[PATCH] vdpa/mlx5: Restore the hardware used index after change map

[Eli Cohen]

When a change of memory map occurs, the hardware resources are destroyed
and then re-created again with the new memory map. In such case, we need
to restore the hardware available and used indices. The driver failed to
restore the used index which is added here.

Fixes 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
---
This patch is being sent again a single patch the fixes hot memory
addtion to a qemy process.

 drivers/vdpa/mlx5/net/mlx5_vnet.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 88dde3455bfd..839f57c64a6f 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -87,6 +87,7 @@ struct mlx5_vq_restore_info {
 	u64 device_addr;
 	u64 driver_addr;
 	u16 avail_index;
+	u16 used_index;
 	bool ready;
 	struct vdpa_callback cb;
 	bool restore;
@@ -121,6 +122,7 @@ struct mlx5_vdpa_virtqueue {
 	u32 virtq_id;
 	struct mlx5_vdpa_net *ndev;
 	u16 avail_idx;
+	u16 used_idx;
 	int fw_state;
 
 	/* keep last in the struct */
@@ -804,6 +806,7 @@ static int create_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtque
 
 	obj_context = MLX5_ADDR_OF(create_virtio_net_q_in, in, obj_context);
 	MLX5_SET(virtio_net_q_object, obj_context, hw_available_index, mvq->avail_idx);
+	MLX5_SET(virtio_net_q_object, obj_context, hw_used_index, mvq->used_idx);
 	MLX5_SET(virtio_net_q_object, obj_context, queue_feature_bit_mask_12_3,
 		 get_features_12_3(ndev->mvdev.actual_features));
 	vq_ctx = MLX5_ADDR_OF(virtio_net_q_object, obj_context, virtio_q_context);
@@ -1022,6 +1025,7 @@ static int connect_qps(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *m
 struct mlx5_virtq_attr {
 	u8 state;
 	u16 available_index;
+	u16 used_index;
 };
 
 static int query_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq,
@@ -1052,6 +1056,7 @@ static int query_virtqueue(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueu
 	memset(attr, 0, sizeof(*attr));
 	attr->state = MLX5_GET(virtio_net_q_object, obj_context, state);
 	attr->available_index = MLX5_GET(virtio_net_q_object, obj_context, hw_available_index);
+	attr->used_index = MLX5_GET(virtio_net_q_object, obj_context, hw_used_index);
 	kfree(out);
 	return 0;
 
@@ -1610,6 +1615,7 @@ static int save_channel_info(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqu
 		return err;
 
 	ri->avail_index = attr.available_index;
+	ri->used_index = attr.used_index;
 	ri->ready = mvq->ready;
 	ri->num_ent = mvq->num_ent;
 	ri->desc_addr = mvq->desc_addr;
@@ -1654,6 +1660,7 @@ static void restore_channels_info(struct mlx5_vdpa_net *ndev)
 			continue;
 
 		mvq->avail_idx = ri->avail_index;
+		mvq->used_idx = ri->used_index;
 		mvq->ready = ri->ready;
 		mvq->num_ent = ri->num_ent;
 		mvq->desc_addr = ri->desc_addr;
-- 
2.29.2