On Fri, Mar 15, 2024 at 4:23 PM Stefano Garzarella <sgarz...@redhat.com> wrote: > > On Thu, Mar 14, 2024 at 11:17:01AM +0800, Jason Wang wrote: > >On Wed, Feb 7, 2024 at 5:27 PM Stefano Garzarella <sgarz...@redhat.com> > >wrote: > >> > >> vhost_vdpa_set_vring_ready() could already fail, but if Linux's > >> patch [1] will be merged, it may fail with more chance if > >> userspace does not activate virtqueues before DRIVER_OK when > >> VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK is not negotiated. > > > >I wonder what happens if we just leave it as is. > > Are you referring to this patch or the kernel patch?
This patch. > > Here I'm just checking the return value of vhost_vdpa_set_vring_ready(). > It can return an error also without that kernel patch, so IMHO is > better to check the return value here in QEMU. > > What issue do you see with this patch applied? For the parent which can enable after driver_ok but not advertise it. (To say the truth, I'm not sure if we need to care about this) > > > > >VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK: We do know enabling could be > >done after driver_ok. > >Without VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK: We don't know whether > >enabling could be done after driver_ok or not. > > I see your point, indeed I didn't send a v2 of that patch. > Maybe we should document that, because it could be interpreted that if > VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK is not negotiated the enabling > should always be done before driver_ok (which is true for example in > VDUSE). I see, so I think we probably need the fix. > > BTW I think we should discuss it in the kernel patch. > > Thanks, > Stefano > > > > >Thanks > > > >> > >> So better check its return value anyway. > >> > >> [1] > >> https://lore.kernel.org/virtualization/20240206145154.118044-1-sgarz...@redhat.com/T/#u > >> > >> Signed-off-by: Stefano Garzarella <sgarz...@redhat.com> > >> --- > >> Note: This patch conflicts with [2], but the resolution is simple, > >> so for now I sent a patch for the current master, but I'll rebase > >> this patch if we merge the other one first. Will go through [2]. Thanks > >> > >> [2] > >> https://lore.kernel.org/qemu-devel/20240202132521.32714-1-kw...@redhat.com/ > >> --- > >> hw/virtio/vdpa-dev.c | 8 +++++++- > >> net/vhost-vdpa.c | 15 ++++++++++++--- > >> 2 files changed, 19 insertions(+), 4 deletions(-) > >> > >> diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c > >> index eb9ecea83b..d57cd76c18 100644 > >> --- a/hw/virtio/vdpa-dev.c > >> +++ b/hw/virtio/vdpa-dev.c > >> @@ -259,7 +259,11 @@ static int vhost_vdpa_device_start(VirtIODevice > >> *vdev, Error **errp) > >> goto err_guest_notifiers; > >> } > >> for (i = 0; i < s->dev.nvqs; ++i) { > >> - vhost_vdpa_set_vring_ready(&s->vdpa, i); > >> + ret = vhost_vdpa_set_vring_ready(&s->vdpa, i); > >> + if (ret < 0) { > >> + error_setg_errno(errp, -ret, "Error starting vring %d", i); > >> + goto err_dev_stop; > >> + } > >> } > >> s->started = true; > >> > >> @@ -274,6 +278,8 @@ static int vhost_vdpa_device_start(VirtIODevice *vdev, > >> Error **errp) > >> > >> return ret; > >> > >> +err_dev_stop: > >> + vhost_dev_stop(&s->dev, vdev, false); > >> err_guest_notifiers: > >> k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false); > >> err_host_notifiers: > >> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c > >> index 3726ee5d67..e3d8036479 100644 > >> --- a/net/vhost-vdpa.c > >> +++ b/net/vhost-vdpa.c > >> @@ -381,7 +381,10 @@ static int vhost_vdpa_net_data_load(NetClientState > >> *nc) > >> } > >> > >> for (int i = 0; i < v->dev->nvqs; ++i) { > >> - vhost_vdpa_set_vring_ready(v, i + v->dev->vq_index); > >> + int ret = vhost_vdpa_set_vring_ready(v, i + v->dev->vq_index); > >> + if (ret < 0) { > >> + return ret; > >> + } > >> } > >> return 0; > >> } > >> @@ -1213,7 +1216,10 @@ static int vhost_vdpa_net_cvq_load(NetClientState > >> *nc) > >> > >> assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); > >> > >> - vhost_vdpa_set_vring_ready(v, v->dev->vq_index); > >> + r = vhost_vdpa_set_vring_ready(v, v->dev->vq_index); > >> + if (unlikely(r < 0)) { > >> + return r; > >> + } > >> > >> if (v->shadow_vqs_enabled) { > >> n = VIRTIO_NET(v->dev->vdev); > >> @@ -1252,7 +1258,10 @@ static int vhost_vdpa_net_cvq_load(NetClientState > >> *nc) > >> } > >> > >> for (int i = 0; i < v->dev->vq_index; ++i) { > >> - vhost_vdpa_set_vring_ready(v, i); > >> + r = vhost_vdpa_set_vring_ready(v, i); > >> + if (unlikely(r < 0)) { > >> + return r; > >> + } > >> } > >> > >> return 0; > >> -- > >> 2.43.0 > >> > > >
