On Tue, Apr 4, 2023 at 9:30?PM Eli Cohen <elic at nvidia.com>
wrote:>
>
> On 04/04/2023 10:04, Eli Cohen wrote:
> >
> > On 04/04/2023 5:24, Jason Wang wrote:
> >>
> >> ? 2023/4/4 00:20, Eli Cohen ??:
> >>> 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>
> >>> ---
> >>> drivers/vdpa/mlx5/net/mlx5_vnet.c | 139
> >>> ++++++++++++++++++++++++++++--
> >>> drivers/vdpa/mlx5/net/mlx5_vnet.h | 14 +++
> >>> 2 files changed, 144 insertions(+), 9 deletions(-)
> >>>
> >>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> >>> b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> >>> index 520646ae7fa0..215a46cf8a98 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;
> >>
> >>
> >> Just spot that this structure is defined in mlx5_vnet.c but
it's
> >> nothing net specific. I think it's better to move it with the
> >> interrupt bypassing logic here to core/ (we can do it in the
future).
> > Right.
> >>
> >>
> >>> /* keep last in the struct */
> >>> struct mlx5_vq_restore_info ri;
> >>> @@ -792,6 +794,13 @@ 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);
> >>> @@ -829,9 +838,15 @@ 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)));
> >>> @@ -1174,6 +1189,32 @@ 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].usecount) {
> >>> + irqp->entries[i].usecount++;
> >>
> >>
> >> If we can't get a usercount which is greater than 1, it might
be
> >> better to use boolean instead.
> > Will fix.
> >>
> >>
> >>> + 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].usecount--;
> >>> +}
> >>> +
> >>> static int setup_vq(struct mlx5_vdpa_net *ndev, struct
> >>> mlx5_vdpa_virtqueue *mvq)
> >>> {
> >>> u16 idx = mvq->index;
> >>> @@ -1203,27 +1244,31 @@ 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);
> >>> @@ -1267,6 +1312,7 @@ static void teardown_vq(struct
mlx5_vdpa_net
> >>> *ndev, struct mlx5_vdpa_virtqueue *
> >>> return;
> >>> suspend_vq(ndev, mvq);
> >>> + dealloc_vector(ndev, mvq);
> >>> destroy_virtqueue(ndev, mvq);
> >>> counter_set_dealloc(ndev, mvq);
> >>> qp_destroy(ndev, &mvq->vqqp);
> >>> @@ -2374,6 +2420,7 @@ 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;
> >>> }
> >>> @@ -2418,6 +2465,7 @@ 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;
> >>> }
> >>> }
> >>> @@ -2693,6 +2741,22 @@ 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);
> >>> + ndev->irqp.num_ent--;
> >>> + }
> >>> + kfree(ndev->irqp.entries);
> >>> +}
> >>> +
> >>> static void mlx5_vdpa_free(struct vdpa_device *vdev)
> >>> {
> >>> struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> >>> @@ -2708,6 +2772,7 @@ 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);
> >>> }
> >>> @@ -2736,9 +2801,23 @@ 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)
> >>> @@ -3095,6 +3174,35 @@ 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'm not sure I get the meaning of the irq handler. Note that
even if
> >> we support get_vq_irq() it does not means the posted interrupt can
> >> work for each interrupt. It work only if several conditions are
met
> >> (for example the VCPU is running).
> >
> > Not sure I get it. Can you be explicit what needs to be done to make
> > sure the interrupts will go through directly to the vCPU?
> >
> >>
> >> So if this is the fallback irq handler when we can do post
interrupt,
> >> should we trigger the virtqueue callback here?
> >
> > It's not a fallback. I should remove it completely.
>
> Actually it can't be removed. If we do remove it, we will fail
> request_irq() due to this code from request_threaded_irq():
>
> if (!handler) {
> if (!thread_fn)
> return -EINVAL;
>
> handler = irq_default_primary_handler;
> }
>
> If no errors were encountered, we don't expect the handlers to ever be
> called since the interrupts go directly to the guest vCPU.
So the question is what happens if the setup doesn't support PI. It
looks to me we can reach this handler.
Thanks
>
> So I am thinking, maybe I should just put a WARN_ONCE in the handler.
>
> I am also taking the opportunity to say that I will be on vacation till
> March 13 so I won't be able to respond to emails.
>
> >
> >>
> >>
> >>> +}
> >>> +
> >>> +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;
> >>> +
> >>> + 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 = mlx5_msix_alloc(ndev->mvdev.mdev,
int_handler,
> >>> NULL, ent->name);
> >>> + 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)
> >>> {
> >>> @@ -3171,6 +3279,7 @@ 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;
> >>> @@ -3358,6 +3467,17 @@ 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", },
> >>> {},
> >>> @@ -3369,6 +3489,7 @@ static struct auxiliary_driver
mlx5v_driver = {
> >>> .name = "vnet",
> >>> .probe = mlx5v_probe,
> >>> .remove = mlx5v_remove,
> >>> + .shutdown = mlx5v_shutdown,
> >>
> >>
> >> So we allocate the irq during dev_add, it seems cleaner if we do
that
> >> in the dev_del.
> > Not sure what you mean here. You're saying I should not call
> > free_irqs() in mlx5v_shutdown()
> >>
> >> Note that mlx5v_remove will call vdpa_mgmtdev_unregister() which
will
> >> call dev_del.
> >>
> >> Thanks
> >>
> >>
> >>> .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..e5063b310d3c 100644
> >>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.h
> >>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.h
> >>> @@ -26,6 +26,19 @@ 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;
> >>> + int usecount;
> >>> + char name[MLX5_VDPA_IRQ_NAME_LEN];
> >>> +};
> >>> +
> >>> +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 +62,7 @@ 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;
> >>> };
> >>
>