From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com> Implement the multifd device state transfer via additional per-device thread spawned from save_live_complete_precopy_begin handler.
Switch between doing the data transfer in the new handler and doing it in the old save_state handler depending on the x-migration-multifd-transfer device property value. Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com> --- hw/vfio/migration.c | 207 ++++++++++++++++++++++++++++++++++ hw/vfio/trace-events | 3 + include/hw/vfio/vfio-common.h | 9 ++ 3 files changed, 219 insertions(+) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index 719e36800ab5..28a835f8a945 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -643,6 +643,16 @@ static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp) uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE; int ret; + /* Make a copy of this setting at the start in case it is changed mid-migration */ + migration->multifd_transfer = vbasedev->migration_multifd_transfer; + + if (migration->multifd_transfer && !migration_has_device_state_support()) { + error_setg(errp, + "%s: Multifd device transfer requested but unsupported in the current config", + vbasedev->name); + return -EINVAL; + } + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); vfio_query_stop_copy_size(vbasedev, &stop_copy_size); @@ -692,6 +702,8 @@ static int vfio_save_setup(QEMUFile *f, void *opaque, Error **errp) return ret; } +static void vfio_save_complete_precopy_async_thread_thread_terminate(VFIODevice *vbasedev); + static void vfio_save_cleanup(void *opaque) { VFIODevice *vbasedev = opaque; @@ -699,6 +711,8 @@ static void vfio_save_cleanup(void *opaque) Error *local_err = NULL; int ret; + vfio_save_complete_precopy_async_thread_thread_terminate(vbasedev); + /* * Changing device state from STOP_COPY to STOP can take time. Do it here, * after migration has completed, so it won't increase downtime. @@ -712,6 +726,7 @@ static void vfio_save_cleanup(void *opaque) } } + g_clear_pointer(&migration->idstr, g_free); g_free(migration->data_buffer); migration->data_buffer = NULL; migration->precopy_init_size = 0; @@ -823,10 +838,17 @@ static int vfio_save_iterate(QEMUFile *f, void *opaque) static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) { VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; ssize_t data_size; int ret; Error *local_err = NULL; + if (migration->multifd_transfer) { + /* Emit dummy NOP data */ + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); + return 0; + } + trace_vfio_save_complete_precopy_started(vbasedev->name); /* We reach here with device state STOP or STOP_COPY only */ @@ -852,12 +874,188 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) return ret; } +static int vfio_save_complete_precopy_async_thread_config_state(VFIODevice *vbasedev, uint32_t idx) +{ + VFIOMigration *migration = vbasedev->migration; + g_autoptr(QIOChannelBuffer) bioc = NULL; + QEMUFile *f = NULL; + int ret; + g_autofree VFIODeviceStatePacket *packet = NULL; + size_t packet_len; + + bioc = qio_channel_buffer_new(0); + qio_channel_set_name(QIO_CHANNEL(bioc), "vfio-device-config-save"); + + f = qemu_file_new_output(QIO_CHANNEL(bioc)); + + ret = vfio_save_device_config_state(f, vbasedev, NULL); + if (ret) { + return ret; + } + + ret = qemu_fflush(f); + if (ret) { + goto ret_close_file; + } + + packet_len = sizeof(*packet) + bioc->usage; + packet = g_malloc0(packet_len); + packet->idx = idx; + packet->flags = VFIO_DEVICE_STATE_CONFIG_STATE; + memcpy(&packet->data, bioc->data, bioc->usage); + + ret = multifd_queue_device_state(migration->idstr, migration->instance_id, + (char *)packet, packet_len); + + bytes_transferred += packet_len; + +ret_close_file: + g_clear_pointer(&f, qemu_fclose); + return ret; +} + +static void *vfio_save_complete_precopy_async_thread(void *opaque) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + int *ret = &migration->save_complete_precopy_thread_ret; + g_autofree VFIODeviceStatePacket *packet = NULL; + uint32_t idx; + + /* We reach here with device state STOP or STOP_COPY only */ + *ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY, + VFIO_DEVICE_STATE_STOP, NULL); + if (*ret) { + return NULL; + } + + packet = g_malloc0(sizeof(*packet) + migration->data_buffer_size); + + for (idx = 0; ; idx++) { + ssize_t data_size; + size_t packet_size; + + data_size = read(migration->data_fd, &packet->data, + migration->data_buffer_size); + if (data_size < 0) { + if (errno != ENOMSG) { + *ret = -errno; + return NULL; + } + + /* + * Pre-copy emptied all the device state for now. For more information, + * please refer to the Linux kernel VFIO uAPI. + */ + data_size = 0; + } + + if (data_size == 0) + break; + + packet->idx = idx; + packet_size = sizeof(*packet) + data_size; + + *ret = multifd_queue_device_state(migration->idstr, migration->instance_id, + (char *)packet, packet_size); + if (*ret) { + return NULL; + } + + bytes_transferred += packet_size; + } + + *ret = vfio_save_complete_precopy_async_thread_config_state(vbasedev, idx); + if (*ret) { + return