Re: [Qemu-devel] [PATCH v7 0/7] vhost-user-blk: Add support for backend reconnecting

[Yongji Xie]

On Wed, 13 Mar 2019 at 09:08, Michael S. Tsirkin <address@hidden> wrote:
>
> On Thu, Feb 28, 2019 at 04:53:48PM +0800, address@hidden wrote:
> > From: Xie Yongji <address@hidden>
> >
> > This patchset is aimed at supporting qemu to reconnect
> > vhost-user-blk backend after vhost-user-blk backend crash or
> > restart.
> >
> > The patch 1 introduces two new messages VHOST_USER_GET_INFLIGHT_FD
> > and VHOST_USER_SET_INFLIGHT_FD to support transferring shared
> > buffer between qemu and backend.
> >
> > The patch 2 deletes some redundant check in contrib/libvhost-user.c.
> >
> > The patch 3,4 are the corresponding libvhost-user patches of
> > patch 1. Make libvhost-user support VHOST_USER_GET_INFLIGHT_FD
> > and VHOST_USER_SET_INFLIGHT_FD.
> >
> > The patch 5 allows vhost-user-blk to use the two new messages
> > to get/set inflight buffer from/to backend.
> >
> > The patch 6 supports vhost-user-blk to reconnect backend when
> > connection closed.
> >
> > The patch 7 introduces VHOST_USER_PROTOCOL_F_SLAVE_SHMFD
> > to vhost-user-blk backend which is used to tell qemu that
> > we support reconnecting now.
> >
> > To use it, we could start qemu with:
> >
> > qemu-system-x86_64 \
> >         -chardev socket,id=char0,path=/path/vhost.socket,reconnect=1, \
> >         -device vhost-user-blk-pci,chardev=char0 \
> >
> > and start vhost-user-blk backend with:
> >
> > vhost-user-blk -b /path/file -s /path/vhost.socket
> >
> > Then we can restart vhost-user-blk at any time during VM running.
>
> So I merged the vhost user specific bits, but block
> bits will really need at least an ack from one of block
> developers.
>

Thank you. I will send the vhost-user-blk bit for qemu 4.1.

Thanks,
Yongji