OvmfPkg/IncompatiblePciDeviceSupportDxe: ignore CSM presence

The UEFI protocol database cannot contain gEfiLegacyBiosProtocolGuid any
longer, after excluding LegacyBiosDxe from the OVMF platforms. Therefore,
instruct PciBusDxe from IncompatiblePciDeviceSupportDxe to allocate 64-bit
BARs above 4 GB regardless of a CSM.

Regression test: in commit 855743f71774 ("OvmfPkg: prevent 64-bit MMIO BAR
degradation if there is no CSM", 2016-05-25), where we introduced
IncompatiblePciDeviceSupportDxe, we said, "By default, the PCI Bus driver
considers an option ROM reason enough for allocating the 64-bit MMIO BARs
in 32-bit address space". Therefore it suffices to verify the 64-bit BARs
of a device for which QEMU provides an option ROM. The simplest case is
the virtio-net-pci device. And indeed, with this patch applied, the log
contains:

> PciBus: Discovered PCI @ [04|00|00]  [VID = 0x1AF4, DID = 0x1041]
>    BAR[1]: Type =  Mem32; Alignment = 0xFFF;    Length = 0x1000;        Offset = 0x14
>    BAR[4]: Type = PMem64; Alignment = 0x3FFF;   Length = 0x4000;        Offset = 0x20

This portion shows that Bus|Device|Function 04|00|00 is a (modern)
virito-net-pci device [VID = 0x1AF4, DID = 0x1041].

> PciBus: Resource Map for Bridge [00|01|03]
> Type =  Mem32; Base = 0x81200000;       Length = 0x200000;      Alignment = 0x1FFFFF
>    Base = Padding;      Length = 0x200000;      Alignment = 0x1FFFFF
>    Base = 0x81200000;   Length = 0x1000;        Alignment = 0xFFF;      Owner = PCI [04|00|00:14]
> Type =  Mem32; Base = 0x81A43000;       Length = 0x1000;        Alignment = 0xFFF
> Type = PMem64; Base = 0x800200000;      Length = 0x100000;      Alignment = 0xFFFFF
>    Base = 0x800200000;  Length = 0x4000;        Alignment = 0x3FFF;     Owner = PCI [04|00|00:20]

This quote shows that 04|00|00 has a BAR at 0x8_0020_0000.

(It also shows that the device is behind a bridge (PCIe root port) whose
own BDF is 00|01|03.)

> [Security] 3rd party image[7CEEB418] can be loaded after EndOfDxe: PciRoot(0x0)/Pci(0x1,0x3)/Pci(0x0,0x0)/Offset(0x10E00,0x273FF).
> None of Tcg2Protocol/CcMeasurementProtocol is installed.
> InstallProtocolInterface: [EfiLoadedImageProtocol] 7D2E5140
> Loading driver at 0x0007CA9F000 EntryPoint=0x0007CAA5447 1af41000.efi
> InstallProtocolInterface: [EfiLoadedImageDevicePathProtocol] 7D5B2198

And this part finally shows that the iPXE option ROM for the device
(1af41000.efi) was detected and is loaded. (Same PCIe root port, and PCIe
root ports can only host a single device.)

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=4588
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20231110235820.644381-14-lersek@redhat.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Corvin Köhne <corvink@FreeBSD.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

0 files changed, 0 insertions, 0 deletions