On Tue, Apr 07, 2026 at 01:35:26PM -0400, Andrew Stellman wrote:
> Fixes: 77cf524654a8 ("virtio_pci: split up vp_interrupt")
>
> Should I resend as v2 with the tag included, or is adding it on your end
> easier?
how was this tested? I don't think a unit test is sufficient here, FYI.
> On Tue, Apr 7, 2026 at 12:20 PM Michael S. Tsirkin <[email protected]> wrote:
>
> On Tue, Apr 07, 2026 at 08:39:03AM -0400, Andrew Stellman wrote:
> > vp_interrupt() unconditionally returns the result of
> > vp_vring_interrupt(). When a config-change interrupt fires but no vring
> > activity is pending, vp_vring_interrupt() returns IRQ_NONE — even
> > though the interrupt was legitimately handled by vp_config_changed().
> > Over time this causes the IRQ subsystem to flag the line as spurious.
> >
> > Track the return value explicitly: set ret to IRQ_HANDLED when the
> > config-change bit is set, OR it with the vring result, and return the
> > combined value.
> >
> > Signed-off-by: Andrew Stellman <[email protected]>
>
> Fixes tag?
>
> > ---
> > drivers/virtio/virtio_pci_common.c | 10 ++++++++--
> > 1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/
> virtio_pci_common.c
> > index 0b9d66b..1d1ab02 100644
> > --- a/drivers/virtio/virtio_pci_common.c
> > +++ b/drivers/virtio/virtio_pci_common.c
> > @@ -106,6 +106,7 @@ static irqreturn_t vp_vring_interrupt(int irq, void
> *opaque)
> > static irqreturn_t vp_interrupt(int irq, void *opaque)
> > {
> > struct virtio_pci_device *vp_dev = opaque;
> > + irqreturn_t ret = IRQ_NONE;
> > u8 isr;
> >
> > /* reading the ISR has the effect of also clearing it so it's very
> > @@ -117,10 +118,15 @@ static irqreturn_t vp_interrupt(int irq, void
> *opaque)
> > return IRQ_NONE;
> >
> > /* Configuration change? Tell driver if it wants to know. */
> > - if (isr & VIRTIO_PCI_ISR_CONFIG)
> > + if (isr & VIRTIO_PCI_ISR_CONFIG) {
> > vp_config_changed(irq, opaque);
> > + ret = IRQ_HANDLED;
> > + }
> >
> > - return vp_vring_interrupt(irq, opaque);
> > + if (vp_vring_interrupt(irq, opaque) == IRQ_HANDLED)
> > + ret = IRQ_HANDLED;
> > +
> > + return ret;
> > }
> >
> > static int vp_request_msix_vectors(struct virtio_device *vdev, int
> nvectors,
> > --
> > 2.34.1
>
>
