mlx5: Fix missing device local_dma_lkey

The mlx5 driver exposes device capability IB_DEVICE_LOCAL_DMA_LKEY
but does not set the the device local_dma_lkey. This breaks
rpcrdma drivers.

Query and set this lkey when creating the device resources.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx5/main.c

@@ -1256,10 +1256,18 @@ static int create_dev_resources(struct mlx5_ib_resources *devr)
 	struct ib_srq_init_attr attr;
 	struct mlx5_ib_dev *dev;
 	struct ib_cq_init_attr cq_attr = {.cqe = 1};
+	u32 rsvd_lkey;
 	int ret = 0;
 
 	dev = container_of(devr, struct mlx5_ib_dev, devr);
 
+	ret = mlx5_core_query_special_context(dev->mdev, &rsvd_lkey);
+	if (ret) {
+		pr_err("Failed to query special context %d\n", ret);
+		return ret;
+	}
+	dev->ib_dev.local_dma_lkey = rsvd_lkey;
+
 	devr->p0 = mlx5_ib_alloc_pd(&dev->ib_dev, NULL, NULL);
 	if (IS_ERR(devr->p0)) {
 		ret = PTR_ERR(devr->p0);
@@ -1421,7 +1429,6 @@ static void *mlx5_ib_add(struct mlx5_core_dev *mdev)
 	strlcpy(dev->ib_dev.name, "mlx5_%d", IB_DEVICE_NAME_MAX);
 	dev->ib_dev.owner		= THIS_MODULE;
 	dev->ib_dev.node_type		= RDMA_NODE_IB_CA;
-	dev->ib_dev.local_dma_lkey	= 0 /* not supported for now */;
 	dev->num_ports		= MLX5_CAP_GEN(mdev, num_ports);
 	dev->ib_dev.phys_port_cnt     = dev->num_ports;
 	dev->ib_dev.num_comp_vectors    =

drivers/net/ethernet/mellanox/mlx5/core/fw.c

@@ -200,3 +200,25 @@ int mlx5_cmd_teardown_hca(struct mlx5_core_dev *dev)
 
 	return err;
 }
+
+int mlx5_core_query_special_context(struct mlx5_core_dev *dev, u32 *rsvd_lkey)
+{
+	struct mlx5_cmd_query_special_contexts_mbox_in in;
+	struct mlx5_cmd_query_special_contexts_mbox_out out;
+	int err;
+
+	memset(&in, 0, sizeof(in));
+	memset(&out, 0, sizeof(out));
+	in.hdr.opcode = cpu_to_be16(MLX5_CMD_OP_QUERY_SPECIAL_CONTEXTS);
+	err = mlx5_cmd_exec(dev, &in, sizeof(in), &out, sizeof(out));
+	if (err)
+		return err;
+
+	if (out.hdr.status)
+		err = mlx5_cmd_status_to_err(&out.hdr);
+
+	*rsvd_lkey = be32_to_cpu(out.resd_lkey);
+
+	return err;
+}
+EXPORT_SYMBOL(mlx5_core_query_special_context);

include/linux/mlx5/device.h

@@ -402,6 +402,17 @@ struct mlx5_cmd_teardown_hca_mbox_out {
 	u8			rsvd[8];
 };
 
+struct mlx5_cmd_query_special_contexts_mbox_in {
+	struct mlx5_inbox_hdr	hdr;
+	u8			rsvd[8];
+};
+
+struct mlx5_cmd_query_special_contexts_mbox_out {
+	struct mlx5_outbox_hdr	hdr;
+	__be32                  dump_fill_mkey;
+	__be32                  resd_lkey;
+};
+
 struct mlx5_cmd_layout {
 	u8		type;
 	u8		rsvd0[3];

include/linux/mlx5/driver.h

@@ -828,6 +828,7 @@ void *mlx5_get_protocol_dev(struct mlx5_core_dev *mdev, int protocol);
 int mlx5_register_interface(struct mlx5_interface *intf);
 void mlx5_unregister_interface(struct mlx5_interface *intf);
 int mlx5_core_query_vendor_id(struct mlx5_core_dev *mdev, u32 *vendor_id);
+int mlx5_core_query_special_context(struct mlx5_core_dev *dev, u32 *rsvd_lkey);
 
 struct mlx5_profile {
 	u64	mask;