> -----Original Message-----
> From: Xia, Chenbo <chenbo....@intel.com>
> Sent: Monday, October 17, 2022 2:47 PM
> To: Liu, Changpeng <changpeng....@intel.com>; dev@dpdk.org
> Cc: Maxime Coquelin <maxime.coque...@redhat.com>; David Marchand
> <david.march...@redhat.com>
> Subject: RE: [PATCH v2] vhost: add new `rte_vhost_vring_call_nonblock` API
>
> Hi Changpeng,
>
> > -----Original Message-----
> > From: Liu, Changpeng <changpeng....@intel.com>
> > Sent: Wednesday, October 12, 2022 2:40 PM
> > To: dev@dpdk.org
> > Cc: Liu, Changpeng <changpeng....@intel.com>; Maxime Coquelin
> > <maxime.coque...@redhat.com>; Xia, Chenbo <chenbo....@intel.com>; David
> > Marchand <david.march...@redhat.com>
> > Subject: [PATCH v2] vhost: add new `rte_vhost_vring_call_nonblock` API
> >
> > Vhost-user library locks all VQ's access lock when processing
> > vring based messages, such as SET_VRING_KICK and SET_VRING_CALL,
> > and the data processing thread may already be started, e.g: SPDK
> > vhost-blk and vhost-scsi will start the data processing thread
> > when one vring is ready, then deadlock may happen when SPDK is
> > posting interrupts to VM. Here, we add a new API which allows
> > caller to try again later for this case.
> >
> > Bugzilla ID: 1015
> > Fixes: c5736998305d ("vhost: fix missing virtqueue lock protection")
> >
> > Signed-off-by: Changpeng Liu <changpeng....@intel.com>
> > ---
> > lib/vhost/rte_vhost.h | 15 +++++++++++++++
> > lib/vhost/version.map | 3 +++
> > lib/vhost/vhost.c | 30 ++++++++++++++++++++++++++++++
> > 3 files changed, 48 insertions(+)
>
> For new API, we need to update release_22_11.rst and vhost_lib.rst.
Thanks Chenbo, a new v3 is sent for review.
>
> You can refer to
> http://patchwork.dpdk.org/project/dpdk/patch/20221013092708.4922-2-
> xuan.d...@intel.com/
>
> Thanks,
> Chenbo
>
> >
> > diff --git a/lib/vhost/rte_vhost.h b/lib/vhost/rte_vhost.h
> > index bb7d86a432..d22b25cd4e 100644
> > --- a/lib/vhost/rte_vhost.h
> > +++ b/lib/vhost/rte_vhost.h
> > @@ -909,6 +909,21 @@ rte_vhost_clr_inflight_desc_packed(int vid, uint16_t
> > vring_idx,
> > */
> > int rte_vhost_vring_call(int vid, uint16_t vring_idx);
> >
> > +/**
> > + * Notify the guest that used descriptors have been added to the vring.
> > This
> > + * function acts as a memory barrier. This function will return -EAGAIN
> > when
> > + * vq's access lock is held by other thread, user should try again later.
> > + *
> > + * @param vid
> > + * vhost device ID
> > + * @param vring_idx
> > + * vring index
> > + * @return
> > + * 0 on success, -1 on failure, -EAGAIN for another retry
> > + */
> > +__rte_experimental
> > +int rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx);
> > +
> > /**
> > * Get vhost RX queue avail count.
> > *
> > diff --git a/lib/vhost/version.map b/lib/vhost/version.map
> > index 7a00b65740..c8c44b8326 100644
> > --- a/lib/vhost/version.map
> > +++ b/lib/vhost/version.map
> > @@ -94,6 +94,9 @@ EXPERIMENTAL {
> > rte_vhost_async_try_dequeue_burst;
> > rte_vhost_driver_get_vdpa_dev_type;
> > rte_vhost_clear_queue;
> > +
> > + # added in 22.11
> > + rte_vhost_vring_call_nonblock;
> > };
> >
> > INTERNAL {
> > diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
> > index 8740aa2788..ed6efb003f 100644
> > --- a/lib/vhost/vhost.c
> > +++ b/lib/vhost/vhost.c
> > @@ -1317,6 +1317,36 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
> > return 0;
> > }
> >
> > +int
> > +rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx)
> > +{
> > + struct virtio_net *dev;
> > + struct vhost_virtqueue *vq;
> > +
> > + dev = get_device(vid);
> > + if (!dev)
> > + return -1;
> > +
> > + if (vring_idx >= VHOST_MAX_VRING)
> > + return -1;
> > +
> > + vq = dev->virtqueue[vring_idx];
> > + if (!vq)
> > + return -1;
> > +
> > + if (!rte_spinlock_trylock(&vq->access_lock))
> > + return -EAGAIN;
> > +
> > + if (vq_is_packed(dev))
> > + vhost_vring_call_packed(dev, vq);
> > + else
> > + vhost_vring_call_split(dev, vq);
> > +
> > + rte_spinlock_unlock(&vq->access_lock);
> > +
> > + return 0;
> > +}
> > +
> > uint16_t
> > rte_vhost_avail_entries(int vid, uint16_t queue_id)
> > {
> > --
> > 2.21.3
