linux-kernel - Re: [PATCH] Do not name control queue for virtio-net

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:   Thu, 22 Sep 2022 05:16:03 -0400
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     Junbo <junbo4242@...il.com>
Cc:     Jason Wang <jasowang@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, bpf@...r.kernel.org
Subject: Re: [PATCH] Do not name control queue for virtio-net

On Sun, Sep 18, 2022 at 05:00:20PM +0800, Junbo wrote:
> hi Michael
> 
> in virtio-net.c
>     /* Parameters for control virtqueue, if any */
>     if (vi->has_cvq) {
>         callbacks[total_vqs - 1] = NULL;
>         names[total_vqs - 1] = "control";
>     }
> 
> I think the Author who write the code maybe want to name the control queue to
> 'virtioX-control',

That would be me I suspect ;)

> but it never worked, we can see the name still be
> 'virtioX-config' in /proc/interrupts,

Nope, what you see in /proc/interrupts are the interrupts, not the queue
name.

> for example 
>  43:          0          0          0          0          0          0        
>  0          0   PCI-MSI-edge      virtio0-config
>  44:         64          0          0          0          0          0      
> 1845          0   PCI-MSI-edge      virtio0-input.0
>  45:          1          0          0          0          0          0        
>  0          0   PCI-MSI-edge      virtio0-output.0
> 
> Because in function vp_request_msix_vectors, it just allocate 'xxxx-config' to
> every virtio devices, even the virtio device do not need it.

Oh yes, we can fix that. The result will be this line disappearing for
devices without a config interrupt. Not for net though, that
generally uses a config interrupt for things like link
state detection.


> in /proc/
> interrupts, we can see that each virtio device's first interrupt always named
> 'virtioX-config'.
> 
> So I think it's better to not explicitly give the "control" here, it's
> useless...  


it's used for debugging.