Migration pull for 9.1

- Het's new test cases for "channels"
 - Het's fix for a typo for vsock parsing
 - Cedric's VFIO error report series
 - Cedric's one more patch for dirty-bitmap error reports
 - Zhijian's rdma deprecation patch
 - Yuan's zeropage optimization to fix double faults on anon mem
 - Zhijian's COLO fix on a crash
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Merge tag 'migration-20240423-pull-request' of https://gitlab.com/peterx/qemu into staging

Migration pull for 9.1

- Het's new test cases for "channels"
- Het's fix for a typo for vsock parsing
- Cedric's VFIO error report series
- Cedric's one more patch for dirty-bitmap error reports
- Zhijian's rdma deprecation patch
- Yuan's zeropage optimization to fix double faults on anon mem
- Zhijian's COLO fix on a crash

# -----BEGIN PGP SIGNATURE-----
#
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# ZGhhdC5jb20ACgkQO1/MzfOr1wbQiwD/V5nSJzSuAG4Ra1Fjo+LRG2TT6qk8eNCi
# fIytehSw6cYA/0wqarxOF0tr7ikeyhtG3w4xFf44kk6KcPkoVSl1tqoL
# =pJmQ
# -----END PGP SIGNATURE-----
# gpg: Signature made Tue 23 Apr 2024 03:37:19 PM PDT
# gpg:                using EDDSA key B9184DC20CC457DACF7DD1A93B5FCCCDF3ABD706
# gpg:                issuer "peterx@redhat.com"
# gpg: Good signature from "Peter Xu <xzpeter@gmail.com>" [unknown]
# gpg:                 aka "Peter Xu <peterx@redhat.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: B918 4DC2 0CC4 57DA CF7D  D1A9 3B5F CCCD F3AB D706

* tag 'migration-20240423-pull-request' of https://gitlab.com/peterx/qemu: (26 commits)
  migration/colo: Fix bdrv_graph_rdlock_main_loop: Assertion `!qemu_in_coroutine()' failed.
  migration/multifd: solve zero page causing multiple page faults
  migration: Add Error** argument to add_bitmaps_to_list()
  migration: Modify ram_init_bitmaps() to report dirty tracking errors
  migration: Add Error** argument to xbzrle_init()
  migration: Add Error** argument to ram_state_init()
  memory: Add Error** argument to the global_dirty_log routines
  migration: Introduce ram_bitmaps_destroy()
  memory: Add Error** argument to .log_global_start() handler
  migration: Add Error** argument to .load_setup() handler
  migration: Add Error** argument to .save_setup() handler
  migration: Add Error** argument to qemu_savevm_state_setup()
  migration: Add Error** argument to vmstate_save()
  migration: Always report an error in ram_save_setup()
  migration: Always report an error in block_save_setup()
  vfio: Always report an error in vfio_save_setup()
  s390/stattrib: Add Error** argument to set_migrationmode() handler
  tests/qtest/migration: Fix typo for vsock in SocketAddress_to_str
  tests/qtest/migration: Add negative tests to validate migration QAPIs
  tests/qtest/migration: Add multifd_tcp_plain test using list of channels instead of uri
  ...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

hw/i386/xen/xen-hvm.c

@@ -457,11 +457,12 @@ static void xen_log_sync(MemoryListener *listener, MemoryRegionSection *section)
                           int128_get64(section->size));
 }
 
-static void xen_log_global_start(MemoryListener *listener)
+static bool xen_log_global_start(MemoryListener *listener, Error **errp)
 {
     if (xen_enabled()) {
         xen_in_migration = true;
     }
+    return true;
 }
 
 static void xen_log_global_stop(MemoryListener *listener)
@@ -668,7 +669,7 @@ void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length)
 void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
 {
     if (enable) {
-        memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
+        memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION, errp);
     } else {
         memory_global_dirty_log_stop(GLOBAL_DIRTY_MIGRATION);
     }

hw/ppc/spapr.c

@@ -2174,7 +2174,7 @@ static const VMStateDescription vmstate_spapr = {
     }
 };
 
-static int htab_save_setup(QEMUFile *f, void *opaque)
+static int htab_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     SpaprMachineState *spapr = opaque;
 

hw/s390x/s390-stattrib-kvm.c

@@ -17,6 +17,7 @@
 #include "sysemu/kvm.h"
 #include "exec/ram_addr.h"
 #include "kvm/kvm_s390x.h"
+#include "qapi/error.h"
 
 Object *kvm_s390_stattrib_create(void)
 {
@@ -137,14 +138,21 @@ static void kvm_s390_stattrib_synchronize(S390StAttribState *sa)
     }
 }
 
-static int kvm_s390_stattrib_set_migrationmode(S390StAttribState *sa, bool val)
+static int kvm_s390_stattrib_set_migrationmode(S390StAttribState *sa, bool val,
+                                               Error **errp)
 {
     struct kvm_device_attr attr = {
         .group = KVM_S390_VM_MIGRATION,
         .attr = val,
         .addr = 0,
     };
-    return kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attr);
+    int r;
+
+    r = kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attr);
+    if (r) {
+        error_setg_errno(errp, -r, "setting KVM_S390_VM_MIGRATION failed");
+    }
+    return r;
 }
 
 static long long kvm_s390_stattrib_get_dirtycount(S390StAttribState *sa)

hw/s390x/s390-stattrib.c

@@ -60,11 +60,13 @@ void hmp_migrationmode(Monitor *mon, const QDict *qdict)
     S390StAttribState *sas = s390_get_stattrib_device();
     S390StAttribClass *sac = S390_STATTRIB_GET_CLASS(sas);
     uint64_t what = qdict_get_int(qdict, "mode");
+    Error *local_err = NULL;
     int r;
 
-    r = sac->set_migrationmode(sas, what);
+    r = sac->set_migrationmode(sas, what, &local_err);
     if (r < 0) {
-        monitor_printf(mon, "Error: %s", strerror(-r));
+        monitor_printf(mon, "Error: %s", error_get_pretty(local_err));
+        error_free(local_err);
     }
 }
 
@@ -166,7 +168,7 @@ static int cmma_load(QEMUFile *f, void *opaque, int version_id)
     return ret;
 }
 
-static int cmma_save_setup(QEMUFile *f, void *opaque)
+static int cmma_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     S390StAttribState *sas = S390_STATTRIB(opaque);
     S390StAttribClass *sac = S390_STATTRIB_GET_CLASS(sas);
@@ -175,7 +177,7 @@ static int cmma_save_setup(QEMUFile *f, void *opaque)
      * Signal that we want to start a migration, thus needing PGSTE dirty
      * tracking.
      */
-    res = sac->set_migrationmode(sas, 1);
+    res = sac->set_migrationmode(sas, true, errp);
     if (res) {
         return res;
     }
@@ -260,7 +262,7 @@ static void cmma_save_cleanup(void *opaque)
 {
     S390StAttribState *sas = S390_STATTRIB(opaque);
     S390StAttribClass *sac = S390_STATTRIB_GET_CLASS(sas);
-    sac->set_migrationmode(sas, 0);
+    sac->set_migrationmode(sas, false, NULL);
 }
 
 static bool cmma_active(void *opaque)
@@ -293,7 +295,8 @@ static long long qemu_s390_get_dirtycount_stub(S390StAttribState *sa)
 {
     return 0;
 }
-static int qemu_s390_set_migrationmode_stub(S390StAttribState *sa, bool value)
+static int qemu_s390_set_migrationmode_stub(S390StAttribState *sa, bool value,
+                                            Error **errp)
 {
     return 0;
 }

hw/vfio/common.c

@@ -1066,7 +1066,8 @@ out:
     return ret;
 }
 
-static void vfio_listener_log_global_start(MemoryListener *listener)
+static bool vfio_listener_log_global_start(MemoryListener *listener,
+                                           Error **errp)
 {
     VFIOContainerBase *bcontainer = container_of(listener, VFIOContainerBase,
                                                  listener);
@@ -1083,6 +1084,7 @@ static void vfio_listener_log_global_start(MemoryListener *listener)
                      ret, strerror(-ret));
         vfio_set_migration_error(ret);
     }
+    return !ret;
 }
 
 static void vfio_listener_log_global_stop(MemoryListener *listener)

hw/vfio/migration.c

@@ -376,11 +376,12 @@ static int vfio_save_prepare(void *opaque, Error **errp)
     return 0;
 }
 
