Re: [Qemu-devel] [PATCH v3 0/4] dataplane: virtio-blk live migration with x-data-plane=on

[Kevin Wolf <kwolf@redhat.com>]

Am 29.07.2013 um 15:01 hat Stefan Hajnoczi geschrieben:
> v3:
>  * Fix spice migration, also needed for dataplane migration [kwolf]
> 
> v2:
>  * Rebase onto qemu.git/master
>  * Split bdrv_in_use() into separate patch, it's a bug fix [bonzini]
> 
> These patches add live migration support to -device virtio-blk-pci,x-data-plane=on.
> 
> Patches 1 & 2 make migration state notifiers reliable and fix spice migration.
> Dataplane migration faces the same issues so I'm including the patches here.
> 
> Patch 3 implements a switch from dataplane mode back to regular virtio-blk mode
> when migration starts.  This way live migration works.
> 
> Patch 4 is a bug fix: we need to check the device is not in use when creating
> the dataplane thread.  It applies to live migration but it turns out the same
> problem can be hit without migration too, see the commit description.
> 
> If migration is cancelled or the guest accesses the virtio-blk device after
> completion, dataplane starts again.
> 
> Since this approach is so small, it's more palatable for QEMU 1.6 than trying
> to make vring.c log dirty memory.  It makes dataplane usable in situations
> where live migration is a requirement.
> 
> Stefan Hajnoczi (4):
>   migration: notify migration state before starting thread
>   migration: fix spice migration
>   dataplane: enable virtio-blk x-data-plane=on live migration
>   dataplane: refuse to start if device is already in use
> 
>  hw/block/dataplane/virtio-blk.c | 17 ++++++++---------
>  hw/block/virtio-blk.c           | 32 ++++++++++++++++++++++++++++++++
>  include/hw/virtio/virtio-blk.h  |  1 +
>  include/migration/migration.h   |  2 +-
>  migration.c                     |  8 +++++---
>  ui/spice-core.c                 |  2 +-
>  6 files changed, 48 insertions(+), 14 deletions(-)

Reviewed-by: Kevin Wolf <kwolf@redhat.com>