[dpdk-dev] [RFC] virtio-user: ctrl vq support for packed

[Jens Freimann]

This adds support to virtio-user for control virtqueues
and reverts commit "5e4e7a752 net/virtio-user: fail if
cq used with packed vq".

I add a struct virtio_user_queue to have a place for wrap
counters and avail/used index (which is not needed for split
ring because it has those in shared memory).

This is a RFC because it only supports in-order use of descriptors
in the ring. I'm looking for ideas how to change this without the
.next field in the descriptor as we have it with split virtqueues.

Signed-off-by: Jens Freimann <jfreimann at redhat.com>
---
 drivers/net/virtio/virtio_ethdev.c            |  11 +-
 .../net/virtio/virtio_user/virtio_user_dev.c  | 101 ++++++++++++++++--
 .../net/virtio/virtio_user/virtio_user_dev.h  |  14 ++-
 drivers/net/virtio/virtio_user_ethdev.c       |  25 ++++-
 4 files changed, 135 insertions(+), 16 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 446c338fc..010ab6489 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -153,6 +153,7 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 	uint16_t flags;
 	int sum = 0;
 	int k;
+	int ndescs = 0;
 
 	/*
 	 * Format is enforced in qemu code:
@@ -162,7 +163,6 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 	 */
 	head = vq->vq_avail_idx;
 	wrap_counter = vq->avail_wrap_counter;
-	desc[head].flags = VRING_DESC_F_NEXT;
 	desc[head].addr = cvq->virtio_net_hdr_mem;
 	desc[head].len = sizeof(struct virtio_net_ctrl_hdr);
 	vq->vq_free_cnt--;
@@ -170,6 +170,7 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 		vq->vq_avail_idx -= vq->vq_nentries;
 		vq->avail_wrap_counter ^= 1;
 	}
+	ndescs++;
 
 	for (k = 0; k < pkt_num; k++) {
 		desc[vq->vq_avail_idx].addr = cvq->virtio_net_hdr_mem
@@ -188,6 +189,7 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 			vq->vq_avail_idx -= vq->vq_nentries;
 			vq->avail_wrap_counter ^= 1;
 		}
+		ndescs++;
 	}
 
 
@@ -198,6 +200,7 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 	flags |= VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
 		 VRING_DESC_F_USED(!vq->avail_wrap_counter);
 	desc[vq->vq_avail_idx].flags = flags;
+
 	flags = VRING_DESC_F_NEXT;
 	flags |= VRING_DESC_F_AVAIL(wrap_counter) |
 		 VRING_DESC_F_USED(!wrap_counter);
@@ -209,6 +212,7 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 		vq->vq_avail_idx -= vq->vq_nentries;
 		vq->avail_wrap_counter ^= 1;
 	}
+	ndescs++;
 
 	virtqueue_notify(vq);
 
@@ -220,8 +224,9 @@ virtio_pq_send_command(struct virtnet_ctl *cvq, struct virtio_pmd_ctrl *ctrl,
 
 	/* now get used descriptors */
 	while (desc_is_used(&desc[vq->vq_used_cons_idx], vq)) {
-		vq->vq_free_cnt++;
-		if (++vq->vq_used_cons_idx >= vq->vq_nentries) {
+		vq->vq_free_cnt += ndescs;
+		vq->vq_used_cons_idx += ndescs;
+		if (vq->vq_used_cons_idx >= vq->vq_nentries) {
 			vq->vq_used_cons_idx -= vq->vq_nentries;
 			vq->used_wrap_counter ^= 1;
 		}
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 5560bd9a3..b324d4391 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -43,15 +43,26 @@ virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
 	struct vhost_vring_file file;
 	struct vhost_vring_state state;
 	struct vring *vring = &dev->vrings[queue_sel];
+	struct vring_packed *pq_vring = &dev->packed_vrings[queue_sel];
 	struct vhost_vring_addr addr = {
 		.index = queue_sel,
-		.desc_user_addr = (uint64_t)(uintptr_t)vring->desc,
-		.avail_user_addr = (uint64_t)(uintptr_t)vring->avail,
-		.used_user_addr = (uint64_t)(uintptr_t)vring->used,
 		.log_guest_addr = 0,
 		.flags = 0, /* disable log */
 	};
 
