net/virtio-user: add multiple queues in device emulation

The main purpose of this patch is to enable multi-queue. But
multi-queue requires ctrl-queue so that driver can send how many
queues will be enabled through ctrl-queue messages.

So we partially implement ctrl-queue to handle control command
with class of VIRTIO_NET_CTRL_MQ and with cmd of
VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET to handle mq support. This patch
provides a function, virtio_user_handle_cq(), for driver to handle
ctrl-queue messages.

Besides, multi-queue requires VIRTIO_NET_F_MQ and VIRTIO_NET_F_CTRL_VQ
are enabled when we do feature negotiation.

Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index c4ba437..3d12a32 100644 (file)
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -131,11 +131,14 @@ virtio_user_start_device(struct virtio_user_dev *dev)
                }
        }
 
-       /* After setup all virtqueues, we need to set_features so that
-        * these features can be set into each virtqueue in vhost side.
-        * And before that, make sure VIRTIO_NET_F_MAC is stripped.
+       /* After setup all virtqueues, we need to set_features so that these
+        * features can be set into each virtqueue in vhost side. And before
+        * that, make sure VHOST_USER_F_PROTOCOL_FEATURES is added if mq is
+        * enabled, and VIRTIO_NET_F_MAC is stripped.
         */
        features = dev->features;
+       if (dev->max_queue_pairs > 1)
+               features |= VHOST_USER_MQ;
        features &= ~(1ull << VIRTIO_NET_F_MAC);
        ret = vhost_user_sock(dev->vhostfd, VHOST_USER_SET_FEATURES, &features);
        if (ret < 0)
@@ -185,8 +188,6 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
        dev->mac_specified = 0;
        parse_mac(dev, mac);
        dev->vhostfd = -1;
-       /* TODO: cq */
-       RTE_SET_USED(cq);
 
        dev->vhostfd = vhost_user_setup(dev->path);
        if (dev->vhostfd < 0) {
@@ -205,9 +206,31 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
        }
        if (dev->mac_specified)
                dev->features |= (1ull << VIRTIO_NET_F_MAC);
-       /* disable it until we support CQ */
-       dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
-       dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_RX);
+
+       if (!cq) {
+               dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
+               /* Also disable features depends on VIRTIO_NET_F_CTRL_VQ */
+               dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_RX);
+               dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_VLAN);
+               dev->features &= ~(1ull << VIRTIO_NET_F_GUEST_ANNOUNCE);
+               dev->features &= ~(1ull << VIRTIO_NET_F_MQ);
+               dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_MAC_ADDR);
+       } else {
+               /* vhost user backend does not need to know ctrl-q, so
+                * actually we need add this bit into features. However,
+                * DPDK vhost-user does send features with this bit, so we
+                * check it instead of OR it for now.
+                */
+               if (!(dev->features & (1ull << VIRTIO_NET_F_CTRL_VQ)))
+                       PMD_INIT_LOG(INFO, "vhost does not support ctrl-q");
+       }
+
+       if (dev->max_queue_pairs > 1) {
+               if (!(dev->features & VHOST_USER_MQ)) {
+                       PMD_INIT_LOG(ERR, "MQ not supported by the backend");
+                       return -1;
+               }
+       }
 
        return 0;
 }
@@ -224,3 +247,87 @@ virtio_user_dev_uninit(struct virtio_user_dev *dev)
 
        close(dev->vhostfd);
 }
+
+static uint8_t
+virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs)
+{
+       uint16_t i;
+       uint8_t ret = 0;
+
+       if (q_pairs > dev->max_queue_pairs) {
+               PMD_INIT_LOG(ERR, "multi-q config %u, but only %u supported",
+                            q_pairs, dev->max_queue_pairs);
+               return -1;
+       }
+
+       for (i = 0; i < q_pairs; ++i)
+               ret |= vhost_user_enable_queue_pair(dev->vhostfd, i, 1);
+       for (i = q_pairs; i < dev->max_queue_pairs; ++i)
+               ret |= vhost_user_enable_queue_pair(dev->vhostfd, i, 0);
+
+       dev->queue_pairs = q_pairs;
+
+       return ret;
+}
+
+static uint32_t
+virtio_user_handle_ctrl_msg(struct virtio_user_dev *dev, struct vring *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 = vring->desc[idx_hdr].next;
+       n_descs++;
+
+       i = idx_data;
+       while (vring->desc[i].flags == VRING_DESC_F_NEXT) {
+               i = vring->desc[i].next;
+               n_descs++;
+       }
+
+       /* locate desc for status */
+       idx_status = i;
+       n_descs++;
+
+       hdr = (void *)(uintptr_t)vring->desc[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[idx_data].addr;
+               status = virtio_user_handle_mq(dev, queues);
+       }
+
+       /* Update status */
+       *(virtio_net_ctrl_ack *)(uintptr_t)vring->desc[idx_status].addr = status;
+
+       return n_descs;
+}
+
+void
+virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx)
+{
+       uint16_t avail_idx, desc_idx;
+       struct vring_used_elem *uep;
+       uint32_t n_descs;
+       struct vring *vring = &dev->vrings[queue_idx];
+
+       /* Consume avail ring, using used ring idx as first one */
+       while (vring->used->idx != vring->avail->idx) {
+               avail_idx = (vring->used->idx) & (vring->num - 1);
+               desc_idx = vring->avail->ring[avail_idx];
+
+               n_descs = virtio_user_handle_ctrl_msg(dev, vring, desc_idx);
+
+               /* Update used ring */
+               uep = &vring->used->ring[avail_idx];
+               uep->id = avail_idx;
+               uep->len = n_descs;
+
+               vring->used->idx++;
+       }
+}

diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
index 68bee37..33690b5 100644 (file)
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
@@ -58,5 +58,5 @@ int virtio_user_stop_device(struct virtio_user_dev *dev);
 int virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
                         int cq, int queue_size, const char *mac);
 void virtio_user_dev_uninit(struct virtio_user_dev *dev);
-
+void virtio_user_handle_cq(struct virtio_user_dev *dev, uint16_t queue_idx);
 #endif