Merge tag 'migration-20230726-pull-request' of https://gitlab.com/juan.quintela/qemu into staging

Migration Pull request

Hi

This is the migration PULL request.  It is the same than yesterday with proper PULL headers.
It pass CI. It contains:
- Fabiano rosas trheadinfo cleanups
- Hyman Huang dirtylimit changes
- Part of my changes
- Peter Xu documentation
- Tejus updato to migration descriptions
- Wei want improvements for postocpy and multifd setup

Please apply.

Thanks, Juan.

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# gpg:                 aka "Juan Quintela <quintela@trasno.org>" [undefined]
# 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: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* tag 'migration-20230726-pull-request' of https://gitlab.com/juan.quintela/qemu: (25 commits)
  migration/rdma: Split qemu_fopen_rdma() into input/output functions
  qemu-file: Make qemu_file_get_error_obj() static
  qemu-file: Simplify qemu_file_shutdown()
  qemu_file: Make qemu_file_is_writable() static
  migration: Change qemu_file_transferred to noflush
  qemu-file: Rename qemu_file_transferred_ fast -> noflush
  qtest/migration-tests.c: use "-incoming defer" for postcopy tests
  migration: enforce multifd and postcopy preempt to be set before incoming
  migration: Update error description whenever migration fails
  docs/migration: Update postcopy bits
  migration: skipped field is really obsolete.
  migration-test: machine_opts is really arch specific
  migration-test: Create arch_opts
  migration-test: Make machine_opts regular with other options
  migration-test: Be consistent for ppc
  migration: Extend query-migrate to provide dirty page limit info
  migration: Implement dirty-limit convergence algo
  migration: Put the detection logic before auto-converge checking
  migration: Refactor auto-converge capability logic
  migration: Introduce dirty-limit capability
  ...

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

20 files changed, 510 insertions, 155 deletions

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 02ea5a8..1c35f55 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -451,3 +451,13 @@ both, older and future versions of QEMU.
 The ``blacklist`` config file option has been renamed to ``block-rpcs``
 (to be in sync with the renaming of the corresponding command line
 option).
+
+Migration
+---------
+
+``skipped`` MigrationStats field (since 8.1)
+''''''''''''''''''''''''''''''''''''''''''''
+
+``skipped`` field in Migration stats has been deprecated.  It hasn't
+been used for more than 10 years.
+
diff --git a/docs/devel/migration.rst b/docs/devel/migration.rst
index 6f65c23..c3e1400 100644
--- a/docs/devel/migration.rst
+++ b/docs/devel/migration.rst
@@ -594,8 +594,7 @@ Postcopy
 'Postcopy' migration is a way to deal with migrations that refuse to converge
 (or take too long to converge) its plus side is that there is an upper bound on
 the amount of migration traffic and time it takes, the down side is that during
-the postcopy phase, a failure of *either* side or the network connection causes
-the guest to be lost.
+the postcopy phase, a failure of *either* side causes the guest to be lost.
 
 In postcopy the destination CPUs are started before all the memory has been
 transferred, and accesses to pages that are yet to be transferred cause
@@ -721,6 +720,42 @@ processing.
    is no longer used by migration, while the listen thread carries on servicing
    page data until the end of migration.
 
+Postcopy Recovery
+-----------------
+
+Comparing to precopy, postcopy is special on error handlings.  When any
+error happens (in this case, mostly network errors), QEMU cannot easily
+fail a migration because VM data resides in both source and destination
+QEMU instances.  On the other hand, when issue happens QEMU on both sides
+will go into a paused state.  It'll need a recovery phase to continue a
+paused postcopy migration.
+
+The recovery phase normally contains a few steps:
+
+  - When network issue occurs, both QEMU will go into PAUSED state
+
+  - When the network is recovered (or a new network is provided), the admin
+    can setup the new channel for migration using QMP command
+    'migrate-recover' on destination node, preparing for a resume.
+
+  - On source host, the admin can continue the interrupted postcopy
+    migration using QMP command 'migrate' with resume=true flag set.
+
+  - After the connection is re-established, QEMU will continue the postcopy
+    migration on both sides.
+
+During a paused postcopy migration, the VM can logically still continue
+running, and it will not be impacted from any page access to pages that
+were already migrated to destination VM before the interruption happens.
+However, if any of the missing pages got accessed on destination VM, the VM
+thread will be halted waiting for the page to be migrated, it means it can
+be halted until the recovery is complete.
+
+The impact of accessing missing pages can be relevant to different
+configurations of the guest.  For example, when with async page fault
+enabled, logically the guest can proactively schedule out the threads
+accessing missing pages.
+
 Postcopy states
 ---------------
 
@@ -765,36 +800,31 @@ ADVISE->DISCARD->LISTEN->RUNNING->END
     (although it can't do the cleanup it would do as it
     finishes a normal migration).
 
+ - Paused
+
+    Postcopy can run into a paused state (normally on both sides when
+    happens), where all threads will be temporarily halted mostly due to
+    network errors.  When reaching paused state, migration will make sure
+    the qemu binary on both sides maintain the data without corrupting
+    the VM.  To continue the migration, the admin needs to fix the
+    migration channel using the QMP command 'migrate-recover' on the
+    destination node, then resume the migration using QMP command 'migrate'
+    again on source node, with resume=true flag set.
+
  - End
 
     The listen thread can now quit, and perform the cleanup of migration
     state, the migration is now complete.
 
-Source side page maps
----------------------
+Source side page map
+--------------------
 
-The source side keeps two bitmaps during postcopy; 'the migration bitmap'
-and 'unsent map'.  The 'migration bitmap' is basically the same as in
-the precopy case, and holds a bit to indicate that page is 'dirty' -
-i.e. needs sending.  During the precopy phase this is updated as the CPU
-dirties pages, however during postcopy the CPUs are stopped and nothing
-should dirty anything any more.
-
-The 'unsent map' is used for the transition to postcopy. It is a bitmap that
-has a bit cleared whenever a page is sent to the destination, however during
-the transition to postcopy mode it is combined with the migration bitmap
-to form a set of pages that:
-
-   a) Have been sent but then redirtied (which must be discarded)
-   b) Have not yet been sent - which also must be discarded to cause any
-      transparent huge pages built during precopy to be broken.
-
-Note that the contents of the unsentmap are sacrificed during the calculation
-of the discard set and thus aren't valid once in postcopy.  The dirtymap
-is still valid and is used to ensure that no page is sent more than once.  Any
-request for a page that has already been sent is ignored.  Duplicate requests
-such as this can happen as a page is sent at about the same time the
-destination accesses it.
+The 'migration bitmap' in postcopy is basically the same as in the precopy,
+where each of the bit to indicate that page is 'dirty' - i.e. needs
+sending.  During the precopy phase this is updated as the CPU dirties
+pages, however during postcopy the CPUs are stopped and nothing should
+dirty anything any more. Instead, dirty bits are cleared when the relevant
+pages are sent during postcopy.
 
 Postcopy with hugepages
 -----------------------
@@ -853,6 +883,16 @@ Retro-fitting postcopy to existing clients is possible:
      guest memory access is made while holding a lock then all other
      threads waiting for that lock will also be blocked.
 
