On Tue, Nov 02, 2021 at 06:08:39AM +0000, Xueming(Steven) Li wrote:
> 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.
I think it's cleaner if qemu handles this itself like it did before, it
knows vm is stopped without getting called.
> >
> >
> > > @@ -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
> >
>
