vdpa/mlx5: Fix queue type selection logic

get_queue_type() comments that splict virtqueue is preferred, however,
the actual logic preferred packed virtqueues. Since firmware has not
supported packed virtqueues we ended up using split virtqueues as was
desired.

Since we do not advertise support for packed virtqueues, we add a check
to verify split virtqueues are indeed supported.

Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20210811053759.66752-1-elic@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 2a31467f7ac5a0639a3d430c7551b9339c428f68..b1230fa2f5d1c09131fdfe9589356f2c7c4ba55d 100644 (file)
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -753,12 +753,12 @@ static int get_queue_type(struct mlx5_vdpa_net *ndev)
        type_mask = MLX5_CAP_DEV_VDPA_EMULATION(ndev->mvdev.mdev, virtio_queue_type);
 
        /* prefer split queue */
-       if (type_mask & MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_PACKED)
-               return MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_PACKED;
+       if (type_mask & MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_SPLIT)
+               return MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_SPLIT;
 
-       WARN_ON(!(type_mask & MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_SPLIT));
+       WARN_ON(!(type_mask & MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_PACKED));
 
-       return MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_SPLIT;
+       return MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_PACKED;
 }
 
 static bool vq_is_tx(u16 idx)
@@ -2030,6 +2030,12 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name)
                return -ENOSPC;
 
        mdev = mgtdev->madev->mdev;
+       if (!(MLX5_CAP_DEV_VDPA_EMULATION(mdev, virtio_queue_type) &
+           MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_SPLIT)) {
+               dev_warn(mdev->device, "missing support for split virtqueues\n");
+               return -EOPNOTSUPP;
+       }
+
        /* we save one virtqueue for control virtqueue should we require it */
        max_vqs = MLX5_CAP_DEV_VDPA_EMULATION(mdev, max_num_virtio_queues);
        max_vqs = min_t(u32, max_vqs, MLX5_MAX_SUPPORTED_VQS);

diff --git a/include/linux/mlx5/mlx5_ifc_vdpa.h b/include/linux/mlx5/mlx5_ifc_vdpa.h
index 98b56b75c625b272d985bd2df8eb72c718eec9bf..1a9c9d94cb59f3a0e6c3f62d00d7c95111cb7ffe 100644 (file)
--- a/include/linux/mlx5/mlx5_ifc_vdpa.h
+++ b/include/linux/mlx5/mlx5_ifc_vdpa.h
@@ -11,13 +11,15 @@ enum {
 };
 
 enum {
-       MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_SPLIT   = 0x1, // do I check this caps?
-       MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_PACKED  = 0x2,
+       MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_SPLIT   = 0,
+       MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_PACKED  = 1,
 };
 
 enum {
-       MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_SPLIT   = 0,
-       MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_PACKED  = 1,
+       MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_SPLIT =
+               BIT(MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_SPLIT),
+       MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_PACKED =
+               BIT(MLX5_VIRTIO_EMULATION_VIRTIO_QUEUE_TYPE_PACKED),
 };
 
 struct mlx5_ifc_virtio_q_bits {