[PATCH] vdpa/mlx5: Support interrupt bypassing

Dragos Tatulea
Thu, 08 Jun 2023 16:25:55 -0000

On Wed, 2023-06-07 at 22:00 +0300, Dragos Tatulea via Virtualization
wrote:
> From: Eli Cohen <elic at nvidia.com>
>
> Add support for generation of interrupts from the device directly to the
> VM to the VCPU thus avoiding the overhead on the host CPU.
>
> When supported, the driver will attempt to allocate vectors for each
> data virtqueue. If a vector for a virtqueue cannot be provided it will
> use the QP mode where notifications go through the driver.
>
> In addition, we add a shutdown callback to make sure allocated
> interrupts are released in case of shutdown to allow clean shutdown.
>
> Signed-off-by: Eli Cohen <elic at nvidia.com>
> Signed-off-by: Saeed Mahameed <saeedm at nvidia.com>
>
Just realized that this patch should have been marked as a v3. Let me know if I
should resend it.

> ---
> ?drivers/vdpa/mlx5/net/mlx5_vnet.c | 165 ++++++++++++++++++++++++++++--
> ?drivers/vdpa/mlx5/net/mlx5_vnet.h |? 15 +++
> ?2 files changed, 171 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 279ac6a558d2..9138ef2fb2c8 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -83,6 +83,7 @@ struct mlx5_vq_restore_info {
> ????????u64 driver_addr;
> ????????u16 avail_index;
> ????????u16 used_index;
> +???????struct msi_map map;
> ????????bool ready;
> ????????bool restore;
> ?};
> @@ -118,6 +119,7 @@ struct mlx5_vdpa_virtqueue {
> ????????u16 avail_idx;
> ????????u16 used_idx;
> ????????int fw_state;
> +???????struct msi_map map;
> ?
> ????????/* keep last in the struct */
> ????????struct mlx5_vq_restore_info ri;
> @@ -808,6 +810,13 @@ static bool counters_supported(const struct
mlx5_vdpa_dev
> *mvdev)
> ?????????????? BIT_ULL(MLX5_OBJ_TYPE_VIRTIO_Q_COUNTERS);
> ?}
> ?
> +static bool msix_mode_supported(struct mlx5_vdpa_dev *mvdev)
> +{
> +???????return MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, event_mode)
&
> +???????????????(1 << MLX5_VIRTIO_Q_EVENT_MODE_MSIX_MODE) &&
> +???????????????pci_msix_can_alloc_dyn(mvdev->mdev->pdev);
> +}
> +
> ?static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct
> mlx5_vdpa_virtqueue *mvq)
> ?{
> ????????int inlen = MLX5_ST_SZ_BYTES(create_virtio_net_q_in);
> @@ -849,9 +858,15 @@ static int create_virtqueue(struct mlx5_vdpa_net
*ndev,
> struct mlx5_vdpa_virtque
> ????????if (vq_is_tx(mvq->index))
> ????????????????MLX5_SET(virtio_net_q_object, obj_context, tisn_or_qpn,
ndev-
> >res.tisn);
> ?
> -???????MLX5_SET(virtio_q, vq_ctx, event_mode,
> MLX5_VIRTIO_Q_EVENT_MODE_QP_MODE);
> +???????if (mvq->map.virq) {
> +???????????????MLX5_SET(virtio_q, vq_ctx, event_mode,
> MLX5_VIRTIO_Q_EVENT_MODE_MSIX_MODE);
> +???????????????MLX5_SET(virtio_q, vq_ctx, event_qpn_or_msix,
mvq->map.index);
> +???????} else {
> +???????????????MLX5_SET(virtio_q, vq_ctx, event_mode,
> MLX5_VIRTIO_Q_EVENT_MODE_QP_MODE);
> +???????????????MLX5_SET(virtio_q, vq_ctx, event_qpn_or_msix, mvq-
> >fwqp.mqp.qpn);
> +???????}
> +
> ????????MLX5_SET(virtio_q, vq_ctx, queue_index, mvq->index);
> -???????MLX5_SET(virtio_q, vq_ctx, event_qpn_or_msix,
mvq->fwqp.mqp.qpn);
> ????????MLX5_SET(virtio_q, vq_ctx, queue_size, mvq->num_ent);
> ????????MLX5_SET(virtio_q, vq_ctx, virtio_version_1_0,
> ???????????????? !!(ndev->mvdev.actual_features &
> BIT_ULL(VIRTIO_F_VERSION_1)));
> @@ -1194,6 +1209,56 @@ static void counter_set_dealloc(struct mlx5_vdpa_net
> *ndev, struct mlx5_vdpa_vir
> ????????????????mlx5_vdpa_warn(&ndev->mvdev, "dealloc counter
set 0x%x\n",
> mvq->counter_set_id);
> ?}
> ?
> +static irqreturn_t mlx5_vdpa_int_handler(int irq, void *priv)
> +{
> +???????struct vdpa_callback *cb = priv;
> +
> +???????if (cb->callback)
> +???????????????return cb->callback(cb->private);
> +
> +???????return IRQ_HANDLED;
> +}
> +
> +static void alloc_vector(struct mlx5_vdpa_net *ndev,
> +??????????????????????? struct mlx5_vdpa_virtqueue *mvq)
> +{
> +???????struct mlx5_vdpa_irq_pool *irqp = &ndev->irqp;
> +???????struct mlx5_vdpa_irq_pool_entry *ent;
> +???????int err;
> +???????int i;
> +
> +???????for (i = 0; i < irqp->num_ent; i++) {
> +???????????????ent = &irqp->entries[i];
> +???????????????if (!ent->used) {
> +???????????????????????snprintf(ent->name, MLX5_VDPA_IRQ_NAME_LEN,
"%s-vq-
> %d",
> +??????????????????????????????? dev_name(&ndev->mvdev.vdev.dev),
mvq->index);
> +???????????????????????ent->dev_id =
&ndev->event_cbs[mvq->index];
> +???????????????????????err = request_irq(ent->map.virq,
> mlx5_vdpa_int_handler, 0,
> +???????????????????????????????????????? ent->name, ent->dev_id);
> +???????????????????????if (err)
> +???????????????????????????????return;
> +
> +???????????????????????ent->used = true;
> +???????????????????????mvq->map = ent->map;
> +???????????????????????return;
> +???????????????}
> +???????}
> +}
> +
> +static void dealloc_vector(struct mlx5_vdpa_net *ndev,
> +????????????????????????? struct mlx5_vdpa_virtqueue *mvq)
> +{
> +???????struct mlx5_vdpa_irq_pool *irqp = &ndev->irqp;
> +???????int i;
> +
> +???????for (i = 0; i < irqp->num_ent; i++)
> +???????????????if (mvq->map.virq == irqp->entries[i].map.virq) {
> +???????????????????????free_irq(mvq->map.virq,
irqp->entries[i].dev_id);
> +???????????????????????irqp->entries[i].used = false;
> +???????????????????????return;
> +???????????????}
> +}
> +
> ?static int setup_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue
> *mvq)
> ?{
> ????????u16 idx = mvq->index;
> @@ -1223,27 +1288,31 @@ static int setup_vq(struct mlx5_vdpa_net *ndev,
struct
> mlx5_vdpa_virtqueue *mvq)
> ?
> ????????err = counter_set_alloc(ndev, mvq);
> ????????if (err)
> -???????????????goto err_counter;
> +???????????????goto err_connect;
> ?
> +???????alloc_vector(ndev, mvq);
> ????????err = create_virtqueue(ndev, mvq);
> ????????if (err)
> -???????????????goto err_connect;
> +???????????????goto err_vq;
> ?
> ????????if (mvq->ready) {
> ????????????????err = modify_virtqueue(ndev, mvq,
> MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY);
> ????????????????if (err) {
> ????????????????????????mlx5_vdpa_warn(&ndev->mvdev, "failed to
modify to
> ready vq idx %d(%d)\n",
> ?????????????????????????????????????? idx, err);
> -???????????????????????goto err_connect;
> +???????????????????????goto err_modify;
> ????????????????}
> ????????}
> ?
> ????????mvq->initialized = true;
> ????????return 0;
> ?