+Postcopy Preemption Mode
+------------------------
+
+Postcopy preempt is a new capability introduced in 8.0 QEMU release, it
+allows urgent pages (those got page fault requested from destination QEMU
+explicitly) to be sent in a separate preempt channel, rather than queued in
+the background migration channel.  Anyone who cares about latencies of page
+faults during a postcopy migration should enable this feature.  By default,
+it's not enabled.
+
 Firmware
 ========
 
diff --git a/include/sysemu/dirtylimit.h b/include/sysemu/dirtylimit.h
index 8d2c1f3..d11ebbb 100644
--- a/include/sysemu/dirtylimit.h
+++ b/include/sysemu/dirtylimit.h
@@ -34,4 +34,6 @@ void dirtylimit_set_vcpu(int cpu_index,
 void dirtylimit_set_all(uint64_t quota,
                         bool enable);
 void dirtylimit_vcpu_execute(CPUState *cpu);
+uint64_t dirtylimit_throttle_time_per_round(void);
+uint64_t dirtylimit_ring_full_time(void);
 #endif
diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index 9885d7c..c115ef2 100644
--- a/migration/migration-hmp-cmds.c
+++ b/migration/migration-hmp-cmds.c
@@ -190,6 +190,16 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
                        info->cpu_throttle_percentage);
     }
 
+    if (info->has_dirty_limit_throttle_time_per_round) {
+        monitor_printf(mon, "dirty-limit throttle time: %" PRIu64 " us\n",
+                       info->dirty_limit_throttle_time_per_round);
+    }
+
+    if (info->has_dirty_limit_ring_full_time) {
+        monitor_printf(mon, "dirty-limit ring full time: %" PRIu64 " us\n",
+                       info->dirty_limit_ring_full_time);
+    }
+
     if (info->has_postcopy_blocktime) {
         monitor_printf(mon, "postcopy blocktime: %u\n",
                        info->postcopy_blocktime);
@@ -364,6 +374,14 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
                 }
             }
         }
+
+        monitor_printf(mon, "%s: %" PRIu64 " ms\n",
+        MigrationParameter_str(MIGRATION_PARAMETER_X_VCPU_DIRTY_LIMIT_PERIOD),
+        params->x_vcpu_dirty_limit_period);
+
+        monitor_printf(mon, "%s: %" PRIu64 " MB/s\n",
+            MigrationParameter_str(MIGRATION_PARAMETER_VCPU_DIRTY_LIMIT),
+            params->vcpu_dirty_limit);
     }
 
     qapi_free_MigrationParameters(params);
@@ -620,6 +638,14 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
         error_setg(&err, "The block-bitmap-mapping parameter can only be set "
                    "through QMP");
         break;
+    case MIGRATION_PARAMETER_X_VCPU_DIRTY_LIMIT_PERIOD:
+        p->has_x_vcpu_dirty_limit_period = true;
+        visit_type_size(v, param, &p->x_vcpu_dirty_limit_period, &err);
+        break;
+    case MIGRATION_PARAMETER_VCPU_DIRTY_LIMIT:
+        p->has_vcpu_dirty_limit = true;
+        visit_type_size(v, param, &p->vcpu_dirty_limit, &err);
+        break;
     default:
         assert(0);
     }
diff --git a/migration/migration.c b/migration/migration.c
index 91bba63..5528acb 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -64,6 +64,7 @@
 #include "yank_functions.h"
 #include "sysemu/qtest.h"
 #include "options.h"
+#include "sysemu/dirtylimit.h"
 
 static NotifierList migration_state_notifiers =
     NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
@@ -166,6 +167,9 @@ void migration_cancel(const Error *error)
     if (error) {
         migrate_set_error(current_migration, error);
     }
+    if (migrate_dirty_limit()) {
+        qmp_cancel_vcpu_dirty_limit(false, -1, NULL);
+    }
     migrate_fd_cancel(current_migration);
 }
 
@@ -971,6 +975,15 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s)
         info->ram->dirty_pages_rate =
            stat64_get(&mig_stats.dirty_pages_rate);
     }
+
+    if (migrate_dirty_limit() && dirtylimit_in_service()) {
+        info->has_dirty_limit_throttle_time_per_round = true;
+        info->dirty_limit_throttle_time_per_round =
+                            dirtylimit_throttle_time_per_round();
+
+        info->has_dirty_limit_ring_full_time = true;
+        info->dirty_limit_ring_full_time = dirtylimit_ring_full_time();
+    }
 }
 
 static void populate_disk_info(MigrationInfo *info)
@@ -1676,7 +1689,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
         if (!resume_requested) {
             yank_unregister_instance(MIGRATION_YANK_INSTANCE);
         }
-        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
+        error_setg(&local_err, QERR_INVALID_PARAMETER_VALUE, "uri",
                    "a valid migration protocol");
         migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
                           MIGRATION_STATUS_FAILED);
@@ -2069,7 +2082,7 @@ migration_wait_main_channel(MigrationState *ms)
  * Switch from normal iteration to postcopy
  * Returns non-0 on error
  */
-static int postcopy_start(MigrationState *ms)
+static int postcopy_start(MigrationState *ms, Error **errp)
 {
     int ret;
     QIOChannelBuffer *bioc;
@@ -2179,7 +2192,7 @@ static int postcopy_start(MigrationState *ms)
      */
     ret = qemu_file_get_error(ms->to_dst_file);
     if (ret) {
-        error_report("postcopy_start: Migration stream errored (pre package)");
+        error_setg(errp, "postcopy_start: Migration stream errored (pre package)");
         goto fail_closefb;
     }
 
@@ -2216,7 +2229,7 @@ static int postcopy_start(MigrationState *ms)
 
     ret = qemu_file_get_error(ms->to_dst_file);
     if (ret) {
-        error_report("postcopy_start: Migration stream errored");
+        error_setg(errp, "postcopy_start: Migration stream errored");
         migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
                               MIGRATION_STATUS_FAILED);
     }
@@ -2737,6 +2750,7 @@ typedef enum {
 static MigIterateState migration_iteration_run(MigrationState *s)
 {
     uint64_t must_precopy, can_postcopy;
+    Error *local_err = NULL;
     bool in_postcopy = s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE;
     bool can_switchover = migration_can_switchover(s);
 
@@ -2760,8 +2774,9 @@ static MigIterateState migration_iteration_run(MigrationState *s)
     /* Still a significant amount to transfer */
     if (!in_postcopy && must_precopy <= s->threshold_size && can_switchover &&
         qatomic_read(&s->start_postcopy)) {
-        if (postcopy_start(s)) {
-            error_report("%s: postcopy failed to start", __func__);
+        if (postcopy_start(s, &local_err)) {
+            migrate_set_error(s, local_err);
+            error_report_err(local_err);
         }
         return MIG_ITERATE_SKIP;
     }
@@ -2953,7 +2968,7 @@ static void *migration_thread(void *opaque)
     MigThrError thr_error;
     bool urgent = false;
 
-    thread = MigrationThreadAdd("live_migration", qemu_get_thread_id());
+    thread = migration_threads_add("live_migration", qemu_get_thread_id());
 
     rcu_register_thread();
 
@@ -3031,7 +3046,7 @@ static void *migration_thread(void *opaque)
     migration_iteration_finish(s);
     object_unref(OBJECT(s));
     rcu_unregister_thread();
-    MigrationThreadDel(thread);
+    migration_threads_remove(thread);
     return NULL;
 }
 
