[PATCH RFC 1/3] vdpa/mlx5: Implement susupend virtqueue callback

Eli Cohen
2022-06-16T13:27:48Z

Implement the suspend callback allowing to suspend the virtqueues so
they stop processing descriptors. This is required to allow the shadow
virtqueue to kick in.

Signed-off-by: Eli Cohen <elic@nvidia.com>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 68 +++++++++++++++++++++++++++++-
include/linux/mlx5/mlx5_ifc_vdpa.h | 8 ++++
2 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index fb0b23e71383..ea4bc8a0cd25 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -895,6 +895,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
if (err)
goto err_cmd;

+ mvq->fw_state = MLX5_VIRTIO_NET_Q_OBJECT_STATE_INIT;
kfree(in);
mvq->virtq_id = MLX5_GET(general_obj_out_cmd_hdr, out, obj_id);

@@ -922,6 +923,7 @@ static void destroy_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtq
mlx5_vdpa_warn(&ndev->mvdev, "destroy virtqueue 0x%x\n", mvq->virtq_id);
return;
}
+ mvq->fw_state = MLX5_VIRTIO_NET_Q_OBJECT_NONE;
umems_destroy(ndev, mvq);
}

@@ -1121,6 +1123,20 @@ static int query_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueu
return err;
}

+static bool is_valid_state_change(int oldstate, int newstate)
+{
+ switch (oldstate) {
+ case MLX5_VIRTIO_NET_Q_OBJECT_STATE_INIT:
+ return newstate == MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY;
+ case MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY:
+ return newstate == MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND;
+ case MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND:
+ case MLX5_VIRTIO_NET_Q_OBJECT_STATE_ERR:
+ default:
+ return false;
+ }
+}
+
static int modify_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq, int state)
{
int inlen = MLX5_ST_SZ_BYTES(modify_virtio_net_q_in);
@@ -1130,6 +1146,12 @@ static int modify_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
void *in;
int err;

+ if (mvq->fw_state == MLX5_VIRTIO_NET_Q_OBJECT_NONE)
+ return 0;
+
+ if (!is_valid_state_change(mvq->fw_state, state))
+ return -EINVAL;
+
in = kzalloc(inlen, GFP_KERNEL);
if (!in)
return -ENOMEM;
@@ -1991,6 +2013,7 @@ static void mlx5_vdpa_set_vq_ready(struct vdpa_device *vdev, u16 idx, bool ready
struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
struct mlx5_vdpa_virtqueue *mvq;
+ int err;

if (!mvdev->actual_features)
return;
@@ -2004,8 +2027,16 @@ static void mlx5_vdpa_set_vq_ready(struct vdpa_device *vdev, u16 idx, bool ready
}

mvq = &ndev->vqs[idx];
- if (!ready)
+ if (!ready) {
suspend_vq(ndev, mvq);
+ } else {
+ err = modify_virtqueue(ndev, mvq, MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY);
+ if (err) {
+ mlx5_vdpa_warn(mvdev, "modify VQ %d to ready failed (%d)\n", idx, err);
+ ready = false;
+ }
+ }
+

mvq->ready = ready;
}
@@ -2732,6 +2763,39 @@ static int mlx5_vdpa_get_vendor_vq_stats(struct vdpa_device *vdev, u16 idx,
return err;
}

+static void mlx5_vdpa_cvq_suspend(struct mlx5_vdpa_dev *mvdev, bool suspend)
+{
+ struct mlx5_control_vq *cvq;
+
+ if (!(mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ)))
+ return;
+
+ cvq = &mvdev->cvq;
+ cvq->ready = !suspend;
+}
+
+static int mlx5_vdpa_suspend(struct vdpa_device *vdev, bool suspend)
+{
+ struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+ struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
+ struct mlx5_vdpa_virtqueue *mvq;
+ int i;
+
+ if (!suspend) {
+ mlx5_vdpa_warn(mvdev, "Resume of virtqueues is not supported\n");
+ return -EOPNOTSUPP;
+ }
+
+ down_write(&ndev->reslock);
+ for (i = 0; i < ndev->cur_num_vqs; i++) {
+ mvq = &ndev->vqs[i];
+ suspend_vq(ndev, mvq);
+ }
+ mlx5_vdpa_cvq_suspend(mvdev, suspend);
+ up_write(&ndev->reslock);
+ return 0;
+}
+
static const struct vdpa_config_ops mlx5_vdpa_ops = {
.set_vq_address = mlx5_vdpa_set_vq_address,
.set_vq_num = mlx5_vdpa_set_vq_num,
@@ -2762,6 +2826,7 @@ static const struct vdpa_config_ops mlx5_vdpa_ops = {
.get_generation = mlx5_vdpa_get_generation,
.set_map = mlx5_vdpa_set_map,
.free = mlx5_vdpa_free,
+ .suspend = mlx5_vdpa_suspend,
};

static int query_mtu(struct mlx5_core_dev *mdev, u16 *mtu)
@@ -2827,6 +2892,7 @@ static void init_mvqs(struct mlx5_vdpa_net *ndev)
mvq->index = i;
mvq->ndev = ndev;
mvq->fwqp.fw = true;
+ mvq->fw_state = MLX5_VIRTIO_NET_Q_OBJECT_NONE;
}
for (; i < ndev->mvdev.max_vqs; i++) {
mvq = &ndev->vqs[i];
diff --git a/include/linux/mlx5/mlx5_ifc_vdpa.h b/include/linux/mlx5/mlx5_ifc_vdpa.h
index 4414ed5b6ed2..423562f39d3c 100644
--- a/include/linux/mlx5/mlx5_ifc_vdpa.h
+++ b/include/linux/mlx5/mlx5_ifc_vdpa.h
@@ -150,6 +150,14 @@ enum {
MLX5_VIRTIO_NET_Q_OBJECT_STATE_ERR = 0x3,
};

+/* This indicates that the object was not created or has alreadyi
+ * been desroyed. It is very safe to assume that this object will never
+ * have so many states
+ */
+enum {
+ MLX5_VIRTIO_NET_Q_OBJECT_NONE = 0xffffffff
+};
+
enum {
MLX5_RQTC_LIST_Q_TYPE_RQ = 0x0,
MLX5_RQTC_LIST_Q_TYPE_VIRTIO_NET_Q = 0x1,
--
2.35.1