[dpdk-dev] [PATCH] vhost: fix wait for valid descriptor
Tan, Jianfeng
jianfeng.tan at intel.com
Sun Feb 11 05:21:20 CET 2018
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Tomasz Kulasek
> Sent: Saturday, February 10, 2018 1:35 AM
> To: yliu at fridaylinux.org
> Cc: dev at dpdk.org; yuanhan.liu at linux.intel.com; stable at dpdk.org; Liu,
> Changpeng
> Subject: [dpdk-dev] [PATCH] vhost: fix wait for valid descriptor
>
> For each virt queue's kickfd and callfd, there are 2 invalid
> status: VIRTIO_UNINITIALIZED_EVENTFD and VIRTIO_INVALID_EVENTFD.
> Don't set the virt queue to ready status until got the valid
> descriptor.
Cannot remember why we introduce two invalid status.
If we treat "VIRTIO_INVALID_EVENTFD" as an indicator to judge if device is ready, then defining one status (invalid) is enough.
Thanks,
Jianfeng
>
> This is safe for polling mode drivers in Guest OS, the backend
> vhost process will not post notification to interrupt vector for
> PMD mode in guest, but the interrupt vector still valid.
>
> Fixes: e049ca6d10e0 ("vhost-user: prepare multiple queue setup")
> Cc: yuanhan.liu at linux.intel.com
> Cc: stable at dpdk.org
>
> Signed-off-by: Changpeng Liu <changpeng.liu at intel.com>
> Signed-off-by: Tomasz Kulasek <tomaszx.kulasek at intel.com>
> ---
> lib/librte_vhost/vhost_user.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 65ee33919..4508f697b 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -766,7 +766,9 @@ vq_is_ready(struct vhost_virtqueue *vq)
> {
> return vq && vq->desc && vq->avail && vq->used &&
> vq->kickfd != VIRTIO_UNINITIALIZED_EVENTFD &&
> - vq->callfd != VIRTIO_UNINITIALIZED_EVENTFD;
> + vq->callfd != VIRTIO_UNINITIALIZED_EVENTFD &&
> + vq->kickfd != VIRTIO_INVALID_EVENTFD &&
> + vq->callfd != VIRTIO_INVALID_EVENTFD;
> }
>
> static int
> --
> 2.14.1
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