@@ -3252,8 +3267,10 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
      */
     if (migrate_postcopy_ram() || migrate_return_path()) {
         if (open_return_path_on_source(s, !resume)) {
-            error_report("Unable to open return-path for postcopy");
+            error_setg(&local_err, "Unable to open return-path for postcopy");
             migrate_set_state(&s->state, s->state, MIGRATION_STATUS_FAILED);
+            migrate_set_error(s, local_err);
+            error_report_err(local_err);
             migrate_fd_cleanup(s);
             return;
         }
@@ -3277,6 +3294,7 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
     }
 
     if (multifd_save_setup(&local_err) != 0) {
+        migrate_set_error(s, local_err);
         error_report_err(local_err);
         migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
                           MIGRATION_STATUS_FAILED);
diff --git a/migration/multifd.c b/migration/multifd.c
index 0e3ae87..0f6b203 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -651,7 +651,7 @@ static void *multifd_send_thread(void *opaque)
     int ret = 0;
     bool use_zero_copy_send = migrate_zero_copy_send();
 
-    thread = MigrationThreadAdd(p->name, qemu_get_thread_id());
+    thread = migration_threads_add(p->name, qemu_get_thread_id());
 
     trace_multifd_send_thread_start(p->id);
     rcu_register_thread();
@@ -767,7 +767,7 @@ out:
     qemu_mutex_unlock(&p->mutex);
 
     rcu_unregister_thread();
-    MigrationThreadDel(thread);
+    migration_threads_remove(thread);
     trace_multifd_send_thread_end(p->id, p->num_packets, p->total_normal_pages);
 
     return NULL;
diff --git a/migration/options.c b/migration/options.c
index 5a9505a..1d1e132 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -27,6 +27,7 @@
 #include "qemu-file.h"
 #include "ram.h"
 #include "options.h"
+#include "sysemu/kvm.h"
 
 /* Maximum migrate downtime set to 2000 seconds */
 #define MAX_MIGRATE_DOWNTIME_SECONDS 2000
@@ -80,6 +81,9 @@
 #define DEFINE_PROP_MIG_CAP(name, x)             \
     DEFINE_PROP_BOOL(name, MigrationState, capabilities[x], false)
 
+#define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD     1000    /* milliseconds */
+#define DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT            1       /* MB/s */
+
 Property migration_properties[] = {
     DEFINE_PROP_BOOL("store-global-state", MigrationState,
                      store_global_state, true),
@@ -163,6 +167,12 @@ Property migration_properties[] = {
     DEFINE_PROP_STRING("tls-creds", MigrationState, parameters.tls_creds),
     DEFINE_PROP_STRING("tls-hostname", MigrationState, parameters.tls_hostname),
     DEFINE_PROP_STRING("tls-authz", MigrationState, parameters.tls_authz),
+    DEFINE_PROP_UINT64("x-vcpu-dirty-limit-period", MigrationState,
+                       parameters.x_vcpu_dirty_limit_period,
+                       DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT_PERIOD),
+    DEFINE_PROP_UINT64("vcpu-dirty-limit", MigrationState,
+                       parameters.vcpu_dirty_limit,
+                       DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT),
 
     /* Migration capabilities */
     DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
@@ -187,7 +197,7 @@ Property migration_properties[] = {
 #endif
     DEFINE_PROP_MIG_CAP("x-switchover-ack",
                         MIGRATION_CAPABILITY_SWITCHOVER_ACK),
-
+    DEFINE_PROP_MIG_CAP("x-dirty-limit", MIGRATION_CAPABILITY_DIRTY_LIMIT),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -233,6 +243,13 @@ bool migrate_dirty_bitmaps(void)
     return s->capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS];
 }
 
+bool migrate_dirty_limit(void)
+{
+    MigrationState *s = migrate_get_current();
+
+    return s->capabilities[MIGRATION_CAPABILITY_DIRTY_LIMIT];
+}
+
 bool migrate_events(void)
 {
     MigrationState *s = migrate_get_current();
@@ -424,6 +441,11 @@ INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
     MIGRATION_CAPABILITY_VALIDATE_UUID,
     MIGRATION_CAPABILITY_ZERO_COPY_SEND);
 
+static bool migrate_incoming_started(void)
+{
+    return !!migration_incoming_get_current()->transport_data;
+}
+
 /**
  * @migration_caps_check - check capability compatibility
  *
@@ -547,6 +569,12 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
             error_setg(errp, "Postcopy preempt not compatible with compress");
             return false;
         }
+
+        if (migrate_incoming_started()) {
+            error_setg(errp,
+                       "Postcopy preempt must be set before incoming starts");
+            return false;
+        }
     }
 
     if (new_caps[MIGRATION_CAPABILITY_MULTIFD]) {
@@ -554,6 +582,10 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
             error_setg(errp, "Multifd is not compatible with compress");
             return false;
         }
+        if (migrate_incoming_started()) {
+            error_setg(errp, "Multifd must be set before incoming starts");
+            return false;
+        }
     }
 
     if (new_caps[MIGRATION_CAPABILITY_SWITCHOVER_ACK]) {
@@ -563,6 +595,19 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
             return false;
         }
     }
+    if (new_caps[MIGRATION_CAPABILITY_DIRTY_LIMIT]) {
+        if (new_caps[MIGRATION_CAPABILITY_AUTO_CONVERGE]) {
+            error_setg(errp, "dirty-limit conflicts with auto-converge"
+                       " either of then available currently");
+            return false;
+        }
+
+        if (!kvm_enabled() || !kvm_dirty_ring_enabled()) {
+            error_setg(errp, "dirty-limit requires KVM with accelerator"
+                   " property 'dirty-ring-size' set");
+            return false;
+        }
+    }
 
     return true;
 }
@@ -908,6 +953,11 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
                        s->parameters.block_bitmap_mapping);
     }
 
+    params->has_x_vcpu_dirty_limit_period = true;
+    params->x_vcpu_dirty_limit_period = s->parameters.x_vcpu_dirty_limit_period;
+    params->has_vcpu_dirty_limit = true;
+    params->vcpu_dirty_limit = s->parameters.vcpu_dirty_limit;
+
     return params;
 }
 
@@ -940,6 +990,8 @@ void migrate_params_init(MigrationParameters *params)
     params->has_announce_max = true;
     params->has_announce_rounds = true;
     params->has_announce_step = true;
+    params->has_x_vcpu_dirty_limit_period = true;
+    params->has_vcpu_dirty_limit = true;
 }
 
 /*
@@ -1100,6 +1152,23 @@ bool migrate_params_check(MigrationParameters *params, Error **errp)
     }
 #endif
 
+    if (params->has_x_vcpu_dirty_limit_period &&
+        (params->x_vcpu_dirty_limit_period < 1 ||
+         params->x_vcpu_dirty_limit_period > 1000)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   "x-vcpu-dirty-limit-period",
+                   "a value between 1 and 1000");
+        return false;
+    }
+
+    if (params->has_vcpu_dirty_limit &&
+        (params->vcpu_dirty_limit < 1)) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
+                   "vcpu_dirty_limit",
+                   "is invalid, it must greater then 1 MB/s");
+        return false;
+    }
+
     return true;
 }
 
@@ -1199,6 +1268,14 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
         dest->has_block_bitmap_mapping = true;
         dest->block_bitmap_mapping = params->block_bitmap_mapping;
     }
+
+    if (params->has_x_vcpu_dirty_limit_period) {
+        dest->x_vcpu_dirty_limit_period =
+            params->x_vcpu_dirty_limit_period;
+    }
+    if (params->has_vcpu_dirty_limit) {
+        dest->vcpu_dirty_limit = params->vcpu_dirty_limit;
+    }
 }
 
 static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
@@ -1317,6 +1394,14 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
             QAPI_CLONE(BitmapMigrationNodeAliasList,
                        params->block_bitmap_mapping);
     }
+
+    if (params->has_x_vcpu_dirty_limit_period) {
+        s->parameters.x_vcpu_dirty_limit_period =
+            params->x_vcpu_dirty_limit_period;
+    }
+    if (params->has_vcpu_dirty_limit) {
+        s->parameters.vcpu_dirty_limit = params->vcpu_dirty_limit;
+    }
 }
 
 void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
diff --git a/migration/options.h b/migration/options.h
index 9aaf363..045e2a4 100644
--- a/migration/options.h
+++ b/migration/options.h
@@ -29,6 +29,7 @@ bool migrate_block(void);
 bool migrate_colo(void);
 bool migrate_compress(void);
 bool migrate_dirty_bitmaps(void);
+bool migrate_dirty_limit(void);
 bool migrate_events(void);
 bool migrate_ignore_shared(void);
 bool migrate_late_block_activate(void);
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index acc2826..19c33c9 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -65,8 +65,6 @@ struct QEMUFile {
  */
 int qemu_file_shutdown(QEMUFile *f)
 {
-    int ret = 0;
-
     /*
      * We must set qemufile error before the real shutdown(), otherwise
      * there can be a race window where we thought IO all went though
@@ -96,22 +94,10 @@ int qemu_file_shutdown(QEMUFile *f)
     }
 
     if (qio_channel_shutdown(f->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL) < 0) {
-        ret = -EIO;
+        return -EIO;
     }
 
-    return ret;
-}
-
-bool qemu_file_mode_is_not_valid(const char *mode)
-{
-    if (mode == NULL ||
-        (mode[0] != 'r' && mode[0] != 'w') ||
-        mode[1] != 'b' || mode[2] != 0) {
-        fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
-        return true;
-    }
-
-    return false;
+    return 0;
 }
 
 static QEMUFile *qemu_file_new_impl(QIOChannel *ioc, bool is_writable)
@@ -160,7 +146,7 @@ void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks)
  * is not 0.
  *
  */
-int qemu_file_get_error_obj(QEMUFile *f, Error **errp)
+static int qemu_file_get_error_obj(QEMUFile *f, Error **errp)
 {
     if (errp) {
         *errp = f->last_error_obj ? error_copy(f->last_error_obj) : NULL;
@@ -228,7 +214,7 @@ void qemu_file_set_error(QEMUFile *f, int ret)
     qemu_file_set_error_obj(f, ret, NULL);
 }
 
-bool qemu_file_is_writable(QEMUFile *f)
+static bool qemu_file_is_writable(QEMUFile *f)
 {
     return f->is_writable;
 }
@@ -694,7 +680,7 @@ int coroutine_mixed_fn qemu_get_byte(QEMUFile *f)
     return result;
 }
 
-uint64_t qemu_file_transferred_fast(QEMUFile *f)
+uint64_t qemu_file_transferred_noflush(QEMUFile *f)
 {
     uint64_t ret = f->total_transferred;
     int i;
diff --git a/migration/qemu-file.h b/migration/qemu-file.h
index e649718..47015f5 100644
--- a/migration/qemu-file.h
+++ b/migration/qemu-file.h
@@ -86,16 +86,15 @@ int qemu_fclose(QEMUFile *f);
 uint64_t qemu_file_transferred(QEMUFile *f);
 
 /*
- * qemu_file_transferred_fast:
+ * qemu_file_transferred_noflush:
  *
- * As qemu_file_transferred except for writable
- * files, where no flush is performed and the reported
- * amount will include the size of any queued buffers,
- * on top of the amount actually transferred.
+ * As qemu_file_transferred except for writable files, where no flush
+ * is performed and the reported amount will include the size of any
+ * queued buffers, on top of the amount actually transferred.
  *
  * Returns: the total bytes transferred and queued
  */
-uint64_t qemu_file_transferred_fast(QEMUFile *f);
+uint64_t qemu_file_transferred_noflush(QEMUFile *f);
 
 /*
  * put_buffer without copying the buffer.
@@ -103,8 +102,6 @@ uint64_t qemu_file_transferred_fast(QEMUFile *f);
  */
 void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
                            bool may_free);
-bool qemu_file_mode_is_not_valid(const char *mode);
-bool qemu_file_is_writable(QEMUFile *f);
 
 #include "migration/qemu-file-types.h"
 
@@ -130,7 +127,6 @@ void qemu_file_skip(QEMUFile *f, int size);
  * accounting information tracks the total migration traffic.
  */
 void qemu_file_credit_transfer(QEMUFile *f, size_t size);
-int qemu_file_get_error_obj(QEMUFile *f, Error **errp);
 int qemu_file_get_error_obj_any(QEMUFile *f1, QEMUFile *f2, Error **errp);
 void qemu_file_set_error_obj(QEMUFile *f, int ret, Error *err);
 void qemu_file_set_error(QEMUFile *f, int ret);
diff --git a/migration/ram.c b/migration/ram.c
index 0ada647..9040d66 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -46,6 +46,7 @@
 #include "qapi/error.h"
 #include "qapi/qapi-types-migration.h"
 #include "qapi/qapi-events-migration.h"
+#include "qapi/qapi-commands-migration.h"
 #include "qapi/qmp/qerror.h"
 #include "trace.h"
 #include "exec/ram_addr.h"
@@ -59,6 +60,8 @@
 #include "multifd.h"
 #include "sysemu/runstate.h"
 #include "options.h"
+#include "sysemu/dirtylimit.h"
+#include "sysemu/kvm.h"
 
 #include "hw/boards.h" /* for machine_dump_guest_core() */
 
@@ -984,6 +987,37 @@ static void migration_update_rates(RAMState *rs, int64_t end_time)
     }
 }
 
