[PATCH v11 08/10] migration: Implement MigrateChannelList to qmp migration flow.

[Het Gala]

Integrate MigrateChannelList with all transport backends
(socket, exec and rdma) for both src and dest migration
endpoints for qmp migration.

For current series, limit the size of MigrateChannelList
to single element (single interface) as runtime check.

Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---
 migration/migration.c | 95 +++++++++++++++++++++++--------------------
 1 file changed, 52 insertions(+), 43 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 6f948988ec..3eae32e616 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -432,9 +432,10 @@ void migrate_add_address(SocketAddress *address)
 }
 
 static bool migrate_uri_parse(const char *uri,
-                              MigrationAddress **channel,
+                              MigrationChannel **channel,
                               Error **errp)
 {
+    g_autoptr(MigrationChannel) val = g_new0(MigrationChannel, 1);
     g_autoptr(MigrationAddress) addr = g_new0(MigrationAddress, 1);
     SocketAddress *saddr = &addr->u.socket;
     InetSocketAddress *isock = &addr->u.rdma;
@@ -471,7 +472,9 @@ static bool migrate_uri_parse(const char *uri,
         return false;
     }
 
-    *channel = addr;
+    val->channel_type = MIGRATION_CHANNEL_TYPE_MAIN;
+    val->addr = addr;
+    *channel = val;
     return true;
 }
 
@@ -479,41 +482,44 @@ static void qemu_start_incoming_migration(const char 
*uri, bool has_channels,
                                           MigrationChannelList *channels,
                                           Error **errp)
 {
-    g_autoptr(MigrationAddress) channel = g_new0(MigrationAddress, 1);
+    g_autoptr(MigrationChannel) channel = g_new0(MigrationChannel, 1);
+    g_autoptr(MigrationAddress) addr = g_new0(MigrationAddress, 1);
 
     /*
      * Having preliminary checks for uri and channel
      */
-    if (has_channels) {
-        error_setg(errp, "'channels' argument should not be set yet.");
-        return;
-    }
-
     if (uri && has_channels) {
         error_setg(errp, "'uri' and 'channels' arguments are mutually "
                    "exclusive; exactly one of the two should be present in "
                    "'migrate-incoming' qmp command ");
         return;
-    }
-
-    if (!uri && !has_channels) {
+    } else if (channels) {
+        /* To verify that Migrate channel list has only item */
+        if (channels->next) {
+            error_setg(errp, "Channel list has more than one entries");
+            return;
+        }
+        channel = channels->value;
+    } else if (uri) {
+        /* caller uses the old URI syntax */
+        if (!migrate_uri_parse(uri, &channel, errp)) {
+            return;
+        }
+    } else {
         error_setg(errp, "neither 'uri' or 'channels' argument are "
                    "specified in 'migrate-incoming' qmp command ");
         return;
     }
-
-    if (uri && !migrate_uri_parse(uri, &channel, errp)) {
-        return;
-    }
+    addr = channel->addr;
 
     /* transport mechanism not suitable for migration? */
-    if (!migration_channels_and_transport_compatible(channel, errp)) {
+    if (!migration_channels_and_transport_compatible(addr, errp)) {
         return;
     }
 
