vfio: selftests: Add helpers to re-enable interrupts

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>

0 files changed, 0 insertions, 0 deletions