On Wed, Nov 28, 2018 at 11:34:46AM +0100, Maxime Coquelin wrote:
>
>
> On 11/22/18 3:06 PM, w...@redhat.com wrote:
> >From: Wei Xu <w...@redhat.com>
> >
> >tweaked vhost-net code to test migration.
> >
> >@@ -1414,64 +1430,20 @@ long vhost_vring_ioctl(struct vhost_dev
> > r = -EFAULT;
> > break;
> > }
> >+ vq->last_avail_idx = s.num & 0x7FFF;
> >+ /* Forget the cached index value. */
> >+ vq->avail_idx = vq->last_avail_idx;
> >+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
> >+ vq->last_avail_wrap_counter = !!(s.num & 0x8000);
> >+ vq->avail_wrap_counter = vq->last_avail_wrap_counter;
> >+
> >+ vq->last_used_idx = (s.num & 0x7fFF0000) >> 16;
> >+ vq->last_used_wrap_counter = !!(s.num & 0x80000000);
> >+ }
> >+ break;
> >+ case VHOST_GET_VRING_BASE:
> >+ s.index = idx;
> >+ s.num = vq->last_avail_idx;
> >+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
> >+ s.num |= vq->last_avail_wrap_counter << 15;
> >+ s.num |= vq->last_used_idx << 16;
> >+ s.num |= vq->last_used_wrap_counter << 31;
> >+ }
> >+ if (copy_to_user(argp, &s, sizeof(s)))
> >+ r = -EFAULT;
> >+ break;
> >
> >Signed-off-by: Wei Xu <w...@redhat.com>
> >---
> > hw/virtio/virtio.c | 35 ++++++++++++++++++++++++++++++-----
> > include/hw/virtio/virtio.h | 4 ++--
> > 2 files changed, 32 insertions(+), 7 deletions(-)
> >
> >diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> >index 64d5c04..7487d3d 100644
> >--- a/hw/virtio/virtio.c
> >+++ b/hw/virtio/virtio.c
> >@@ -2963,19 +2963,40 @@ hwaddr virtio_queue_get_used_size(VirtIODevice
> >*vdev, int n)
> > }
> > }
> >-uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
> >+int virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
> > {
> >- return vdev->vq[n].last_avail_idx;
> >+ int idx;
> >+
> >+ if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
>
> Also, I think you want to use virtio_vdev_has_feature() here instead,
> else it will set wrap counter in the case ring_packed=on in the QEMU
> command line but the feature has not been negotiated.
>
>
> For example, with ring_packed=on and with stock Fedora 28 kernel, which
> does not support packed ring, I get this warning with DPDK vhost user
> backend:
>
> VHOST_CONFIG: last_used_idx (32768) and vq->used->idx (0) mismatches;
> some packets maybe resent for Tx and dropped for Rx
Thanks, will fix it.
Wei
>
> >+ idx = vdev->vq[n].last_avail_idx;
> >+ idx |= ((int)vdev->vq[n].avail_wrap_counter) << 15;
> >+ idx |= (vdev->vq[n].used_idx) << 16;
> >+ idx |= ((int)vdev->vq[n].used_wrap_counter) << 31;
> >+ } else {
> >+ idx = (int)vdev->vq[n].last_avail_idx;
> >+ }
> >+ return idx;
> > }
> >-void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t
> >idx)
> >+void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, int idx)
> > {
> >- vdev->vq[n].last_avail_idx = idx;
> >- vdev->vq[n].shadow_avail_idx = idx;
> >+ if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
> >+ vdev->vq[n].last_avail_idx = idx & 0x7fff;
> >+ vdev->vq[n].avail_wrap_counter = !!(idx & 0x8000);
> >+ vdev->vq[n].used_idx = (idx & 0x7fff0000) >> 16;
> >+ vdev->vq[n].used_wrap_counter = !!(idx & 0x80000000);
> >+ } else {
> >+ vdev->vq[n].last_avail_idx = idx;
> >+ vdev->vq[n].shadow_avail_idx = idx;
> >+ }
> > }
> > void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
> > {
> >+ if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
> >+ return;
> >+ }
> >+
> > rcu_read_lock();
> > if (vdev->vq[n].vring.desc) {
> > vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]);
> >@@ -2986,6 +3007,10 @@ void virtio_queue_restore_last_avail_idx(VirtIODevice
> >*vdev, int n)
> > void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
> > {
> >+ if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
> >+ return;
> >+ }
> >+
> > rcu_read_lock();
> > if (vdev->vq[n].vring.desc) {
> > vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
> >diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> >index 9c1fa07..a6fdf3f 100644
> >--- a/include/hw/virtio/virtio.h
> >+++ b/include/hw/virtio/virtio.h
> >@@ -272,8 +272,8 @@ hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev,
> >int n);
> > hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n);
> > hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n);
> > hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n);
> >-uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n);
> >-void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t
> >idx);
> >+int virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n);
> >+void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, int idx);
> > void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n);
> > void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n);
> > void virtio_queue_update_used_idx(VirtIODevice *vdev, int n);
> >
