[dpdk-dev] [PATCH] vhost: Fix default value of kickfd and callfd
Tan, Jianfeng
jianfeng.tan at intel.com
Thu Mar 10 07:25:09 CET 2016
On 3/10/2016 2:14 PM, Tetsuya Mukawa wrote:
> Currently, default value of kickfd and callfd is -1.
> If the value is -1, current code guess kickfd and callfd hasn't been
> initialized yet. And vhost library will guess the virtqueue isn't ready
> for processing.
> But callfd and kickfd will be set as -1 when "--enable-kvm"
> isn't specified in QEMU command line. It means we cannot treat -1 as
> uninitialized state. The patch changes default value to -2. And the
> patch defines -2 as VIRTIO_UNINITIALIZED_EVENTFD.
>
> Signed-off-by: Tetsuya Mukawa <mukawa at igel.co.jp>
> ---
> lib/librte_vhost/rte_virtio_net.h | 1 +
> lib/librte_vhost/vhost_user/virtio-net-user.c | 7 ++++---
> lib/librte_vhost/virtio-net.c | 4 ++--
> 3 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
> index 7d1fde2..d745707 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -89,6 +89,7 @@ struct vhost_virtqueue {
> uint16_t vhost_hlen; /**< Vhost header length (varies depending on RX merge buffers. */
> volatile uint16_t last_used_idx; /**< Last index used on the available ring */
> volatile uint16_t last_used_idx_res; /**< Used for multiple devices reserving buffers. */
> +#define VIRTIO_UNINITIALIZED_EVENTFD (-2)
> int callfd; /**< Used to notify the guest (trigger interrupt). */
> int kickfd; /**< Currently unused as polling mode is enabled. */
> int enabled;
> diff --git a/lib/librte_vhost/vhost_user/virtio-net-user.c b/lib/librte_vhost/vhost_user/virtio-net-user.c
> index 65b5652..591f9bf 100644
> --- a/lib/librte_vhost/vhost_user/virtio-net-user.c
> +++ b/lib/librte_vhost/vhost_user/virtio-net-user.c
> @@ -225,8 +225,8 @@ static int
> vq_is_ready(struct vhost_virtqueue *vq)
> {
> return vq && vq->desc &&
> - vq->kickfd != -1 &&
> - vq->callfd != -1;
> + vq->kickfd != VIRTIO_UNINITIALIZED_EVENTFD &&
> + vq->callfd != VIRTIO_UNINITIALIZED_EVENTFD;
> }
>
> static int
> @@ -318,7 +318,8 @@ user_get_vring_base(struct vhost_device_ctx ctx,
> */
> if (dev->virtqueue[state->index]->kickfd >= 0) {
> close(dev->virtqueue[state->index]->kickfd);
Then -1 will be a valid value, need to check if it's not -1 to close()?
Nevertheless, close(-1) brings no big problem.
Thanks,
Jianfeng
> - dev->virtqueue[state->index]->kickfd = -1;
> + dev->virtqueue[state->index]->kickfd =
> + VIRTIO_UNINITIALIZED_EVENTFD;
> }
>
> return 0;
> diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
> index fe1a77e..3498e9d 100644
> --- a/lib/librte_vhost/virtio-net.c
> +++ b/lib/librte_vhost/virtio-net.c
> @@ -263,8 +263,8 @@ init_vring_queue(struct vhost_virtqueue *vq, int qp_idx)
> {
> memset(vq, 0, sizeof(struct vhost_virtqueue));
>
> - vq->kickfd = -1;
> - vq->callfd = -1;
> + vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
> + vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
>
> /* Backends are set to -1 indicating an inactive device. */
> vq->backend = -1;
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