From: Alex Williamson <[email protected]> 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(). Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Alex Williamson <[email protected]> --- .../lib/include/libvfio/vfio_pci_device.h | 2 ++ .../selftests/vfio/lib/vfio_pci_device.c | 22 +++++++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h index 2858885a89bb..a362e2b2bfda 100644 --- a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h +++ b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h @@ -68,6 +68,8 @@ void vfio_pci_config_access(struct vfio_pci_device *device, bool write, void vfio_pci_irq_enable(struct vfio_pci_device *device, u32 index, u32 vector, int count); void vfio_pci_irq_disable(struct vfio_pci_device *device, u32 index); +void vfio_pci_irq_reenable(struct vfio_pci_device *device, u32 index, + u32 vector, int count); void vfio_pci_irq_trigger(struct vfio_pci_device *device, u32 index, u32 vector); static inline void fcntl_set_nonblock(int fd) diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c index fc75e04ef010..7b8394d0ac50 100644 --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c @@ -106,6 +106,28 @@ void vfio_pci_irq_disable(struct vfio_pci_device *device, u32 index) vfio_pci_irq_set(device, index, 0, 0, NULL); } +/* + * Re-issue VFIO_DEVICE_SET_IRQS for an already-enabled vector range using + * the existing eventfds. Intended for drivers that need to re-arm device + * interrupts after a VFIO_DEVICE_RESET, which tears down the kernel-side + * IRQ trigger but leaves user-side eventfds intact. Recreating the + * eventfds would invalidate any test-fixture cache of the fd, so this + * helper deliberately preserves them. + */ +void vfio_pci_irq_reenable(struct vfio_pci_device *device, u32 index, + u32 vector, int count) +{ + int i; + + check_supported_irq_index(index); + + for (i = vector; i < vector + count; i++) + VFIO_ASSERT_GE(device->msi_eventfds[i], 0, + "vector %d eventfd not allocated\n", i); + + vfio_pci_irq_set(device, index, vector, count, device->msi_eventfds + vector); +} + static void vfio_pci_irq_get(struct vfio_pci_device *device, u32 index, struct vfio_irq_info *irq_info) { -- 2.54.0.794.g4f17f83d09-goog
