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Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device |
Date: |
Wed, 7 Jun 2017 14:56:57 -0400 (EDT) |
> > This could be documented,
>
> It is documented AFAIK. Pls take a look at the spec documentation.
Found it now. It's not under GET_VRING_BASE, it's under "starting
and stopping rings"---fair enough.
In the case of vhost-user-scsi, however, QEMU also must not proceed
until vhost-user-scsi has drained the pending I/O---and this pending
I/O would be completed _after_ QEMU has sent GET_VRING_BASE.
Is this handled by VHOST_USER_PROTOCOL_F_REPLY_ACK already? If so,
migration would be denied if the server lacks that protocol feature.
Paolo
> > but perhaps it's best to add a START_STOP
> > feature and message to the vhost-user protocol?
>
> We just never need to GET_VRING_BASE if ring keeps going -
> makes no sense since base gets invalidated immediately.
>
>
>
> > The feature then can be optional for vhost-user-net and mandatory for
> > vhost-user-scsi. When this is done we can remove .unmigratable.
> >
> > Thanks,
> >
> > Paolo
>
> If vhost-user-scsi does not stop the ring after responding to
> GET_VRING_BASE, it's just a bug that needs to be fixed.
>
> > > >
> > > > Can you please send a version of your patch that uses .unmigratable?
> > >
> > > Sure I can do that. We can work on the migration later on.
> > >
> > > >
> > > > I'll send a v6 that momentarily drops vhost-scsi, but I intend to
> > > > include it again in the next pull request.
> > >
> > > Sounds good to me.
> > >
> > > Felipe
> > >
> > > >
> > > > Thanks,
> > > >
> > > > Paolo
> > >
> > >
>
- [Qemu-devel] [PULL v5 00/33] Misc patches for 2017-06-01, Paolo Bonzini, 2017/06/07
- [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Paolo Bonzini, 2017/06/07
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Peter Maydell, 2017/06/07
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Paolo Bonzini, 2017/06/07
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Felipe Franciosi, 2017/06/07
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Paolo Bonzini, 2017/06/07
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Michael S. Tsirkin, 2017/06/07
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device,
Paolo Bonzini <=
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Michael S. Tsirkin, 2017/06/07
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Felipe Franciosi, 2017/06/08
- Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device, Paolo Bonzini, 2017/06/08