+/*
+ * Enable dirty-limit to throttle down the guest
+ */
+static void migration_dirty_limit_guest(void)
+{
+    /*
+     * dirty page rate quota for all vCPUs fetched from
+     * migration parameter 'vcpu_dirty_limit'
+     */
+    static int64_t quota_dirtyrate;
+    MigrationState *s = migrate_get_current();
+
+    /*
+     * If dirty limit already enabled and migration parameter
+     * vcpu-dirty-limit untouched.
+     */
+    if (dirtylimit_in_service() &&
+        quota_dirtyrate == s->parameters.vcpu_dirty_limit) {
+        return;
+    }
+
+    quota_dirtyrate = s->parameters.vcpu_dirty_limit;
+
+    /*
+     * Set all vCPU a quota dirtyrate, note that the second
+     * parameter will be ignored if setting all vCPU for the vm
+     */
+    qmp_set_vcpu_dirty_limit(false, -1, quota_dirtyrate, NULL);
+    trace_migration_dirty_limit_guest(quota_dirtyrate);
+}
+
 static void migration_trigger_throttle(RAMState *rs)
 {
     uint64_t threshold = migrate_throttle_trigger_threshold();
@@ -995,19 +1029,26 @@ static void migration_trigger_throttle(RAMState *rs)
     /* During block migration the auto-converge logic incorrectly detects
      * that ram migration makes no progress. Avoid this by disabling the
      * throttling logic during the bulk phase of block migration. */
-    if (migrate_auto_converge() && !blk_mig_bulk_active()) {
-        /* The following detection logic can be refined later. For now:
-           Check to see if the ratio between dirtied bytes and the approx.
-           amount of bytes that just got transferred since the last time
-           we were in this routine reaches the threshold. If that happens
-           twice, start or increase throttling. */
-
-        if ((bytes_dirty_period > bytes_dirty_threshold) &&
-            (++rs->dirty_rate_high_cnt >= 2)) {
+    if (blk_mig_bulk_active()) {
+        return;
+    }
+
+    /*
+     * The following detection logic can be refined later. For now:
+     * Check to see if the ratio between dirtied bytes and the approx.
+     * amount of bytes that just got transferred since the last time
+     * we were in this routine reaches the threshold. If that happens
+     * twice, start or increase throttling.
+     */
+    if ((bytes_dirty_period > bytes_dirty_threshold) &&
+        (++rs->dirty_rate_high_cnt >= 2)) {
+        rs->dirty_rate_high_cnt = 0;
+        if (migrate_auto_converge()) {
             trace_migration_throttle();
-            rs->dirty_rate_high_cnt = 0;
             mig_throttle_guest_down(bytes_dirty_period,
                                     bytes_dirty_threshold);
+        } else if (migrate_dirty_limit()) {
+            migration_dirty_limit_guest();
         }
     }
 }
diff --git a/migration/rdma.c b/migration/rdma.c
index dd1c039..ca430d3 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -4053,27 +4053,26 @@ static void qio_channel_rdma_register_types(void)
 
 type_init(qio_channel_rdma_register_types);
 
-static QEMUFile *qemu_fopen_rdma(RDMAContext *rdma, const char *mode)
+static QEMUFile *rdma_new_input(RDMAContext *rdma)
 {
-    QIOChannelRDMA *rioc;
+    QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(object_new(TYPE_QIO_CHANNEL_RDMA));
 
-    if (qemu_file_mode_is_not_valid(mode)) {
-        return NULL;
-    }
+    rioc->file = qemu_file_new_input(QIO_CHANNEL(rioc));
+    rioc->rdmain = rdma;
+    rioc->rdmaout = rdma->return_path;
+    qemu_file_set_hooks(rioc->file, &rdma_read_hooks);
+
+    return rioc->file;
+}
 
-    rioc = QIO_CHANNEL_RDMA(object_new(TYPE_QIO_CHANNEL_RDMA));
+static QEMUFile *rdma_new_output(RDMAContext *rdma)
+{
+    QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(object_new(TYPE_QIO_CHANNEL_RDMA));
 
-    if (mode[0] == 'w') {
-        rioc->file = qemu_file_new_output(QIO_CHANNEL(rioc));
-        rioc->rdmaout = rdma;
-        rioc->rdmain = rdma->return_path;
-        qemu_file_set_hooks(rioc->file, &rdma_write_hooks);
-    } else {
-        rioc->file = qemu_file_new_input(QIO_CHANNEL(rioc));
-        rioc->rdmain = rdma;
-        rioc->rdmaout = rdma->return_path;
-        qemu_file_set_hooks(rioc->file, &rdma_read_hooks);
-    }
+    rioc->file = qemu_file_new_output(QIO_CHANNEL(rioc));
+    rioc->rdmaout = rdma;
+    rioc->rdmain = rdma->return_path;
+    qemu_file_set_hooks(rioc->file, &rdma_write_hooks);
 
     return rioc->file;
 }
@@ -4099,9 +4098,9 @@ static void rdma_accept_incoming_migration(void *opaque)
         return;
     }
 
-    f = qemu_fopen_rdma(rdma, "rb");
+    f = rdma_new_input(rdma);
     if (f == NULL) {
-        fprintf(stderr, "RDMA ERROR: could not qemu_fopen_rdma\n");
+        fprintf(stderr, "RDMA ERROR: could not open RDMA for input\n");
         qemu_rdma_cleanup(rdma);
         return;
     }
@@ -4224,7 +4223,7 @@ void rdma_start_outgoing_migration(void *opaque,
 
     trace_rdma_start_outgoing_migration_after_rdma_connect();
 
-    s->to_dst_file = qemu_fopen_rdma(rdma, "wb");
+    s->to_dst_file = rdma_new_output(rdma);
     migrate_fd_connect(s, NULL);
     return;
 return_path_err:
diff --git a/migration/savevm.c b/migration/savevm.c
index 51e40e3..a2cb885 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -927,9 +927,9 @@ static int vmstate_load(QEMUFile *f, SaveStateEntry *se)
 static void vmstate_save_old_style(QEMUFile *f, SaveStateEntry *se,
                                    JSONWriter *vmdesc)
 {
-    uint64_t old_offset = qemu_file_transferred_fast(f);
+    uint64_t old_offset = qemu_file_transferred_noflush(f);
     se->ops->save_state(f, se->opaque);
-    uint64_t size = qemu_file_transferred_fast(f) - old_offset;
+    uint64_t size = qemu_file_transferred_noflush(f) - old_offset;
 
     if (vmdesc) {
         json_writer_int64(vmdesc, "size", size);
@@ -3007,7 +3007,7 @@ bool save_snapshot(const char *name, bool overwrite, const char *vmstate,
         goto the_end;
     }
     ret = qemu_savevm_state(f, errp);
-    vm_state_size = qemu_file_transferred(f);
+    vm_state_size = qemu_file_transferred_noflush(f);
     ret2 = qemu_fclose(f);
     if (ret < 0) {
         goto the_end;
diff --git a/migration/threadinfo.c b/migration/threadinfo.c
index 1de8b31..262990d 100644
--- a/migration/threadinfo.c
+++ b/migration/threadinfo.c
@@ -10,23 +10,35 @@
  *  See the COPYING file in the top-level directory.
  */
 
+#include "qemu/osdep.h"
+#include "qemu/queue.h"
+#include "qemu/lockable.h"
 #include "threadinfo.h"
 
+QemuMutex migration_threads_lock;
 static QLIST_HEAD(, MigrationThread) migration_threads;
 
-MigrationThread *MigrationThreadAdd(const char *name, int thread_id)
+static void __attribute__((constructor)) migration_threads_init(void)
+{
+    qemu_mutex_init(&migration_threads_lock);
+}
+
+MigrationThread *migration_threads_add(const char *name, int thread_id)
 {
     MigrationThread *thread =  g_new0(MigrationThread, 1);
     thread->name = name;
     thread->thread_id = thread_id;
 
-    QLIST_INSERT_HEAD(&migration_threads, thread, node);
+    WITH_QEMU_LOCK_GUARD(&migration_threads_lock) {
+        QLIST_INSERT_HEAD(&migration_threads, thread, node);
+    }
 
     return thread;
 }
 
-void MigrationThreadDel(MigrationThread *thread)
+void migration_threads_remove(MigrationThread *thread)
 {
+    QEMU_LOCK_GUARD(&migration_threads_lock);
     if (thread) {
         QLIST_REMOVE(thread, node);
         g_free(thread);
@@ -39,6 +51,7 @@ MigrationThreadInfoList *qmp_query_migrationthreads(Error **errp)
     MigrationThreadInfoList **tail = &head;
     MigrationThread *thread = NULL;
 
