[dpdk-dev] [PATCH] vhost: Fix default value of kickfd and callfd

[Tetsuya Mukawa]

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);
-               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;
-- 
2.1.4