Re: [PATCH v2] MdeModulePkg/NonDiscoverablePciDeviceDxe: expose unique B/D/F identifiers

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 10 October 2018 at 10:55, Zeng, Star <star.zeng@intel.com> wrote:
> Reviewed-by: Star Zeng <star.zeng@intel.com>
>

Thanks. Pushed as 2730470f9d3b..1a3bee20820c

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Ard Biesheuvel
> Sent: Wednesday, October 10, 2018 4:35 PM
> To: edk2-devel@lists.01.org
> Cc: Zeng, Star <star.zeng@intel.com>
> Subject: [edk2] [PATCH v2] 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>
> ---
> v2: add sanity check on id value so we don't exceed 256 buses
>     initialize counter to 0 explicitly - this isn't strictly necessary but clarifies
>     the code
>
>  MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceDxe.c | 10 ++++++++++
>  MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.c  | 10 +++++++---
>  MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.h  |  6 ++++++
>  3 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceDxe.c b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceDxe.c
> index 3e9ff6620d8d..2483c7296912 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 0e42ae4bf6ec..58cb5d8b1fc5 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 e641189267ee..5b4c57fa2a8e 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;
>
>  /**
> --
> 2.19.1
>
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