[PATCH AUTOSEL 6.4 05/17] vdpa/mlx5: Correct default number of queues when MQ is on

[Sasha Levin <sashal@kernel.org>]

From: Dragos Tatulea <dtatulea@nvidia.com>

[ Upstream commit 3fe024193340b225d1fd410d78c495434a9d68e0 ]

The standard specifies that the initial number of queues is the
default, which is 1 (1 tx, 1 rx).

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20230727172354.68243-2-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 279ac6a558d29..93a2520223b66 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2447,7 +2447,15 @@ static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
 	else
 		ndev->rqt_size = 1;
 
-	ndev->cur_num_vqs = 2 * ndev->rqt_size;
+	/* Device must start with 1 queue pair, as per VIRTIO v1.2 spec, section
+	 * 5.1.6.5.5 "Device operation in multiqueue mode":
+	 *
+	 * Multiqueue is disabled by default.
+	 * The driver enables multiqueue by sending a command using class
+	 * VIRTIO_NET_CTRL_MQ. The command selects the mode of multiqueue
+	 * operation, as follows: ...
+	 */
+	ndev->cur_num_vqs = 2;
 
 	update_cvq_info(mvdev);
 	return err;
-- 
2.40.1