On 2026-06-24 8:26 AM, Fabiano Rosas wrote:
> Dongli Zhang <[email protected]> writes:
>
>> Currently the cpr-transfer source QEMU instance cannot be driven entirely
>> via HMP. The source must use QMP in order to specify both the
>> main migration channel and the CPR channel.
>>
>> Extend the HMP migrate command with an optional CPR channel URI. When the
>> migration mode is cpr-transfer, HMP uses this URI to build a
>> CPR MigrationChannel in addition to the main migration channel. The new
>> argument is rejected unless the migration mode is cpr-transfer, so existing
>> HMP migrate usage is unchanged.
>>
>> For example, source QEMU HMP commands can be something like below. The
>> "unix:/tmp/cpr.sock" is for CPR URI.
>>
>> (qemu) migrate_set_parameter mode cpr-transfer
>> (qemu) migrate tcp:0:50002 unix:/tmp/cpr.sock
>>
>> Signed-off-by: Dongli Zhang <[email protected]>
>> ---
>> hmp-commands.hx | 11 +++++++----
>> migration/migration-hmp-cmds.c | 18 ++++++++++++++++++
>> 2 files changed, 25 insertions(+), 4 deletions(-)
>>
>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>> index 7ae2468a3d..021e51b142 100644
>> --- a/hmp-commands.hx
>> +++ b/hmp-commands.hx
>> @@ -928,16 +928,17 @@ ERST
>>
>> {
>> .name = "migrate",
>> - .args_type = "detach:-d,resume:-r,uri:s",
>> - .params = "[-d] [-r] uri",
>> + .args_type = "detach:-d,resume:-r,uri:s,uri-cpr:s?",
>> + .params = "[-d] [-r] uri [uri-cpr]",
>> .help = "migrate to URI (using -d to not wait for completion)"
>> - "\n\t\t\t -r to resume a paused postcopy migration",
>> + "\n\t\t\t -r to resume a paused postcopy migration"
>> + "\n\t\t\t uri-cpr specifies CPR URI for cpr-transfer
>> mode",
>> .cmd = hmp_migrate,
>> },
>>
>>
>> SRST
>> -``migrate [-d] [-r]`` *uri*
>> +``migrate [-d] [-r]`` *uri* [*uri-cpr*]
>> Migrate the VM to *uri*.
>>
>> ``-d``
>> @@ -945,6 +946,8 @@ SRST
>> query an ongoing migration process, use "info migrate".
>> ``-r``
>> Resume a paused postcopy migration.
>> + ``uri-cpr``
>> + Specify CPR URI for cpr-transfer mode. It must be a UNIX domain socket.
>> ERST
>>
>> {
>> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
>> index 8b385f560e..42ca652bb3 100644
>> --- a/migration/migration-hmp-cmds.c
>> +++ b/migration/migration-hmp-cmds.c
>> @@ -836,9 +836,11 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
>> bool detach = qdict_get_try_bool(qdict, "detach", false);
>> bool resume = qdict_get_try_bool(qdict, "resume", false);
>> const char *uri = qdict_get_str(qdict, "uri");
>> + const char *uri_cpr = qdict_get_try_str(qdict, "uri-cpr");
>> Error *err = NULL;
>> g_autoptr(MigrationChannelList) caps = NULL;
>> g_autoptr(MigrationChannel) channel = NULL;
>> + g_autoptr(MigrationChannel) channel_cpr = NULL;
>>
>> if (!migrate_uri_parse(uri, &channel, &err)) {
>> hmp_handle_error(mon, err);
>> @@ -846,6 +848,22 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
>> }
>> QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel));
>>
>> + if (uri_cpr) {
>> + if (migrate_mode() != MIG_MODE_CPR_TRANSFER) {
>> + error_setg(&err, "uri-cpr requires cpr-transfer mode");
>
> Most users probably won't know what an uri-cpr is. Maybe: "a second uri
> can only be used in cpr-transfer mode".
>
Will do. Thank you very much for suggestion!
Dongli Zhang
