On Mon, 2021-11-01 at 17:06 -0400, Michael S. Tsirkin wrote:
> On Mon, Nov 01, 2021 at 04:38:12PM +0800, Xueming Li wrote:
> > When vhost-user vdpa client suspend, backend may close all resources,
> > VQ notifier mmap address become invalid, restore MR which contains
> > the invalid address is wrong. vdpa client will set VQ notifier after
> > reconnect.
> >
> > This patch removes VQ notifier restore and related flags to avoid reusing
> > invalid address.
> >
> > Fixes: 44866521bd6e ("vhost-user: support registering external host
> > notifiers")
> > Cc: qemu-sta...@nongnu.org
> > Cc: Yuwei Zhang <zhangyuwei.9...@bytedance.com>
> > Signed-off-by: Xueming Li <xuemi...@nvidia.com>
> > ---
> > hw/virtio/vhost-user.c | 19 +------------------
> > include/hw/virtio/vhost-user.h | 1 -
> > 2 files changed, 1 insertion(+), 19 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index bf6e50223c..c671719e9b 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -1143,19 +1143,6 @@ static int vhost_user_set_vring_num(struct vhost_dev
> > *dev,
> > return vhost_set_vring(dev, VHOST_USER_SET_VRING_NUM, ring);
> > }
> >
> > -static void vhost_user_host_notifier_restore(struct vhost_dev *dev,
> > - int queue_idx)
> > -{
> > - struct vhost_user *u = dev->opaque;
> > - VhostUserHostNotifier *n = &u->user->notifier[queue_idx];
> > - VirtIODevice *vdev = dev->vdev;
> > -
> > - if (n->addr && !n->set) {
> > - virtio_queue_set_host_notifier_mr(vdev, queue_idx, &n->mr, true);
> > - n->set = true;
> > - }
> > -}
> > -
> > static void vhost_user_host_notifier_remove(struct vhost_dev *dev,
> > int queue_idx)
> > {
> > @@ -1163,17 +1150,14 @@ static void vhost_user_host_notifier_remove(struct
> > vhost_dev *dev,
> > VhostUserHostNotifier *n = &u->user->notifier[queue_idx];
> > VirtIODevice *vdev = dev->vdev;
> >
> > - if (n->addr && n->set) {
> > + if (n->addr) {
> > virtio_queue_set_host_notifier_mr(vdev, queue_idx, &n->mr, false);
> > - n->set = false;
> > }
> > }
> >
>
> So on vq stop we still remove the notifier...
>
> > static int vhost_user_set_vring_base(struct vhost_dev *dev,
> > struct vhost_vring_state *ring)
> > {
> > - vhost_user_host_notifier_restore(dev, ring->index);
> > -
> > return vhost_set_vring(dev, VHOST_USER_SET_VRING_BASE, ring);
> > }
> >
>
> but on vq start we do not reinstate it? Does this not mean that
> notifiers won't work after stop then start?
Yes, backend initially work w/o host notifier, request VM driver to
install notifier if needed - call this function through slave socket.
>
>
> > @@ -1538,7 +1522,6 @@ static int
> > vhost_user_slave_handle_vring_host_notifier(struct vhost_dev *dev,
> > }
> >
> > n->addr = addr;
> > - n->set = true;
> >
> > return 0;
> > }
> > diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h
> > index a9abca3288..f6012b2078 100644
> > --- a/include/hw/virtio/vhost-user.h
> > +++ b/include/hw/virtio/vhost-user.h
> > @@ -14,7 +14,6 @@
> > typedef struct VhostUserHostNotifier {
> > MemoryRegion mr;
> > void *addr;
> > - bool set;
> > } VhostUserHostNotifier;
> >
> > typedef struct VhostUserState {
> > --
> > 2.33.0
>
