On Tue, Feb 02, 2021 at 09:14:02AM -0800, Si-Wei Liu wrote:
> On Tue, Feb 2, 2021 at 6:34 AM Eli Cohen <e...@nvidia.com> wrote:
> >
> > 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 <e...@nvidia.com>
> > ---
> > 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);
>
> The saved indexes will apply to the new virtqueue object whenever it
> is created. In virtio spec, these indexes will reset back to zero when
> the virtio device is reset. But I don't see how it's done today. IOW,
> I don't see where avail_idx and used_idx get cleared from the mvq for
> device reset via set_status().
>
Right, but this is not strictly related to this patch. I will post
another patch to fix this.
BTW, can you describe a secnario that would cause a reset (through
calling set_status()) that happens after the VQ has been used?
> -Siwei
>
>
> > 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
> >
