migration: incoming channel

Extend the -incoming option to allow an @MigrationChannel to be specified.
This allows channels other than 'main' to be described on the command
line, which will be needed for CPR.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Acked-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1736967650-129648-13-git-send-email-steven.sistare@oracle.com
Signed-off-by: Fabiano Rosas <farosas@suse.de>

migration/migration.c

@@ -695,7 +695,8 @@ static void qemu_start_incoming_migration(const char *uri, bool has_channels,
     if (channels) {
         /* To verify that Migrate channel list has only item */
         if (channels->next) {
-            error_setg(errp, "Channel list has more than one entries");
+            error_setg(errp, "Channel list must have only one entry, "
+                             "for type 'main'");
             return;
         }
         addr = channels->value->addr;
@@ -2054,6 +2055,7 @@ void qmp_migrate(const char *uri, bool has_channels,
     MigrationState *s = migrate_get_current();
     g_autoptr(MigrationChannel) channel = NULL;
     MigrationAddress *addr = NULL;
+    MigrationChannel *channelv[MIGRATION_CHANNEL_TYPE__MAX] = { NULL };
 
     /*
      * Having preliminary checks for uri and channel
@@ -2064,12 +2066,21 @@ void qmp_migrate(const char *uri, bool has_channels,
     }
 
     if (channels) {
-        /* To verify that Migrate channel list has only item */
+        for ( ; channels; channels = channels->next) {
-        if (channels->next) {
+            MigrationChannelType type = channels->value->channel_type;
-            error_setg(errp, "Channel list has more than one entries");
+
+            if (channelv[type]) {
+                error_setg(errp, "Channel list has more than one %s entry",
+                           MigrationChannelType_str(type));
+                return;
+            }
+            channelv[type] = channels->value;
+        }
+        addr = channelv[MIGRATION_CHANNEL_TYPE_MAIN]->addr;
+        if (!addr) {
+            error_setg(errp, "Channel list has no main entry");
             return;
         }
-        addr = channels->value->addr;
     }
 
     if (uri) {

qemu-options.hx

@@ -4940,10 +4940,18 @@ DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
     "-incoming exec:cmdline\n" \
     "                accept incoming migration on given file descriptor\n" \
     "                or from given external command\n" \
+    "-incoming <channel>\n" \
+    "                accept incoming migration on the migration channel\n" \
     "-incoming defer\n" \
     "                wait for the URI to be specified via migrate_incoming\n",
     QEMU_ARCH_ALL)
 SRST
+The -incoming option specifies the migration channel for an incoming
+migration.  It may be used multiple times to specify multiple
+migration channel types.  The channel type is specified in <channel>,
+or is 'main' for all other forms of -incoming.  If multiple -incoming
+options are specified for a channel type, the last one takes precedence.
+
 ``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]``
   \ 
 ``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]``
@@ -4963,6 +4971,19 @@ SRST
     Accept incoming migration as an output from specified external
     command.
 
+``-incoming <channel>``
+    Accept incoming migration on the migration channel.  For the syntax
+    of <channel>, see the QAPI documentation of ``MigrationChannel``.
+    Examples:
+    ::
+
+        -incoming '{"channel-type": "main",
+                    "addr": { "transport": "socket",
+                              "type": "unix",
+                              "path": "my.sock" }}'
+
+        -incoming main,addr.transport=socket,addr.type=unix,addr.path=my.sock
+
 ``-incoming defer``
     Wait for the URI to be specified via migrate\_incoming. The monitor
     can be used to change settings (such as migration parameters) prior

system/vl.c

@@ -123,6 +123,7 @@
 #include "qapi/qapi-visit-block-core.h"
 #include "qapi/qapi-visit-compat.h"
 #include "qapi/qapi-visit-machine.h"
+#include "qapi/qapi-visit-migration.h"
 #include "qapi/qapi-visit-ui.h"
 #include "qapi/qapi-commands-block-core.h"
 #include "qapi/qapi-commands-migration.h"
@@ -159,6 +160,8 @@ typedef struct DeviceOption {
 static const char *cpu_option;
 static const char *mem_path;
 static const char *incoming;
+static const char *incoming_str[MIGRATION_CHANNEL_TYPE__MAX];
+static MigrationChannel *incoming_channels[MIGRATION_CHANNEL_TYPE__MAX];
 static const char *loadvm;
 static const char *accelerators;
 static bool have_custom_ram_size;
@@ -1813,6 +1816,30 @@ static void object_option_add_visitor(Visitor *v)
     QTAILQ_INSERT_TAIL(&object_opts, opt, next);
 }
 
+static void incoming_option_parse(const char *str)
+{
+    MigrationChannelType type = MIGRATION_CHANNEL_TYPE_MAIN;
+    MigrationChannel *channel;
+    Visitor *v;
+
+    if (!strcmp(str, "defer")) {
+        channel = NULL;
+    } else if (migrate_is_uri(str)) {
+        migrate_uri_parse(str, &channel, &error_fatal);
+    } else {
+        v = qobject_input_visitor_new_str(str, "channel-type", &error_fatal);
+        visit_type_MigrationChannel(v, NULL, &channel, &error_fatal);
+        visit_free(v);
+        type = channel->channel_type;
+    }
+
+    /* New incoming spec replaces the previous */
+    qapi_free_MigrationChannel(incoming_channels[type]);
+    incoming_channels[type] = channel;
+    incoming_str[type] = str;
+    incoming = incoming_str[MIGRATION_CHANNEL_TYPE_MAIN];
+}
+
 static void object_option_parse(const char *str)
 {
     QemuOpts *opts;
@@ -2738,8 +2765,11 @@ void qmp_x_exit_preconfig(Error **errp)
     if (incoming) {
         Error *local_err = NULL;
         if (strcmp(incoming, "defer") != 0) {
-            qmp_migrate_incoming(incoming, false, NULL, true, true,
+            g_autofree MigrationChannelList *channels =
-                                 &local_err);
+                g_new0(MigrationChannelList, 1);
+
+            channels->value = incoming_channels[MIGRATION_CHANNEL_TYPE_MAIN];
+            qmp_migrate_incoming(NULL, true, channels, true, true, &local_err);
             if (local_err) {
                 error_reportf_err(local_err, "-incoming %s: ", incoming);
                 exit(1);
@@ -3458,7 +3488,7 @@ void qemu_init(int argc, char **argv)
                 if (!incoming) {
                     runstate_set(RUN_STATE_INMIGRATE);
                 }
-                incoming = optarg;
+                incoming_option_parse(optarg);
                 break;
             case QEMU_OPTION_only_migratable:
                 only_migratable = 1;