+    QEMU_LOCK_GUARD(&migration_threads_lock);
     QLIST_FOREACH(thread, &migration_threads, node) {
         MigrationThreadInfo *info = g_new0(MigrationThreadInfo, 1);
         info->name = g_strdup(thread->name);
diff --git a/migration/threadinfo.h b/migration/threadinfo.h
index 4d69423..2f356ff 100644
--- a/migration/threadinfo.h
+++ b/migration/threadinfo.h
@@ -10,8 +10,6 @@
  *  See the COPYING file in the top-level directory.
  */
 
-#include "qemu/queue.h"
-#include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-migration.h"
 
@@ -23,6 +21,5 @@ struct MigrationThread {
     QLIST_ENTRY(MigrationThread) node;
 };
 
-MigrationThread *MigrationThreadAdd(const char *name, int thread_id);
-
-void MigrationThreadDel(MigrationThread *info);
+MigrationThread *migration_threads_add(const char *name, int thread_id);
+void migration_threads_remove(MigrationThread *info);
diff --git a/migration/trace-events b/migration/trace-events
index 4e43fe2..4666f19 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -93,6 +93,7 @@ migration_bitmap_sync_start(void) ""
 migration_bitmap_sync_end(uint64_t dirty_pages) "dirty_pages %" PRIu64
 migration_bitmap_clear_dirty(char *str, uint64_t start, uint64_t size, unsigned long page) "rb %s start 0x%"PRIx64" size 0x%"PRIx64" page 0x%lx"
 migration_throttle(void) ""
+migration_dirty_limit_guest(int64_t dirtyrate) "guest dirty page rate limit %" PRIi64 " MB/s"
 ram_discard_range(const char *rbname, uint64_t start, size_t len) "%s: start: %" PRIx64 " %zx"
 ram_load_loop(const char *rbname, uint64_t addr, int flags, void *host) "%s: addr: 0x%" PRIx64 " flags: 0x%x host: %p"
 ram_load_postcopy_loop(int channel, uint64_t addr, int flags) "chan=%d addr=0x%" PRIx64 " flags=0x%x"
diff --git a/migration/vmstate.c b/migration/vmstate.c
index af01d54..31842c3 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -361,7 +361,7 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
                 void *curr_elem = first_elem + size * i;
 
                 vmsd_desc_field_start(vmsd, vmdesc_loop, field, i, n_elems);
-                old_offset = qemu_file_transferred_fast(f);
+                old_offset = qemu_file_transferred_noflush(f);
                 if (field->flags & VMS_ARRAY_OF_POINTER) {
                     assert(curr_elem);
                     curr_elem = *(void **)curr_elem;
@@ -391,7 +391,7 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
                     return ret;
                 }
 
-                written_bytes = qemu_file_transferred_fast(f) - old_offset;
+                written_bytes = qemu_file_transferred_noflush(f) - old_offset;
                 vmsd_desc_field_end(vmsd, vmdesc_loop, field, written_bytes, i);
 
                 /* Compressed arrays only care about the first element */
diff --git a/qapi/migration.json b/qapi/migration.json
index 2a6565a..388425b 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -23,7 +23,8 @@
 #
 # @duplicate: number of duplicate (zero) pages (since 1.2)
 #
-# @skipped: number of skipped zero pages (since 1.5)
+# @skipped: number of skipped zero pages. Always zero, only provided for
+#     compatibility (since 1.5)
 #
 # @normal: number of normal pages (since 1.2)
 #
@@ -62,11 +63,18 @@
 #     between 0 and @dirty-sync-count * @multifd-channels.  (since
 #     7.1)
 #
+# Features:
+#
+# @deprecated: Member @skipped is always zero since 1.5.3
+#
 # Since: 0.14
+#
 ##
 { 'struct': 'MigrationStats',
   'data': {'transferred': 'int', 'remaining': 'int', 'total': 'int' ,
-           'duplicate': 'int', 'skipped': 'int', 'normal': 'int',
+           'duplicate': 'int',
+           'skipped': { 'type': 'int', 'features': ['deprecated'] },
+           'normal': 'int',
            'normal-bytes': 'int', 'dirty-pages-rate': 'int',
            'mbps': 'number', 'dirty-sync-count': 'int',
            'postcopy-requests': 'int', 'page-size': 'int',
@@ -250,6 +258,18 @@
 #     blocked.  Present and non-empty when migration is blocked.
 #     (since 6.0)
 #
+# @dirty-limit-throttle-time-per-round: Maximum throttle time (in microseconds) of virtual
+#                                       CPUs each dirty ring full round, which shows how
+#                                       MigrationCapability dirty-limit affects the guest
+#                                       during live migration. (since 8.1)
+#
+# @dirty-limit-ring-full-time: Estimated average dirty ring full time (in microseconds)
+#                              each dirty ring full round, note that the value equals
+#                              dirty ring memory size divided by average dirty page rate
+#                              of virtual CPU, which can be used to observe the average
+#                              memory load of virtual CPU indirectly. Note that zero
+#                              means guest doesn't dirty memory (since 8.1)
+#
 # Since: 0.14
 ##
 { 'struct': 'MigrationInfo',
@@ -267,7 +287,9 @@
            '*postcopy-blocktime': 'uint32',
            '*postcopy-vcpu-blocktime': ['uint32'],
            '*compression': 'CompressionStats',
-           '*socket-address': ['SocketAddress'] } }
+           '*socket-address': ['SocketAddress'],
+           '*dirty-limit-throttle-time-per-round': 'uint64',
+           '*dirty-limit-ring-full-time': 'uint64'} }
 
 ##
 # @query-migrate:
@@ -497,6 +519,16 @@
 #     are present.  'return-path' capability must be enabled to use
 #     it.  (since 8.1)
 #
+# @dirty-limit: If enabled, migration will use the dirty-limit algo to
+#               throttle down guest instead of auto-converge algo.
+#               Throttle algo only works when vCPU's dirtyrate greater
+#               than 'vcpu-dirty-limit', read processes in guest os
+#               aren't penalized any more, so this algo can improve
+#               performance of vCPU during live migration. This is an
+#               optional performance feature and should not affect the
+#               correctness of the existing auto-converge algo.
+#               (since 8.1)
+#
 # Features:
 #
 # @unstable: Members @x-colo and @x-ignore-shared are experimental.
@@ -512,7 +544,8 @@
            'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate',
            { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
            'validate-uuid', 'background-snapshot',
-           'zero-copy-send', 'postcopy-preempt', 'switchover-ack'] }
+           'zero-copy-send', 'postcopy-preempt', 'switchover-ack',
+           'dirty-limit'] }
 
