Michael S. Tsirkin
2022-Jun-30 09:46 UTC
[PATCH v1 1/1] virtio: Restore semantics of vq->broken in virtqueues
On Thu, Jun 30, 2022 at 09:36:46AM +0000, Alexander Atanasov wrote:> virtio: harden vring IRQ (8b4ec69d7e09) changed the use > of vq->broken. As result vring_interrupt handles IRQs for > broken drivers as IRQ_NONE and not IRQ_HANDLED and made impossible > to initiallize vqs before the driver is ready, i.e. in probe method. > Balloon driver does this and it can not load because it fails in > vqs_init with -EIO. > > So instead of changing the original intent ot the flag introduce > a new flag vq->ready which servers the purpose to check of early IRQs > and restore the behaviour of the vq->broken flag. > > Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>Does commit c346dae4f3fbce51bbd4f2ec5e8c6f9b91e93163 Author: Jason Wang <jasowang at redhat.com> Date: Wed Jun 22 09:29:40 2022 +0800 virtio: disable notification hardening by default solve the problem for you?> --- > drivers/virtio/virtio_ring.c | 20 ++++++++++++++------ > include/linux/virtio.h | 2 +- > include/linux/virtio_config.h | 10 +++++----- > 3 files changed, 20 insertions(+), 12 deletions(-) > > Cc: Thomas Gleixner <tglx at linutronix.de> > Cc: Peter Zijlstra <peterz at infradead.org> > Cc: "Paul E. McKenney" <paulmck at kernel.org> > Cc: Marc Zyngier <maz at kernel.org> > Cc: Halil Pasic <pasic at linux.ibm.com> > Cc: Cornelia Huck <cohuck at redhat.com> > Cc: Vineeth Vijayan <vneethv at linux.ibm.com> > Cc: Peter Oberparleiter <oberpar at linux.ibm.com> > Cc: linux-s390 at vger.kernel.org > Cc: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 13a7348cedff..dca3cc774584 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -100,6 +100,9 @@ struct vring_virtqueue { > /* Other side has made a mess, don't try any more. */ > bool broken; > > + /* the queue is ready to handle interrupts */ > + bool ready; > + > /* Host supports indirect buffers */ > bool indirect; > > @@ -1688,7 +1691,8 @@ static struct virtqueue *vring_create_virtqueue_packed( > vq->we_own_ring = true; > vq->notify = notify; > vq->weak_barriers = weak_barriers; > - vq->broken = true; > + vq->broken = false; > + vq->ready = false; > vq->last_used_idx = 0; > vq->event_triggered = false; > vq->num_added = 0; > @@ -2134,7 +2138,10 @@ irqreturn_t vring_interrupt(int irq, void *_vq) > return IRQ_NONE; > } > > - if (unlikely(vq->broken)) { > + if (unlikely(vq->broken)) > + return IRQ_HANDLED; > + > + if (unlikely(!vq->ready)) { > dev_warn_once(&vq->vq.vdev->dev, > "virtio vring IRQ raised before DRIVER_OK"); > return IRQ_NONE; > @@ -2180,7 +2187,8 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, > vq->we_own_ring = false; > vq->notify = notify; > vq->weak_barriers = weak_barriers; > - vq->broken = true; > + vq->broken = false; > + vq->ready = false; > vq->last_used_idx = 0; > vq->event_triggered = false; > vq->num_added = 0; > @@ -2405,7 +2413,7 @@ EXPORT_SYMBOL_GPL(virtio_break_device); > * (probing and restoring). This function should only be called by the > * core, not directly by the driver. > */ > -void __virtio_unbreak_device(struct virtio_device *dev) > +void __virtio_device_ready(struct virtio_device *dev) > { > struct virtqueue *_vq; > > @@ -2414,11 +2422,11 @@ void __virtio_unbreak_device(struct virtio_device *dev) > struct vring_virtqueue *vq = to_vvq(_vq); > > /* Pairs with READ_ONCE() in virtqueue_is_broken(). */ > - WRITE_ONCE(vq->broken, false); > + WRITE_ONCE(vq->ready, true); > } > spin_unlock(&dev->vqs_list_lock); > } > -EXPORT_SYMBOL_GPL(__virtio_unbreak_device); > +EXPORT_SYMBOL_GPL(__virtio_device_ready); > > dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq) > { > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index d8fdf170637c..538c5959949a 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -131,7 +131,7 @@ void unregister_virtio_device(struct virtio_device *dev); > bool is_virtio_device(struct device *dev); > > void virtio_break_device(struct virtio_device *dev); > -void __virtio_unbreak_device(struct virtio_device *dev); > +void __virtio_device_ready(struct virtio_device *dev); > > void virtio_config_changed(struct virtio_device *dev); > #ifdef CONFIG_PM_SLEEP > diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h > index 49c7c32815f1..35cf1b26e05a 100644 > --- a/include/linux/virtio_config.h > +++ b/include/linux/virtio_config.h > @@ -259,21 +259,21 @@ void virtio_device_ready(struct virtio_device *dev) > > /* > * The virtio_synchronize_cbs() makes sure vring_interrupt() > - * will see the driver specific setup if it sees vq->broken > + * will see the driver specific setup if it sees vq->ready > * as false (even if the notifications come before DRIVER_OK). > */ > virtio_synchronize_cbs(dev); > - __virtio_unbreak_device(dev); > + __virtio_device_ready(dev); > /* > - * The transport should ensure the visibility of vq->broken > + * The transport should ensure the visibility of vq->ready > * before setting DRIVER_OK. See the comments for the transport > * specific set_status() method. > * > * A well behaved device will only notify a virtqueue after > * DRIVER_OK, this means the device should "see" the coherenct > - * memory write that set vq->broken as false which is done by > + * memory write that set vq->ready as true which is done by > * the driver when it sees DRIVER_OK, then the following > - * driver's vring_interrupt() will see vq->broken as false so > + * driver's vring_interrupt() will see vq->true as true so > * we won't lose any notification. > */ > dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); > -- > 2.25.1