27.08.2019, 17:02, "Eric Blake" <ebl...@redhat.com>:
> On 8/27/19 7:02 AM, Yury Kotov wrote:
>> This capability realizes simple source validation by UUID.
>> It's useful for live migration between hosts.
>>
>> Signed-off-by: Yury Kotov <yury-ko...@yandex-team.ru>
>> ---
>> migration/migration.c | 9 +++++++++
>> migration/migration.h | 1 +
>> migration/savevm.c | 45 +++++++++++++++++++++++++++++++++++++++++++
>> qapi/migration.json | 5 ++++-
>> 4 files changed, 59 insertions(+), 1 deletion(-)
>
> Any reason why this is marked experimental? It seems useful enough that
> we could probably just add it as a fully-supported feature (dropping the
> x- prefix) - but I'll leave that up to the migration maintainers.
>
I thought that all new capabilities have x- prefix... May be it's really
unnecessary here, I'm not sure.
> In fact, do we even need this to be a tunable feature? Why not just
> always enable it? As long as the UUID is sent in a way that new->old
> doesn't break the old qemu from receiving the migration stream, and that
> old->new copes with UUID being absent, then new->new will always benefit
> from the additional safety check.
>
In such case we couldn't migrate from e.g. 4.2 to 3.1
If it's not a problem then we can always use it.
>> +++ b/qapi/migration.json
>> @@ -415,6 +415,9 @@
>> #
>> # @x-ignore-shared: If enabled, QEMU will not migrate shared memory (since
>> 4.0)
>> #
>> +# @x-validate-uuid: Check whether the UUID is the same on both sides or
>> not.
>> +# (since 4.2)
>
> Maybe:
>
> @x-validate-uuid: Send the UUID of the source to allow the destination
> to ensure it is the same.
>
> if we even need a tunable capability.
>
Yes, it sounds better. Thanks!
>> +#
>> # Since: 1.2
>> ##
>> { 'enum': 'MigrationCapability',
>> @@ -422,7 +425,7 @@
>> 'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
>> 'block', 'return-path', 'pause-before-switchover', 'multifd',
>> 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate',
>> - 'x-ignore-shared' ] }
>> + 'x-ignore-shared', 'x-validate-uuid' ] }
>>
>> ##
>> # @MigrationCapabilityStatus:
>
> --
> Eric Blake, Principal Software Engineer
> Red Hat, Inc. +1-919-301-3226
> Virtualization: qemu.org | libvirt.org
Regards,
Yury
