Re: [Qemu-devel] [PATCH 0/3] Introduce a new --only-migratable option

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Michael S. Tsirkin (mst@redhat.com) wrote:
> On Thu, Dec 15, 2016 at 12:36:59AM +0530, Ashijeet Acharya wrote:
> > This series adds a new command line option "--only-migratable" which will only
> > allow addition of those devices to a QEMU instance which are migratable and do
> > not abruptly fail QEMU after migration.
> > 
> > Patch 1 adds the new option "-only-migratable".
> > 
> > Patch 2 adds compatibility for various "device adding" options for both via
> > command line and hotplug methods.
> > 
> > Patch 3 handles the special case of devices which become unmigratable dynamically
> > by making call to "migrate_add_blocker". Here we fail the particular action of the
> > device which results in an unmigratable VM.
> > Eg: 9pfs fails to mount the filesystem.
> 
> I guess that's possible but wouldn't it be cleaner to add introspection
> so management can find out what can migrate?
> Further, what should be removed (e.g. by hotplug) if you do want
> to migrate.
> 
> As it is, you get a failure but no easy way for tools to
> find out what was the failure reason.

You get the device name of the device that's failed don't you?
Where would you add introspection?

Dave

> 
> > Ashijeet Acharya (3):
> >   migration: Add a new option to enable only-migratable
> >   migration: Allow "device add" options to only add migratable devices
> >   migration: disallow migrate_add_blocker during migration
> > 
> >  block/qcow.c                  | 11 ++++++++++-
> >  block/vdi.c                   | 11 ++++++++++-
> >  block/vhdx.c                  | 20 ++++++++++++++------
> >  block/vmdk.c                  | 12 +++++++++++-
> >  block/vpc.c                   | 15 ++++++++++++---
> >  block/vvfat.c                 | 24 ++++++++++++++++--------
> >  hw/9pfs/9p.c                  | 22 ++++++++++++++++++----
> >  hw/display/virtio-gpu.c       | 35 ++++++++++++++++++++++-------------
> >  hw/intc/arm_gic_kvm.c         | 20 ++++++++++++++------
> >  hw/intc/arm_gicv3_its_kvm.c   | 21 ++++++++++++++-------
> >  hw/intc/arm_gicv3_kvm.c       | 22 +++++++++++++++-------
> >  hw/misc/ivshmem.c             | 17 +++++++++++++----
> >  hw/scsi/vhost-scsi.c          | 27 +++++++++++++++++++++------
> >  hw/usb/bus.c                  | 15 +++++++++++++++
> >  hw/virtio/vhost.c             | 11 ++++++++++-
> >  include/migration/migration.h |  9 ++++++++-
> >  migration/migration.c         | 42 ++++++++++++++++++++++++++++++++++++++++--
> >  qdev-monitor.c                |  9 +++++++++
> >  qemu-options.hx               | 10 ++++++++++
> >  stubs/migr-blocker.c          |  3 ++-
> >  target-i386/kvm.c             | 19 ++++++++++++++++---
> >  vl.c                          |  4 ++++
> >  22 files changed, 304 insertions(+), 75 deletions(-)
> > 
> > -- 
> > 2.6.2
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK