[PATCH v5 0/5] vfio: selftests: Add driver for Intel Ethernet Gigabit Controller (IGB)

[Josh Hilke <jrhilke@google.com>]

This v5 of a series which adds a VFIO selftest driver for the Intel
Gigabit Ethernet controller (IGB), specifically targeting the 82576
device. IGB is fully virtualized in QEMU, making it suitable for running
VFIO selftests without specialized hardware.

v4: https://lore.kernel.org/kvm/20260710-igb_v3_b4-v4-0-56e7e2576cc1@google.com/

I restructured the series by folding Alex Williamson's advanced
descriptor support, MSI-X routing configuration, and completion timeout
patches directly into the initial driver patch. Hopefully this ensures a
clean baseline driver so that Sashiko doesn't complain about bugs which
are fixed in later patches in the series.

Also enabled Multicast Promiscuous (MPE) and Broadcast Accept (BAM)
modes because any test data where the first byte's least significant bit
is 1 will be treated as a multicast/broadcast frame and dropped by the
hardware's MAC filter.

Implemented a few other minor fixes from Sashiko. See changelog.

Testing
=======
- VFIO selftests builds clean at every commit
- vfio_pci_driver_test passes using IGB driver + QEMU. Use the following
  command to run the tests:

  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"
--------
Changelog:

v4 -> v5:
- Reordered igb_remove() to reset the device before disabling MSI-X (Sashiko)
- Refactored hardware reset logic into igb_reset() helper.
- Simplified reset completion check to usleep + assertion instead of retry loop (Sashiko).
- Allow arbitrary test data by enabling Multicast Promiscuous (MPE)
  and Broadcast Accept (BAM) modes (Sashiko).
- Fixed igb_send_msi() to use MSIX_VECTOR_MASK instead of magic number (Sashiko).

v3 -> v4
- Enable MSI-X mode in GPIE (Sashiko)
- Fix hardware initilization order to avoid race conditions (Alex/Sashiko)
- Add memory barrier to prevent speculative reads (Alex/Sashiko)
- Clean up stale references in commit messages and comments (Alex/Sashiko)
- Add a comment to address software/firmware semaphore (Alex/Sashiko)

v2 -> v3
- Poll reset bit and document the required wait time (David/Sashiko)
- Fix the logic for enabling PCI_COMMAND_MEMORY (David/Sashiko)
- Fail the test if autonegotation fails (David/Sashiko)
- Handle endianness conversions (David/Sashiko)
- Use real IGB headers at the start of the series (David)
- Add E1000_TXD_CMD_IFCS to the TX descriptor command word (Sashiko)

v1 -> v2
- Removed the chunking loop in igb_memcpy_start() (David)
- Removed redundant writes to status_error and hdr_addr (David)
- Include official IGB header files (David)

Signed-off-by: Josh Hilke <jrhilke@google.com>
---
Changes in v5:
- Restructured the series from 9 to 5 code patches by folding advanced descriptor
  support, MSI-X routing configuration, extended memcpy completion timeout, and
  PCIe completion timeout retry disable directly into the initial driver patch.
  This ensures a clean, fully-functional baseline driver from PATCH 01 and avoids
  intermediate legacy descriptor, timeout, and bus-spamming bugs.
- Reordered igb_remove() to reset the device before disabling MSI-X.
- Switched igb_irq_clear() to write-to-clear as required by the datasheet when
  EIAC is programmed.
- Refactored hardware reset logic into igb_reset() helper with proper sleep
  (1ms mandated by datasheet section 4.2.1.6.1) and poll-assertion.
- Simplified reset completion check to usleep + assertion instead of retry loop.
- Allowed arbitrary loopback test data by enabling Multicast Promiscuous (MPE)
  and Broadcast Accept (BAM) modes.
- Fixed igb_send_msi() to use MSIX_VECTOR_MASK instead of magic number.
- Link to v4: https://lore.kernel.org/r/20260710-igb_v3_b4-v4-0-56e7e2576cc1@google.com

---
Alex Williamson (4):
      vfio: selftests: igb: Use PHY internal loopback on 82576
      vfio: selftests: Add helpers to re-enable interrupts
      vfio: selftests: igb: Factor hardware programming into igb_hw_init()
      vfio: selftests: igb: Recover after DMA-read faults

Josh Hilke (1):
      vfio: selftests: igb: Add driver for Intel 82576 device

 .../selftests/vfio/lib/drivers/igb/e1000_82575.h   |   1 +
 .../selftests/vfio/lib/drivers/igb/e1000_defines.h |   1 +
 .../selftests/vfio/lib/drivers/igb/e1000_regs.h    |   1 +
 tools/testing/selftests/vfio/lib/drivers/igb/igb.c | 564 +++++++++++++++++++++
 .../vfio/lib/include/libvfio/vfio_pci_device.h     |  14 +
 tools/testing/selftests/vfio/lib/libvfio.mk        |   1 +
 tools/testing/selftests/vfio/lib/vfio_pci_device.c |  22 +
 tools/testing/selftests/vfio/lib/vfio_pci_driver.c |   2 +
 8 files changed, 606 insertions(+)
---
base-commit: de61419bb27f985cb878b19942a55b026c9c865a
change-id: 20260707-igb_v3_b4-49194c14373c

Best regards,
-- 
Josh Hilke <jrhilke@google.com>