rte_vhost: introduce get/set vring base idx APIs

Adapted our custom rte_vhost APIs to the upstream DPDK
version which has independently added similar APIs.
This will potentially allow us to remove our internal
rte_vhost copy.

rte_vhost_set_vhost_vring_last_idx() was renamed to
rte_vhost_set_vring_base() and the last vring indices
have to be acquired with a newly introduced rte_vhost_get_vring_base()
rather than rte_vhost_get_vhost_vring().

This is only a refactor, no functionality is changed.

Change-Id: I1ca2c1216635c117832c9d9c784d5661145c04cd
Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/446081
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

lib/vhost/rte_vhost/rte_vhost.h

@@ -83,9 +83,6 @@ struct rte_vhost_vring {
 	int			callfd;
 	int			kickfd;
 	uint16_t		size;
-
-	uint16_t		last_avail_idx;
-	uint16_t		last_used_idx;
 };
 
 /**
@@ -469,7 +466,10 @@ int rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
  * @return
  *  0 on success, -1 on failure
  */
-int rte_vhost_set_vhost_vring_last_idx(int vid, uint16_t vring_idx,
+int rte_vhost_set_vring_base(int vid, uint16_t queue_id,
-			      uint16_t last_avail_idx, uint16_t last_used_idx);
+		uint16_t last_avail_idx, uint16_t last_used_idx);
+
+int rte_vhost_get_vring_base(int vid, uint16_t queue_id,
+		uint16_t *last_avail_idx, uint16_t *last_used_idx);
 
 #endif /* _RTE_VHOST_H_ */

lib/vhost/rte_vhost/vhost.c

@@ -386,9 +386,6 @@ rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
 	vring->kickfd  = vq->kickfd;
 	vring->size    = vq->size;
 
-	vring->last_avail_idx = vq->last_avail_idx;
-	vring->last_used_idx = vq->last_used_idx;
-
 	return 0;
 }
 
@@ -459,8 +456,9 @@ rte_vhost_log_used_vring(int vid, uint16_t vring_idx,
 }
 
 int
-rte_vhost_set_vhost_vring_last_idx(int vid, uint16_t vring_idx,
+rte_vhost_set_vring_base(int vid, uint16_t vring_idx,
-			      uint16_t last_avail_idx, uint16_t last_used_idx) {
+		uint16_t last_avail_idx, uint16_t last_used_idx)
+{
 	struct virtio_net *dev;
 	struct vhost_virtqueue *vq;
 
@@ -480,3 +478,27 @@ rte_vhost_set_vhost_vring_last_idx(int vid, uint16_t vring_idx,
 
 	return 0;
 }
+
+int
+rte_vhost_get_vring_base(int vid, uint16_t vring_idx,
+		uint16_t *last_avail_idx, uint16_t *last_used_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;
+
+	*last_avail_idx = vq->last_avail_idx;
+	*last_used_idx = vq->last_used_idx;
+
+	return 0;
+}

lib/vhost/vhost.c

@@ -182,7 +182,7 @@ spdk_vhost_vq_avail_ring_get(struct spdk_vhost_virtqueue *virtqueue, uint16_t *r
 	struct rte_vhost_vring *vring = &virtqueue->vring;
 	struct vring_avail *avail = vring->avail;
 	uint16_t size_mask = vring->size - 1;
-	uint16_t last_idx = vring->last_avail_idx, avail_idx = avail->idx;
+	uint16_t last_idx = virtqueue->last_avail_idx, avail_idx = avail->idx;
 	uint16_t count, i;
 
 	count = avail_idx - last_idx;
@@ -198,7 +198,7 @@ spdk_vhost_vq_avail_ring_get(struct spdk_vhost_virtqueue *virtqueue, uint16_t *r
 	}
 
 	count = spdk_min(count, reqs_len);
-	vring->last_avail_idx += count;
+	virtqueue->last_avail_idx += count;
 	for (i = 0; i < count; i++) {
 		reqs[i] = vring->avail->ring[(last_idx + i) & size_mask];
 	}
@@ -259,7 +259,7 @@ spdk_vhost_vq_used_signal(struct spdk_vhost_session *vsession,
 
 	SPDK_DEBUGLOG(SPDK_LOG_VHOST_RING,
 		      "Queue %td - USED RING: sending IRQ: last used %"PRIu16"\n",
-		      virtqueue - vsession->virtqueue, virtqueue->vring.last_used_idx);
+		      virtqueue - vsession->virtqueue, virtqueue->last_used_idx);
 
 	eventfd_write(virtqueue->vring.callfd, (eventfd_t)1);
 	return 1;
@@ -401,15 +401,15 @@ spdk_vhost_vq_used_ring_enqueue(struct spdk_vhost_session *vsession,
 {
 	struct rte_vhost_vring *vring = &virtqueue->vring;
 	struct vring_used *used = vring->used;
-	uint16_t last_idx = vring->last_used_idx & (vring->size - 1);
+	uint16_t last_idx = virtqueue->last_used_idx & (vring->size - 1);
 
 	SPDK_DEBUGLOG(SPDK_LOG_VHOST_RING,
 		      "Queue %td - USED RING: last_idx=%"PRIu16" req id=%"PRIu16" len=%"PRIu32"\n",
-		      virtqueue - vsession->virtqueue, vring->last_used_idx, id, len);
+		      virtqueue - vsession->virtqueue, virtqueue->last_used_idx, id, len);
 
 	spdk_vhost_log_req_desc(vsession, virtqueue, id);
 
