Re: [Qemu-devel] [RFC 0/2] vhost-vfio: introduce mdev based HW vhost backend

[Jason Wang <jasowang@redhat.com>]

On 2018/11/9 上午12:48, Liang, Cunming wrote:
>> -----Original Message-----
>> From: Jason Wang [mailto:jasowang@redhat.com]
>> Sent: Thursday, November 8, 2018 2:16 AM
>> To: Liang, Cunming<cunming.liang@intel.com>; Wang, Xiao W
>> <xiao.w.wang@intel.com>;mst@redhat.com;alex.williamson@redhat.com
>> Cc:qemu-devel@nongnu.org; Bie, Tiwei<tiwei.bie@intel.com>; Ye, Xiaolong
>> <xiaolong.ye@intel.com>; Wang, Zhihong<zhihong.wang@intel.com>; Daly, Dan
>> <dan.daly@intel.com>
>> Subject: Re: [RFC 0/2] vhost-vfio: introduce mdev based HW vhost backend
>>
>>
>> On 2018/11/7 下午11:08, Liang, Cunming wrote:
>>>>>> believe.
>>>>> [LC] Agreed, so it reuses CMD defined by vhost-kernel ioctl. But
>>>>> VFIO provides
>>>> device specific things (e.g. DMAR, INTR and etc.) which is the extra
>>>> APIs being introduced by this transport.
>>>>
>>>>
>>>> I'm not quite sure I understand here. I think having vhost-kernel
>>>> compatible ioctl does not conflict of using VFIO ioctl like DMA or INTR?
>>>>
>>>> Btw, VFIO DMA ioctl is even not a must from my point of view,
>>>> vhost-mdev can forward the mem table information to device driver and
>>>> let it call DMA API to map/umap pages.
>>> [LC] If not regarding vhost-mdev as a device, then forward mem table won't be a
>> concern.
>>> If introducing a new mdev bus driver (vhost-mdev) which allows mdev instance to
>> be a new type of provider for vhost-kernel. It becomes a pretty good alternative to
>> fully leverage vhost-kernel ioctl.
>>> I'm not sure it's the same view as yours when you says reusing vhost-kernel ioctl.
>>>
>> Yes it is.
> [LC] It sounds a pretty good idea to me. Let us spend some time to figure out the next level detail, and sync-up further plan in community call.:)
>

Cool, thanks.