-static int vfio_save_setup(QEMUFile *f, void *opaque)
+static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     VFIODevice *vbasedev = opaque;
     VFIOMigration *migration = vbasedev->migration;
     uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
+    int ret;
 
     qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
 
@@ -389,19 +390,19 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
                                       stop_copy_size);
     migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
     if (!migration->data_buffer) {
-        error_report("%s: Failed to allocate migration data buffer",
+        error_setg(errp, "%s: Failed to allocate migration data buffer",
-                     vbasedev->name);
+                   vbasedev->name);
         return -ENOMEM;
     }
 
     if (vfio_precopy_supported(vbasedev)) {
-        int ret;
-
         switch (migration->device_state) {
         case VFIO_DEVICE_STATE_RUNNING:
             ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_PRE_COPY,
                                            VFIO_DEVICE_STATE_RUNNING);
             if (ret) {
+                error_setg(errp, "%s: Failed to set new PRE_COPY state",
+                           vbasedev->name);
                 return ret;
             }
 
@@ -412,6 +413,8 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
             /* vfio_save_complete_precopy() will go to STOP_COPY */
             break;
         default:
+            error_setg(errp, "%s: Invalid device state %d", vbasedev->name,
+                       migration->device_state);
             return -EINVAL;
         }
     }
@@ -420,7 +423,12 @@ static int vfio_save_setup(QEMUFile *f, void *opaque)
 
     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
 
-    return qemu_file_get_error(f);
+    ret = qemu_file_get_error(f);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "%s: save setup failed", vbasedev->name);
+    }
+
+    return ret;
 }
 
 static void vfio_save_cleanup(void *opaque)
@@ -580,12 +588,17 @@ static void vfio_save_state(QEMUFile *f, void *opaque)
     }
 }
 
-static int vfio_load_setup(QEMUFile *f, void *opaque)
+static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     VFIODevice *vbasedev = opaque;
+    int ret;
 
-    return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
+    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
                                    vbasedev->migration->device_state);
+    if (ret) {
+        error_setg(errp, "%s: Failed to set RESUMING state", vbasedev->name);
+    }
+    return ret;
 }
 
 static int vfio_load_cleanup(void *opaque)

hw/virtio/vhost.c

@@ -1044,7 +1044,7 @@ check_dev_state:
     return r;
 }
 
-static void vhost_log_global_start(MemoryListener *listener)
+static bool vhost_log_global_start(MemoryListener *listener, Error **errp)
 {
     int r;
 
@@ -1052,6 +1052,7 @@ static void vhost_log_global_start(MemoryListener *listener)
     if (r < 0) {
         abort();
     }
+    return true;
 }
 
 static void vhost_log_global_stop(MemoryListener *listener)

include/exec/memory.h

@@ -1001,8 +1001,11 @@ struct MemoryListener {
      * active at that time.
      *
      * @listener: The #MemoryListener.
+     * @errp: pointer to Error*, to store an error if it happens.
+     *
+     * Return: true on success, else false setting @errp with error.
      */
-    void (*log_global_start)(MemoryListener *listener);
+    bool (*log_global_start)(MemoryListener *listener, Error **errp);
 
     /**
      * @log_global_stop:
@@ -2581,8 +2584,11 @@ void memory_listener_unregister(MemoryListener *listener);
  * memory_global_dirty_log_start: begin dirty logging for all regions
  *
  * @flags: purpose of starting dirty log, migration or dirty rate
+ * @errp: pointer to Error*, to store an error if it happens.
+ *
+ * Return: true on success, else false setting @errp with error.
  */
-void memory_global_dirty_log_start(unsigned int flags);
+bool memory_global_dirty_log_start(unsigned int flags, Error **errp);
 
 /**
  * memory_global_dirty_log_stop: end dirty logging for all regions

include/exec/ramblock.h

@@ -58,7 +58,7 @@ struct RAMBlock {
     off_t bitmap_offset;
     uint64_t pages_offset;
 
-    /* bitmap of already received pages in postcopy */
+    /* Bitmap of already received pages.  Only used on destination side. */
     unsigned long *receivedmap;
 
     /*

include/hw/s390x/storage-attributes.h

@@ -39,7 +39,7 @@ struct S390StAttribClass {
     int (*set_stattr)(S390StAttribState *sa, uint64_t start_gfn,
                       uint32_t count, uint8_t *values);
     void (*synchronize)(S390StAttribState *sa);
-    int (*set_migrationmode)(S390StAttribState *sa, bool value);
+    int (*set_migrationmode)(S390StAttribState *sa, bool value, Error **errp);
     int (*get_active)(S390StAttribState *sa);
     long long (*get_dirtycount)(S390StAttribState *sa);
 };

include/migration/register.h

@@ -60,10 +60,11 @@ typedef struct SaveVMHandlers {
      *
      * @f: QEMUFile where to send the data
      * @opaque: data pointer passed to register_savevm_live()
+     * @errp: pointer to Error*, to store an error if it happens.
      *
      * Returns zero to indicate success and negative for error
      */
-    int (*save_setup)(QEMUFile *f, void *opaque);
+    int (*save_setup)(QEMUFile *f, void *opaque, Error **errp);
 
     /**
      * @save_cleanup
@@ -233,10 +234,11 @@ typedef struct SaveVMHandlers {
      *
      * @f: QEMUFile where to receive the data
      * @opaque: data pointer passed to register_savevm_live()
+     * @errp: pointer to Error*, to store an error if it happens.
      *
      * Returns zero to indicate success and negative for error
      */
-    int (*load_setup)(QEMUFile *f, void *opaque);
+    int (*load_setup)(QEMUFile *f, void *opaque, Error **errp);
 
     /**
      * @load_cleanup

migration/block-dirty-bitmap.c

@@ -481,13 +481,13 @@ static void dirty_bitmap_do_save_cleanup(DBMSaveState *s)
 
 /* Called with the BQL taken. */
 static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
-                               const char *bs_name, GHashTable *alias_map)
+                               const char *bs_name, GHashTable *alias_map,
+                               Error **errp)
 {
     BdrvDirtyBitmap *bitmap;
     SaveBitmapState *dbms;
     GHashTable *bitmap_aliases;
     const char *node_alias, *bitmap_name, *bitmap_alias;
-    Error *local_err = NULL;
 
     /* When an alias map is given, @bs_name must be @bs's node name */
     assert(!alias_map || !strcmp(bs_name, bdrv_get_node_name(bs)));
@@ -504,8 +504,8 @@ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
     bitmap_name = bdrv_dirty_bitmap_name(bitmap);
 
     if (!bs_name || strcmp(bs_name, "") == 0) {
-        error_report("Bitmap '%s' in unnamed node can't be migrated",
+        error_setg(errp, "Bitmap '%s' in unnamed node can't be migrated",
-                     bitmap_name);
+                   bitmap_name);
         return -1;
     }
 
@@ -525,9 +525,9 @@ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
     }
 
     if (node_alias[0] == '#') {
-        error_report("Bitmap '%s' in a node with auto-generated "
+        error_setg(errp, "Bitmap '%s' in a node with auto-generated "
-                     "name '%s' can't be migrated",
+                   "name '%s' can't be migrated",
-                     bitmap_name, node_alias);
+                   bitmap_name, node_alias);
         return -1;
     }
 
@@ -538,8 +538,7 @@ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
             continue;
         }
 
-        if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, &local_err)) {
+        if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, errp)) {
-            error_report_err(local_err);
             return -1;
         }
 
@@ -558,9 +557,9 @@ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
             }
         } else {
             if (strlen(bitmap_name) > UINT8_MAX) {
-                error_report("Cannot migrate bitmap '%s' on node '%s': "
+                error_setg(errp, "Cannot migrate bitmap '%s' on node '%s': "
-                             "Name is longer than %u bytes",
+                           "Name is longer than %u bytes",
-                             bitmap_name, bs_name, UINT8_MAX);
+                           bitmap_name, bs_name, UINT8_MAX);
                 return -1;
             }
             bitmap_alias = bitmap_name;
@@ -599,7 +598,7 @@ static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,
 }
 
 /* Called with the BQL taken. */
-static int init_dirty_bitmap_migration(DBMSaveState *s)
+static int init_dirty_bitmap_migration(DBMSaveState *s, Error **errp)
 {
     BlockDriverState *bs;
     SaveBitmapState *dbms;
@@ -643,7 +642,7 @@ static int init_dirty_bitmap_migration(DBMSaveState *s)
             }
 
             if (bs && bs->drv && !bs->drv->is_filter) {
-                if (add_bitmaps_to_list(s, bs, name, NULL)) {
+                if (add_bitmaps_to_list(s, bs, name, NULL, errp)) {
                     goto fail;
                 }
                 g_hash_table_add(handled_by_blk, bs);
@@ -656,7 +655,8 @@ static int init_dirty_bitmap_migration(DBMSaveState *s)
             continue;
         }
 
-        if (add_bitmaps_to_list(s, bs, bdrv_get_node_name(bs), alias_map)) {
+        if (add_bitmaps_to_list(s, bs, bdrv_get_node_name(bs), alias_map,
+                                errp)) {
             goto fail;
         }
     }
@@ -1213,12 +1213,12 @@ fail:
     return ret;
 }
 