-	vring->last_used_idx++;
+	virtqueue->last_used_idx++;
 	used->ring[last_idx].id = id;
 	used->ring[last_idx].len = len;
 
@@ -417,7 +417,7 @@ spdk_vhost_vq_used_ring_enqueue(struct spdk_vhost_session *vsession,
 	spdk_smp_wmb();
 
 	spdk_vhost_log_used_vring_elem(vsession, virtqueue, last_idx);
-	* (volatile uint16_t *) &used->idx = vring->last_used_idx;
+	* (volatile uint16_t *) &used->idx = virtqueue->last_used_idx;
 	spdk_vhost_log_used_vring_idx(vsession, virtqueue);
 
 	/* Ensure all our used ring changes are visible to the guest at the time
@@ -999,7 +999,7 @@ stop_device(int vid)
 {
 	struct spdk_vhost_dev *vdev;
 	struct spdk_vhost_session *vsession;
-	struct rte_vhost_vring *q;
+	struct spdk_vhost_virtqueue *q;
 	int rc;
 	uint16_t i;
 
@@ -1026,11 +1026,11 @@ stop_device(int vid)
 	}
 
 	for (i = 0; i < vsession->max_queues; i++) {
-		q = &vsession->virtqueue[i].vring;
+		q = &vsession->virtqueue[i];
-		if (q->desc == NULL) {
+		if (q->vring.desc == NULL) {
 			continue;
 		}
-		rte_vhost_set_vhost_vring_last_idx(vsession->vid, i, q->last_avail_idx, q->last_used_idx);
+		rte_vhost_set_vring_base(vsession->vid, i, q->last_avail_idx, q->last_used_idx);
 	}
 
 	spdk_vhost_session_mem_unregister(vsession);
@@ -1066,12 +1066,18 @@ start_device(int vid)
 	vsession->max_queues = 0;
 	memset(vsession->virtqueue, 0, sizeof(vsession->virtqueue));
 	for (i = 0; i < SPDK_VHOST_MAX_VQUEUES; i++) {
-		if (rte_vhost_get_vhost_vring(vid, i, &vsession->virtqueue[i].vring)) {
+		struct spdk_vhost_virtqueue *q = &vsession->virtqueue[i];
+
+		if (rte_vhost_get_vhost_vring(vid, i, &q->vring)) {
 			continue;
 		}
 
-		if (vsession->virtqueue[i].vring.desc == NULL ||
+		if (q->vring.desc == NULL || q->vring.size == 0) {
-		    vsession->virtqueue[i].vring.size == 0) {
+			continue;
+		}
+
+		if (rte_vhost_get_vring_base(vsession->vid, i, &q->last_avail_idx, &q->last_used_idx)) {
+			q->vring.desc = NULL;
 			continue;
 		}
 

lib/vhost/vhost_internal.h

@@ -95,6 +95,9 @@
 
 struct spdk_vhost_virtqueue {
 	struct rte_vhost_vring vring;
+	uint16_t last_avail_idx;
+	uint16_t last_used_idx;
+
 	void *tasks;
 
 	/* Request count from last stats check */

lib/vhost/vhost_scsi.c

@@ -415,7 +415,7 @@ process_ctrl_request(struct spdk_vhost_scsi_task *task)
 
 	SPDK_DEBUGLOG(SPDK_LOG_VHOST_SCSI_QUEUE,
 		      "Processing controlq descriptor: desc %d/%p, desc_addr %p, len %d, flags %d, last_used_idx %d; kickfd %d; size %d\n",
-		      task->req_idx, desc, (void *)desc->addr, desc->len, desc->flags, task->vq->vring.last_used_idx,
+		      task->req_idx, desc, (void *)desc->addr, desc->len, desc->flags, task->vq->last_used_idx,
 		      task->vq->vring.kickfd, task->vq->vring.size);
 	SPDK_LOGDUMP(SPDK_LOG_VHOST_SCSI_QUEUE, "Request descriptor", (uint8_t *)ctrl_req, desc->len);
 

test/unit/lib/vhost/vhost.c/vhost_ut.c

@@ -42,6 +42,10 @@
 
 #include "vhost/vhost.c"
 
+DEFINE_STUB(rte_vhost_set_vring_base, int, (int vid, uint16_t queue_id,
+		uint16_t last_avail_idx, uint16_t last_used_idx), 0);
+DEFINE_STUB(rte_vhost_get_vring_base, int, (int vid, uint16_t queue_id,
+		uint16_t *last_avail_idx, uint16_t *last_used_idx), 0);
 DEFINE_STUB(rte_vhost_driver_unregister, int, (const char *path), 0);
 DEFINE_STUB(spdk_event_allocate, struct spdk_event *,
 	    (uint32_t lcore, spdk_event_fn fn, void *arg1, void *arg2), NULL);
@@ -96,8 +100,6 @@ DEFINE_STUB(spdk_vhost_nvme_admin_passthrough, int, (int vid, void *cmd, void *c
 DEFINE_STUB(spdk_vhost_nvme_set_cq_call, int, (int vid, uint16_t qid, int fd), 0);
 DEFINE_STUB(spdk_vhost_nvme_set_bar_mr, int, (int vid, void *bar, uint64_t bar_size), 0);
 DEFINE_STUB(spdk_vhost_nvme_get_cap, int, (int vid, uint64_t *cap), 0);
-DEFINE_STUB(rte_vhost_set_vhost_vring_last_idx, int,
-	    (int vid, uint16_t vring_idx, uint16_t last_avail_idx, uint16_t last_used_idx), 0);
 
 void *
 spdk_call_unaffinitized(void *cb(void *arg), void *arg)