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authorJason Wang <jasowang@redhat.com>2022-05-27 14:01:19 +0800
committerMichael S. Tsirkin <mst@redhat.com>2022-05-31 12:45:10 -0400
commit8b4ec69d7e098a7ddf832e1e7840de53ed474c77 (patch)
treebdb4776afb38a0ab34b028987924967a941fe2f7 /drivers/virtio/virtio_ring.c
parentbe83f04d2529e8dc4273efdd1ccf7b7502741071 (diff)
downloadlinux-8b4ec69d7e098a7ddf832e1e7840de53ed474c77.tar.bz2
virtio: harden vring IRQ
This is a rework on the previous IRQ hardening that is done for virtio-pci where several drawbacks were found and were reverted: 1) try to use IRQF_NO_AUTOEN which is not friendly to affinity managed IRQ that is used by some device such as virtio-blk 2) done only for PCI transport The vq->broken is re-used in this patch for implementing the IRQ hardening. The vq->broken is set to true during both initialization and reset. And the vq->broken is set to false in virtio_device_ready(). Then vring_interrupt() can check and return when vq->broken is true. And in this case, switch to return IRQ_NONE to let the interrupt core aware of such invalid interrupt to prevent IRQ storm. The reason of using a per queue variable instead of a per device one is that we may need it for per queue reset hardening in the future. Note that the hardening is only done for vring interrupt since the config interrupt hardening is already done in commit 22b7050a024d7 ("virtio: defer config changed notifications"). But the method that is used by config interrupt can't be reused by the vring interrupt handler because it uses spinlock to do the synchronization which is expensive. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Halil Pasic <pasic@linux.ibm.com> Cc: Cornelia Huck <cohuck@redhat.com> Cc: Vineeth Vijayan <vneethv@linux.ibm.com> Cc: Peter Oberparleiter <oberpar@linux.ibm.com> Cc: linux-s390@vger.kernel.org Signed-off-by: Jason Wang <jasowang@redhat.com> Message-Id: <20220527060120.20964-9-jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Diffstat (limited to 'drivers/virtio/virtio_ring.c')
-rw-r--r--drivers/virtio/virtio_ring.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 9c231e1fded7..13a7348cedff 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1688,7 +1688,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
vq->we_own_ring = true;
vq->notify = notify;
vq->weak_barriers = weak_barriers;
- vq->broken = false;
+ vq->broken = true;
vq->last_used_idx = 0;
vq->event_triggered = false;
vq->num_added = 0;
@@ -2134,8 +2134,11 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
return IRQ_NONE;
}
- if (unlikely(vq->broken))
- return IRQ_HANDLED;
+ if (unlikely(vq->broken)) {
+ dev_warn_once(&vq->vq.vdev->dev,
+ "virtio vring IRQ raised before DRIVER_OK");
+ return IRQ_NONE;
+ }
/* Just a hint for performance: so it's ok that this can be racy! */
if (vq->event)
@@ -2177,7 +2180,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
vq->we_own_ring = false;
vq->notify = notify;
vq->weak_barriers = weak_barriers;
- vq->broken = false;
+ vq->broken = true;
vq->last_used_idx = 0;
vq->event_triggered = false;
vq->num_added = 0;