On 2018年05月23日 00:54, Wei Xu wrote:
On Wed, May 16, 2018 at 08:32:20PM +0800, Jason Wang wrote:Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> --- drivers/vhost/net.c | 3 +- drivers/vhost/vhost.c | 539 ++++++++++++++++++++++++++++++++++++++++++++++---- drivers/vhost/vhost.h | 8 +- 3 files changed, 513 insertions(+), 37 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 8304c30..f2a0f5b 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1358,6 +1382,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg break; } vq->last_avail_idx = s.num; + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) + vq->avail_wrap_counter = s.num >> 31; /* Forget the cached index value. */ vq->avail_idx = vq->last_avail_idx; break; @@ -1366,6 +1392,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg s.num = vq->last_avail_idx; if (copy_to_user(argp, &s, sizeof s)) r = -EFAULT; + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) + s.num |= vq->avail_wrap_counter << 31; break; case VHOST_SET_VRING_ADDR: if (copy_from_user(&a, argp, sizeof a)) {'last_used_idx' also needs to be saved/restored here. I have figured out the root cause of broken device after reloading 'virtio-net' module, all indices have been reset for a reloading but 'last_used_idx' is not properly reset in this case. This confuses handle_rx()/tx(). Wei
Good catch, so we probably need a new ioctl to sync between qemu and vhost. Something like VHOST_SET/GET_USED_BASE. Thanks
