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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>
This commit is contained in:
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
View File

@ -84,6 +84,8 @@ static inline void vfio_pci_cmd_clear(struct vfio_pci_device *device, u16 bits)
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)
@ -108,6 +110,12 @@ 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)
{
@ -119,6 +127,12 @@ 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);

22
tools/testing/selftests/vfio/lib/vfio_pci_device.c
View File

@ -105,6 +105,28 @@ 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)
{