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References: <20211122160812.25125-1-arnaud.pouliquen@foss.st.com>
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From:   Jason Wang <jasowang@redhat.com>
Date:   Tue, 23 Nov 2021 10:15:32 +0800
Message-ID: <CACGkMEsQVVMx_+ezoVZ86xEFuadNOzjwcNBnv+-h-pE0JnXhxw@mail.gmail.com>
Subject: Re: [PATCH] rpmsg: virtio: don't let virtio core to validate used length
To:     Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        linux-remoteproc@vger.kernel.org,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-stm32@st-md-mailman.stormreply.com,
        "Michael S . Tsirkin" <mst@redhat.com>
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On Tue, Nov 23, 2021 at 12:08 AM Arnaud Pouliquen
<arnaud.pouliquen@foss.st.com> wrote:
>
> For RX virtqueue, the used length is validated in all the three paths
> (big, small and mergeable). For control vq, we never tries to use used
> length. So this patch forbids the core to validate the used length.

If I understand the code correctly, the function that calls
virtqueue_get_buf() ares:

rpmsg_recv_done()
get_a_tx_buf()

So it looks to me like the above change log needs some tweak? (It
looks like a copy from the virtio-net patch).

The codes are fine.

Thanks

>
> Without patch the rpmsg client sample does not work.
>
> Fixes: 939779f5152d ("virtio_ring: validate used buffer length")
>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> ---
> base-commit: fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf
> ---
>  drivers/rpmsg/virtio_rpmsg_bus.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> index 9c112aa65040..5f73f19c2c38 100644
> --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> @@ -1054,6 +1054,7 @@ static struct virtio_driver virtio_ipc_driver = {
>         .feature_table_size = ARRAY_SIZE(features),
>         .driver.name    = KBUILD_MODNAME,
>         .driver.owner   = THIS_MODULE,
> +       .suppress_used_validation = true,
>         .id_table       = id_table,
>         .probe          = rpmsg_probe,
>         .remove         = rpmsg_remove,
> --
> 2.17.1
>