> -err_connect:
> +err_modify:
> +???????destroy_virtqueue(ndev, mvq);
> +err_vq:
> +???????dealloc_vector(ndev, mvq);
> ????????counter_set_dealloc(ndev, mvq);
> -err_counter:
> +err_connect:
> ????????qp_destroy(ndev, &mvq->vqqp);
> ?err_vqqp:
> ????????qp_destroy(ndev, &mvq->fwqp);
> @@ -1288,6 +1357,7 @@ static void teardown_vq(struct mlx5_vdpa_net *ndev,
> struct mlx5_vdpa_virtqueue *
> ?
> ????????suspend_vq(ndev, mvq);
> ????????destroy_virtqueue(ndev, mvq);
> +???????dealloc_vector(ndev, mvq);
> ????????counter_set_dealloc(ndev, mvq);
> ????????qp_destroy(ndev, &mvq->vqqp);
> ????????qp_destroy(ndev, &mvq->fwqp);
> @@ -2505,6 +2575,7 @@ static int save_channel_info(struct mlx5_vdpa_net
*ndev,
> struct mlx5_vdpa_virtqu
> ????????ri->desc_addr = mvq->desc_addr;
> ????????ri->device_addr = mvq->device_addr;
> ????????ri->driver_addr = mvq->driver_addr;
> +???????ri->map = mvq->map;
> ????????ri->restore = true;
> ????????return 0;
> ?}
> @@ -2549,6 +2620,7 @@ static void restore_channels_info(struct
mlx5_vdpa_net
> *ndev)
> ????????????????mvq->desc_addr = ri->desc_addr;
> ????????????????mvq->device_addr = ri->device_addr;
> ????????????????mvq->driver_addr = ri->driver_addr;
> +???????????????mvq->map = ri->map;
> ????????}
> ?}
> ?
> @@ -2833,6 +2905,25 @@ static struct device *mlx5_get_vq_dma_dev(struct
> vdpa_device *vdev, u16 idx)
> ????????return mvdev->vdev.dma_dev;
> ?}
> ?
> +static void free_irqs(struct mlx5_vdpa_net *ndev)
> +{
> +???????struct mlx5_vdpa_irq_pool_entry *ent;
> +???????int i;
> +
> +???????if (!msix_mode_supported(&ndev->mvdev))
> +???????????????return;
> +
> +???????if (!ndev->irqp.entries)
> +???????????????return;
> +
> +???????for (i = ndev->irqp.num_ent - 1; i >= 0; i--) {
> +???????????????ent = ndev->irqp.entries + i;
> +???????????????if (ent->map.virq)
> +???????????????????????pci_msix_free_irq(ndev->mvdev.mdev->pdev,
ent->map);
> +???????}
> +???????kfree(ndev->irqp.entries);
> +}
> +
> ?static void mlx5_vdpa_free(struct vdpa_device *vdev)
> ?{
> ????????struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> @@ -2848,6 +2939,7 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev)
> ????????????????mlx5_mpfs_del_mac(pfmdev, ndev->config.mac);
> ????????}
> ????????mlx5_vdpa_free_resources(&ndev->mvdev);
> +???????free_irqs(ndev);
> ????????kfree(ndev->event_cbs);
> ????????kfree(ndev->vqs);
> ?}
> @@ -2876,9 +2968,23 @@ static struct vdpa_notification_area
> mlx5_get_vq_notification(struct vdpa_device
> ????????return ret;
> ?}
> ?
> -static int mlx5_get_vq_irq(struct vdpa_device *vdv, u16 idx)
> +static int mlx5_get_vq_irq(struct vdpa_device *vdev, u16 idx)
> ?{
> -???????return -EOPNOTSUPP;
> +???????struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> +???????struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> +???????struct mlx5_vdpa_virtqueue *mvq;
> +
> +???????if (!is_index_valid(mvdev, idx))
> +???????????????return -EINVAL;
> +
> +???????if (is_ctrl_vq_idx(mvdev, idx))
> +???????????????return -EOPNOTSUPP;
> +
> +???????mvq = &ndev->vqs[idx];
> +???????if (!mvq->map.virq)
> +???????????????return -EOPNOTSUPP;
> +
> +???????return mvq->map.virq;
> ?}
> ?
> ?static u64 mlx5_vdpa_get_driver_features(struct vdpa_device *vdev)
> @@ -3155,6 +3261,34 @@ static int config_func_mtu(struct mlx5_core_dev
*mdev,
> u16 mtu)
> ????????return err;
> ?}
> ?
