kernel/git/stable/linux.git/tools/testing/selftests/vfio, branch master

vfio: selftests: Retry on EAGAIN during device reset

2026-08-10T19:24:40+00:00

Add retry logic to vfio_pci_device_reset() to handle the case where PCI resets fail due to lock contention, in which case pci_try_reset_function() returns -EAGAIN. Suggested-by: David Matlack Signed-off-by: Josh Hilke Acked-by: David Matlack Link: https://lore.kernel.org/r/20260805-igb_v3_b4-v10-3-9c86dc849c0d@google.com Signed-off-by: Alex Williamson

vfio: selftests: igb: Add driver for Intel 82576 device

2026-08-10T19:24:40+00:00

Add a VFIO selftest driver for the Intel Gigabit Ethernet controller (IGB), specifically targeting the 82576 device. IGB is fully virtualized in QEMU which makes it easy to run VFIO selftests without needing any specific hardware. Since IGB is an Ethernet device, it cannot support DMA transfers smaller than the minimum Ethernet payload size (60 bytes) without hardware padding corrupting adjacent memory. The driver asserts that the transfer size is at least 60 bytes to prevent this. All VFIO selftest drivers must implement DMA/memcpy operations, but IGB doesn't have a native memcpy feature, so the loopback feature (described in section 3.5.6.3 of IGB specification) is used to implement it. To support testing on both QEMU and physical hardware, the driver uses PHY internal loopback with some QEMU-specific fallbacks. The driver also supports MSI-X routing and interrupt management, and disables PCIe completion timeout retries to ensure clean recovery during invalid-DMA tests. Users can verify the driver works in QEMU by building the kernel, building VFIO selftests, and then running the vfio_pci_driver_test using this command: vng \ --run arch/x86/boot/bzImage \ --user root \ --disable-microvm \ --memory 32G \ --cpus 8 \ --qemu-opts="-M q35,accel=kvm,kernel-irqchip=split" \ --qemu-opts="-device intel-iommu,intremap=on,caching-mode=on,device-iotlb=on" \ --qemu-opts="-netdev user,id=net0 -device igb,netdev=net0,addr=09.0" \ --append "console=ttyS0 earlyprintk=ttyS0 intel_iommu=on iommu=pt" \ --exec "modprobe vfio-pci && \ ./tools/testing/selftests/vfio/scripts/setup.sh 0000:00:09.0 && \ ./tools/testing/selftests/vfio/scripts/run.sh ./tools/testing/selftests/vfio/vfio_pci_driver_test" Assisted-by: Claude:claude-opus-4-7 Assisted-by: Gemini:gemini-3.1-pro-preview Co-developed-by: Alex Williamson Signed-off-by: Alex Williamson Signed-off-by: Josh Hilke Acked-by: David Matlack Link: https://lore.kernel.org/r/20260805-igb_v3_b4-v10-2-9c86dc849c0d@google.com Signed-off-by: Alex Williamson

vfio: selftests: Add helpers to re-enable interrupts

2026-08-10T19:24:40+00:00

Selftest drivers that recover from a fault by issuing VFIO_DEVICE_RESET need to re-arm device interrupts afterwards. VFIO_DEVICE_RESET tears down the kernel-side IRQ trigger so a subsequent VFIO_DEVICE_SET_IRQS is required, but the user-side eventfds (and any fd cached in a test fixture) are still valid and must be preserved. vfio_pci_irq_enable() refuses to be called for vectors that already have an eventfd (VFIO_ASSERT_LT), and vfio_pci_irq_disable() closes all eventfds before resetting the trigger, so neither is suitable. Add vfio_pci_irq_reenable(device, index, vector, count) which asserts that the requested range has existing eventfds and re-issues VFIO_DEVICE_SET_IRQS using them. Signature mirrors vfio_pci_irq_enable(). Add vfio_pci_msi{,x}_reenable() wrappers around vfio_pci_irq_reenable() for additional ease of use and readability. Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Alex Williamson Reviewed-by: David Matlack Acked-by: David Matlack Link: https://lore.kernel.org/r/20260805-igb_v3_b4-v10-1-9c86dc849c0d@google.com Signed-off-by: Alex Williamson

vfio: selftests: Avoid VLAs

2026-07-17T14:39:35+00:00

Allocate VFIO ioctl requests dynamically instead of using VLAs. GCC 11.5.0 rejects initialized VLAs with: error: variable-sized object may not be initialized The replaced stack u8 arrays also do not guarantee native struct alignment for the aliased pointers. Fixes: 19faf6fd969c ("vfio: selftests: Add a helper library for VFIO selftests") Fixes: 20face8c75ff ("vfio: selftests: Add helper to set/override a vf_token") Assisted-by: Codex:gpt-5.5-high Reviewed-by: Vipin Sharma Reviewed-by: David Matlack Signed-off-by: Alex Mastro Link: https://lore.kernel.org/r/20260617-scratch-amastro-vfio-selftests-avoid-vlas-v4-2-b9f52f1e2c5a@fb.com Signed-off-by: Alex Williamson

