Re: [dpdk-dev] [PATCH v2 2/2] vhost: Add vhost-user-blk example which support inflight

[Tiwei Bie <tiwei.bie@intel.com>]

On Thu, Jul 11, 2019 at 10:23:11AM +0800, Yu, Jin wrote:
> > -----Original Message-----
> > From: Bie, Tiwei
> > Sent: Wednesday, July 10, 2019 3:26 PM
> > To: Yu, Jin <jin.yu@intel.com>
> > Cc: dev@dpdk.org; Liu, Changpeng <changpeng.liu@intel.com>;
> > maxime.coquelin@redhat.com; Wang, Zhihong <zhihong.wang@intel.com>
> > Subject: Re: [PATCH v2 2/2] vhost: Add vhost-user-blk example which
> > support inflight
> > 
> > On Wed, Jul 10, 2019 at 06:43:56PM +0800, JinYu wrote:
> > > A vhost-user-blk example that support inflight feature. It uses the
> > > new APIs that introduced in the first patch, so It can show how there
> > > APIs work to support inflight feature.
> > >
> > > Signed-off-by: JinYu <jin.yu@intel.com>
> > > ---
> > > V1 - add the case.
> > > ---
> > >  examples/vhost_blk/Makefile           |  67 +++
> > >  examples/vhost_blk/blk.c              | 118 ++++++
> > >  examples/vhost_blk/blk_spec.h         |  95 +++++
> > >  examples/vhost_blk/meson.build        |  20 +
> > >  examples/vhost_blk/vhost_blk.c        | 589 ++++++++++++++++++++++++++
> > >  examples/vhost_blk/vhost_blk.h        |  96 +++++
> > >  examples/vhost_blk/vhost_blk_compat.c | 193 +++++++++
> > >  7 files changed, 1178 insertions(+)
> > >  create mode 100644 examples/vhost_blk/Makefile  create mode 100644
> > > examples/vhost_blk/blk.c  create mode 100644
> > > examples/vhost_blk/blk_spec.h  create mode 100644
> > > examples/vhost_blk/meson.build  create mode 100644
> > > examples/vhost_blk/vhost_blk.c  create mode 100644
> > > examples/vhost_blk/vhost_blk.h  create mode 100644
> > > examples/vhost_blk/vhost_blk_compat.c
> > >
> > [...]
> > 
> > I don't know much about SCSI yet. Could you provide some details about why
> > vhost-SCSI doesn't work with this inflight feature?
> We need the Qemu and vhost backend cooperate to support the inflight feature.
> So if we want to make it works, we need 2 patches, one is for Qemu, the other is for backend.
> Baidu has already submitted an vhost-user-blk patch to Qemu which is for this feature, that's why 
> the vhost-user-blk example can support this feature.

So, we can't do it in vhost_scsi example just because we
don't have the corresponding support in QEMU? Technically,
is it possible to enable the inflight feature support for
vhost-user-scsi in QEMU?

Thanks,
Tiwei