Re: [Qemu-devel] [PATCH v1 0/6] Extend vhost-user to support VFIO based accelerators

[Stefan Hajnoczi]

On Thu, Jan 25, 2018 at 4:10 PM, Liang, Cunming <address@hidden> wrote:
>> -----Original Message-----
>> From: Stefan Hajnoczi [mailto:address@hidden
>> Sent: Thursday, January 25, 2018 10:22 PM
>> To: Bie, Tiwei <address@hidden>
>> Cc: address@hidden; address@hidden;
>> address@hidden; address@hidden; address@hidden;
>> address@hidden; address@hidden; Tan, Jianfeng
>> <address@hidden>; Liang, Cunming <address@hidden>;
>> Wang, Xiao W <address@hidden>; Wang, Zhihong
>> <address@hidden>; Daly, Dan <address@hidden>
>> Subject: Re: [Qemu-devel] [PATCH v1 0/6] Extend vhost-user to support
>> VFIO based accelerators
>>
>> On Thu, Jan 25, 2018 at 12:03:22PM +0800, Tiwei Bie wrote:
>> > Why extend vhost-user for vDPA
>> > ==============================
>> >
>> > We have already implemented various virtual switches (e.g. OVS-DPDK)
>> > based on vhost-user for VMs in the Cloud. They are purely software
>> > running on CPU cores. When we have accelerators for such NFVi
>> > applications, it's ideal if the applications could keep using the
>> > original interface (i.e. vhost-user netdev) with QEMU, and
>> > infrastructure is able to decide when and how to switch between CPU
>> > and
>> accelerators within the interface.
>> > And the switching (i.e. switch between CPU and accelerators) can be
>> > done flexibly and quickly inside the applications.
>> >
>> > More details about this can be found from the Cunming's discussions
>> > on the RFC patch set.
>> >
>> > The previous links:
>> > RFC:
>> > http://lists.nongnu.org/archive/html/qemu-devel/2017-12/msg04844.htm
>> > l
>>
>> Is vDPA also useful in the simpler use case where there is no NFVi 
>> application?
> There're separate patches to have non-DPDK vDPA(aka. vhost-vfio, a new vhost 
> backend proposed) support, which is the scope of stage-II as we mentioned in 
> community call.
> Stay tuned for the RFC patch. Main idea is that the virtio compatible device 
> driver register as a mdev to talk with qemu vhost-vfio.

Thanks!

Stefan