-static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)
+static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     DBMSaveState *s = &((DBMState *)opaque)->save;
     SaveBitmapState *dbms = NULL;
 
-    if (init_dirty_bitmap_migration(s) < 0) {
+    if (init_dirty_bitmap_migration(s, errp) < 0) {
         return -1;
     }
 

migration/block.c

@@ -367,7 +367,7 @@ static void unset_dirty_tracking(void)
     }
 }
 
-static int init_blk_migration(QEMUFile *f)
+static int init_blk_migration(QEMUFile *f, Error **errp)
 {
     BlockDriverState *bs;
     BlkMigDevState *bmds;
@@ -378,7 +378,6 @@ static int init_blk_migration(QEMUFile *f)
         BlkMigDevState *bmds;
         BlockDriverState *bs;
     } *bmds_bs;
-    Error *local_err = NULL;
     int ret;
 
     GRAPH_RDLOCK_GUARD_MAINLOOP();
@@ -406,6 +405,8 @@ static int init_blk_migration(QEMUFile *f)
             continue;
         }
         if (sectors < 0) {
+            error_setg(errp, "Error getting length of block device %s",
+                       bdrv_get_device_name(bs));
             ret = sectors;
             bdrv_next_cleanup(&it);
             goto out;
@@ -442,9 +443,8 @@ static int init_blk_migration(QEMUFile *f)
         bs = bmds_bs[i].bs;
 
         if (bmds) {
-            ret = blk_insert_bs(bmds->blk, bs, &local_err);
+            ret = blk_insert_bs(bmds->blk, bs, errp);
             if (ret < 0) {
-                error_report_err(local_err);
                 goto out;
             }
 
@@ -711,7 +711,7 @@ static void block_migration_cleanup(void *opaque)
     blk_mig_unlock();
 }
 
-static int block_save_setup(QEMUFile *f, void *opaque)
+static int block_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     int ret;
 
@@ -721,7 +721,7 @@ static int block_save_setup(QEMUFile *f, void *opaque)
     warn_report("block migration is deprecated;"
                 " use blockdev-mirror with NBD instead");
 
-    ret = init_blk_migration(f);
+    ret = init_blk_migration(f, errp);
     if (ret < 0) {
         return ret;
     }
@@ -729,10 +729,15 @@ static int block_save_setup(QEMUFile *f, void *opaque)
     /* start track dirty blocks */
     ret = set_dirty_tracking();
     if (ret) {
+        error_setg_errno(errp, -ret, "Failed to start block dirty tracking");
         return ret;
     }
 
     ret = flush_blks(f);
+    if (ret) {
+        error_setg_errno(errp, -ret, "Flushing block failed");
+        return ret;
+    }
     blk_mig_reset_dirty_cursor();
     qemu_put_be64(f, BLK_MIG_FLAG_EOS);
 

migration/colo.c

@@ -835,6 +835,16 @@ static void *colo_process_incoming_thread(void *opaque)
         return NULL;
     }
 
+    /* Make sure all file formats throw away their mutable metadata */
+    bql_lock();
+    bdrv_activate_all(&local_err);
+    if (local_err) {
+        bql_unlock();
+        error_report_err(local_err);
+        return NULL;
+    }
+    bql_unlock();
+
     failover_init_state();
 
     mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
@@ -922,7 +932,6 @@ out:
 int coroutine_fn colo_incoming_co(void)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
-    Error *local_err = NULL;
     QemuThread th;
 
     assert(bql_locked());
@@ -931,13 +940,6 @@ int coroutine_fn colo_incoming_co(void)
         return 0;
     }
 
-    /* Make sure all file formats throw away their mutable metadata */
-    bdrv_activate_all(&local_err);
-    if (local_err) {
-        error_report_err(local_err);
-        return -EINVAL;
-    }
-
     qemu_thread_create(&th, "COLO incoming", colo_process_incoming_thread,
                        mis, QEMU_THREAD_JOINABLE);
 

migration/dirtyrate.c

@@ -90,9 +90,15 @@ static int64_t do_calculate_dirtyrate(DirtyPageRecord dirty_pages,
 
 void global_dirty_log_change(unsigned int flag, bool start)
 {
+    Error *local_err = NULL;
+    bool ret;
+
     bql_lock();
     if (start) {
-        memory_global_dirty_log_start(flag);
+        ret = memory_global_dirty_log_start(flag, &local_err);
+        if (!ret) {
+            error_report_err(local_err);
+        }
     } else {
         memory_global_dirty_log_stop(flag);
     }
@@ -608,9 +614,12 @@ static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
 {
     int64_t start_time;
     DirtyPageRecord dirty_pages;
+    Error *local_err = NULL;
 
     bql_lock();
-    memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
+    if (!memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE, &local_err)) {
+        error_report_err(local_err);
+    }
 
     /*
      * 1'round of log sync may return all 1 bits with

migration/migration.c

@@ -3431,6 +3431,8 @@ static void *migration_thread(void *opaque)
     int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
     MigThrError thr_error;
     bool urgent = false;
+    Error *local_err = NULL;
+    int ret;
 
     thread = migration_threads_add("live_migration", qemu_get_thread_id());
 
@@ -3474,12 +3476,24 @@ static void *migration_thread(void *opaque)
     }
 
     bql_lock();
-    qemu_savevm_state_setup(s->to_dst_file);
+    ret = qemu_savevm_state_setup(s->to_dst_file, &local_err);
     bql_unlock();
 
     qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
                                MIGRATION_STATUS_ACTIVE);
 
+    /*
+     * Handle SETUP failures after waiting for virtio-net-failover
+     * devices to unplug. This to preserve migration state transitions.
+     */
+    if (ret) {
+        migrate_set_error(s, local_err);
+        error_free(local_err);
+        migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
+                          MIGRATION_STATUS_FAILED);
+        goto out;
+    }
+
     s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
 
     trace_migration_thread_setup_complete();
@@ -3553,6 +3567,8 @@ static void *bg_migration_thread(void *opaque)
     MigThrError thr_error;
     QEMUFile *fb;
     bool early_fail = true;
+    Error *local_err = NULL;
+    int ret;
 
     rcu_register_thread();
     object_ref(OBJECT(s));
@@ -3586,12 +3602,24 @@ static void *bg_migration_thread(void *opaque)
 
     bql_lock();
     qemu_savevm_state_header(s->to_dst_file);
-    qemu_savevm_state_setup(s->to_dst_file);
+    ret = qemu_savevm_state_setup(s->to_dst_file, &local_err);
     bql_unlock();
 
     qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
                                MIGRATION_STATUS_ACTIVE);
 
+    /*
+     * Handle SETUP failures after waiting for virtio-net-failover
+     * devices to unplug. This to preserve migration state transitions.
+     */
+    if (ret) {
+        migrate_set_error(s, local_err);
+        error_free(local_err);
+        migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
+                          MIGRATION_STATUS_FAILED);
+        goto fail_setup;
+    }
+
     s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
 
     trace_migration_thread_setup_complete();
@@ -3660,6 +3688,7 @@ fail:
         bql_unlock();
     }
 
+fail_setup:
     bg_migration_iteration_finish(s);
 
     qemu_fclose(fb);

migration/multifd-zero-page.c

@@ -80,8 +80,10 @@ void multifd_recv_zero_page_process(MultiFDRecvParams *p)
 {
     for (int i = 0; i < p->zero_num; i++) {
         void *page = p->host + p->zero[i];
-        if (!buffer_is_zero(page, p->page_size)) {
+        if (ramblock_recv_bitmap_test_byte_offset(p->block, p->zero[i])) {
             memset(page, 0, p->page_size);
+        } else {
+            ramblock_recv_bitmap_set_offset(p->block, p->zero[i]);
         }
     }
 }

migration/multifd-zlib.c

@@ -284,6 +284,7 @@ static int zlib_recv(MultiFDRecvParams *p, Error **errp)
         int flush = Z_NO_FLUSH;
         unsigned long start = zs->total_out;
 
+        ramblock_recv_bitmap_set_offset(p->block, p->normal[i]);
         if (i == p->normal_num - 1) {
             flush = Z_SYNC_FLUSH;
         }

migration/multifd-zstd.c

@@ -278,6 +278,7 @@ static int zstd_recv(MultiFDRecvParams *p, Error **errp)
     z->in.pos = 0;
 
     for (i = 0; i < p->normal_num; i++) {
+        ramblock_recv_bitmap_set_offset(p->block, p->normal[i]);
         z->out.dst = p->host + p->normal[i];
         z->out.size = p->page_size;
         z->out.pos = 0;

migration/multifd.c

@@ -277,6 +277,7 @@ static int nocomp_recv(MultiFDRecvParams *p, Error **errp)
     for (int i = 0; i < p->normal_num; i++) {
         p->iov[i].iov_base = p->host + p->normal[i];
         p->iov[i].iov_len = p->page_size;
+        ramblock_recv_bitmap_set_offset(p->block, p->normal[i]);
     }
     return qio_channel_readv_all(p->c, p->iov, p->normal_num, errp);
 }

migration/ram.c

@@ -275,6 +275,10 @@ void ramblock_recv_bitmap_set_range(RAMBlock *rb, void *host_addr,
                       nr);
 }
 
