Applied to next-virtio/for-next-net. Thanks, Maxime
On Tue, Sep 16, 2025 at 11:36 AM Maxime Coquelin <[email protected]> wrote: > > Add workaround to poll virtqueue ready states before starting device > when VIRTIO_DEVICE_STATUS_DRIVER_OK is set in vduse_events_handler(). > > For each virtqueue, poll using VDUSE_VQ_GET_INFO ioctl to check > vq_info->ready state with configurable retry limit. This addresses > timing issues where device start was attempted before all virtqueues > were properly initialized and ready. > > A notification mechanism will be introduced in the next version of > the VDUSE uAPI. When it lands, we would only apply this workaround > when the kernel does not support it. > > Fixes: a9120db8b98b ("vhost: add VDUSE device startup") > Cc: [email protected] > > Reviewed-by: David Marchand <[email protected]> > Signed-off-by: Maxime Coquelin <[email protected]> > --- > lib/vhost/vduse.c | 61 +++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 59 insertions(+), 2 deletions(-) > > diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c > index 9de7f04a4f..422c4ab8f3 100644 > --- a/lib/vhost/vduse.c > +++ b/lib/vhost/vduse.c > @@ -272,6 +272,55 @@ vduse_vring_cleanup(struct virtio_net *dev, unsigned int > index) > vq->last_avail_idx = 0; > } > > +/* > + * Tests show that virtqueues get ready at the first retry at worst, > + * but let's be on the safe side and allow more retries. > + */ > +#define VDUSE_VQ_READY_POLL_MAX_RETRIES 100 > + > +static int > +vduse_wait_for_virtqueues_ready(struct virtio_net *dev) > +{ > + unsigned int i; > + int ret; > + > + for (i = 0; i < dev->nr_vring; i++) { > + int retry_count = 0; > + > + while (retry_count < VDUSE_VQ_READY_POLL_MAX_RETRIES) { > + struct vduse_vq_info vq_info = { 0 }; > + > + vq_info.index = i; > + ret = ioctl(dev->vduse_dev_fd, VDUSE_VQ_GET_INFO, > &vq_info); > + if (ret) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "Failed to get VQ %u info while > polling ready state: %s", > + i, strerror(errno)); > + return -1; > + } > + > + if (vq_info.ready) { > + VHOST_CONFIG_LOG(dev->ifname, DEBUG, > + "VQ %u is ready after %u retries", i, > retry_count); > + break; > + } > + > + retry_count++; > + usleep(1000); > + } > + > + if (retry_count >= VDUSE_VQ_READY_POLL_MAX_RETRIES) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "VQ %u ready state polling timeout after %u > retries", > + i, VDUSE_VQ_READY_POLL_MAX_RETRIES); > + return -1; > + } > + } > + > + VHOST_CONFIG_LOG(dev->ifname, INFO, "All virtqueues are ready after > polling"); > + return 0; > +} > + > static void > vduse_device_start(struct virtio_net *dev, bool reconnect) > { > @@ -414,10 +463,18 @@ vduse_events_handler(int fd, void *arg, int *close > __rte_unused) > } > > if ((old_status ^ dev->status) & VIRTIO_DEVICE_STATUS_DRIVER_OK) { > - if (dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK) > + if (dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK) { > + /* Poll virtqueues ready states before starting > device */ > + ret = vduse_wait_for_virtqueues_ready(dev); > + if (ret < 0) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "Failed to wait for virtqueues ready, > aborting device start"); > + return; > + } > vduse_device_start(dev, false); > - else > + } else { > vduse_device_stop(dev); > + } > } > > VHOST_CONFIG_LOG(dev->ifname, INFO, "Request %s (%u) handled > successfully", > -- > 2.51.0 >
