[dpdk-dev] [PATCH v4 02/12] vhost: support multiple queues in virtio dev
Yuanhan Liu
yuanhan.liu at linux.intel.com
Wed Aug 19 05:52:44 CEST 2015
Hi Changchun,
On Wed, Aug 12, 2015 at 04:02:37PM +0800, Ouyang Changchun wrote:
> Each virtio device could have multiple queues, say 2 or 4, at most 8.
> Enabling this feature allows virtio device/port on guest has the ability to
> use different vCPU to receive/transmit packets from/to each queue.
>
> In multiple queues mode, virtio device readiness means all queues of
> this virtio device are ready, cleanup/destroy a virtio device also
> requires clearing all queues belong to it.
>
> Signed-off-by: Changchun Ouyang <changchun.ouyang at intel.com>
> ---
[snip ..]
> /*
> + * Initialise all variables in vring queue pair.
> + */
> +static void
> +init_vring_queue_pair(struct virtio_net *dev, uint16_t qp_idx)
> +{
> + uint32_t virt_rx_q_idx = qp_idx * VIRTIO_QNUM + VIRTIO_RXQ;
> + uint32_t virt_tx_q_idx = qp_idx * VIRTIO_QNUM + VIRTIO_TXQ;
> + memset(dev->virtqueue[virt_rx_q_idx], 0, sizeof(struct vhost_virtqueue));
> + memset(dev->virtqueue[virt_tx_q_idx], 0, sizeof(struct vhost_virtqueue));
> +
> + dev->virtqueue[virt_rx_q_idx]->kickfd = (eventfd_t)-1;
> + dev->virtqueue[virt_rx_q_idx]->callfd = (eventfd_t)-1;
> + dev->virtqueue[virt_tx_q_idx]->kickfd = (eventfd_t)-1;
> + dev->virtqueue[virt_tx_q_idx]->callfd = (eventfd_t)-1;
> +
> + /* Backends are set to -1 indicating an inactive device. */
> + dev->virtqueue[virt_rx_q_idx]->backend = VIRTIO_DEV_STOPPED;
> + dev->virtqueue[virt_tx_q_idx]->backend = VIRTIO_DEV_STOPPED;
> +}
> +
> +/*
> * Initialise all variables in device structure.
> */
> static void
> @@ -258,17 +294,34 @@ init_device(struct virtio_net *dev)
> /* Set everything to 0. */
There is a trick here. Let me fill the context first:
283 static void
284 init_device(struct virtio_net *dev)
285 {
286 uint64_t vq_offset;
287
288 /*
289 * Virtqueues have already been malloced so
290 * we don't want to set them to NULL.
291 */
292 vq_offset = offsetof(struct virtio_net, mem);
293
294 /* Set everything to 0. */
295 memset((void *)(uintptr_t)((uint64_t)(uintptr_t)dev + vq_offset), 0,
296 (sizeof(struct virtio_net) - (size_t)vq_offset));
297
298 init_vring_queue_pair(dev, 0);
This piece of code's intention is to memset everything to zero, except
the `virtqueue' field, for, as the comment stated, we have already
allocated virtqueue.
It works only when `virtqueue' field is before `mem' field, and it was
before:
struct virtio_net {
struct vhost_virtqueue *virtqueue[VIRTIO_QNUM]; /**< Contains all virtqueue information. */
struct virtio_memory *mem; /**< QEMU memory and memory region information. */
...
After this patch, it becomes:
struct virtio_net {
struct virtio_memory *mem; /**< QEMU memory and memory region information. */
struct vhost_virtqueue **virtqueue; /**< Contains all virtqueue information. */
...
Which actually wipes all stuff inside `struct virtio_net`, resulting to
setting `virtqueue' to NULL as well.
While reading the code(without you patch applied), I thought that it's
error-prone, as it is very likely that someone else besides the author
doesn't know such undocumented rule. And you just gave me an example :)
Huawei, I'm proposing a fix to call rte_zmalloc() for allocating new_ll_dev
to get rid of such issue. What do you think?