+void ramblock_recv_bitmap_set_offset(RAMBlock *rb, uint64_t byte_offset)
+{
+    set_bit_atomic(byte_offset >> TARGET_PAGE_BITS, rb->receivedmap);
+}
 #define  RAMBLOCK_RECV_BITMAP_ENDING  (0x0123456789abcdefULL)
 
 /*
@@ -2438,10 +2442,23 @@ static void xbzrle_cleanup(void)
     XBZRLE_cache_unlock();
 }
 
+static void ram_bitmaps_destroy(void)
+{
+    RAMBlock *block;
+
+    RAMBLOCK_FOREACH_NOT_IGNORED(block) {
+        g_free(block->clear_bmap);
+        block->clear_bmap = NULL;
+        g_free(block->bmap);
+        block->bmap = NULL;
+        g_free(block->file_bmap);
+        block->file_bmap = NULL;
+    }
+}
+
 static void ram_save_cleanup(void *opaque)
 {
     RAMState **rsp = opaque;
-    RAMBlock *block;
 
     /* We don't use dirty log with background snapshots */
     if (!migrate_background_snapshot()) {
@@ -2458,12 +2475,7 @@ static void ram_save_cleanup(void *opaque)
         }
     }
 
-    RAMBLOCK_FOREACH_NOT_IGNORED(block) {
+    ram_bitmaps_destroy();
-        g_free(block->clear_bmap);
-        block->clear_bmap = NULL;
-        g_free(block->bmap);
-        block->bmap = NULL;
-    }
 
     xbzrle_cleanup();
     compress_threads_save_cleanup();
@@ -2719,44 +2731,41 @@ int ram_discard_range(const char *rbname, uint64_t start, size_t length)
  * For every allocation, we will try not to crash the VM if the
  * allocation failed.
  */
-static int xbzrle_init(void)
+static bool xbzrle_init(Error **errp)
 {
-    Error *local_err = NULL;
-
     if (!migrate_xbzrle()) {
-        return 0;
+        return true;
     }
 
     XBZRLE_cache_lock();
 
     XBZRLE.zero_target_page = g_try_malloc0(TARGET_PAGE_SIZE);
     if (!XBZRLE.zero_target_page) {
-        error_report("%s: Error allocating zero page", __func__);
+        error_setg(errp, "%s: Error allocating zero page", __func__);
         goto err_out;
     }
 
     XBZRLE.cache = cache_init(migrate_xbzrle_cache_size(),
-                              TARGET_PAGE_SIZE, &local_err);
+                              TARGET_PAGE_SIZE, errp);
     if (!XBZRLE.cache) {
-        error_report_err(local_err);
         goto free_zero_page;
     }
 
     XBZRLE.encoded_buf = g_try_malloc0(TARGET_PAGE_SIZE);
     if (!XBZRLE.encoded_buf) {
-        error_report("%s: Error allocating encoded_buf", __func__);
+        error_setg(errp, "%s: Error allocating encoded_buf", __func__);
         goto free_cache;
     }
 
     XBZRLE.current_buf = g_try_malloc(TARGET_PAGE_SIZE);
     if (!XBZRLE.current_buf) {
-        error_report("%s: Error allocating current_buf", __func__);
+        error_setg(errp, "%s: Error allocating current_buf", __func__);
         goto free_encoded_buf;
     }
 
     /* We are all good */
     XBZRLE_cache_unlock();
-    return 0;
+    return true;
 
 free_encoded_buf:
     g_free(XBZRLE.encoded_buf);
@@ -2769,16 +2778,16 @@ free_zero_page:
     XBZRLE.zero_target_page = NULL;
 err_out:
     XBZRLE_cache_unlock();
-    return -ENOMEM;
+    return false;
 }
 
-static int ram_state_init(RAMState **rsp)
+static bool ram_state_init(RAMState **rsp, Error **errp)
 {
     *rsp = g_try_new0(RAMState, 1);
 
     if (!*rsp) {
-        error_report("%s: Init ramstate fail", __func__);
+        error_setg(errp, "%s: Init ramstate fail", __func__);
-        return -1;
+        return false;
     }
 
     qemu_mutex_init(&(*rsp)->bitmap_mutex);
@@ -2794,7 +2803,7 @@ static int ram_state_init(RAMState **rsp)
     (*rsp)->migration_dirty_pages = (*rsp)->ram_bytes_total >> TARGET_PAGE_BITS;
     ram_state_reset(*rsp);
 
-    return 0;
+    return true;
 }
 
 static void ram_list_init_bitmaps(void)
@@ -2852,39 +2861,53 @@ static void migration_bitmap_clear_discarded_pages(RAMState *rs)
     }
 }
 
-static void ram_init_bitmaps(RAMState *rs)
+static bool ram_init_bitmaps(RAMState *rs, Error **errp)
 {
+    bool ret = true;
+
     qemu_mutex_lock_ramlist();
 
     WITH_RCU_READ_LOCK_GUARD() {
         ram_list_init_bitmaps();
         /* We don't use dirty log with background snapshots */
         if (!migrate_background_snapshot()) {
-            memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
+            ret = memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION, errp);
+            if (!ret) {
+                goto out_unlock;
+            }
             migration_bitmap_sync_precopy(rs, false);
         }
     }
+out_unlock:
     qemu_mutex_unlock_ramlist();
 
+    if (!ret) {
+        ram_bitmaps_destroy();
+        return false;
+    }
+
     /*
      * After an eventual first bitmap sync, fixup the initial bitmap
      * containing all 1s to exclude any discarded pages from migration.
      */
     migration_bitmap_clear_discarded_pages(rs);
+    return true;
 }
 
-static int ram_init_all(RAMState **rsp)
+static int ram_init_all(RAMState **rsp, Error **errp)
 {
-    if (ram_state_init(rsp)) {
+    if (!ram_state_init(rsp, errp)) {
         return -1;
     }
 
-    if (xbzrle_init()) {
+    if (!xbzrle_init(errp)) {
         ram_state_cleanup(rsp);
         return -1;
     }
 
-    ram_init_bitmaps(*rsp);
+    if (!ram_init_bitmaps(*rsp, errp)) {
+        return -1;
+    }
 
     return 0;
 }
@@ -3066,20 +3089,22 @@ static bool mapped_ram_read_header(QEMUFile *file, MappedRamHeader *header,
  *
  * @f: QEMUFile where to send the data
  * @opaque: RAMState pointer
+ * @errp: pointer to Error*, to store an error if it happens.
  */
-static int ram_save_setup(QEMUFile *f, void *opaque)
+static int ram_save_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     RAMState **rsp = opaque;
     RAMBlock *block;
     int ret, max_hg_page_size;
 
     if (compress_threads_save_setup()) {
+        error_setg(errp, "%s: failed to start compress threads", __func__);
         return -1;
     }
 
     /* migration has already setup the bitmap, reuse it. */
     if (!migration_in_colo_state()) {
-        if (ram_init_all(rsp) != 0) {
+        if (ram_init_all(rsp, errp) != 0) {
             compress_threads_save_cleanup();
             return -1;
         }
@@ -3116,12 +3141,14 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
 
     ret = rdma_registration_start(f, RAM_CONTROL_SETUP);
     if (ret < 0) {
+        error_setg(errp, "%s: failed to start RDMA registration", __func__);
         qemu_file_set_error(f, ret);
         return ret;
     }
 
     ret = rdma_registration_stop(f, RAM_CONTROL_SETUP);
     if (ret < 0) {
+        error_setg(errp, "%s: failed to stop RDMA registration", __func__);
         qemu_file_set_error(f, ret);
         return ret;
     }
@@ -3138,6 +3165,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     ret = multifd_send_sync_main();
     bql_lock();
     if (ret < 0) {
+        error_setg(errp, "%s: multifd synchronization failed", __func__);
         return ret;
     }
 
@@ -3147,7 +3175,11 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     }
 
     qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
-    return qemu_fflush(f);
+    ret = qemu_fflush(f);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "%s failed", __func__);
+    }
+    return ret;
 }
 
 static void ram_save_file_bmap(QEMUFile *f)
@@ -3592,7 +3624,11 @@ void ram_handle_zero(void *host, uint64_t size)
 
 static void colo_init_ram_state(void)
 {
-    ram_state_init(&ram_state);
+    Error *local_err = NULL;
+
+    if (!ram_state_init(&ram_state, &local_err)) {
+        error_report_err(local_err);
+    }
 }
 
