Re: [PATCH v10 00/10] migration: Modify 'migrate' and 'migrate-incoming' QAPI commands for migration

[Het Gala <het.gala@nutanix.com>]

Hi,

A gentle reminder for Juan and other migration maintainers for the 
review of this patchset series if any changes are required or give to 
queue them. There are more patchset series coming after this. As 
discussed earlier, we have broken down it into 4 different patchset 
series. This is just Part1 of the 4 patchset series. Ultimate goal is to 
'introduce multiple interface support on top of existing multifd 
capability'.

On 27/07/23 4:59 pm, Het Gala wrote:
> This is just a ping for Juan and other migration maintainers, if it's 
> possible to have a look at the migration patches for new QAPI design 
> and suggest some review comments if any.
>
> Update till now : Have got acked-by label from Markus for the new 
> migrate QAPI design, and reviewd-by label from Daniel on the QAPI 
> implementation side patches.
>
> On 26/07/23 7:48 pm, Het Gala wrote:
>> This is v10 patchset of modified 'migrate' and 'migrate-incoming' 
>> QAPI design
>> for upstream review.
>>
>> Would like to thank all the maintainers that actively participated in 
>> the v9
>> patchset discussion and gave insightful suggestions to improve the 
>> patches.
>>
>>
>> Link to previous upstream community patchset links:
>> v1: https://lists.gnu.org/archive/html/qemu-devel/2022-12/msg04339.html
>> v2: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg02106.html
>> v3: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg02473.html
>> v4: https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg03064.html
>> v5: https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg04845.html
>> v6: https://lists.gnu.org/archive/html/qemu-devel/2023-06/msg01251.html
>> v7: https://lists.gnu.org/archive/html/qemu-devel/2023-07/msg02027.html
>> v8: https://lists.gnu.org/archive/html/qemu-devel/2023-07/msg02770.html
>> v9: https://lists.gnu.org/archive/html/qemu-devel/2023-07/msg04216.html
>>
>> v9 -> v10 changelog:
>> -------------------
>> - Patch6 : Added extra checks for migration arguments.
>> - Patch8 : Added checks for 'uri' and 'channels' both not present.
>> - Patch9 : Missed adding hmp_handle_error call to print error messages.
>> Abstract:
>> ---------
>>
>> Current QAPI 'migrate' command design (for initiating a migration
>> stream) contains information regarding different migrate transport 
>> mechanism
>> (tcp / unix / exec), dest-host IP address, and binding port number in 
>> form of
>> a string. Thus the design does seem to have some design issues. Some 
>> of the
>> issues, stated below are:
>>
>> 1. Use of string URIs is a data encoding scheme within a data 
>> encoding scheme.
>>     QEMU code should directly be able to work with the results from 
>> QAPI,
>>     without resorting to do a second level of parsing (eg. 
>> socket_parse()).
>> 2. For features / parameters related to migration, the migration 
>> tunables needs
>>     to be defined and updated upfront. For example, 
>> 'migrate-set-capability'
>>     and 'migrate-set-parameter' is required to enable multifd 
>> capability and
>>     multifd-number of channels respectively. Instead, 
>> 'Multifd-channels' can
>>     directly be represented as a single additional parameter to 
>> 'migrate'
>>     QAPI. 'migrate-set-capability' and 'migrate-set-parameter' 
>> commands could
>>     be used for runtime tunables that need setting after migration 
>> has already
>>     started.
>>
>> The current patchset focuses on solving the first problem of multi-level
>> encoding of URIs. The patch defines 'migrate' command as a QAPI 
>> discriminated
>> union for the various transport backends (like socket, exec and 
>> rdma), and on
>> basis of transport backends, different migration parameters are defined.
>>
>> (uri) string -->  (channel) Channel-type
>>                              Transport-type
>>                              Migration parameters based on transport 
>> type
>> ------------------------------------------------------------------------------ 
>>
>>
>> Het Gala (10):
>>    migration: New QAPI type 'MigrateAddress'
>>    migration: convert migration 'uri' into 'MigrateAddress'
>>    migration: convert socket backend to accept MigrateAddress
>>    migration: convert rdma backend to accept MigrateAddress
>>    migration: convert exec backend to accept MigrateAddress.
>>    migration: New migrate and migrate-incoming argument 'channels'
>>    migration: modify migration_channels_and_uri_compatible() for new 
>> QAPI
>>      syntax
>>    migration: Implement MigrateChannelList to qmp migration flow.
>>    migration: Implement MigrateChannelList to hmp migration flow.
>>    migration: modify test_multifd_tcp_none() to use new QAPI syntax.
>>
>>   migration/exec.c               |  72 +++++++++----
>>   migration/exec.h               |   8 +-
>>   migration/migration-hmp-cmds.c |  17 ++-
>>   migration/migration.c          | 190 ++++++++++++++++++++++++++-------
>>   migration/migration.h          |   3 +-
>>   migration/rdma.c               |  34 +++---
>>   migration/rdma.h               |   6 +-
>>   migration/socket.c             |  39 ++-----
>>   migration/socket.h             |   7 +-
>>   qapi/migration.json            | 150 +++++++++++++++++++++++++-
>>   softmmu/vl.c                   |   2 +-
>>   tests/qtest/migration-test.c   |   7 +-
>>   12 files changed, 409 insertions(+), 126 deletions(-)
> Regards,
> Het Gala
Regards,
Het Gala