[PATCH v13 0/4] vfio: selftest: Add NVIDIA GPU Falcon DMA test driver

[Alex Williamson <alex.williamson@nvidia.com>]

Patch 1:

Add a chunking loop to vfio_pci_driver_memcpy() so that it handles
arbitrarily sized memcpy requests by breaking them into
max_memcpy_size-sized chunks. This allows tests to request any memcpy
size. Update the test to use a size of 4x max_memcpy_size to exercise
the chunking logic.

Patch 2:

Add vfio_pci_cmd_set()/vfio_pci_cmd_clear() macros for PCI_COMMAND
operations.

Patch 3:

Allow drivers that cannot trigger MSI interrupts to leave the
send_msi callback NULL. Tests check ops->send_msi directly and
gracefully skip MSI-related operations when it is absent.

Patch 4:

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.

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

[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 for lucky v13:
 - Respin from Alex.  No fundamental changes here, so keeping
   Rubin's authorships, sign-offs, and cover letter.
 - Throughout: updated subject for consistency (David)
 - Patch 1 & 3: No change, R-b collected
 - Patch 2: Macros converted to static inlines (David)
 - Patch 4: 
   - Formats %ll -> %l (David)
   - Converted size_to_dma_encoding() size testing/manipulation
     to asserts (David)
   - Re-introduced iterative transfer for non-power-of-2 memcpy (David)
     Testing this revealed we need some gymnastics to also avoid
     transfers crossing block boundaries, so we use the largest power-
     of-2 taking into account the transfer size as well as source and
     destination IOVA addresses.
   - Function renaming for consistency (David).

Rubin Du (4):
  vfio: selftests: Add memcpy chunking to vfio_pci_driver_memcpy()
  vfio: selftests: Add generic PCI command register helpers
  vfio: selftests: Allow drivers without send_msi() support
  vfio: selftests: Add NVIDIA Falcon driver for DMA testing

 .../selftests/vfio/lib/drivers/nv_falcon/hw.h | 350 ++++++++
 .../vfio/lib/drivers/nv_falcon/nv_falcon.c    | 789 ++++++++++++++++++
 .../lib/include/libvfio/vfio_pci_device.h     |  14 +
 tools/testing/selftests/vfio/lib/libvfio.mk   |   2 +
 .../selftests/vfio/lib/vfio_pci_driver.c      |  21 +-
 .../selftests/vfio/vfio_pci_driver_test.c     |  57 +-
 6 files changed, 1210 insertions(+), 23 deletions(-)
 create mode 100644 tools/testing/selftests/vfio/lib/drivers/nv_falcon/hw.h
 create mode 100644 tools/testing/selftests/vfio/lib/drivers/nv_falcon/nv_falcon.c

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2.51.0