[dpdk-dev] [PATCH v2] vhost: Fix default value of kickfd and callfd

[Tetsuya Mukawa <mukawa@igel.co.jp>]

Currently, default values of kickfd and callfd are -1.
If the values are -1, current code guesses kickfd and callfd haven'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 values to -2. And the
patch defines -2 as VIRTIO_UNINITIALIZED_EVENTFD.

Signed-off-by: Tetsuya Mukawa <mukawa@igel.co.jp>
---
 lib/librte_vhost/rte_virtio_net.h             |  1 +
 lib/librte_vhost/vhost_user/virtio-net-user.c | 10 +++++-----
 lib/librte_vhost/virtio-net.c                 |  4 ++--
 3 files changed, 8 insertions(+), 7 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..4c156a6 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
@@ -316,10 +316,10 @@ user_get_vring_base(struct vhost_device_ctx ctx,
 	 * sent and only sent in vhost_vring_stop.
 	 * TODO: cleanup the vring, it isn't usable since here.
 	 */
-	if (dev->virtqueue[state->index]->kickfd >= 0) {
+	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