diff options
| author | Andrew Stellman <astellman@stellman-greene.com> | 2026-09-04 10:13:18 -0400 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2026-09-07 18:54:03 -0400 |
| commit | 93fa09455fb1a9624b73d42ac1f83771f4818e80 (patch) | |
| tree | dbd16ce79b649abb989e7dd38f5d3eb169b28770 | |
| parent | 8dd505a45de0e63829d8bb4116b1d66db64813be (diff) | |
virtio-pci: return IRQ_HANDLED after non-zero ISR
vp_interrupt() reads the ISR before dispatching config-change and
vring handling. Reading the ISR also clears it, so once the read
returns non-zero the interrupt was from this device and has already
been consumed.
Currently vp_interrupt() returns the result of vp_vring_interrupt().
For a config-change interrupt with no vring work, that can return
IRQ_NONE even though the ISR was non-zero and the interrupt was
handled.
Call vp_vring_interrupt() for any queue work, but once the ISR is
non-zero return IRQ_HANDLED.
Tested with QEMU virtio-blk-pci forced to INTx using vectors=0 and
pci=nomsi. On an idle device, 200 config-change interrupts were
generated using QMP block_resize.
Before this change, irq_handler_exit reported ret=unhandled and
/proc/irq/11/spurious increased from 0 to 200 unhandled interrupts.
After this change, irq_handler_exit reported ret=handled and the
unhandled count remained at 0.
The issue was found during an LLM-assisted Quality Playbook review.
Fixes: 77cf524654a8 ("virtio_pci: split up vp_interrupt")
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: LLM
Signed-off-by: Andrew Stellman <astellman@stellman-greene.com>
Message-ID: <20260904141318.30278-1-astellman@stellman-greene.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| -rw-r--r-- | drivers/virtio/virtio_pci_common.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 10371ecbc054..b90c174450b2 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -120,7 +120,9 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) if (isr & VIRTIO_PCI_ISR_CONFIG) vp_config_changed(irq, opaque); - return vp_vring_interrupt(irq, opaque); + vp_vring_interrupt(irq, opaque); + + return IRQ_HANDLED; } static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, |