 /*
@@ -3647,6 +3683,8 @@ int colo_init_ram_cache(void)
 void colo_incoming_start_dirty_log(void)
 {
     RAMBlock *block = NULL;
+    Error *local_err = NULL;
+
     /* For memory_global_dirty_log_start below. */
     bql_lock();
     qemu_mutex_lock_ramlist();
@@ -3658,7 +3696,10 @@ void colo_incoming_start_dirty_log(void)
             /* Discard this dirty bitmap record */
             bitmap_zero(block->bmap, block->max_length >> TARGET_PAGE_BITS);
         }
-        memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
+        if (!memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION,
+                                           &local_err)) {
+            error_report_err(local_err);
+        }
     }
     ram_state->migration_dirty_pages = 0;
     qemu_mutex_unlock_ramlist();
@@ -3694,8 +3735,9 @@ void colo_release_ram_cache(void)
  *
  * @f: QEMUFile where to receive the data
  * @opaque: RAMState pointer
+ * @errp: pointer to Error*, to store an error if it happens.
  */
-static int ram_load_setup(QEMUFile *f, void *opaque)
+static int ram_load_setup(QEMUFile *f, void *opaque, Error **errp)
 {
     xbzrle_load_setup();
     ramblock_recv_map_init();

migration/ram.h

@@ -69,6 +69,7 @@ int ramblock_recv_bitmap_test(RAMBlock *rb, void *host_addr);
 bool ramblock_recv_bitmap_test_byte_offset(RAMBlock *rb, uint64_t byte_offset);
 void ramblock_recv_bitmap_set(RAMBlock *rb, void *host_addr);
 void ramblock_recv_bitmap_set_range(RAMBlock *rb, void *host_addr, size_t nr);
+void ramblock_recv_bitmap_set_offset(RAMBlock *rb, uint64_t byte_offset);
 int64_t ramblock_recv_bitmap_send(QEMUFile *file,
                                   const char *block_name);
 bool ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *rb, Error **errp);

migration/savevm.c

@@ -1009,11 +1009,10 @@ static void save_section_footer(QEMUFile *f, SaveStateEntry *se)
     }
 }
 
-static int vmstate_save(QEMUFile *f, SaveStateEntry *se, JSONWriter *vmdesc)
+static int vmstate_save(QEMUFile *f, SaveStateEntry *se, JSONWriter *vmdesc,
+                        Error **errp)
 {
     int ret;
-    Error *local_err = NULL;
-    MigrationState *s = migrate_get_current();
 
     if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
         return 0;
@@ -1035,10 +1034,9 @@ static int vmstate_save(QEMUFile *f, SaveStateEntry *se, JSONWriter *vmdesc)
     if (!se->vmsd) {
         vmstate_save_old_style(f, se, vmdesc);
     } else {
-        ret = vmstate_save_state_with_err(f, se->vmsd, se->opaque, vmdesc, &local_err);
+        ret = vmstate_save_state_with_err(f, se->vmsd, se->opaque, vmdesc,
+                                          errp);
         if (ret) {
-            migrate_set_error(s, local_err);
-            error_report_err(local_err);
             return ret;
         }
     }
@@ -1312,11 +1310,11 @@ int qemu_savevm_state_prepare(Error **errp)
     return 0;
 }
 
-void qemu_savevm_state_setup(QEMUFile *f)
+int qemu_savevm_state_setup(QEMUFile *f, Error **errp)
 {
+    ERRP_GUARD();
     MigrationState *ms = migrate_get_current();
     SaveStateEntry *se;
-    Error *local_err = NULL;
     int ret = 0;
 
     json_writer_int64(ms->vmdesc, "page_size", qemu_target_page_size());
@@ -1325,8 +1323,9 @@ void qemu_savevm_state_setup(QEMUFile *f)
     trace_savevm_state_setup();
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         if (se->vmsd && se->vmsd->early_setup) {
-            ret = vmstate_save(f, se, ms->vmdesc);
+            ret = vmstate_save(f, se, ms->vmdesc, errp);
             if (ret) {
+                migrate_set_error(ms, *errp);
                 qemu_file_set_error(f, ret);
                 break;
             }
@@ -1343,7 +1342,7 @@ void qemu_savevm_state_setup(QEMUFile *f)
         }
         save_section_header(f, se, QEMU_VM_SECTION_START);
 
-        ret = se->ops->save_setup(f, se->opaque);
+        ret = se->ops->save_setup(f, se->opaque, errp);
         save_section_footer(f, se);
         if (ret < 0) {
             qemu_file_set_error(f, ret);
@@ -1352,12 +1351,11 @@ void qemu_savevm_state_setup(QEMUFile *f)
     }
 
     if (ret) {
-        return;
+        return ret;
     }
 
-    if (precopy_notify(PRECOPY_NOTIFY_SETUP, &local_err)) {
+    /* TODO: Should we check that errp is set in case of failure ? */
-        error_report_err(local_err);
+    return precopy_notify(PRECOPY_NOTIFY_SETUP, errp);
-    }
 }
 
 int qemu_savevm_state_resume_prepare(MigrationState *s)
@@ -1542,6 +1540,7 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
     JSONWriter *vmdesc = ms->vmdesc;
     int vmdesc_len;
     SaveStateEntry *se;
+    Error *local_err = NULL;
     int ret;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
@@ -1552,8 +1551,10 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
 
         start_ts_each = qemu_clock_get_us(QEMU_CLOCK_REALTIME);
 
-        ret = vmstate_save(f, se, vmdesc);
+        ret = vmstate_save(f, se, vmdesc, &local_err);
         if (ret) {
+            migrate_set_error(ms, local_err);
+            error_report_err(local_err);
             qemu_file_set_error(f, ret);
             return ret;
         }
@@ -1568,7 +1569,6 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
          * bdrv_activate_all() on the other end won't fail. */
         ret = bdrv_inactivate_all();
         if (ret) {
-            Error *local_err = NULL;
             error_setg(&local_err, "%s: bdrv_inactivate_all() failed (%d)",
                        __func__, ret);
             migrate_set_error(ms, local_err);
@@ -1723,7 +1723,10 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
     ms->to_dst_file = f;
 
     qemu_savevm_state_header(f);
-    qemu_savevm_state_setup(f);
+    ret = qemu_savevm_state_setup(f, errp);
+    if (ret) {
+        goto cleanup;
+    }
 
     while (qemu_file_get_error(f) == 0) {
         if (qemu_savevm_state_iterate(f, false) > 0) {
@@ -1736,10 +1739,11 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
         qemu_savevm_state_complete_precopy(f, false, false);
         ret = qemu_file_get_error(f);
     }
-    qemu_savevm_state_cleanup();
     if (ret != 0) {
         error_setg_errno(errp, -ret, "Error while writing VM state");
     }
+cleanup:
+    qemu_savevm_state_cleanup();
 
     if (ret != 0) {
         status = MIGRATION_STATUS_FAILED;
@@ -1764,6 +1768,8 @@ void qemu_savevm_live_state(QEMUFile *f)
 
 int qemu_save_device_state(QEMUFile *f)
 {
+    MigrationState *ms = migrate_get_current();
+    Error *local_err = NULL;
     SaveStateEntry *se;
 
     if (!migration_in_colo_state()) {
@@ -1778,8 +1784,10 @@ int qemu_save_device_state(QEMUFile *f)
         if (se->is_ram) {
             continue;
         }
-        ret = vmstate_save(f, se, NULL);
+        ret = vmstate_save(f, se, NULL, &local_err);
         if (ret) {
+            migrate_set_error(ms, local_err);
+            error_report_err(local_err);
             return ret;
         }
     }
@@ -2760,8 +2768,9 @@ static void qemu_loadvm_state_switchover_ack_needed(MigrationIncomingState *mis)
     trace_loadvm_state_switchover_ack_needed(mis->switchover_ack_pending_num);
 }
 
-static int qemu_loadvm_state_setup(QEMUFile *f)
+static int qemu_loadvm_state_setup(QEMUFile *f, Error **errp)
 {
+    ERRP_GUARD();
     SaveStateEntry *se;
     int ret;
 
@@ -2776,10 +2785,11 @@ static int qemu_loadvm_state_setup(QEMUFile *f)
             }
         }
 
-        ret = se->ops->load_setup(f, se->opaque);
+        ret = se->ops->load_setup(f, se->opaque, errp);
         if (ret < 0) {
+            error_prepend(errp, "Load state of device %s failed: ",
+                          se->idstr);
             qemu_file_set_error(f, ret);
-            error_report("Load state of device %s failed", se->idstr);
             return ret;
         }
     }
@@ -2960,7 +2970,8 @@ int qemu_loadvm_state(QEMUFile *f)
         return ret;
     }
 
