address window just below 1TB.
> +**/
> +STATIC VOID
> +PlatformReservationConflictCB (
> +  IN     EFI_E820_ENTRY64       *E820Entry,
> +  IN OUT EFI_HOB_PLATFORM_INFO  *PlatformInfoHob
> +  )
> +{
> +  UINT64  IntersectionBase;
> +  UINT64  IntersectionEnd;
> +  UINT64  NewBase;
> +
> +  IntersectionBase = MAX (
> +                       E820Entry->BaseAddr,
> +                       PlatformInfoHob->PcdPciMmio64Base
> +                       );
> +  IntersectionEnd = MIN (
> +                      E820Entry->BaseAddr + E820Entry->Length,
> +                      PlatformInfoHob->PcdPciMmio64Base +
> +                      PlatformInfoHob->PcdPciMmio64Size
> +                      );
> +
> +  if (IntersectionBase >= IntersectionEnd) {
> +    return;  // no overlap
> +  }
> +
> +  NewBase = E820Entry->BaseAddr - PlatformInfoHob->PcdPciMmio64Size;
> +  NewBase = NewBase & ~(PlatformInfoHob->PcdPciMmio64Size - 1);
> +
> +  DEBUG ((
> +    DEBUG_INFO,
> +    "%a: move mmio: 0x%Lx => %Lx\n",
> +    __FUNCTION__,
> +    PlatformInfoHob->PcdPciMmio64Base,
> +    NewBase
> +    ));
> +  PlatformInfoHob->PcdPciMmio64Base = NewBase;
> +}
> +
>  /**
>    Iterate over the entries in QEMU's fw_cfg E820 RAM map, call the
>    passed callback for each entry.
> @@ -650,6 +694,7 @@ PlatformDynamicMmioWindow (
>      DEBUG ((DEBUG_INFO, "%a:   MMIO Space 0x%Lx (%Ld GB)\n", __func__, MmioSpace, RShiftU64 (MmioSpace, 30)));
>      PlatformInfoHob->PcdPciMmio64Size = MmioSpace;
>      PlatformInfoHob->PcdPciMmio64Base = AddrSpace - MmioSpace;
> +    PlatformScanE820 (PlatformReservationConflictCB, PlatformInfoHob);
>    } else {
>      DEBUG ((DEBUG_INFO, "%a: using classic mmio window\n", __func__));
>    }

Reviewed-by: Laszlo Ersek <lersek@redhat.com>