Messages in this thread | | | Subject | Re: [RFC V4 PATCH 7/8] vhost: packed ring support | From | Jason Wang <> | Date | Wed, 23 May 2018 09:39:28 +0800 |
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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@redhat.com> >> --- >> 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
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