vfio: selftests: Add allocation assert helpers

2026-07-17T14:39:35+00:00

Add {malloc,calloc}_assert() helpers alongside the existing *_assert() helpers. Use them for VFIO selftest allocations that immediately assert a non-NULL result. Assisted-by: Codex:gpt-5.5-high Signed-off-by: Alex Mastro Reviewed-by: David Matlack Link: https://lore.kernel.org/r/20260617-scratch-amastro-vfio-selftests-avoid-vlas-v4-1-b9f52f1e2c5a@fb.com Signed-off-by: Alex Williamson

vfio: selftests: Add NVIDIA Falcon driver for DMA testing

2026-07-17T14:39:35+00:00

Add a new VFIO PCI driver for NVIDIA GPUs that enables DMA testing via the Falcon (Fast Logic Controller) microcontrollers. This driver extracts and adapts the DMA test functionality from NVIDIA's gpu-admin-tools project and integrates it into the existing VFIO selftest framework. Falcons are general-purpose microcontrollers present on NVIDIA GPUs that can perform DMA operations between system memory and device memory. By leveraging Falcon DMA, this driver allows NVIDIA GPUs to be tested alongside Intel IOAT and DSA devices using the same selftest infrastructure. The driver is named 'nv_falcon' to reflect that it specifically controls the Falcon microcontrollers for DMA operations, rather than exposing general GPU functionality. Reference implementation: https://github.com/NVIDIA/gpu-admin-tools Signed-off-by: Alex Williamson Signed-off-by: Rubin Du Acked-by: David Matlack Link: https://lore.kernel.org/r/20260609232855.3808971-5-rubind@nvidia.com Signed-off-by: Alex Williamson

vfio: selftests: Allow drivers without send_msi() support

2026-07-17T14:39:34+00:00

Allow drivers that cannot trigger MSI interrupts to leave the send_msi callback NULL. Add an fcntl_set_msi_nonblock() wrapper that only sets nonblocking mode when send_msi is available, and update ASSERT_NO_MSI() to skip when the driver lacks MSI support. The send_msi test SKIPs and mix_and_match skips the MSI portion per iteration. Reviewed-by: David Matlack Signed-off-by: Alex Williamson Signed-off-by: Rubin Du Link: https://lore.kernel.org/r/20260609232855.3808971-4-rubind@nvidia.com Signed-off-by: Alex Williamson

vfio: selftests: Add generic PCI command register helpers

2026-07-17T14:39:34+00:00

Add vfio_pci_cmd_set()/vfio_pci_cmd_clear() read-modify-write macros for PCI_COMMAND in vfio_pci_device.h. Reviewed-by: David Matlack Signed-off-by: Alex Williamson Signed-off-by: Rubin Du Link: https://lore.kernel.org/r/20260609232855.3808971-3-rubind@nvidia.com Signed-off-by: Alex Williamson

vfio: selftests: Add memcpy chunking to vfio_pci_driver_memcpy()

2026-07-17T14:39:34+00:00

Add a chunking loop to vfio_pci_driver_memcpy() so that it breaks up large memcpy requests into max_memcpy_size-sized chunks. This allows callers to request any size without worrying about per-driver limits. The memcpy_start()/memcpy_wait() semantics are unchanged. Update the test to use 4x max_memcpy_size so it exercises the new chunking path (4 iterations) while keeping execution fast for drivers with small DMA transfer sizes. Reviewed-by: David Matlack Signed-off-by: Alex Williamson Signed-off-by: Rubin Du Link: https://lore.kernel.org/r/20260609232855.3808971-2-rubind@nvidia.com Signed-off-by: Alex Williamson

vfio: selftests: Add luuid to libvfio.mk's list of libraries, not to the Makefile

2026-06-30T21:50:55+00:00

Link to the uuid library as part of libvfio.mk instead of as only linking it via VFIO selftests' Makefile, as the whole point of providing libvfio.mk is to allow linking the VFIO library functionality into KVM selftests, without KVM selftests having to know the gory details or duplicate code. Cc: Raghavendra Rao Ananta Cc: David Matlack Cc: Vipin Sharma Cc: Alex Williamson Fixes: e65f1bf8a2db ("vfio: selftests: Extend container/iommufd setup for passing vf_token") Signed-off-by: Sean Christopherson Reviewed-by: David Matlack Link: https://lore.kernel.org/r/20260630212805.474418-1-seanjc@google.com Signed-off-by: Alex Williamson