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Message-ID: <1691665672.3006196-1-xuanzhuo@linux.alibaba.com>
Subject: Re: [PATCH v2] virtio-net: Zero max_tx_vq field for VIRTIO_NET_CTRL_MQ_HASH_CONFIG case
Date:   Thu, 10 Aug 2023 19:07:52 +0800
From:   Xuan Zhuo <xuanzhuo@linux.alibaba.com>
To:     Hawkins Jiawei <yin31149@gmail.com>
Cc:     eperezma@redhat.com, 18801353760@163.com,
        Andrew Melnychenko <andrew@daynix.com>, stable@vger.kernel.org,
        Jason Wang <jasowang@redhat.com>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        linux-kernel@vger.kernel.org, yin31149@gmail.com
References: <20230810110405.25558-1-yin31149@gmail.com>
In-Reply-To: <20230810110405.25558-1-yin31149@gmail.com>
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On Thu, 10 Aug 2023 19:04:05 +0800, Hawkins Jiawei <yin31149@gmail.com> wro=
te:
> Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data
> for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and
> VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.
>
> According to the VirtIO standard, "Field reserved MUST contain zeroes.
> It is defined to make the structure to match the layout of
> virtio_net_rss_config structure, defined in 5.1.6.5.7.".
>
> Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq`
> field in struct virtio_net_ctrl_rss, which corresponds to the
> `reserved` field in struct virtio_net_hash_config, is not zeroed,
> thereby violating the VirtIO standard.
>
> This patch solves this problem by zeroing this field in
> virtnet_init_default_rss().
>
> Cc: Andrew Melnychenko <andrew@daynix.com>
> Cc: stable@vger.kernel.org
> Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.")
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Acked-by: Eugenio P=C3=A9rez <eperezma@redhat.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>

Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

> ---
>  drivers/net/virtio_net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 1270c8d23463..8db38634ae82 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2761,7 +2761,7 @@ static void virtnet_init_default_rss(struct virtnet=
_info *vi)
>  		vi->ctrl->rss.indirection_table[i] =3D indir_val;
>  	}
>
> -	vi->ctrl->rss.max_tx_vq =3D vi->curr_queue_pairs;
> +	vi->ctrl->rss.max_tx_vq =3D vi->has_rss ? vi->curr_queue_pairs : 0;
>  	vi->ctrl->rss.hash_key_length =3D vi->rss_key_size;
>
>  	netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);
> --
> 2.34.1
>