[PATCH v2 18/24] mlxbf-tmfifo: sparse tags for config access

[PATCH v2 18/24] mlxbf-tmfifo: sparse tags for config access

[Michael S. Tsirkin]

mlxbf-tmfifo accesses config space using native types -
which works for it since the legacy virtio native types.

This will break if it ever needs to support modern virtio,
so with new tags previously introduced for virtio net config,
sparse now warns for this in drivers.

Since this is a legacy only device, fix it up using
virtio_legacy_is_little_endian for now.

No functional changes.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/platform/mellanox/mlxbf-tmfifo.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
index 5739a9669b29..bbc4e71a16ff 100644
--- a/drivers/platform/mellanox/mlxbf-tmfifo.c
+++ b/drivers/platform/mellanox/mlxbf-tmfifo.c
@@ -625,7 +625,10 @@ static void mlxbf_tmfifo_rxtx_header(struct mlxbf_tmfifo_vring *vring,
 			vdev_id = VIRTIO_ID_NET;
 			hdr_len = sizeof(struct virtio_net_hdr);
 			config = &fifo->vdev[vdev_id]->config.net;
-			if (ntohs(hdr.len) > config->mtu +
+			/* A legacy-only interface for now. */
+			if (ntohs(hdr.len) >
+			    __virtio16_to_cpu(virtio_legacy_is_little_endian(),
+					      config->mtu) +
 			    MLXBF_TMFIFO_NET_L2_OVERHEAD)
 				return;
 		} else {
@@ -1231,8 +1234,12 @@ static int mlxbf_tmfifo_probe(struct platform_device *pdev)
 
 	/* Create the network vdev. */
 	memset(&net_config, 0, sizeof(net_config));
-	net_config.mtu = ETH_DATA_LEN;
-	net_config.status = VIRTIO_NET_S_LINK_UP;
+
+	/* A legacy-only interface for now. */
+	net_config.mtu = __cpu_to_virtio16(virtio_legacy_is_little_endian(),
+					   ETH_DATA_LEN);
+	net_config.status = __cpu_to_virtio16(virtio_legacy_is_little_endian(),
+					      VIRTIO_NET_S_LINK_UP);
 	mlxbf_tmfifo_get_cfg_mac(net_config.mac);
 	rc = mlxbf_tmfifo_create_vdev(dev, fifo, VIRTIO_ID_NET,
 				      MLXBF_TMFIFO_NET_FEATURES, &net_config,
-- 
MST

Re: [PATCH v2 18/24] mlxbf-tmfifo: sparse tags for config access

[Cornelia Huck]

On Mon, 3 Aug 2020 17:00:01 -0400
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> mlxbf-tmfifo accesses config space using native types -
> which works for it since the legacy virtio native types.
> 
> This will break if it ever needs to support modern virtio,
> so with new tags previously introduced for virtio net config,
> sparse now warns for this in drivers.
> 
> Since this is a legacy only device, fix it up using
> virtio_legacy_is_little_endian for now.

I'm wondering if the driver should make this more explicit?

No issues with the patch, though.

> 
> No functional changes.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  drivers/platform/mellanox/mlxbf-tmfifo.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)

Acked-by: Cornelia Huck <cohuck@redhat.com>

Re: [PATCH v2 18/24] mlxbf-tmfifo: sparse tags for config access

[Michael S. Tsirkin]

On Tue, Aug 04, 2020 at 04:56:34PM +0200, Cornelia Huck wrote:
> On Mon, 3 Aug 2020 17:00:01 -0400
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > mlxbf-tmfifo accesses config space using native types -
> > which works for it since the legacy virtio native types.
> > 
> > This will break if it ever needs to support modern virtio,
> > so with new tags previously introduced for virtio net config,
> > sparse now warns for this in drivers.
> > 
> > Since this is a legacy only device, fix it up using
> > virtio_legacy_is_little_endian for now.
> 
> I'm wondering if the driver should make this more explicit?


Not sure how though.

> No issues with the patch, though.
> 
> > 
> > No functional changes.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  drivers/platform/mellanox/mlxbf-tmfifo.c | 13 ++++++++++---
> >  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> Acked-by: Cornelia Huck <cohuck@redhat.com>