[RFC PATCH v2 09/12] migration: Add QMP command start-migration-handler

[Dov Murik <dovmurik@linux.ibm.com>]

The start-migration-handler QMP command starts the mirror vcpu directly
at the migration handler entry point.

This is a temporary workaround to start-up (resume) the mirror vcpu
which runs the in-guest migration handler (both on the source and the
target).

A proper solution would be to start it automatically when the 'migrate'
and 'migrate-incoming' QMP commands are executed.

Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
---
 qapi/migration.json   | 12 ++++++++++++
 migration/migration.c | 12 ++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/qapi/migration.json b/qapi/migration.json
index 69c615ec4d..baff3c6bf7 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1504,6 +1504,18 @@
 ##
 { 'command': 'migrate-incoming', 'data': {'uri': 'str' } }
 
+##
+# @start-migration-handler:
+#
+# Start the mirror vcpu which runs the in-guest migration handler.
+#
+# Returns: nothing on success
+#
+# Since: 6.2
+#
+##
+{ 'command': 'start-migration-handler' }
+
 ##
 # @xen-save-devices-state:
 #
diff --git a/migration/migration.c b/migration/migration.c
index c9bc33fb10..a9f3a79e4f 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -60,6 +60,7 @@
 #include "qemu/yank.h"
 #include "sysemu/cpus.h"
 #include "yank_functions.h"
+#include "confidential-ram.h"
 
 #define MAX_THROTTLE  (128 << 20)      /* Migration transfer speed throttling */
 
@@ -2161,6 +2162,17 @@ void qmp_migrate_incoming(const char *uri, Error **errp)
     once = false;
 }
 
+void qmp_start_migration_handler(Error **errp)
+{
+    CPUState *cpu;
+    CPU_FOREACH(cpu) {
+        if (cpu->mirror_vcpu) {
+            cgs_mh_reset_mirror_vcpu(cpu);
+            cpu_resume(cpu);
+        }
+    }
+}
+
 void qmp_migrate_recover(const char *uri, Error **errp)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
-- 
2.20.1