[PATCH v10 0/2] selftests/vfio: Add NVIDIA GPU Falcon DMA test driver

[Rubin Du <rubind@nvidia.com>]

Patch 1:

Add VFIO_PCI_DRIVER_F_NO_SEND_MSI feature flag for drivers that cannot
trigger MSI interrupts. Drivers that lack MSI support opt-in by setting
this flag.

Change vfio_pci_driver_send_msi() to return int, checking the flag
internally and returning -EOPNOTSUPP when set. Add
fcntl_set_msi_nonblock(self) and update ASSERT_NO_MSI(self) to check
the flag internally.

Patch 2:

Falcons are general-purpose microcontrollers present on NVIDIA GPUs
that can perform DMA operations between system memory and device memory.

Introduce the nv_falcon plugin driver, which extracts and adapts
relevant functionality from NVIDIA's gpu-admin-tools project [1] and
integrates it into the VFIO selftest framework. As a result, any
system equipped with a PCIe slot and a supported NVIDIA GPU can now
run VFIO DMA selftests using commonly available hardware.

The core VFIO selftest infrastructure handles:

- VFIO container/group management
- IOMMU domain setup
- DMA buffer allocation and mapping
- Test orchestration and reporting

The plugin drivers provide device-specific implementations for:

- Probing and initializing device
- Triggering DMA operations
- Verifying DMA completion
- Device cleanup


[1] https://github.com/NVIDIA/gpu-admin-tools

Note on version numbering: v1 through v9 were internal review
iterations that were mistakenly carried over to the upstream
submission. Apologies for the confusion, the internal changelog
has been dropped.

Changes in v10:
- Replaced NULL pointer checks on send_msi() with per-device
  VFIO_PCI_DRIVER_F_NO_SEND_MSI feature flag
- Changed vfio_pci_driver_send_msi() to return int with the feature
  check moved inside, so callers branch on the return value
- Added fcntl_set_msi_nonblock(self) and updated ASSERT_NO_MSI(self)
  macros that check the flag internally
- Moved DMA execution from memcpy_start() to memcpy_wait() so that
  memcpy_start() stores parameters and returns immediately, emulating
  async behavior to conform to the memcpy_start()/memcpy_wait() contract
- Split GPU_ARCH_PASCAL into GPU_ARCH_PASCAL (P100, PMC reset) and
  GPU_ARCH_PASCAL_10X (P4/P40, engine reset) to match per-product
  reset behavior
- Minor cleanups: improved size_to_dma_encoding(), fixed DMA address
  bits mask

Rubin Du (2):
  selftests/vfio: Add NO_SEND_MSI feature flag and MSI helper macros
  selftests/vfio: Add NVIDIA Falcon driver for DMA testing

 .../vfio/lib/drivers/nv_falcons/hw.h          | 365 +++++++++
 .../vfio/lib/drivers/nv_falcons/nv_falcons.c  | 739 ++++++++++++++++++
 .../lib/include/libvfio/vfio_pci_driver.h     |   5 +-
 tools/testing/selftests/vfio/lib/libvfio.mk   |   2 +
 .../selftests/vfio/lib/vfio_pci_driver.c      |   9 +-
 .../selftests/vfio/vfio_pci_driver_test.c     |  41 +-
 6 files changed, 1142 insertions(+), 19 deletions(-)
 create mode 100644 tools/testing/selftests/vfio/lib/drivers/nv_falcons/hw.h
 create mode 100644 tools/testing/selftests/vfio/lib/drivers/nv_falcons/nv_falcons.c

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2.43.0