-    if (qemu_loadvm_state_setup(f) != 0) {
+    if (qemu_loadvm_state_setup(f, &local_err) != 0) {
+        error_report_err(local_err);
         return -EINVAL;
     }
 

migration/savevm.h

@@ -32,7 +32,7 @@
 bool qemu_savevm_state_blocked(Error **errp);
 void qemu_savevm_non_migratable_list(strList **reasons);
 int qemu_savevm_state_prepare(Error **errp);
-void qemu_savevm_state_setup(QEMUFile *f);
+int qemu_savevm_state_setup(QEMUFile *f, Error **errp);
 bool qemu_savevm_state_guest_unplug_pending(void);
 int qemu_savevm_state_resume_prepare(MigrationState *s);
 void qemu_savevm_state_header(QEMUFile *f);

system/memory.c

@@ -2919,7 +2919,30 @@ static unsigned int postponed_stop_flags;
 static VMChangeStateEntry *vmstate_change;
 static void memory_global_dirty_log_stop_postponed_run(void);
 
-void memory_global_dirty_log_start(unsigned int flags)
+static bool memory_global_dirty_log_do_start(Error **errp)
+{
+    MemoryListener *listener;
+
+    QTAILQ_FOREACH(listener, &memory_listeners, link) {
+        if (listener->log_global_start) {
+            if (!listener->log_global_start(listener, errp)) {
+                goto err;
+            }
+        }
+    }
+    return true;
+
+err:
+    while ((listener = QTAILQ_PREV(listener, link)) != NULL) {
+        if (listener->log_global_stop) {
+            listener->log_global_stop(listener);
+        }
+    }
+
+    return false;
+}
+
+bool memory_global_dirty_log_start(unsigned int flags, Error **errp)
 {
     unsigned int old_flags;
 
@@ -2933,7 +2956,7 @@ void memory_global_dirty_log_start(unsigned int flags)
 
     flags &= ~global_dirty_tracking;
     if (!flags) {
-        return;
+        return true;
     }
 
     old_flags = global_dirty_tracking;
@@ -2941,11 +2964,17 @@ void memory_global_dirty_log_start(unsigned int flags)
     trace_global_dirty_changed(global_dirty_tracking);
 
     if (!old_flags) {
-        MEMORY_LISTENER_CALL_GLOBAL(log_global_start, Forward);
+        if (!memory_global_dirty_log_do_start(errp)) {
+            global_dirty_tracking &= ~flags;
+            trace_global_dirty_changed(global_dirty_tracking);
+            return false;
+        }
+
         memory_region_transaction_begin();
         memory_region_update_pending = true;
         memory_region_transaction_commit();
     }
+    return true;
 }
 
 static void memory_global_dirty_log_do_stop(unsigned int flags)
@@ -3019,8 +3048,15 @@ static void listener_add_address_space(MemoryListener *listener,
         listener->begin(listener);
     }
     if (global_dirty_tracking) {
+        /*
+         * Currently only VFIO can fail log_global_start(), and it's not
+         * yet allowed to hotplug any PCI device during migration. So this
+         * should never fail when invoked, guard it with error_abort.  If
+         * it can start to fail in the future, we need to be able to fail
+         * the whole listener_add_address_space() and its callers.
+         */
         if (listener->log_global_start) {
-            listener->log_global_start(listener);
+            listener->log_global_start(listener, &error_abort);
         }
     }
 

tests/qtest/migration-helpers.c

@@ -13,6 +13,11 @@
 #include "qemu/osdep.h"
 #include "qemu/ctype.h"
 #include "qapi/qmp/qjson.h"
+#include "qapi/qapi-visit-sockets.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qlist.h"
+#include "qemu/cutils.h"
 
 #include "migration-helpers.h"
 
@@ -24,6 +29,127 @@
  */
 #define MIGRATION_STATUS_WAIT_TIMEOUT 120
 
+static char *SocketAddress_to_str(SocketAddress *addr)
+{
+    switch (addr->type) {
+    case SOCKET_ADDRESS_TYPE_INET:
+        return g_strdup_printf("tcp:%s:%s",
+                               addr->u.inet.host,
+                               addr->u.inet.port);
+    case SOCKET_ADDRESS_TYPE_UNIX:
+        return g_strdup_printf("unix:%s",
+                               addr->u.q_unix.path);
+    case SOCKET_ADDRESS_TYPE_FD:
+        return g_strdup_printf("fd:%s", addr->u.fd.str);
+    case SOCKET_ADDRESS_TYPE_VSOCK:
+        return g_strdup_printf("vsock:%s:%s",
+                               addr->u.vsock.cid,
+                               addr->u.vsock.port);
+    default:
+        return g_strdup("unknown address type");
+    }
+}
+
+static QDict *SocketAddress_to_qdict(SocketAddress *addr)
+{
+    QDict *dict = qdict_new();
+
+    switch (addr->type) {
+    case SOCKET_ADDRESS_TYPE_INET:
+        qdict_put_str(dict, "type", "inet");
+        qdict_put_str(dict, "host", addr->u.inet.host);
+        qdict_put_str(dict, "port", addr->u.inet.port);
+        break;
+    case SOCKET_ADDRESS_TYPE_UNIX:
+        qdict_put_str(dict, "type", "unix");
+        qdict_put_str(dict, "path", addr->u.q_unix.path);
+        break;
+    case SOCKET_ADDRESS_TYPE_FD:
+        qdict_put_str(dict, "type", "fd");
+        qdict_put_str(dict, "str", addr->u.fd.str);
+        break;
+    case SOCKET_ADDRESS_TYPE_VSOCK:
+        qdict_put_str(dict, "type", "vsock");
+        qdict_put_str(dict, "cid", addr->u.vsock.cid);
+        qdict_put_str(dict, "port", addr->u.vsock.port);
+        break;
+    default:
+        g_assert_not_reached();
+        break;
+    }
+
+    return dict;
+}
+
+static SocketAddress *migrate_get_socket_address(QTestState *who)
+{
+    QDict *rsp;
+    SocketAddressList *addrs;
+    SocketAddress *addr;
+    Visitor *iv = NULL;
+    QObject *object;
+
+    rsp = migrate_query(who);
+    object = qdict_get(rsp, "socket-address");
+
+    iv = qobject_input_visitor_new(object);
+    visit_type_SocketAddressList(iv, NULL, &addrs, &error_abort);
+    addr = addrs->value;
+    visit_free(iv);
+
+    qobject_unref(rsp);
+    return addr;
+}
+
+static char *
+migrate_get_connect_uri(QTestState *who)
+{
+    SocketAddress *addrs;
+    char *connect_uri;
+
+    addrs = migrate_get_socket_address(who);
+    connect_uri = SocketAddress_to_str(addrs);
+
+    qapi_free_SocketAddress(addrs);
+    return connect_uri;
+}
+
+static QDict *
+migrate_get_connect_qdict(QTestState *who)
+{
+    SocketAddress *addrs;
+    QDict *connect_qdict;
+
+    addrs = migrate_get_socket_address(who);
+    connect_qdict = SocketAddress_to_qdict(addrs);
+
+    qapi_free_SocketAddress(addrs);
+    return connect_qdict;
+}
+
+static void migrate_set_ports(QTestState *to, QList *channel_list)
+{
+    QDict *addr;
+    QListEntry *entry;
+    const char *addr_port = NULL;
+
+    addr = migrate_get_connect_qdict(to);
+
+    QLIST_FOREACH_ENTRY(channel_list, entry) {
+        QDict *channel = qobject_to(QDict, qlist_entry_obj(entry));
+        QDict *addrdict = qdict_get_qdict(channel, "addr");
+
+        if (qdict_haskey(addrdict, "port") &&
+            qdict_haskey(addr, "port") &&
+            (strcmp(qdict_get_str(addrdict, "port"), "0") == 0)) {
+                addr_port = qdict_get_str(addr, "port");
+                qdict_put_str(addrdict, "port", g_strdup(addr_port));
+        }
+    }
+
+    qobject_unref(addr);
+}
+
 bool migrate_watch_for_events(QTestState *who, const char *name,
                               QDict *event, void *opaque)
 {
@@ -43,7 +169,8 @@ bool migrate_watch_for_events(QTestState *who, const char *name,
     return false;
 }
 
