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From:   Jason Wang <jasowang@redhat.com>
Date:   Thu, 10 Aug 2023 12:12:24 +0800
Message-ID: <CACGkMEu_vzfcD=BzkL=HAkfi+RVq1F2vpDDQBGg54O_PL1fWGQ@mail.gmail.com>
Subject: Re: [PATCH] virtio-net: Zero max_tx_vq field for VIRTIO_NET_CTRL_MQ_HASH_CONFIG
 case
To:     Hawkins Jiawei <yin31149@gmail.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, eperezma@redhat.com,
        18801353760@163.com, virtualization@lists.linux-foundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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On Thu, Aug 10, 2023 at 11:16=E2=80=AFAM Hawkins Jiawei <yin31149@gmail.com=
> wrote:
>
> 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.

This is tricky.

>
> 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().
>
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> ---

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks