From: Alex Williamson 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 --- .../vfio/lib/include/libvfio/vfio_pci_device.h | 14 ++++++++++++++ tools/testing/selftests/vfio/lib/vfio_pci_device.c | 22 ++++++++++++++++++++++ 2 files changed, 36 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..2e67afc0d580 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) @@ -92,6 +94,12 @@ static inline void vfio_pci_msi_disable(struct vfio_pci_device *device) vfio_pci_irq_disable(device, VFIO_PCI_MSI_IRQ_INDEX); } +static inline void vfio_pci_msi_reenable(struct vfio_pci_device *device, + u32 vector, int count) +{ + vfio_pci_irq_reenable(device, VFIO_PCI_MSI_IRQ_INDEX, vector, count); +} + static inline void vfio_pci_msix_enable(struct vfio_pci_device *device, u32 vector, int count) { @@ -103,6 +111,12 @@ static inline void vfio_pci_msix_disable(struct vfio_pci_device *device) vfio_pci_irq_disable(device, VFIO_PCI_MSIX_IRQ_INDEX); } +static inline void vfio_pci_msix_reenable(struct vfio_pci_device *device, + u32 vector, int count) +{ + vfio_pci_irq_reenable(device, VFIO_PCI_MSIX_IRQ_INDEX, vector, count); +} + static inline int __to_iova(struct vfio_pci_device *device, void *vaddr, iova_t *iova) { return __iommu_hva2iova(device->iommu, vaddr, iova); 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) { -- 2.55.0.795.g602f6c329a-goog