-void migrate_qmp_fail(QTestState *who, const char *uri, const char *fmt, ...)
+void migrate_qmp_fail(QTestState *who, const char *uri,
+                      const char *channels, const char *fmt, ...)
 {
     va_list ap;
     QDict *args, *err;
@@ -53,7 +180,15 @@ void migrate_qmp_fail(QTestState *who, const char *uri, const char *fmt, ...)
     va_end(ap);
 
     g_assert(!qdict_haskey(args, "uri"));
-    qdict_put_str(args, "uri", uri);
+    if (uri) {
+        qdict_put_str(args, "uri", uri);
+    }
+
+    g_assert(!qdict_haskey(args, "channels"));
+    if (channels) {
+        QObject *channels_obj = qobject_from_json(channels, &error_abort);
+        qdict_put_obj(args, "channels", channels_obj);
+    }
 
     err = qtest_qmp_assert_failure_ref(
         who, "{ 'execute': 'migrate', 'arguments': %p}", args);
@@ -68,17 +203,32 @@ void migrate_qmp_fail(QTestState *who, const char *uri, const char *fmt, ...)
  * Arguments are built from @fmt... (formatted like
  * qobject_from_jsonf_nofail()) with "uri": @uri spliced in.
  */
-void migrate_qmp(QTestState *who, const char *uri, const char *fmt, ...)
+void migrate_qmp(QTestState *who, QTestState *to, const char *uri,
+                 const char *channels, const char *fmt, ...)
 {
     va_list ap;
     QDict *args;
+    g_autofree char *connect_uri = NULL;
 
     va_start(ap, fmt);
     args = qdict_from_vjsonf_nofail(fmt, ap);
     va_end(ap);
 
     g_assert(!qdict_haskey(args, "uri"));
-    qdict_put_str(args, "uri", uri);
+    if (uri) {
+        qdict_put_str(args, "uri", uri);
+    } else if (!channels) {
+        connect_uri = migrate_get_connect_uri(to);
+        qdict_put_str(args, "uri", connect_uri);
+    }
+
+    g_assert(!qdict_haskey(args, "channels"));
+    if (channels) {
+        QObject *channels_obj = qobject_from_json(channels, &error_abort);
+        QList *channel_list = qobject_to(QList, channels_obj);
+        migrate_set_ports(to, channel_list);
+        qdict_put_obj(args, "channels", channels_obj);
+    }
 
     qtest_qmp_assert_success(who,
                              "{ 'execute': 'migrate', 'arguments': %p}", args);

tests/qtest/migration-helpers.h

@@ -25,15 +25,17 @@ typedef struct QTestMigrationState {
 bool migrate_watch_for_events(QTestState *who, const char *name,
                               QDict *event, void *opaque);
 
-G_GNUC_PRINTF(3, 4)
+G_GNUC_PRINTF(5, 6)
-void migrate_qmp(QTestState *who, const char *uri, const char *fmt, ...);
+void migrate_qmp(QTestState *who, QTestState *to, const char *uri,
+                 const char *channels, const char *fmt, ...);
 
 G_GNUC_PRINTF(3, 4)
 void migrate_incoming_qmp(QTestState *who, const char *uri,
                           const char *fmt, ...);
 
-G_GNUC_PRINTF(3, 4)
+G_GNUC_PRINTF(4, 5)
-void migrate_qmp_fail(QTestState *who, const char *uri, const char *fmt, ...);
+void migrate_qmp_fail(QTestState *who, const char *uri,
+                      const char *channels, const char *fmt, ...);
 
 void migrate_set_capability(QTestState *who, const char *capability,
                             bool value);

tests/qtest/migration-test.c

@@ -13,16 +13,12 @@
 #include "qemu/osdep.h"
 
 #include "libqtest.h"
-#include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
 #include "qemu/range.h"
 #include "qemu/sockets.h"
 #include "chardev/char.h"
-#include "qapi/qapi-visit-sockets.h"
-#include "qapi/qobject-input-visitor.h"
-#include "qapi/qobject-output-visitor.h"
 #include "crypto/tlscredspsk.h"
 #include "qapi/qmp/qlist.h"
 
@@ -369,50 +365,6 @@ static void cleanup(const char *filename)
     unlink(path);
 }
 
-static char *SocketAddress_to_str(SocketAddress *addr)
-{
-    switch (addr->type) {
-    case SOCKET_ADDRESS_TYPE_INET:
-        return g_strdup_printf("tcp:%s:%s",
-                               addr->u.inet.host,
-                               addr->u.inet.port);
-    case SOCKET_ADDRESS_TYPE_UNIX:
-        return g_strdup_printf("unix:%s",
-                               addr->u.q_unix.path);
-    case SOCKET_ADDRESS_TYPE_FD:
-        return g_strdup_printf("fd:%s", addr->u.fd.str);
-    case SOCKET_ADDRESS_TYPE_VSOCK:
-        return g_strdup_printf("tcp:%s:%s",
-                               addr->u.vsock.cid,
-                               addr->u.vsock.port);
-    default:
-        return g_strdup("unknown address type");
-    }
-}
-
-static char *migrate_get_socket_address(QTestState *who, const char *parameter)
-{
-    QDict *rsp;
-    char *result;
-    SocketAddressList *addrs;
-    Visitor *iv = NULL;
-    QObject *object;
-
-    rsp = migrate_query(who);
-    object = qdict_get(rsp, parameter);
-
-    iv = qobject_input_visitor_new(object);
-    visit_type_SocketAddressList(iv, NULL, &addrs, &error_abort);
-    visit_free(iv);
-
-    /* we are only using a single address */
-    result = SocketAddress_to_str(addrs->value);
-
-    qapi_free_SocketAddressList(addrs);
-    qobject_unref(rsp);
-    return result;
-}
-
 static long long migrate_get_parameter_int(QTestState *who,
                                            const char *parameter)
 {
@@ -703,6 +655,13 @@ typedef struct {
      */
     const char *connect_uri;
 
+    /*
+     * Optional: JSON-formatted list of src QEMU URIs. If a port is
+     * defined as '0' in any QDict key a value of '0' will be
+     * automatically converted to the correct destination port.
+     */
+    const char *connect_channels;
+
     /* Optional: callback to run at start to set migration parameters */
     TestMigrateStartHook start_hook;
     /* Optional: callback to run at finish to cleanup */
@@ -1349,8 +1308,7 @@ static int migrate_postcopy_prepare(QTestState **from_ptr,
     wait_for_serial("src_serial");
     wait_for_suspend(from, &src_state);
 
-    g_autofree char *uri = migrate_get_socket_address(to, "socket-address");
+    migrate_qmp(from, to, NULL, NULL, "{}");
-    migrate_qmp(from, uri, "{}");
 
     migrate_wait_for_dirty_mem(from, to);
 
@@ -1500,7 +1458,7 @@ static void postcopy_recover_fail(QTestState *from, QTestState *to)
     g_assert_cmpint(ret, ==, 1);
 
     migrate_recover(to, "fd:fd-mig");
-    migrate_qmp(from, "fd:fd-mig", "{'resume': true}");
+    migrate_qmp(from, to, "fd:fd-mig", NULL, "{'resume': true}");
 
     /*
      * Make sure both QEMU instances will go into RECOVER stage, then test
@@ -1588,7 +1546,7 @@ static void test_postcopy_recovery_common(MigrateCommon *args)
      * Try to rebuild the migration channel using the resume flag and
      * the newly created channel
      */
-    migrate_qmp(from, uri, "{'resume': true}");
+    migrate_qmp(from, to, uri, NULL, "{'resume': true}");
 
     /* Restore the postcopy bandwidth to unlimited */
     migrate_set_parameter_int(from, "max-postcopy-bandwidth", 0);
@@ -1669,7 +1627,7 @@ static void test_baddest(void)
     if (test_migrate_start(&from, &to, "tcp:127.0.0.1:0", &args)) {
         return;
     }
-    migrate_qmp(from, "tcp:127.0.0.1:0", "{}");
+    migrate_qmp(from, to, "tcp:127.0.0.1:0", NULL, "{}");
     wait_for_migration_fail(from, false);
     test_migrate_end(from, to, false);
 }
@@ -1708,7 +1666,7 @@ static void test_analyze_script(void)
     uri = g_strdup_printf("exec:cat > %s", file);
 
     migrate_ensure_converge(from);
-    migrate_qmp(from, uri, "{}");
+    migrate_qmp(from, to, uri, NULL, "{}");
     wait_for_migration_complete(from);
 
     pid = fork();
@@ -1733,7 +1691,6 @@ static void test_precopy_common(MigrateCommon *args)
 {
     QTestState *from, *to;
     void *data_hook = NULL;
-    g_autofree char *connect_uri = NULL;
 
     if (test_migrate_start(&from, &to, args->listen_uri, &args->start)) {
         return;
@@ -1766,18 +1723,12 @@ static void test_precopy_common(MigrateCommon *args)
         }
     }
 
-    if (!args->connect_uri) {
-        connect_uri = migrate_get_socket_address(to, "socket-address");
-    } else {
-        connect_uri = g_strdup(args->connect_uri);
-    }
-
     if (args->result == MIG_TEST_QMP_ERROR) {
-        migrate_qmp_fail(from, connect_uri, "{}");
+        migrate_qmp_fail(from, args->connect_uri, args->connect_channels, "{}");
         goto finish;
     }
 