> +static void allocate_irqs(struct mlx5_vdpa_net *ndev)
> +{
> +???????struct mlx5_vdpa_irq_pool_entry *ent;
> +???????int i;
> +
> +???????if (!msix_mode_supported(&ndev->mvdev))
> +???????????????return;
> +
> +???????if (!ndev->mvdev.mdev->pdev)
> +???????????????return;
> +
> +???????ndev->irqp.entries = kcalloc(ndev->mvdev.max_vqs,
sizeof(*ndev-
> >irqp.entries), GFP_KERNEL);
> +???????if (!ndev->irqp.entries)
> +???????????????return;
> +
> +
> +???????for (i = 0; i < ndev->mvdev.max_vqs; i++) {
> +???????????????ent = ndev->irqp.entries + i;
> +???????????????snprintf(ent->name, MLX5_VDPA_IRQ_NAME_LEN,
"%s-vq-%d",
> +??????????????????????? dev_name(&ndev->mvdev.vdev.dev), i);
> +???????????????ent->map =
pci_msix_alloc_irq_at(ndev->mvdev.mdev->pdev,
> MSI_ANY_INDEX, NULL);
> +???????????????if (!ent->map.virq)
> +???????????????????????return;
> +
> +???????????????ndev->irqp.num_ent++;
> +???????}
> +}
> +
> ?static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char
*name,
> ???????????????????????????? const struct vdpa_dev_set_config *add_config)
> ?{
> @@ -3233,6 +3367,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev
> *v_mdev, const char *name,
> ????????}
> ?
> ????????init_mvqs(ndev);
> +???????allocate_irqs(ndev);
> ????????init_rwsem(&ndev->reslock);
> ????????config = &ndev->config;
> ?
> @@ -3413,6 +3548,17 @@ static void mlx5v_remove(struct auxiliary_device
*adev)
> ????????kfree(mgtdev);
> ?}
> ?
> +static void mlx5v_shutdown(struct auxiliary_device *auxdev)
> +{
> +???????struct mlx5_vdpa_mgmtdev *mgtdev;
> +???????struct mlx5_vdpa_net *ndev;
> +
> +???????mgtdev = auxiliary_get_drvdata(auxdev);
> +???????ndev = mgtdev->ndev;
> +
> +???????free_irqs(ndev);
> +}
> +
> ?static const struct auxiliary_device_id mlx5v_id_table[] = {
> ????????{ .name = MLX5_ADEV_NAME ".vnet", },
> ????????{},
> @@ -3424,6 +3570,7 @@ static struct auxiliary_driver mlx5v_driver = {
> ????????.name = "vnet",
> ????????.probe = mlx5v_probe,
> ????????.remove = mlx5v_remove,
> +???????.shutdown = mlx5v_shutdown,
> ????????.id_table = mlx5v_id_table,
> ?};
> ?
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.h
> b/drivers/vdpa/mlx5/net/mlx5_vnet.h
> index c90a89e1de4d..36c44d9fdd16 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.h
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.h
> @@ -26,6 +26,20 @@ static inline u16 key2vid(u64 key)
> ????????return (u16)(key >> 48) & 0xfff;
> ?}
> ?
> +#define MLX5_VDPA_IRQ_NAME_LEN 32
> +
> +struct mlx5_vdpa_irq_pool_entry {
> +???????struct msi_map map;
> +???????bool used;
> +???????char name[MLX5_VDPA_IRQ_NAME_LEN];
> +???????void *dev_id;
> +};
> +
> +struct mlx5_vdpa_irq_pool {
> +???????int num_ent;
> +???????struct mlx5_vdpa_irq_pool_entry *entries;
> +};
> +
> ?struct mlx5_vdpa_net {
> ????????struct mlx5_vdpa_dev mvdev;
> ????????struct mlx5_vdpa_net_resources res;
> @@ -49,6 +63,7 @@ struct mlx5_vdpa_net {
> ????????struct vdpa_callback config_cb;
> ????????struct mlx5_vdpa_wq_ent cvq_ent;
> ????????struct hlist_head macvlan_hash[MLX5V_MACVLAN_SIZE];
> +???????struct mlx5_vdpa_irq_pool irqp;
> ????????struct dentry *debugfs;
> ?};
> ?