NULL; + } + + trace_vfio_save_complete_precopy_async_finished(vbasedev->name); + + return NULL; +} + +static int vfio_save_complete_precopy_begin(QEMUFile *f, + char *idstr, uint32_t instance_id, + void *opaque) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + int ret; + + migration->save_complete_precopy_thread_ret = 0; + + if (!migration->multifd_transfer) { + /* Emit dummy NOP data */ + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); + return 0; + } + + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE_COMPLETE); + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); + + ret = qemu_fflush(f); + if (ret) { + return ret; + } + + assert(!migration->save_complete_precopy_thread_started); + + assert(!migration->idstr); + migration->idstr = g_strdup(idstr); + migration->instance_id = instance_id; + + qemu_thread_create(&migration->save_complete_precopy_thread, + "vfio-save_complete_precopy", + vfio_save_complete_precopy_async_thread, + opaque, QEMU_THREAD_JOINABLE); + + migration->save_complete_precopy_thread_started = true; + + trace_vfio_save_complete_precopy_async_started(vbasedev->name, idstr, instance_id); + + return 0; +} + +static void vfio_save_complete_precopy_async_thread_thread_terminate(VFIODevice *vbasedev) +{ + VFIOMigration *migration = vbasedev->migration; + + if (!migration->save_complete_precopy_thread_started) { + return; + } + + qemu_thread_join(&migration->save_complete_precopy_thread); + + migration->save_complete_precopy_thread_started = false; + + trace_vfio_save_complete_precopy_async_joined(vbasedev->name, + migration->save_complete_precopy_thread_ret); +} + +static int vfio_save_complete_precopy_end(QEMUFile *f, void *opaque) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + + vfio_save_complete_precopy_async_thread_thread_terminate(vbasedev); + + return migration->save_complete_precopy_thread_ret; +} + static void vfio_save_state(QEMUFile *f, void *opaque) { VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; Error *local_err = NULL; int ret; + if (migration->multifd_transfer) { + /* Emit dummy NOP data */ + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); + return; + } + ret = vfio_save_device_config_state(f, opaque, &local_err); if (ret) { error_prepend(&local_err, @@ -1106,6 +1304,8 @@ static const SaveVMHandlers savevm_vfio_handlers = { .state_pending_exact = vfio_state_pending_exact, .is_active_iterate = vfio_is_active_iterate, .save_live_iterate = vfio_save_iterate, + .save_live_complete_precopy_begin = vfio_save_complete_precopy_begin, + .save_live_complete_precopy_end = vfio_save_complete_precopy_end, .save_live_complete_precopy = vfio_save_complete_precopy, .save_state = vfio_save_state, .load_setup = vfio_load_setup, @@ -1127,6 +1327,10 @@ static void vfio_vmstate_change_prepare(void *opaque, bool running, Error *local_err = NULL; int ret; + if (running) { + vfio_save_complete_precopy_async_thread_thread_terminate(vbasedev); + } + new_state = migration->device_state == VFIO_DEVICE_STATE_PRE_COPY ? VFIO_DEVICE_STATE_PRE_COPY_P2P : VFIO_DEVICE_STATE_RUNNING_P2P; @@ -1153,6 +1357,9 @@ static void vfio_vmstate_change(void *opaque, bool running, RunState state) int ret; if (running) { + /* In case "prepare" callback wasn't registered */ + vfio_save_complete_precopy_async_thread_thread_terminate(vbasedev); + new_state = VFIO_DEVICE_STATE_RUNNING; } else { new_state = diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index 7f224e4d240f..569bb02434f1 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -166,6 +166,9 @@ vfio_save_block(const char *name, int data_size) " (%s) data_size %d" vfio_save_cleanup(const char *name) " (%s)" vfio_save_complete_precopy(const char *name, int ret) " (%s) ret %d" vfio_save_complete_precopy_started(const char *name) " (%s)" +vfio_save_complete_precopy_async_started(const char *name, const char *idstr, uint32_t instance_id) " (%s) idstr %s instance %"PRIu32 +vfio_save_complete_precopy_async_finished(const char *name) " (%s)" +vfio_save_complete_precopy_async_joined(const char *name, int ret) " (%s) ret %d" vfio_save_device_config_state(const char *name) " (%s)" vfio_save_iterate(const char *name, uint64_t precopy_init_size, uint64_t precopy_dirty_size) " (%s) precopy initial size 0x%"PRIx64" precopy dirty size 0x%"PRIx64 vfio_save_iterate_started(const char *name) " (%s)" diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index bc85891d8fff..2d76d3fc8bba 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -70,16 +70,25 @@ typedef struct VFIOMigration { uint64_t mig_flags; uint64_t precopy_init_size; uint64_t precopy_dirty_size; + bool multifd_transfer; bool initial_data_sent; bool save_iterate_run; bool save_iterate_empty_hit; + + QemuThread save_complete_precopy_thread; + int save_complete_precopy_thread_ret; + bool save_complete_precopy_thread_started; + QemuThread load_bufs_thread; Error *load_bufs_thread_errp; bool load_bufs_thread_started; bool load_bufs_thread_finished; bool load_bufs_thread_want_exit; + char *idstr; + uint32_t instance_id; + GArray *load_bufs; bool load_bufs_device_ready; QemuCond load_bufs_device_ready_cond;