Could this cause unaligned memory accesses? This is fine for x86/x86_64,
could cause a fault on Itanium, and will always cause a fault on EBC. It
would be a pretty remote use case but still could happen.
On Sun, Jan 20, 2013 at 1:41 PM, David Woodhouse <dw...@infradead.org>wrote:
> The current vgabios images shipped with qemu violate the PCI Firmware
> Specification by having a PCIR data structure at offset 0x10f, which is
> not DWORD-aligned.
>
> If I relax the check in OVMF, it works fine with SeaBIOS-as-CSM and I
> can initialise the VGA ROM then use INT 10h services for display in EFI.
>
> I've submitted a patch to *fix* the vgabios images, of course, but
> perhaps it's worth being lenient in OVMF?
>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: David Woodhouse <david.woodho...@intel.com>
>
> diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
> b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
> index 910ed41..f5e647d 100644
> --- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
> +++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
> @@ -305,7 +305,6 @@ GetPciLegacyRom (
> RomHeader.Raw = *Rom;
> while (RomHeader.Generic->Signature ==
> PCI_EXPANSION_ROM_HEADER_SIGNATURE) {
> if (RomHeader.Generic->PcirOffset == 0 ||
> - (RomHeader.Generic->PcirOffset & 3) !=0 ||
> *ImageSize < RomHeader.Raw - (UINT8 *) *Rom +
> RomHeader.Generic->PcirOffset + sizeof (PCI_DATA_STRUCTURE)) {
> break;
> }
> @@ -2919,8 +2918,7 @@ LegacyBiosInstallPciRom (
>
> LocalRomImage = *RomImage;
> if (((PCI_EXPANSION_ROM_HEADER *) LocalRomImage)->Signature !=
> PCI_EXPANSION_ROM_HEADER_SIGNATURE ||
> - ((PCI_EXPANSION_ROM_HEADER *) LocalRomImage)->PcirOffset == 0 ||
> - (((PCI_EXPANSION_ROM_HEADER *) LocalRomImage)->PcirOffset & 3 )
> != 0) {
> + ((PCI_EXPANSION_ROM_HEADER *) LocalRomImage)->PcirOffset == 0) {
> mVgaInstallationInProgress = FALSE;
> return EFI_UNSUPPORTED;
> }
> diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciOptionRomSupport.c
> b/MdeModulePkg/Bus/Pci/PciBusDxe/PciOptionRomSupport.c
> index 33dbfa4..21a522c 100644
> --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciOptionRomSupport.c
> +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciOptionRomSupport.c
> @@ -420,7 +420,6 @@ LoadOpRomImage (
> // The PCI Data Structure must be DWORD aligned.
> //
> if (OffsetPcir == 0 ||
> - (OffsetPcir & 3) != 0 ||
> RomImageSize + OffsetPcir + sizeof (PCI_DATA_STRUCTURE) >
> RomSize) {
> break;
> }
>
> --
> David Woodhouse Open Source Technology Centre
> david.woodho...@intel.com Intel Corporation
>
>
>
>
>
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