Re: [PATCH] vdpa/mlx5: Support interrupt bypassing
From: Dragos Tatulea
Date: Thu Jun 08 2023 - 12:26:18 EST
On Wed, 2023-06-07 at 22:00 +0300, Dragos Tatulea via Virtualization wrote:
> From: Eli Cohen <elic@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
>
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;
> };
>