We try to harden virtio device notifications in 8b4ec69d7e09 ("virtio:
harden vring IRQ"). It works with the assumption that the driver or
core can properly call virtio_device_ready() at the right
place. Unfortunately, this seems to be not true and uncover various
bugs of the existing drivers, mainly the issue of using
virtio_device_ready() incorrectly.So let's having a Kconfig option and disable it by default. It gives us a breath to fix the drivers and then we can consider to enable it by default. Signed-off-by: Jason Wang <[email protected]> --- drivers/virtio/Kconfig | 6 ++++++ drivers/virtio/virtio.c | 2 ++ drivers/virtio/virtio_ring.c | 12 ++++++++++++ include/linux/virtio_config.h | 2 ++ 4 files changed, 22 insertions(+) diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index b5adf6abd241..b059c39af3d4 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -35,6 +35,12 @@ menuconfig VIRTIO_MENU if VIRTIO_MENU +config VIRTIO_HARDEN_NOTIFICATION + bool "Harden virtio notification" + help + Enable to this to harden the device notifications and + supress the ones that are illegal. + config VIRTIO_PCI tristate "PCI driver for virtio devices" depends on PCI diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index ef04a96942bf..21dc08d2f32d 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -220,6 +220,7 @@ static int virtio_features_ok(struct virtio_device *dev) * */ void virtio_reset_device(struct virtio_device *dev) { +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION /* * The below virtio_synchronize_cbs() guarantees that any * interrupt for this line arriving after @@ -228,6 +229,7 @@ void virtio_reset_device(struct virtio_device *dev) */ virtio_break_device(dev); virtio_synchronize_cbs(dev); +#endif dev->config->reset(dev); } diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 13a7348cedff..d9d3b6e201fb 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1688,7 +1688,11 @@ static struct virtqueue *vring_create_virtqueue_packed( vq->we_own_ring = true; vq->notify = notify; vq->weak_barriers = weak_barriers; +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION vq->broken = true; +#else + vq->broken = false; +#endif vq->last_used_idx = 0; vq->event_triggered = false; vq->num_added = 0; @@ -2135,9 +2139,13 @@ irqreturn_t vring_interrupt(int irq, void *_vq) } if (unlikely(vq->broken)) { +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION dev_warn_once(&vq->vq.vdev->dev, "virtio vring IRQ raised before DRIVER_OK"); return IRQ_NONE; +#else + return IRQ_HANDLED; +#endif } /* Just a hint for performance: so it's ok that this can be racy! */ @@ -2180,7 +2188,11 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, vq->we_own_ring = false; vq->notify = notify; vq->weak_barriers = weak_barriers; +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION vq->broken = true; +#else + vq->broken = false; +#endif vq->last_used_idx = 0; vq->event_triggered = false; vq->num_added = 0; diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 9a36051ceb76..d15c3cdda2d2 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -257,6 +257,7 @@ void virtio_device_ready(struct virtio_device *dev) WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION /* * The virtio_synchronize_cbs() makes sure vring_interrupt() * will see the driver specific setup if it sees vq->broken @@ -264,6 +265,7 @@ void virtio_device_ready(struct virtio_device *dev) */ virtio_synchronize_cbs(dev); __virtio_unbreak_device(dev); +#endif /* * The transport should ensure the visibility of vq->broken * before setting DRIVER_OK. See the comments for the transport -- 2.25.1 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