-    migrate_qmp(from, connect_uri, "{}");
+    migrate_qmp(from, to, args->connect_uri, args->connect_channels, "{}");
 
     if (args->result != MIG_TEST_SUCCEED) {
         bool allow_active = args->result == MIG_TEST_FAIL;
@@ -1843,7 +1794,6 @@ static void test_file_common(MigrateCommon *args, bool stop_src)
 {
     QTestState *from, *to;
     void *data_hook = NULL;
-    g_autofree char *connect_uri = g_strdup(args->connect_uri);
 
     if (test_migrate_start(&from, &to, args->listen_uri, &args->start)) {
         return;
@@ -1869,18 +1819,18 @@ static void test_file_common(MigrateCommon *args, bool stop_src)
     }
 
     if (args->result == MIG_TEST_QMP_ERROR) {
-        migrate_qmp_fail(from, connect_uri, "{}");
+        migrate_qmp_fail(from, args->connect_uri, NULL, "{}");
         goto finish;
     }
 
-    migrate_qmp(from, connect_uri, "{}");
+    migrate_qmp(from, to, args->connect_uri, NULL, "{}");
     wait_for_migration_complete(from);
 
     /*
      * We need to wait for the source to finish before starting the
      * destination.
      */
-    migrate_incoming_qmp(to, connect_uri, "{}");
+    migrate_incoming_qmp(to, args->connect_uri, "{}");
     wait_for_migration_complete(to);
 
     if (stop_src) {
@@ -2029,7 +1979,7 @@ static void test_ignore_shared(void)
     /* Wait for the first serial output from the source */
     wait_for_serial("src_serial");
 
-    migrate_qmp(from, uri, "{}");
+    migrate_qmp(from, to, uri, NULL, "{}");
 
     migrate_wait_for_dirty_mem(from, to);
 
@@ -2568,7 +2518,7 @@ static void do_test_validate_uuid(MigrateStart *args, bool should_fail)
     /* Wait for the first serial output from the source */
     wait_for_serial("src_serial");
 
-    migrate_qmp(from, uri, "{}");
+    migrate_qmp(from, to, uri, NULL, "{}");
 
     if (should_fail) {
         qtest_set_expected_status(to, EXIT_FAILURE);
@@ -2621,6 +2571,55 @@ static void test_validate_uuid_dst_not_set(void)
     do_test_validate_uuid(&args, false);
 }
 
+static void do_test_validate_uri_channel(MigrateCommon *args)
+{
+    QTestState *from, *to;
+
+    if (test_migrate_start(&from, &to, args->listen_uri, &args->start)) {
+        return;
+    }
+
+    /* Wait for the first serial output from the source */
+    wait_for_serial("src_serial");
+
+    /*
+     * 'uri' and 'channels' validation is checked even before the migration
+     * starts.
+     */
+    migrate_qmp_fail(from, args->connect_uri, args->connect_channels, "{}");
+    test_migrate_end(from, to, false);
+}
+
+static void test_validate_uri_channels_both_set(void)
+{
+    MigrateCommon args = {
+        .start = {
+            .hide_stderr = true,
+        },
+        .listen_uri = "defer",
+        .connect_uri = "tcp:127.0.0.1:0",
+        .connect_channels = "[ { 'channel-type': 'main',"
+                            "    'addr': { 'transport': 'socket',"
+                            "              'type': 'inet',"
+                            "              'host': '127.0.0.1',"
+                            "              'port': '0' } } ]",
+    };
+
+    do_test_validate_uri_channel(&args);
+}
+
+static void test_validate_uri_channels_none_set(void)
+{
+    MigrateCommon args = {
+        .start = {
+            .hide_stderr = true,
+        },
+        .listen_uri = "defer",
+    };
+
+    do_test_validate_uri_channel(&args);
+}
+
 /*
  * The way auto_converge works, we need to do too many passes to
  * run this test.  Auto_converge logic is only run once every
@@ -2671,7 +2670,7 @@ static void test_migrate_auto_converge(void)
     /* Wait for the first serial output from the source */
     wait_for_serial("src_serial");
 
-    migrate_qmp(from, uri, "{}");
+    migrate_qmp(from, to, uri, NULL, "{}");
 
     /* Wait for throttling begins */
     percentage = 0;
@@ -2778,7 +2777,7 @@ test_migrate_precopy_tcp_multifd_zstd_start(QTestState *from,
 }
 #endif /* CONFIG_ZSTD */
 
-static void test_multifd_tcp_none(void)
+static void test_multifd_tcp_uri_none(void)
 {
     MigrateCommon args = {
         .listen_uri = "defer",
@@ -2823,6 +2822,21 @@ static void test_multifd_tcp_no_zero_page(void)
     test_precopy_common(&args);
 }
 
+static void test_multifd_tcp_channels_none(void)
+{
+    MigrateCommon args = {
+        .listen_uri = "defer",
+        .start_hook = test_migrate_precopy_tcp_multifd_start,
+        .live = true,
+        .connect_channels = "[ { 'channel-type': 'main',"
+                            "    'addr': { 'transport': 'socket',"
+                            "              'type': 'inet',"
+                            "              'host': '127.0.0.1',"
+                            "              'port': '0' } } ]",
+    };
+    test_precopy_common(&args);
+}
+
 static void test_multifd_tcp_zlib(void)
 {
     MigrateCommon args = {
@@ -3017,7 +3031,6 @@ static void test_multifd_tcp_cancel(void)
         .hide_stderr = true,
     };
     QTestState *from, *to, *to2;
-    g_autofree char *uri = NULL;
 
     if (test_migrate_start(&from, &to, "defer", &args)) {
         return;
@@ -3038,9 +3051,7 @@ static void test_multifd_tcp_cancel(void)
     /* Wait for the first serial output from the source */
     wait_for_serial("src_serial");
 
-    uri = migrate_get_socket_address(to, "socket-address");
+    migrate_qmp(from, to, NULL, NULL, "{}");
-
-    migrate_qmp(from, uri, "{}");
 
     migrate_wait_for_dirty_mem(from, to);
 
@@ -3065,14 +3076,11 @@ static void test_multifd_tcp_cancel(void)
     /* Start incoming migration from the 1st socket */
     migrate_incoming_qmp(to2, "tcp:127.0.0.1:0", "{}");
 
-    g_free(uri);
-    uri = migrate_get_socket_address(to2, "socket-address");
-
     wait_for_migration_status(from, "cancelled", NULL);
 
     migrate_ensure_non_converge(from);
 
-    migrate_qmp(from, uri, "{}");
+    migrate_qmp(from, to2, NULL, NULL, "{}");
 
     migrate_wait_for_dirty_mem(from, to2);
 
@@ -3405,7 +3413,7 @@ static void test_migrate_dirty_limit(void)
     migrate_dirty_limit_wait_showup(from, dirtylimit_period, dirtylimit_value);
 
     /* Start migrate */
-    migrate_qmp(from, uri, "{}");
+    migrate_qmp(from, to, args.connect_uri, NULL, "{}");
 
     /* Wait for dirty limit throttle begin */
     throttle_us_per_full = 0;
@@ -3446,7 +3454,7 @@ static void test_migrate_dirty_limit(void)
     }
 
     /* Start migrate */
-    migrate_qmp(from, uri, "{}");
+    migrate_qmp(from, to, args.connect_uri, NULL, "{}");
 
     /* Wait for dirty limit throttle begin */
     throttle_us_per_full = 0;
@@ -3720,6 +3728,10 @@ int main(int argc, char **argv)
                        test_validate_uuid_src_not_set);
     migration_test_add("/migration/validate_uuid_dst_not_set",
                        test_validate_uuid_dst_not_set);
+    migration_test_add("/migration/validate_uri/channels/both_set",
+                       test_validate_uri_channels_both_set);
+    migration_test_add("/migration/validate_uri/channels/none_set",
+                       test_validate_uri_channels_none_set);
     /*
      * See explanation why this test is slow on function definition
      */
@@ -3732,8 +3744,10 @@ int main(int argc, char **argv)
                                test_migrate_dirty_limit);
         }
     }
-    migration_test_add("/migration/multifd/tcp/plain/none",
+    migration_test_add("/migration/multifd/tcp/uri/plain/none",
-                       test_multifd_tcp_none);
+                       test_multifd_tcp_uri_none);
+    migration_test_add("/migration/multifd/tcp/channels/plain/none",
+                       test_multifd_tcp_channels_none);
     migration_test_add("/migration/multifd/tcp/plain/zero-page/legacy",
                        test_multifd_tcp_zero_page_legacy);
     migration_test_add("/migration/multifd/tcp/plain/zero-page/none",