 ##
 # @MigrationCapabilityStatus:
@@ -789,9 +822,17 @@
 #     Nodes are mapped to their block device name if there is one, and
 #     to their node name otherwise.  (Since 5.2)
 #
+# @x-vcpu-dirty-limit-period: Periodic time (in milliseconds) of dirty limit during
+#                             live migration. Should be in the range 1 to 1000ms,
+#                             defaults to 1000ms. (Since 8.1)
+#
+# @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
+#                    Defaults to 1. (Since 8.1)
+#
 # Features:
 #
-# @unstable: Member @x-checkpoint-delay is experimental.
+# @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
+#            are experimental.
 #
 # Since: 2.4
 ##
@@ -809,8 +850,10 @@
            'multifd-channels',
            'xbzrle-cache-size', 'max-postcopy-bandwidth',
            'max-cpu-throttle', 'multifd-compression',
-           'multifd-zlib-level' ,'multifd-zstd-level',
-           'block-bitmap-mapping' ] }
+           'multifd-zlib-level', 'multifd-zstd-level',
+           'block-bitmap-mapping',
+           { 'name': 'x-vcpu-dirty-limit-period', 'features': ['unstable'] },
+           'vcpu-dirty-limit'] }
 
 ##
 # @MigrateSetParameters:
@@ -945,9 +988,17 @@
 #     Nodes are mapped to their block device name if there is one, and
 #     to their node name otherwise.  (Since 5.2)
 #
+# @x-vcpu-dirty-limit-period: Periodic time (in milliseconds) of dirty limit during
+#                             live migration. Should be in the range 1 to 1000ms,
+#                             defaults to 1000ms. (Since 8.1)
+#
+# @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
+#                    Defaults to 1. (Since 8.1)
+#
 # Features:
 #
-# @unstable: Member @x-checkpoint-delay is experimental.
+# @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
+#            are experimental.
 #
 # TODO: either fuse back into MigrationParameters, or make
 #     MigrationParameters members mandatory
@@ -982,7 +1033,10 @@
             '*multifd-compression': 'MultiFDCompression',
             '*multifd-zlib-level': 'uint8',
             '*multifd-zstd-level': 'uint8',
-            '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
+            '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ],
+            '*x-vcpu-dirty-limit-period': { 'type': 'uint64',
+                                            'features': [ 'unstable' ] },
+            '*vcpu-dirty-limit': 'uint64'} }
 
 ##
 # @migrate-set-parameters:
@@ -1137,9 +1191,17 @@
 #     Nodes are mapped to their block device name if there is one, and
 #     to their node name otherwise.  (Since 5.2)
 #
+# @x-vcpu-dirty-limit-period: Periodic time (in milliseconds) of dirty limit during
+#                             live migration. Should be in the range 1 to 1000ms,
+#                             defaults to 1000ms. (Since 8.1)
+#
+# @vcpu-dirty-limit: Dirtyrate limit (MB/s) during live migration.
+#                    Defaults to 1. (Since 8.1)
+#
 # Features:
 #
-# @unstable: Member @x-checkpoint-delay is experimental.
+# @unstable: Members @x-checkpoint-delay and @x-vcpu-dirty-limit-period
+#            are experimental.
 #
 # Since: 2.4
 ##
@@ -1171,7 +1233,10 @@
             '*multifd-compression': 'MultiFDCompression',
             '*multifd-zlib-level': 'uint8',
             '*multifd-zstd-level': 'uint8',
-            '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
+            '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ],
+            '*x-vcpu-dirty-limit-period': { 'type': 'uint64',
+                                            'features': [ 'unstable' ] },
+            '*vcpu-dirty-limit': 'uint64'} }
 
 ##
 # @query-migrate-parameters:
diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c
index 015a903..3c275ee 100644
--- a/softmmu/dirtylimit.c
+++ b/softmmu/dirtylimit.c
@@ -24,6 +24,9 @@
 #include "hw/boards.h"
 #include "sysemu/kvm.h"
 #include "trace.h"
+#include "migration/misc.h"
+#include "migration/migration.h"
+#include "migration/options.h"
 
 /*
  * Dirtylimit stop working if dirty page rate error
@@ -75,14 +78,21 @@ static bool dirtylimit_quit;
 
 static void vcpu_dirty_rate_stat_collect(void)
 {
+    MigrationState *s = migrate_get_current();
     VcpuStat stat;
     int i = 0;
+    int64_t period = DIRTYLIMIT_CALC_TIME_MS;
+
+    if (migrate_dirty_limit() &&
+        migration_is_active(s)) {
+        period = s->parameters.x_vcpu_dirty_limit_period;
+    }
 
     /* calculate vcpu dirtyrate */
-    vcpu_calculate_dirtyrate(DIRTYLIMIT_CALC_TIME_MS,
-                             &stat,
-                             GLOBAL_DIRTY_LIMIT,
-                             false);
+    vcpu_calculate_dirtyrate(period,
+                              &stat,
+                              GLOBAL_DIRTY_LIMIT,
+                              false);
 
     for (i = 0; i < stat.nvcpu; i++) {
         vcpu_dirty_rate_stat->stat.rates[i].id = i;
@@ -426,6 +436,23 @@ static void dirtylimit_cleanup(void)
     dirtylimit_state_finalize();
 }
 
+/*
+ * dirty page rate limit is not allowed to set if migration
+ * is running with dirty-limit capability enabled.
+ */
+static bool dirtylimit_is_allowed(void)
+{
+    MigrationState *ms = migrate_get_current();
+
+    if (migration_is_running(ms->state) &&
+        (!qemu_thread_is_self(&ms->thread)) &&
+        migrate_dirty_limit() &&
+        dirtylimit_in_service()) {
+        return false;
+    }
+    return true;
+}
+
 void qmp_cancel_vcpu_dirty_limit(bool has_cpu_index,
                                  int64_t cpu_index,
                                  Error **errp)
@@ -439,6 +466,12 @@ void qmp_cancel_vcpu_dirty_limit(bool has_cpu_index,
         return;
     }
 
+    if (!dirtylimit_is_allowed()) {
+        error_setg(errp, "can't cancel dirty page rate limit while"
+                   " migration is running");
+        return;
+    }
+
     if (!dirtylimit_in_service()) {
         return;
     }
@@ -489,6 +522,12 @@ void qmp_set_vcpu_dirty_limit(bool has_cpu_index,
         return;
     }
 
+    if (!dirtylimit_is_allowed()) {
+        error_setg(errp, "can't set dirty page rate limit while"
+                   " migration is running");
+        return;
+    }
+
     if (!dirty_rate) {
         qmp_cancel_vcpu_dirty_limit(has_cpu_index, cpu_index, errp);
         return;
@@ -515,14 +554,54 @@ void hmp_set_vcpu_dirty_limit(Monitor *mon, const QDict *qdict)
     int64_t cpu_index = qdict_get_try_int(qdict, "cpu_index", -1);
     Error *err = NULL;
 
+    if (dirty_rate < 0) {
+        error_setg(&err, "invalid dirty page limit %" PRId64, dirty_rate);
+        goto out;
+    }
+
     qmp_set_vcpu_dirty_limit(!!(cpu_index != -1), cpu_index, dirty_rate, &err);
-    if (err) {
-        hmp_handle_error(mon, err);
-        return;
+
+out:
+    hmp_handle_error(mon, err);
+}
+
+/* Return the max throttle time of each virtual CPU */
+uint64_t dirtylimit_throttle_time_per_round(void)
+{
+    CPUState *cpu;
+    int64_t max = 0;
+
+    CPU_FOREACH(cpu) {
+        if (cpu->throttle_us_per_full > max) {
+            max = cpu->throttle_us_per_full;
+        }
     }
 
