[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support reg
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers |
Date: |
Thu, 19 Apr 2018 18:59:40 +0300 |
On Thu, Apr 19, 2018 at 05:51:51PM +0200, Paolo Bonzini wrote:
> On 19/04/2018 17:19, Michael S. Tsirkin wrote:
> >> - if we make it 1 when weak barriers are needed, the device also needs
> >> to nack feature negotiation (not allow setting the FEATURES_OK) if the
> >> bit is not set by the driver.
> >> However, that is not enough. Live
> >> migration assumes that it is okay to migrate a virtual machine from a
> >> source that doesn't support a feature to a destination that supports it.
> >> In this case, it would assume that it is okay to migrate from software
> >> virtio to hardware virtio. This is wrong because the destination would
> >> use weak barriers
> >
> > You can't migrate between systems with different sets of device features
> > right now.
>
> Yes, you can, exactly because some features are defined not by the
> machine type but rather by the host kernel. See virtio_net_get_features
> in QEMU's hw/virtio/virtio-net.c, and virtio_set_features_nocheck in
> QEMU's hw/virtio/virtio.c.
>
> Thanks,
>
> Paolo
Oh you are right. Well we can just special-case that one :)
--
MST
- [Qemu-devel] [PATCH v3 3/6] vhost-user: support receiving file descriptors in slave_read, (continued)
- [Qemu-devel] [PATCH v3 3/6] vhost-user: support receiving file descriptors in slave_read, Tiwei Bie, 2018/04/12
- [Qemu-devel] [PATCH v3 4/6] virtio: support setting memory region based host notifier, Tiwei Bie, 2018/04/12
- [Qemu-devel] [PATCH v3 5/6] vhost: allow backends to filter memory sections, Tiwei Bie, 2018/04/12
- [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Tiwei Bie, 2018/04/12
- Re: [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Michael S. Tsirkin, 2018/04/18
- Re: [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Tiwei Bie, 2018/04/19
- Re: [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Liang, Cunming, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Paolo Bonzini, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Michael S. Tsirkin, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Paolo Bonzini, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Paolo Bonzini, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Michael S. Tsirkin, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Liang, Cunming, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Michael S. Tsirkin, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Liang, Cunming, 2018/04/19
- Re: [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Michael S. Tsirkin, 2018/04/19
- Re: [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Paolo Bonzini, 2018/04/19
- Re: [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Michael S. Tsirkin, 2018/04/19
- Re: [Qemu-devel] [PATCH v3 6/6] vhost-user: support registering external host notifiers, Liang, Cunming, 2018/04/19
- Re: [Qemu-devel] [virtio-dev] RE: [PATCH v3 6/6] vhost-user: support registering external host notifiers, Paolo Bonzini, 2018/04/19