netdev - Re: [RFC v4 10/11] vduse: Introduce a workqueue for irq injection

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

Date:   Fri, 5 Mar 2021 11:04:42 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     Yongji Xie <xieyongji@...edance.com>
Cc:     "Michael S. Tsirkin" <mst@...hat.com>,
        Stefan Hajnoczi <stefanha@...hat.com>,
        Stefano Garzarella <sgarzare@...hat.com>,
        Parav Pandit <parav@...dia.com>, Bob Liu <bob.liu@...cle.com>,
        Christoph Hellwig <hch@...radead.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Matthew Wilcox <willy@...radead.org>, viro@...iv.linux.org.uk,
        Jens Axboe <axboe@...nel.dk>, bcrl@...ck.org,
        Jonathan Corbet <corbet@....net>,
        virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        kvm@...r.kernel.org, linux-aio@...ck.org,
        linux-fsdevel@...r.kernel.org
Subject: Re: [RFC v4 10/11] vduse: Introduce a workqueue for irq injection


On 2021/3/4 4:58 下午, Yongji Xie wrote:
> On Thu, Mar 4, 2021 at 2:59 PM Jason Wang <jasowang@...hat.com> wrote:
>>
>> On 2021/2/23 7:50 下午, Xie Yongji wrote:
>>> This patch introduces a workqueue to support injecting
>>> virtqueue's interrupt asynchronously. This is mainly
>>> for performance considerations which makes sure the push()
>>> and pop() for used vring can be asynchronous.
>>
>> Do you have pref numbers for this patch?
>>
> No, I can do some tests for it if needed.
>
> Another problem is the VIRTIO_RING_F_EVENT_IDX feature will be useless
> if we call irq callback in ioctl context. Something like:
>
> virtqueue_push();
> virtio_notify();
>      ioctl()
> -------------------------------------------------
>          irq_cb()
>              virtqueue_get_buf()
>
> The used vring is always empty each time we call virtqueue_push() in
> userspace. Not sure if it is what we expected.


I'm not sure I get the issue.

THe used ring should be filled by virtqueue_push() which is done by 
userspace before?

Thanks


>
> Thanks,
> Yongji
>