-    monitor_printf(mon, "[Please use 'info vcpu_dirty_limit' to query "
-                   "dirty limit for virtual CPU]\n");
+    return max;
+}
+
+/*
+ * Estimate average dirty ring full time of each virtaul CPU.
+ * Return 0 if guest doesn't dirty memory.
+ */
+uint64_t dirtylimit_ring_full_time(void)
+{
+    CPUState *cpu;
+    uint64_t curr_rate = 0;
+    int nvcpus = 0;
+
+    CPU_FOREACH(cpu) {
+        if (cpu->running) {
+            nvcpus++;
+            curr_rate += vcpu_dirty_rate_get(cpu->cpu_index);
+        }
+    }
+
+    if (!curr_rate || !nvcpus) {
+        return 0;
+    }
+
+    return dirtylimit_dirty_ring_full_time(curr_rate / nvcpus);
 }
 
 static struct DirtyLimitInfo *dirtylimit_query_vcpu(int cpu_index)
diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
index e256da1..62d3f37 100644
--- a/tests/qtest/migration-test.c
+++ b/tests/qtest/migration-test.c
@@ -702,6 +702,8 @@ static int test_migrate_start(QTestState **from, QTestState **to,
 {
     g_autofree gchar *arch_source = NULL;
     g_autofree gchar *arch_target = NULL;
+    /* options for source and target */
+    g_autofree gchar *arch_opts = NULL;
     g_autofree gchar *cmd_source = NULL;
     g_autofree gchar *cmd_target = NULL;
     const gchar *ignore_stderr;
@@ -709,7 +711,6 @@ static int test_migrate_start(QTestState **from, QTestState **to,
     g_autofree char *shmem_opts = NULL;
     g_autofree char *shmem_path = NULL;
     const char *arch = qtest_get_arch();
-    const char *machine_opts = NULL;
     const char *memory_size;
 
     if (args->use_shmem) {
@@ -727,36 +728,29 @@ static int test_migrate_start(QTestState **from, QTestState **to,
         assert(sizeof(x86_bootsect) == 512);
         init_bootfile(bootpath, x86_bootsect, sizeof(x86_bootsect));
         memory_size = "150M";
-        arch_source = g_strdup_printf("-drive file=%s,format=raw", bootpath);
-        arch_target = g_strdup(arch_source);
+        arch_opts = g_strdup_printf("-drive file=%s,format=raw", bootpath);
         start_address = X86_TEST_MEM_START;
         end_address = X86_TEST_MEM_END;
     } else if (g_str_equal(arch, "s390x")) {
         init_bootfile(bootpath, s390x_elf, sizeof(s390x_elf));
         memory_size = "128M";
-        arch_source = g_strdup_printf("-bios %s", bootpath);
-        arch_target = g_strdup(arch_source);
+        arch_opts = g_strdup_printf("-bios %s", bootpath);
         start_address = S390_TEST_MEM_START;
         end_address = S390_TEST_MEM_END;
     } else if (strcmp(arch, "ppc64") == 0) {
-        machine_opts = "vsmt=8";
         memory_size = "256M";
         start_address = PPC_TEST_MEM_START;
         end_address = PPC_TEST_MEM_END;
-        arch_source = g_strdup_printf("-nodefaults "
-                                      "-prom-env 'use-nvramrc?=true' -prom-env "
+        arch_source = g_strdup_printf("-prom-env 'use-nvramrc?=true' -prom-env "
                                       "'nvramrc=hex .\" _\" begin %x %x "
                                       "do i c@ 1 + i c! 1000 +loop .\" B\" 0 "
                                       "until'", end_address, start_address);
-        arch_target = g_strdup("");
+        arch_opts = g_strdup("-nodefaults -machine vsmt=8");
     } else if (strcmp(arch, "aarch64") == 0) {
         init_bootfile(bootpath, aarch64_kernel, sizeof(aarch64_kernel));
-        machine_opts = "virt,gic-version=max";
         memory_size = "150M";
-        arch_source = g_strdup_printf("-cpu max "
-                                      "-kernel %s",
-                                      bootpath);
-        arch_target = g_strdup(arch_source);
+        arch_opts = g_strdup_printf("-machine virt,gic-version=max -cpu max "
+                                    "-kernel %s", bootpath);
         start_address = ARM_TEST_MEM_START;
         end_address = ARM_TEST_MEM_END;
 
@@ -791,17 +785,17 @@ static int test_migrate_start(QTestState **from, QTestState **to,
         shmem_opts = g_strdup("");
     }
 
-    cmd_source = g_strdup_printf("-accel kvm%s -accel tcg%s%s "
+    cmd_source = g_strdup_printf("-accel kvm%s -accel tcg "
                                  "-name source,debug-threads=on "
                                  "-m %s "
                                  "-serial file:%s/src_serial "
-                                 "%s %s %s %s",
+                                 "%s %s %s %s %s",
                                  args->use_dirty_ring ?
                                  ",dirty-ring-size=4096" : "",
-                                 machine_opts ? " -machine " : "",
-                                 machine_opts ? machine_opts : "",
                                  memory_size, tmpfs,
-                                 arch_source, shmem_opts,
+                                 arch_opts ? arch_opts : "",
+                                 arch_source ? arch_source : "",
+                                 shmem_opts,
                                  args->opts_source ? args->opts_source : "",
                                  ignore_stderr);
     if (!args->only_target) {
@@ -811,18 +805,18 @@ static int test_migrate_start(QTestState **from, QTestState **to,
                                      &got_src_stop);
     }
 
-    cmd_target = g_strdup_printf("-accel kvm%s -accel tcg%s%s "
+    cmd_target = g_strdup_printf("-accel kvm%s -accel tcg "
                                  "-name target,debug-threads=on "
                                  "-m %s "
                                  "-serial file:%s/dest_serial "
                                  "-incoming %s "
-                                 "%s %s %s %s",
+                                 "%s %s %s %s %s",
                                  args->use_dirty_ring ?
                                  ",dirty-ring-size=4096" : "",
-                                 machine_opts ? " -machine " : "",
-                                 machine_opts ? machine_opts : "",
                                  memory_size, tmpfs, uri,
-                                 arch_target, shmem_opts,
+                                 arch_opts ? arch_opts : "",
+                                 arch_target ? arch_target : "",
+                                 shmem_opts,
                                  args->opts_target ? args->opts_target : "",
                                  ignore_stderr);
     *to = qtest_init(cmd_target);
@@ -1245,10 +1239,9 @@ static int migrate_postcopy_prepare(QTestState **from_ptr,
                                     QTestState **to_ptr,
                                     MigrateCommon *args)
 {
-    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
     QTestState *from, *to;
 
-    if (test_migrate_start(&from, &to, uri, &args->start)) {
+    if (test_migrate_start(&from, &to, "defer", &args->start)) {
         return -1;
     }
 
@@ -1268,10 +1261,13 @@ static int migrate_postcopy_prepare(QTestState **from_ptr,
     migrate_ensure_non_converge(from);
 
     migrate_prepare_for_dirty_mem(from);
+    qtest_qmp_assert_success(to, "{ 'execute': 'migrate-incoming',"
+                             "  'arguments': { 'uri': 'tcp:127.0.0.1:0' }}");
 
     /* Wait for the first serial output from the source */
     wait_for_serial("src_serial");
 
+    g_autofree char *uri = migrate_get_socket_address(to, "socket-address");
     migrate_qmp(from, uri, "{}");
 
     migrate_wait_for_dirty_mem(from, to);