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().
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 <[email protected]>
---
.../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