--yliu
> memset((void *)(uintptr_t)((uint64_t)(uintptr_t)dev + vq_offset), 0,
> (sizeof(struct virtio_net) - (size_t)vq_offset));
> - memset(dev->virtqueue[VIRTIO_RXQ], 0, sizeof(struct vhost_virtqueue));
> - memset(dev->virtqueue[VIRTIO_TXQ], 0, sizeof(struct vhost_virtqueue));
>
> - dev->virtqueue[VIRTIO_RXQ]->kickfd = (eventfd_t)-1;
> - dev->virtqueue[VIRTIO_RXQ]->callfd = (eventfd_t)-1;
> - dev->virtqueue[VIRTIO_TXQ]->kickfd = (eventfd_t)-1;
> - dev->virtqueue[VIRTIO_TXQ]->callfd = (eventfd_t)-1;
> + init_vring_queue_pair(dev, 0);
> + dev->virt_qp_nb = 1;
> +}
> +
> +/*
> + * Alloc mem for vring queue pair.
> + */
> +int
> +alloc_vring_queue_pair(struct virtio_net *dev, uint16_t qp_idx)
> +{
> + struct vhost_virtqueue *virtqueue = NULL;
> + uint32_t virt_rx_q_idx = qp_idx * VIRTIO_QNUM + VIRTIO_RXQ;
> + uint32_t virt_tx_q_idx = qp_idx * VIRTIO_QNUM + VIRTIO_TXQ;
>
> - /* Backends are set to -1 indicating an inactive device. */
> - dev->virtqueue[VIRTIO_RXQ]->backend = VIRTIO_DEV_STOPPED;
> - dev->virtqueue[VIRTIO_TXQ]->backend = VIRTIO_DEV_STOPPED;
> + virtqueue = rte_malloc(NULL, sizeof(struct vhost_virtqueue) * VIRTIO_QNUM, 0);
> + if (virtqueue == NULL) {
> + RTE_LOG(ERR, VHOST_CONFIG,
> + "Failed to allocate memory for virt qp:%d.\n", qp_idx);
> + return -1;
> + }
> +
> + dev->virtqueue[virt_rx_q_idx] = virtqueue;
> + dev->virtqueue[virt_tx_q_idx] = virtqueue + VIRTIO_TXQ;
> +
> + init_vring_queue_pair(dev, qp_idx);
> +
> + return 0;
> }
>
> /*
> @@ -280,7 +333,6 @@ static int
> new_device(struct vhost_device_ctx ctx)
> {
> struct virtio_net_config_ll *new_ll_dev;
> - struct vhost_virtqueue *virtqueue_rx, *virtqueue_tx;
>
> /* Setup device and virtqueues. */
> new_ll_dev = rte_malloc(NULL, sizeof(struct virtio_net_config_ll), 0);
> @@ -291,28 +343,22 @@ new_device(struct vhost_device_ctx ctx)
> return -1;
> }
>
> - virtqueue_rx = rte_malloc(NULL, sizeof(struct vhost_virtqueue), 0);
> - if (virtqueue_rx == NULL) {
> - rte_free(new_ll_dev);
> + new_ll_dev->dev.virtqueue =
> + rte_malloc(NULL, VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX * sizeof(struct vhost_virtqueue *), 0);
> + if (new_ll_dev->dev.virtqueue == NULL) {
> RTE_LOG(ERR, VHOST_CONFIG,
> - "(%"PRIu64") Failed to allocate memory for rxq.\n",
> + "(%"PRIu64") Failed to allocate memory for dev.virtqueue.\n",
> ctx.fh);
> + rte_free(new_ll_dev);
> return -1;
> }
>
> - virtqueue_tx = rte_malloc(NULL, sizeof(struct vhost_virtqueue), 0);
> - if (virtqueue_tx == NULL) {
> - rte_free(virtqueue_rx);
> + if (alloc_vring_queue_pair(&new_ll_dev->dev, 0) == -1) {
> + rte_free(new_ll_dev->dev.virtqueue);
> rte_free(new_ll_dev);
> - RTE_LOG(ERR, VHOST_CONFIG,
> - "(%"PRIu64") Failed to allocate memory for txq.\n",