+	if (dev->features & (1ULL << VIRTIO_F_RING_PACKED)) {
+		addr.desc_user_addr =
+			(uint64_t)(uintptr_t)pq_vring->desc_packed;
+		addr.avail_user_addr =
+			(uint64_t)(uintptr_t)pq_vring->driver_event;
+		addr.used_user_addr =
+			(uint64_t)(uintptr_t)pq_vring->device_event;
+	} else {
+		addr.desc_user_addr = (uint64_t)(uintptr_t)vring->desc;
+		addr.avail_user_addr = (uint64_t)(uintptr_t)vring->avail;
+		addr.used_user_addr = (uint64_t)(uintptr_t)vring->used;
+	}
+
 	state.index = queue_sel;
 	state.num = vring->num;
 	dev->ops->send_request(dev, VHOST_USER_SET_VRING_NUM, &state);
@@ -468,16 +479,10 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
 	if (!in_order)
 		dev->unsupported_features |= (1ull << VIRTIO_F_IN_ORDER);
 
-	if (packed_vq) {
-		if (cq) {
-			PMD_INIT_LOG(ERR, "control vq not supported yet with "
-					  "packed virtqueues\n");
-			return -1;
-		}
+	if (packed_vq)
 		dev->device_features |= (1ull << VIRTIO_F_RING_PACKED);
-	} else {
+	else
 		dev->device_features &= ~(1ull << VIRTIO_F_RING_PACKED);
-	}
 
 	if (dev->mac_specified) {
 		dev->device_features |= (1ull << VIRTIO_NET_F_MAC);
@@ -624,6 +629,80 @@ virtio_user_handle_ctrl_msg(struct virtio_user_dev *dev, struct vring *vring,
 	return n_descs;
 }
 
+static inline int
+desc_is_avail(struct vring_packed_desc *desc, bool wrap_counter)
+{
+	return wrap_counter == !!(desc->flags & VRING_DESC_F_AVAIL(1)) &&
+		wrap_counter != !!(desc->flags & VRING_DESC_F_USED(1));
+}
+
+static uint32_t
+virtio_user_handle_ctrl_msg_pq(struct virtio_user_dev *dev,
+			    struct vring_packed *vring,
+			    uint16_t idx_hdr)
+{
+	struct virtio_net_ctrl_hdr *hdr;
+	virtio_net_ctrl_ack status = ~0;
+	uint16_t i, idx_data, idx_status;
+	uint32_t n_descs = 0;
+
+	/* locate desc for header, data, and status */
+	idx_data = idx_hdr + 1;
+	n_descs++;
+
+	i = idx_data;
+	while (vring->desc_packed[i].flags & VRING_DESC_F_NEXT) {
+		i++;
+		n_descs++;
+	}
+
+	/* locate desc for status */
+	idx_status = i;
+	n_descs++;
+
+	hdr = (void *)(uintptr_t)vring->desc_packed[idx_hdr].addr;
+	if (hdr->class == VIRTIO_NET_CTRL_MQ &&
+	    hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
+		uint16_t queues;
+
+		queues = *(uint16_t *)(uintptr_t)vring->desc_packed[idx_data].addr;
+		status = virtio_user_handle_mq(dev, queues);
+	}
+
+	/* Update status */
+	*(virtio_net_ctrl_ack *)(uintptr_t)vring->desc_packed[idx_status].addr = status;
+
+	return n_descs;
+}
+
+void
+virtio_user_handle_cq_packed(struct virtio_user_dev *dev, uint16_t queue_idx)
+{
+	struct virtio_user_queue *vq = &dev->queues[queue_idx];
+	struct vring_packed *vring = &dev->packed_vrings[queue_idx];
+	uint16_t id, n_descs;
+	bool wrap_counter = vq->used_wrap_counter;
+
+	while (desc_is_avail(&vring->desc_packed[vq->used_idx],
+			     vq->avail_wrap_counter)) {
+		id = vring->desc_packed[vq->used_idx].id;
+
+		n_descs = virtio_user_handle_ctrl_msg_pq(dev, vring, id);
+
+		vring->desc_packed[vq->used_idx].len = n_descs;
+		vring->desc_packed[vq->used_idx].id = vq->used_idx;
+		vq->used_idx += n_descs;
+		if (vq->used_idx >= dev->queue_size) {
+			vq->used_idx -= dev->queue_size;
+			vq->used_wrap_counter ^= 1;
+		}
+	}
+	desc->flags |= VRING_DESC_F_AVAIL(wrap_counter) |
+		       VRING_DESC_F_USED(wrap_counter);
+
+	vq->avail_idx = vq->used_idx;
+}
+
 void
 virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx)
 {
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
index 672a8161a..26a3c6148 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
@@ -11,6 +11,12 @@
 #include "../virtio_ring.h"
 #include "vhost.h"
 
