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>

3 files changed, 23 insertions, 3 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:

diff --git a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.c b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.c
index 0e42ae4bf6..58cb5d8b1f 100644
--- a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.c
+++ b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.c
@@ -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;

diff --git a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.h b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.h
index e641189267..5b4c57fa2a 100644
--- a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.h
+++ b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.h
@@ -100,6 +100,12 @@ typedef struct {
   // on behalf of this device

   //

   LIST_ENTRY                UncachedAllocationList;

+  //

+  // Unique ID for this device instance: needed so that we can report unique

+  // segment/bus/device number for each device instance. Note that this number

+  // may change when disconnecting/reconnecting the driver.

+  //

+  UINTN                     UniqueId;

 } NON_DISCOVERABLE_PCI_DEVICE;

 

 /**