Commit 5bc9c7995c for qemu.org

commit 5bc9c7995ceebc605f27d12b8c4b43a8516ee94c
Author: Fabiano Rosas <farosas@suse.de>
Date:   Fri Jan 23 11:16:43 2026 -0300

    migration: Move setting of QEMUFile into migration_outgoing|incoming_setup

    Centralize, on both sides of migration, the setting of the to_src_file
    and from_dst_file QEMUFiles. This will clean up the interface with
    channel.c and rdma.c, allowing those files to stop dealing with
    QEMUFile themselves.

    (multifd_recv_new_channel was changed to return bool+errp for
    convenience)

    Reviewed-by: Peter Xu <peterx@redhat.com>
    Reviewed-by: Prasad Pandit <pjp@fedoraproject.org>
    Link: https://lore.kernel.org/qemu-devel/20260123141656.6765-14-farosas@suse.de
    Signed-off-by: Fabiano Rosas <farosas@suse.de>

diff --git a/migration/channel.c b/migration/channel.c
index 26cb7bf059..6acce7b2a2 100644
--- a/migration/channel.c
+++ b/migration/channel.c
@@ -14,7 +14,6 @@
 #include "channel.h"
 #include "tls.h"
 #include "migration.h"
-#include "qemu-file.h"
 #include "trace.h"
 #include "qapi/error.h"
 #include "io/channel-tls.h"
@@ -80,14 +79,8 @@ void migration_channel_connect(MigrationState *s, QIOChannel *ioc)
         return;
     }

-    QEMUFile *f = qemu_file_new_output(ioc);
-
     migration_ioc_register_yank(ioc);
-
-    qemu_mutex_lock(&s->qemu_file_lock);
-    s->to_dst_file = f;
-    qemu_mutex_unlock(&s->qemu_file_lock);
-
+    migration_outgoing_setup(ioc);
     migration_connect(s);
 }

diff --git a/migration/migration.c b/migration/migration.c
index 82e431b637..dbb28da38f 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -929,17 +929,56 @@ out:
     migrate_incoming_unref_outgoing_state();
 }

-/**
- * migration_incoming_setup: Setup incoming migration
- * @f: file for main migration channel
+static bool migration_has_main_and_multifd_channels(void);
+
+/*
+ * Returns whether all the necessary channels to proceed with the
+ * incoming migration have been established without error.
  */
-static void migration_incoming_setup(QEMUFile *f)
+bool migration_incoming_setup(QIOChannel *ioc, uint8_t channel, Error **errp)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
+    QEMUFile *f;

-    assert(!mis->from_src_file);
-    mis->from_src_file = f;
-    qemu_file_set_blocking(f, false, &error_abort);
+    if (multifd_recv_setup(errp) != 0) {
+        return false;
+    }
+
+    switch (channel) {
+    case CH_MAIN:
+        f = qemu_file_new_input(ioc);
+        assert(!mis->from_src_file);
+        mis->from_src_file = f;
+        qemu_file_set_blocking(f, false, &error_abort);
+        break;
+
+    case CH_MULTIFD:
+        if (!multifd_recv_new_channel(ioc, errp)) {
+            return false;
+        }
+        break;
+
+    case CH_POSTCOPY:
+        assert(!mis->postcopy_qemufile_dst);
+        f = qemu_file_new_input(ioc);
+        postcopy_preempt_new_channel(mis, f);
+        return false;
+
+    default:
+        g_assert_not_reached();
+    }
+
+    return migration_has_main_and_multifd_channels();
+}
+
+void migration_outgoing_setup(QIOChannel *ioc)
+{
+    MigrationState *s = migrate_get_current();
+    QEMUFile *f = qemu_file_new_output(ioc);
+
+    qemu_mutex_lock(&s->qemu_file_lock);
+    s->to_dst_file = f;
+    qemu_mutex_unlock(&s->qemu_file_lock);
 }

 /* Returns true if recovered from a paused migration, otherwise false */
@@ -987,7 +1026,11 @@ void migration_incoming_process(void)

 void migration_fd_process_incoming(QEMUFile *f)
 {
-    migration_incoming_setup(f);
+    MigrationIncomingState *mis = migration_incoming_get_current();
+
+    assert(!mis->from_src_file);
+    mis->from_src_file = f;
+    qemu_file_set_blocking(f, false, &error_abort);
     migration_incoming_process();
 }

@@ -1010,8 +1053,6 @@ static bool migration_has_main_and_multifd_channels(void)
 void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
-    Error *local_err = NULL;
-    QEMUFile *f;
     uint8_t channel;
     uint32_t channel_magic = 0;
     int ret = 0;
@@ -1065,28 +1106,7 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
         channel = CH_POSTCOPY;
     }

-    if (multifd_recv_setup(errp) != 0) {
-        return;
-    }
-
-    if (channel == CH_MAIN) {
-        f = qemu_file_new_input(ioc);
-        migration_incoming_setup(f);
-    } else if (channel == CH_MULTIFD) {
-        /* Multiple connections */
-        multifd_recv_new_channel(ioc, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
-            return;
-        }
-    } else if (channel == CH_POSTCOPY) {
-        assert(!mis->postcopy_qemufile_dst);
-        f = qemu_file_new_input(ioc);
-        postcopy_preempt_new_channel(mis, f);
-        return;
-    }
-
-    if (migration_has_main_and_multifd_channels()) {
+    if (migration_incoming_setup(ioc, channel, errp)) {
         migration_incoming_process();
     }
 }
diff --git a/migration/migration.h b/migration/migration.h
index d134881eaf..4dcf299719 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -530,6 +530,8 @@ void migrate_set_state(MigrationStatus *state, MigrationStatus old_state,
 void migration_fd_process_incoming(QEMUFile *f);
 void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp);
 void migration_incoming_process(void);
+bool migration_incoming_setup(QIOChannel *ioc, uint8_t channel, Error **errp);
+void migration_outgoing_setup(QIOChannel *ioc);

 bool  migration_has_all_channels(void);

diff --git a/migration/multifd.c b/migration/multifd.c
index a8366cd588..ad6261688f 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -1512,7 +1512,7 @@ bool multifd_recv_all_channels_created(void)
  * Try to receive all multifd channels to get ready for the migration.
  * Sets @errp when failing to receive the current channel.
  */
-void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
+bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
 {
     MultiFDRecvParams *p;
     Error *local_err = NULL;
@@ -1527,7 +1527,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
                                     "failed to receive packet"
                                     " via multifd channel %d: ",
                                     qatomic_read(&multifd_recv_state->count));
-            return;
+            return false;
         }
         trace_multifd_recv_new_channel(id);
     } else {
@@ -1540,7 +1540,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
                    id);
         multifd_recv_terminate_threads(error_copy(local_err));
         error_propagate(errp, local_err);
-        return;
+        return false;
     }
     p->c = ioc;
     object_ref(OBJECT(ioc));
@@ -1549,4 +1549,6 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
     qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
                        QEMU_THREAD_JOINABLE);
     qatomic_inc(&multifd_recv_state->count);
+
+    return true;
 }
diff --git a/migration/multifd.h b/migration/multifd.h
index 9b6d81e7ed..89a395aef2 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -42,7 +42,7 @@ int multifd_recv_setup(Error **errp);
 void multifd_recv_cleanup(void);
 void multifd_recv_shutdown(void);
 bool multifd_recv_all_channels_created(void);
-void multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
+bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
 void multifd_recv_sync_main(void);
 int multifd_send_sync_main(MultiFDSyncReq req);
 bool multifd_queue_page(RAMBlock *block, ram_addr_t offset);