On Wed, Apr 19, 2023 at 12:39:11PM +0800, Jason Wang wrote:
> On Mon, Apr 17, 2023 at 4:35 PM Eli Cohen <elic@xxxxxxxxxx> wrote:
> >
> > 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.
> >
> > Issue: 2211199
> > Change-Id: I7633ee56ca2861a8d0f4935bb29109c8e80f352c
> > Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> > Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
> > ---
> > v1 -> v2:
> > 1. Remove parentheses around return statement
> > 2. Immediately return if vector entry found
> > 3. Use boolean instead of counter on used entry tracking
> > 4. Fix symmetry in teardown_vq()
> >
> > This patch is still under discussion but I wanted to address commnents
> > and have this is the basis for further discussion.
> >
> > drivers/vdpa/mlx5/net/mlx5_vnet.c | 140 ++++++++++++++++++++++++++++--
> > drivers/vdpa/mlx5/net/mlx5_vnet.h | 14 +++
> > 2 files changed, 145 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > index e29e32b306ad..2360c643148f 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 +1209,34 @@ 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 void alloc_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 (!irqp->entries[i].used) {
> > + irqp->entries[i].used = true;
> > + mvq->map = irqp->entries[i].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) {
> > + 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 +1266,31 @@ 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 +1335,7 @@ 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 +2553,7 @@ 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 +2598,7 @@ 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 +2883,21 @@ 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;
> > +
> > + for (i = ndev->irqp.num_ent - 1; i >= 0; i--) {
> > + ent = ndev->irqp.entries + i;
> > + mlx5_msix_free(ndev->mvdev.mdev, 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 +2913,7 @@ 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 +2942,23 @@ 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 +3235,35 @@ static int config_func_mtu(struct mlx5_core_dev *mdev, u16 mtu)
> > return err;
> > }
> >
> > +static irqreturn_t int_handler(int irq, void *nh)
> > +{
> > + return IRQ_HANDLED;
> > +}
>
> I still don't understand when this handler will be called.
>
> E.g IFCVF did:
>
> static irqreturn_t ifcvf_vq_intr_handler(int irq, void *arg)
> {
> struct vring_info *vring = arg;
>
> if (vring->cb.callback)
> return vring->cb.callback(vring->cb.private);
>
> return IRQ_HANDLED;
> }
>
> So when the irq bypass doesn't work it will fall back to a slow path.
>
> Maybe some comments here or changelog would be helpful.
>
> Thanks
Jason I don't understand what you are asking about.
Are you asking why it's ok not to invoke the vring callback?
--
MST
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