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Date:   Thu, 9 Sep 2021 05:18:21 -0400
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Jason Wang <jasowang@redhat.com>
Cc:     Wu Zongyong <wuzongyong@linux.alibaba.com>,
        virtualization <virtualization@lists.linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        wei.yang1@linux.alibaba.com
Subject: Re: [PATCH 5/6] vdpa: add get_vq_num_unchangeable callback in
 vdpa_config_ops
Message-ID: <20210909051706-mutt-send-email-mst@kernel.org>
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On Thu, Sep 09, 2021 at 10:55:03AM +0800, Jason Wang wrote:
> On Wed, Sep 8, 2021 at 8:23 PM Wu Zongyong <wuzongyong@linux.alibaba.com> wrote:
> >
> > This new callback is used to indicate whether the vring size can be
> > change or not. It is useful when we have a legacy virtio pci device as
> > the vdpa device for there is no way to negotiate the vring num by the
> > specification.
> 
> So I'm not sure it's worth bothering. E.g what if we just fail
> VHOST_SET_VRING_NUM it the value doesn't match what hardware has?
> 
> Thanks

More importantly is there and actual plan for supporting
legacy devices? I don't think they currently work at a number
of levels.

-- 
MST