On Wed, Apr 06, 2022 at 04:35:36PM +0800, Jason Wang wrote: > This patch introduce
introduces > a new new > virtio config ops to vring > callbacks. Transport specific method is required to call > synchornize_irq() on the IRQs. For the transport that doesn't provide > synchronize_vqs(), use synchornize_rcu() as a fallback. > > Cc: Thomas Gleixner <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: "Paul E. McKenney" <[email protected]> > Cc: Marc Zyngier <[email protected]> > Signed-off-by: Jason Wang <[email protected]> > --- > include/linux/virtio_config.h | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h > index b341dd62aa4d..08b73d9bbff2 100644 > --- a/include/linux/virtio_config.h > +++ b/include/linux/virtio_config.h > @@ -57,6 +57,8 @@ struct virtio_shm_region { > * include a NULL entry for vqs unused by driver > * Returns 0 on success or error status > * @del_vqs: free virtqueues found by find_vqs(). > + * @synchronize_vqs: synchronize with the virtqueue callbacks. > + * vdev: the virtio_device I think I prefer synchronize_callbacks > * @get_features: get the array of feature bits for this device. > * vdev: the virtio_device > * Returns the first 64 feature bits (all we currently need). > @@ -89,6 +91,7 @@ struct virtio_config_ops { > const char * const names[], const bool *ctx, > struct irq_affinity *desc); > void (*del_vqs)(struct virtio_device *); > + void (*synchronize_vqs)(struct virtio_device *); > u64 (*get_features)(struct virtio_device *vdev); > int (*finalize_features)(struct virtio_device *vdev); > const char *(*bus_name)(struct virtio_device *vdev); > @@ -217,6 +220,19 @@ int virtio_find_vqs_ctx(struct virtio_device *vdev, > unsigned nvqs, > desc); > } > > +/** > + * virtio_synchronize_vqs - synchronize with virtqueue callbacks > + * @vdev: the device > + */ > +static inline > +void virtio_synchronize_vqs(struct virtio_device *dev) > +{ > + if (dev->config->synchronize_vqs) > + dev->config->synchronize_vqs(dev); > + else > + synchronize_rcu(); I am not sure about this fallback and the latency impact. Maybe synchronize_rcu_expedited is better here. > +} > + > /** > * virtio_device_ready - enable vq use in probe function > * @vdev: the device > -- > 2.25.1 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