+struct virtio_user_queue {
+	uint16_t avail_idx, used_idx;
+	uint16_t used_wrap_counter;
+	uint16_t avail_wrap_counter;
+};
+
 struct virtio_user_dev {
 	/* for vhost_user backend */
 	int		vhostfd;
@@ -39,7 +45,12 @@ struct virtio_user_dev {
 	uint16_t	port_id;
 	uint8_t		mac_addr[ETHER_ADDR_LEN];
 	char		path[PATH_MAX];
-	struct vring	vrings[VIRTIO_MAX_VIRTQUEUES];
+	union {
+		struct vring		vrings[VIRTIO_MAX_VIRTQUEUES];
+		struct vring_packed	packed_vrings[VIRTIO_MAX_VIRTQUEUES];
+	};
+	struct virtio_user_queue queues[VIRTIO_MAX_VIRTQUEUES];
+
 	struct virtio_user_backend_ops *ops;
 	pthread_mutex_t	mutex;
 	bool		started;
@@ -53,5 +64,6 @@ int virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
 			 int mrg_rxbuf, int in_order, int packed_vq);
 void virtio_user_dev_uninit(struct virtio_user_dev *dev);
 void virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx);
+void virtio_user_handle_cq_packed(struct virtio_user_dev *dev, uint16_t queue_idx);
 uint8_t virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs);
 #endif
diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
index af2800605..854a01d98 100644
--- a/drivers/net/virtio/virtio_user_ethdev.c
+++ b/drivers/net/virtio/virtio_user_ethdev.c
@@ -277,6 +277,26 @@ virtio_user_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
 	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
 	uint16_t queue_idx = vq->vq_queue_index;
 	uint64_t desc_addr, avail_addr, used_addr;
+	struct virtio_user_queue *vq_user = &dev->queues[queue_idx];
+
+	if (vtpci_packed_queue(hw)) {
+		desc_addr = (uintptr_t)vq->vq_ring_virt_mem;
+		avail_addr = desc_addr + vq->vq_nentries *
+			sizeof(struct vring_packed_desc);
+		used_addr = RTE_ALIGN_CEIL(avail_addr +
+				   sizeof(struct vring_packed_desc_event),
+				   VIRTIO_PCI_VRING_ALIGN);
+		dev->packed_vrings[queue_idx].num = vq->vq_nentries;
+		dev->packed_vrings[queue_idx].desc_packed =
+			(void *)(uintptr_t)desc_addr;
+		dev->packed_vrings[queue_idx].driver_event =
+			(void *)(uintptr_t)avail_addr;
+		dev->packed_vrings[queue_idx].device_event =
+			(void*)(uintptr_t)used_addr;
+		vq_user->avail_wrap_counter = true;
+		vq_user->used_wrap_counter = true;
+		return 0;
+	}
 
 	desc_addr = (uintptr_t)vq->vq_ring_virt_mem;
 	avail_addr = desc_addr + vq->vq_nentries * sizeof(struct vring_desc);
@@ -317,7 +337,10 @@ virtio_user_notify_queue(struct virtio_hw *hw, struct virtqueue *vq)
 	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
 
 	if (hw->cvq && (hw->cvq->vq == vq)) {
-		virtio_user_handle_cq(dev, vq->vq_queue_index);
+		if (vtpci_packed_queue(vq->hw))
+			virtio_user_handle_cq_packed(dev, vq->vq_queue_index);
+		else
+			virtio_user_handle_cq(dev, vq->vq_queue_index);
 		return;
 	}
 
-- 
2.17.2