[PULL 02/10] migration/cpr: Add HMP support for cpr-transfer

[Peter Xu <peterx@redhat.com>]

From: Dongli Zhang <dongli.zhang@oracle.com>

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
option 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
"-c unix:/tmp/cpr.sock" is for CPR URI.

(qemu) migrate_set_parameter mode cpr-transfer
(qemu) migrate -c unix:/tmp/cpr.sock tcp:0:50002

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Dr. David Alan Gilbert <dave@treblig.org>
Acked-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/r/20260728085903.173265-1-dongli.zhang@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration-hmp-cmds.c | 18 ++++++++++++++++++
 hmp-commands.hx                | 12 ++++++++----
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index b04fc4489f..b5eb27467c 100644
--- a/migration/migration-hmp-cmds.c
+++ b/migration/migration-hmp-cmds.c
@@ -837,9 +837,11 @@ 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);
@@ -847,6 +849,22 @@ 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, "-c can only be used in cpr-transfer mode");
+            hmp_handle_error(mon, err);
+            return;
+        }
+
+        if (!migrate_uri_parse(uri_cpr, &channel_cpr, &err)) {
+            hmp_handle_error(mon, err);
+            return;
+        }
+
+        channel_cpr->channel_type = MIGRATION_CHANNEL_TYPE_CPR;
+        QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel_cpr));
+    }
+
     qmp_migrate(NULL, true, caps, true, resume, &err);
     if (hmp_handle_error(mon, err)) {
         return;
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 7ae2468a3d..7f43cf537f 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-cpr:-cs,uri:s",
+        .params     = "[-d] [-r] [-c uri-cpr] uri",
         .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 -c to specify a CPR URI for cpr-transfer mode",
         .cmd        = hmp_migrate,
     },
 
 
 SRST
-``migrate [-d] [-r]`` *uri*
+``migrate [-d] [-r] [-c uri-cpr]`` *uri*
   Migrate the VM to *uri*.
 
   ``-d``
@@ -945,6 +946,9 @@ SRST
     query an ongoing migration process, use "info migrate".
   ``-r``
     Resume a paused postcopy migration.
+  ``-c`` *uri-cpr*
+    Specify the CPR URI for cpr-transfer mode. It must be a UNIX domain
+    socket.
 ERST
 
     {
-- 
2.54.0