> - ctx.fh);
> return -1;
> }
>
> - new_ll_dev->dev.virtqueue[VIRTIO_RXQ] = virtqueue_rx;
> - new_ll_dev->dev.virtqueue[VIRTIO_TXQ] = virtqueue_tx;
> -
> /* Initialise device and virtqueues. */
> init_device(&new_ll_dev->dev);
>
> @@ -396,7 +442,7 @@ set_owner(struct vhost_device_ctx ctx)
> * Called from CUSE IOCTL: VHOST_RESET_OWNER
> */
> static int
> -reset_owner(struct vhost_device_ctx ctx)
> +reset_owner(__rte_unused struct vhost_device_ctx ctx)
> {
> struct virtio_net_config_ll *ll_dev;
>
> @@ -434,6 +480,7 @@ static int
> set_features(struct vhost_device_ctx ctx, uint64_t *pu)
> {
> struct virtio_net *dev;
> + uint32_t q_idx;
>
> dev = get_device(ctx);
> if (dev == NULL)
> @@ -445,22 +492,26 @@ set_features(struct vhost_device_ctx ctx, uint64_t *pu)
> dev->features = *pu;
>
> /* Set the vhost_hlen depending on if VIRTIO_NET_F_MRG_RXBUF is set. */
> - if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
> - LOG_DEBUG(VHOST_CONFIG,
> - "(%"PRIu64") Mergeable RX buffers enabled\n",
> - dev->device_fh);
> - dev->virtqueue[VIRTIO_RXQ]->vhost_hlen =
> - sizeof(struct virtio_net_hdr_mrg_rxbuf);
> - dev->virtqueue[VIRTIO_TXQ]->vhost_hlen =
> - sizeof(struct virtio_net_hdr_mrg_rxbuf);
> - } else {
> - LOG_DEBUG(VHOST_CONFIG,
> - "(%"PRIu64") Mergeable RX buffers disabled\n",
> - dev->device_fh);
> - dev->virtqueue[VIRTIO_RXQ]->vhost_hlen =
> - sizeof(struct virtio_net_hdr);
> - dev->virtqueue[VIRTIO_TXQ]->vhost_hlen =
> - sizeof(struct virtio_net_hdr);
> + for (q_idx = 0; q_idx < dev->virt_qp_nb; q_idx++) {
> + uint32_t virt_rx_q_idx = q_idx * VIRTIO_QNUM + VIRTIO_RXQ;
> + uint32_t virt_tx_q_idx = q_idx * VIRTIO_QNUM + VIRTIO_TXQ;
> + if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)) {
> + LOG_DEBUG(VHOST_CONFIG,
> + "(%"PRIu64") Mergeable RX buffers enabled\n",
> + dev->device_fh);
> + dev->virtqueue[virt_rx_q_idx]->vhost_hlen =
> + sizeof(struct virtio_net_hdr_mrg_rxbuf);
> + dev->virtqueue[virt_tx_q_idx]->vhost_hlen =
> + sizeof(struct virtio_net_hdr_mrg_rxbuf);
> + } else {
> + LOG_DEBUG(VHOST_CONFIG,
> + "(%"PRIu64") Mergeable RX buffers disabled\n",
> + dev->device_fh);
> + dev->virtqueue[virt_rx_q_idx]->vhost_hlen =
> + sizeof(struct virtio_net_hdr);
> + dev->virtqueue[virt_tx_q_idx]->vhost_hlen =
> + sizeof(struct virtio_net_hdr);
> + }
> }
> return 0;
> }
> @@ -826,6 +877,14 @@ int rte_vhost_feature_enable(uint64_t feature_mask)
> return -1;
> }
>
> +uint16_t rte_vhost_qp_num_get(struct virtio_net *dev)
> +{
> + if (dev == NULL)
> + return 0;
> +
> + return dev->virt_qp_nb;
> +}
> +
> /*
> * Register ops so that we can add/remove device to data core.
> */
> --
> 1.8.4.2
>
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