     qapi_event_send_migration(MIGRATION_STATUS_SETUP);
-    if (channel->transport == MIGRATION_ADDRESS_TYPE_SOCKET) {
-        SocketAddress *saddr = &channel->u.socket;
+    if (addr->transport == MIGRATION_ADDRESS_TYPE_SOCKET) {
+        SocketAddress *saddr = &addr->u.socket;
         if (saddr->type == SOCKET_ADDRESS_TYPE_INET ||
             saddr->type == SOCKET_ADDRESS_TYPE_UNIX ||
             saddr->type == SOCKET_ADDRESS_TYPE_VSOCK) {
@@ -522,11 +528,11 @@ static void qemu_start_incoming_migration(const char 
*uri, bool has_channels,
             fd_start_incoming_migration(saddr->u.fd.str, errp);
         }
 #ifdef CONFIG_RDMA
-    } else if (channel->transport == MIGRATION_ADDRESS_TYPE_RDMA) {
-        rdma_start_incoming_migration(&channel->u.rdma, errp);
-#endif
-    } else if (channel->transport == MIGRATION_ADDRESS_TYPE_EXEC) {
-        exec_start_incoming_migration(channel->u.exec.args, errp);
+    } else if (addr->transport == MIGRATION_ADDRESS_TYPE_RDMA) {
+        rdma_start_incoming_migration(&addr->u.rdma, errp);
+ #endif
+    } else if (addr->transport == MIGRATION_ADDRESS_TYPE_EXEC) {
+        exec_start_incoming_migration(addr->u.exec.args, errp);
     } else {
         error_setg(errp, "unknown migration protocol: %s", uri);
     }
@@ -1750,35 +1756,38 @@ void qmp_migrate(const char *uri, bool has_channels,
     bool resume_requested;
     Error *local_err = NULL;
     MigrationState *s = migrate_get_current();
-    g_autoptr(MigrationAddress) channel = g_new0(MigrationAddress, 1);
+    g_autoptr(MigrationChannel) channel = g_new0(MigrationChannel, 1);
+    g_autoptr(MigrationAddress) addr = g_new0(MigrationAddress, 1);
 
     /*
      * Having preliminary checks for uri and channel
      */
-    if (has_channels) {
-        error_setg(errp, "'channels' argument should not be set yet.");
-        return;
-    }
-
     if (uri && has_channels) {
         error_setg(errp, "'uri' and 'channels' arguments are mutually "
                    "exclusive; exactly one of the two should be present in "
                    "'migrate' qmp command ");
         return;
-    }
-
-    if (!uri && !has_channels) {
+    } else if (channels) {
+        /* To verify that Migrate channel list has only item */
+        if (channels->next) {
+            error_setg(errp, "Channel list has more than one entries");
+            return;
+        }
+        channel = channels->value;
+    } else if (uri) {
+        /* caller uses the old URI syntax */
+        if (!migrate_uri_parse(uri, &channel, errp)) {
+            return;
+        }
+    } else {
         error_setg(errp, "neither 'uri' or 'channels' argument are "
                    "specified in 'migrate' qmp command ");
         return;
     }
-
-    if (!migrate_uri_parse(uri, &channel, errp)) {
-        return;
-    }
+    addr = channel->addr;
 
     /* transport mechanism not suitable for migration? */
-    if (!migration_channels_and_transport_compatible(channel, errp)) {
+    if (!migration_channels_and_transport_compatible(addr, errp)) {
         return;
     }
 
@@ -1795,8 +1804,8 @@ void qmp_migrate(const char *uri, bool has_channels,
         }
     }
 
-    if (channel->transport == MIGRATION_ADDRESS_TYPE_SOCKET) {
-        SocketAddress *saddr = &channel->u.socket;
+    if (addr->transport == MIGRATION_ADDRESS_TYPE_SOCKET) {
+        SocketAddress *saddr = &addr->u.socket;
         if (saddr->type == SOCKET_ADDRESS_TYPE_INET ||
             saddr->type == SOCKET_ADDRESS_TYPE_UNIX ||
             saddr->type == SOCKET_ADDRESS_TYPE_VSOCK) {
@@ -1805,11 +1814,11 @@ void qmp_migrate(const char *uri, bool has_channels,
             fd_start_outgoing_migration(s, saddr->u.fd.str, &local_err);
         }
 #ifdef CONFIG_RDMA
-    } else if (channel->transport == MIGRATION_ADDRESS_TYPE_RDMA) {
-        rdma_start_outgoing_migration(s, &channel->u.rdma, &local_err);
+    } else if (addr->transport == MIGRATION_ADDRESS_TYPE_RDMA) {
+        rdma_start_outgoing_migration(s, &addr->u.rdma, &local_err);
 #endif
-    } else if (channel->transport == MIGRATION_ADDRESS_TYPE_EXEC) {
-        exec_start_outgoing_migration(s, channel->u.exec.args, &local_err);
+    } else if (addr->transport == MIGRATION_ADDRESS_TYPE_EXEC) {
+        exec_start_outgoing_migration(s, addr->u.exec.args, &local_err);
     } else {
         error_setg(&local_err, QERR_INVALID_PARAMETER_VALUE, "uri",
                    "a valid migration protocol");
-- 
2.22.3