vfio: selftests: Add helpers to re-enable interrupts

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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 <alex.williamson@nvidia.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Acked-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20260805-igb_v3_b4-v10-1-9c86dc849c0d@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

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Alex Williamson 2026-08-05 00:20:58 +00:00 • committed by Alex Williamson

parent 6edd69813b

commit aabaf84560

2 changed files with 36 additions and 0 deletions

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14

tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h

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22

tools/testing/selftests/vfio/lib/vfio_pci_device.c

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