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MdeModulePkg/NonDiscoverablePciDeviceDxe: expose unique B/D/F identifiers

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Currently, the implementation of EFI_PCI_IO_PROTOCOL::GetLocation()
in NonDiscoverablePciDeviceDxe returns the same set of dummy values
for each instance of the NON_DISCOVERABLE_DEVICE protocol that it
attaches itself to. However, this turns out to be causing problems
in cases where software (such as the ARM Compliance Test Suite [ACS])
attempts to use these values to uniquely identify controllers, since
the collisions create ambiguity in this regard.

So let's modify GetLocation() to return an arbitrary bus/device tuple
on segment 0xff instead. This is guaranteed not to clash with other
non-discoverable PCI devices, and highly unlikely to clash with real
PCIe devices.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
This commit is contained in:
Ard Biesheuvel
2018-10-10 10:34:50 +02:00
parent 2730470f9d
commit 1a3bee2082
3 changed files with 23 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.c
View File

@@ -1181,6 +1181,8 @@ PciIoGetLocation (
OUT UINTN *FunctionNumber
)
{
NON_DISCOVERABLE_PCI_DEVICE *Dev;
if (SegmentNumber == NULL ||
BusNumber == NULL ||
DeviceNumber == NULL ||
@@ -1188,9 +1190,11 @@ PciIoGetLocation (
return EFI_INVALID_PARAMETER;
}
*SegmentNumber = 0;
*BusNumber = 0xff;
*DeviceNumber = 0;
Dev = NON_DISCOVERABLE_PCI_DEVICE_FROM_PCI_IO(This);
*SegmentNumber = 0xff;
*BusNumber = Dev->UniqueId >> 5;
*DeviceNumber = Dev->UniqueId & 0x1f;
*FunctionNumber = 0;
return EFI_SUCCESS;