vdpa/mlx5: Enable hw support for vq descriptor mapping

Vq descriptor mappings are supported in hardware by filling in an
additional mkey which contains the descriptor mappings to the hw vq.

A previous patch in this series added support for hw mkey (mr) creation
for ASID 1.

This patch fills in both the vq data and vq descriptor mkeys based on
group ASID mapping.

The feature is signaled to the vdpa core through the presence of the
.get_vq_desc_group op.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20231018171456.1624030-16-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Author: dtatulea

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -864,6 +864,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	u32 out[MLX5_ST_SZ_DW(create_virtio_net_q_out)] = {};
 	struct mlx5_vdpa_dev *mvdev = &ndev->mvdev;
 	struct mlx5_vdpa_mr *vq_mr;
+	struct mlx5_vdpa_mr *vq_desc_mr;
 	void *obj_context;
 	u16 mlx_features;
 	void *cmd_hdr;
@@ -919,6 +920,11 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 	vq_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP]];
 	if (vq_mr)
 		MLX5_SET(virtio_q, vq_ctx, virtio_q_mkey, vq_mr->mkey);
+
+	vq_desc_mr = mvdev->mr[mvdev->group2asid[MLX5_VDPA_DATAVQ_DESC_GROUP]];
+	if (vq_desc_mr && MLX5_CAP_DEV_VDPA_EMULATION(mvdev->mdev, desc_group_mkey_supported))
+		MLX5_SET(virtio_q, vq_ctx, desc_group_mkey, vq_desc_mr->mkey);
+
 	MLX5_SET(virtio_q, vq_ctx, umem_1_id, mvq->umem1.id);
 	MLX5_SET(virtio_q, vq_ctx, umem_1_size, mvq->umem1.size);
 	MLX5_SET(virtio_q, vq_ctx, umem_2_id, mvq->umem2.id);
@@ -2306,6 +2312,16 @@ static u32 mlx5_vdpa_get_vq_group(struct vdpa_device *vdev, u16 idx)
 	return MLX5_VDPA_DATAVQ_GROUP;
 }
 
+static u32 mlx5_vdpa_get_vq_desc_group(struct vdpa_device *vdev, u16 idx)
+{
+	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+
+	if (is_ctrl_vq_idx(mvdev, idx))
+		return MLX5_VDPA_CVQ_GROUP;
+
+	return MLX5_VDPA_DATAVQ_DESC_GROUP;
+}
+
 static u64 mlx_to_vritio_features(u16 dev_features)
 {
 	u64 result = 0;
@@ -3215,6 +3231,7 @@ static const struct vdpa_config_ops mlx5_vdpa_ops = {
 	.get_vq_irq = mlx5_get_vq_irq,
 	.get_vq_align = mlx5_vdpa_get_vq_align,
 	.get_vq_group = mlx5_vdpa_get_vq_group,
+	.get_vq_desc_group = mlx5_vdpa_get_vq_desc_group, /* Op disabled if not supported. */
 	.get_device_features = mlx5_vdpa_get_device_features,
 	.get_backend_features = mlx5_vdpa_get_backend_features,
 	.set_driver_features = mlx5_vdpa_set_driver_features,
@@ -3314,6 +3331,7 @@ struct mlx5_vdpa_mgmtdev {
 	struct vdpa_mgmt_dev mgtdev;
 	struct mlx5_adev *madev;
 	struct mlx5_vdpa_net *ndev;
+	struct vdpa_config_ops vdpa_ops;
 };
 
 static int config_func_mtu(struct mlx5_core_dev *mdev, u16 mtu)
@@ -3427,7 +3445,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
 		max_vqs = 2;
 	}
 
-	ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mlx5_vdpa_ops,
+	ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mgtdev->vdpa_ops,
 				 MLX5_VDPA_NUMVQ_GROUPS, MLX5_VDPA_NUM_AS, name, false);
 	if (IS_ERR(ndev))
 		return PTR_ERR(ndev);
@@ -3600,6 +3618,10 @@ static int mlx5v_probe(struct auxiliary_device *adev,
 		MLX5_CAP_DEV_VDPA_EMULATION(mdev, max_num_virtio_queues) + 1;
 	mgtdev->mgtdev.supported_features = get_supported_features(mdev);
 	mgtdev->madev = madev;
+	mgtdev->vdpa_ops = mlx5_vdpa_ops;
+
+	if (!MLX5_CAP_DEV_VDPA_EMULATION(mdev, desc_group_mkey_supported))
+		mgtdev->vdpa_ops.get_vq_desc_group = NULL;
 
 	err = vdpa_mgmtdev_register(&mgtdev->mgtdev);
 	if (err)

include/linux/mlx5/mlx5_ifc_vdpa.h

@@ -74,7 +74,11 @@ struct mlx5_ifc_virtio_q_bits {
 	u8    reserved_at_320[0x8];
 	u8    pd[0x18];
 
-	u8    reserved_at_340[0xc0];
+	u8    reserved_at_340[0x20];
+
+	u8    desc_group_mkey[0x20];
+
+	u8    reserved_at_380[0x80];
 };
 
 struct mlx5_ifc_virtio_net_q_object_bits {
@@ -141,6 +145,7 @@ enum {
 	MLX5_VIRTQ_MODIFY_MASK_STATE                    = (u64)1 << 0,
 	MLX5_VIRTQ_MODIFY_MASK_DIRTY_BITMAP_PARAMS      = (u64)1 << 3,
 	MLX5_VIRTQ_MODIFY_MASK_DIRTY_BITMAP_DUMP_ENABLE = (u64)1 << 4,
+	MLX5_VIRTQ_MODIFY_MASK_DESC_GROUP_MKEY          = (u64)1 << 14,
 };
 
 enum {