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

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>

1 files changed, 10 insertions, 0 deletions

diff --git a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceDxe.c b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceDxe.c
index 3e9ff6620d..2483c72969 100644
--- a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceDxe.c
+++ b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceDxe.c
@@ -16,6 +16,9 @@
 

 #include <Protocol/DriverBinding.h>

 

+#define MAX_NON_DISCOVERABLE_PCI_DEVICE_ID   (32 * 256)

+

+STATIC UINTN               mUniqueIdCounter = 0;

 EFI_CPU_ARCH_PROTOCOL      *mCpu;

 

 //

@@ -141,6 +144,11 @@ NonDiscoverablePciDeviceStart (
   NON_DISCOVERABLE_PCI_DEVICE   *Dev;

   EFI_STATUS                    Status;

 

+  ASSERT (mUniqueIdCounter < MAX_NON_DISCOVERABLE_PCI_DEVICE_ID);

+  if (mUniqueIdCounter >= MAX_NON_DISCOVERABLE_PCI_DEVICE_ID) {

+    return EFI_OUT_OF_RESOURCES;

+  }

+

   Dev = AllocateZeroPool (sizeof *Dev);

   if (Dev == NULL) {

     return EFI_OUT_OF_RESOURCES;

@@ -167,6 +175,8 @@ NonDiscoverablePciDeviceStart (
     goto CloseProtocol;

   }

 

+  Dev->UniqueId = mUniqueIdCounter++;

+

   return EFI_SUCCESS;

 

 CloseProtocol: