From 0525b91a0b993f95d29b2ea84155e7e4366c120e Mon Sep 17 00:00:00 2001 From: "Maciej S. Szmigiero" Date: Tue, 4 Mar 2025 23:03:41 +0100 Subject: [PATCH] migration/multifd: Device state transfer support - send side MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit A new function multifd_queue_device_state() is provided for device to queue its state for transmission via a multifd channel. Reviewed-by: Peter Xu Signed-off-by: Maciej S. Szmigiero Link: https://lore.kernel.org/qemu-devel/ebd55768d3e5fecb5eb3f197bad9c0c07e5bc084.1741124640.git.maciej.szmigiero@oracle.com Signed-off-by: Cédric Le Goater --- include/migration/misc.h | 4 ++ migration/meson.build | 1 + migration/multifd-device-state.c | 118 +++++++++++++++++++++++++++++++ migration/multifd-nocomp.c | 14 +++- migration/multifd.c | 42 +++++++++-- migration/multifd.h | 34 ++++++--- 6 files changed, 197 insertions(+), 16 deletions(-) create mode 100644 migration/multifd-device-state.c diff --git a/include/migration/misc.h b/include/migration/misc.h index 4c171f4e89..bd3b725fa0 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -118,4 +118,8 @@ bool migrate_is_uri(const char *uri); bool migrate_uri_parse(const char *uri, MigrationChannel **channel, Error **errp); +/* migration/multifd-device-state.c */ +bool multifd_queue_device_state(char *idstr, uint32_t instance_id, + char *data, size_t len); + #endif diff --git a/migration/meson.build b/migration/meson.build index d3bfe84d62..9aa48b290e 100644 --- a/migration/meson.build +++ b/migration/meson.build @@ -25,6 +25,7 @@ system_ss.add(files( 'migration-hmp-cmds.c', 'migration.c', 'multifd.c', + 'multifd-device-state.c', 'multifd-nocomp.c', 'multifd-zlib.c', 'multifd-zero-page.c', diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c new file mode 100644 index 0000000000..e383e75b1a --- /dev/null +++ b/migration/multifd-device-state.c @@ -0,0 +1,118 @@ +/* + * Multifd device state migration + * + * Copyright (C) 2024,2025 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "qemu/lockable.h" +#include "migration/misc.h" +#include "multifd.h" + +static struct { + QemuMutex queue_job_mutex; + + MultiFDSendData *send_data; +} *multifd_send_device_state; + +size_t multifd_device_state_payload_size(void) +{ + return sizeof(MultiFDDeviceState_t); +} + +void multifd_device_state_send_setup(void) +{ + assert(!multifd_send_device_state); + multifd_send_device_state = g_malloc(sizeof(*multifd_send_device_state)); + + qemu_mutex_init(&multifd_send_device_state->queue_job_mutex); + + multifd_send_device_state->send_data = multifd_send_data_alloc(); +} + +void multifd_device_state_send_cleanup(void) +{ + g_clear_pointer(&multifd_send_device_state->send_data, + multifd_send_data_free); + + qemu_mutex_destroy(&multifd_send_device_state->queue_job_mutex); + + g_clear_pointer(&multifd_send_device_state, g_free); +} + +void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state) +{ + g_clear_pointer(&device_state->idstr, g_free); + g_clear_pointer(&device_state->buf, g_free); +} + +static void multifd_device_state_fill_packet(MultiFDSendParams *p) +{ + MultiFDDeviceState_t *device_state = &p->data->u.device_state; + MultiFDPacketDeviceState_t *packet = p->packet_device_state; + + packet->hdr.flags = cpu_to_be32(p->flags); + strncpy(packet->idstr, device_state->idstr, sizeof(packet->idstr) - 1); + packet->idstr[sizeof(packet->idstr) - 1] = 0; + packet->instance_id = cpu_to_be32(device_state->instance_id); + packet->next_packet_size = cpu_to_be32(p->next_packet_size); +} + +static void multifd_prepare_header_device_state(MultiFDSendParams *p) +{ + p->iov[0].iov_len = sizeof(*p->packet_device_state); + p->iov[0].iov_base = p->packet_device_state; + p->iovs_num++; +} + +void multifd_device_state_send_prepare(MultiFDSendParams *p) +{ + MultiFDDeviceState_t *device_state = &p->data->u.device_state; + + assert(multifd_payload_device_state(p->data)); + + multifd_prepare_header_device_state(p); + + assert(!(p->flags & MULTIFD_FLAG_SYNC)); + + p->next_packet_size = device_state->buf_len; + if (p->next_packet_size > 0) { + p->iov[p->iovs_num].iov_base = device_state->buf; + p->iov[p->iovs_num].iov_len = p->next_packet_size; + p->iovs_num++; + } + + p->flags |= MULTIFD_FLAG_NOCOMP | MULTIFD_FLAG_DEVICE_STATE; + + multifd_device_state_fill_packet(p); +} + +bool multifd_queue_device_state(char *idstr, uint32_t instance_id, + char *data, size_t len) +{ + /* Device state submissions can come from multiple threads */ + QEMU_LOCK_GUARD(&multifd_send_device_state->queue_job_mutex); + MultiFDDeviceState_t *device_state; + + assert(multifd_payload_empty(multifd_send_device_state->send_data)); + + multifd_set_payload_type(multifd_send_device_state->send_data, + MULTIFD_PAYLOAD_DEVICE_STATE); + device_state = &multifd_send_device_state->send_data->u.device_state; + device_state->idstr = g_strdup(idstr); + device_state->instance_id = instance_id; + device_state->buf = g_memdup2(data, len); + device_state->buf_len = len; + + if (!multifd_send(&multifd_send_device_state->send_data)) { + multifd_send_data_clear(multifd_send_device_state->send_data); + return false; + } + + return true; +} diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c index e46e79d8b2..c008046523 100644 --- a/migration/multifd-nocomp.c +++ b/migration/multifd-nocomp.c @@ -14,6 +14,7 @@ #include "exec/ramblock.h" #include "exec/target_page.h" #include "file.h" +#include "migration-stats.h" #include "multifd.h" #include "options.h" #include "qapi/error.h" @@ -85,6 +86,13 @@ static void multifd_nocomp_send_cleanup(MultiFDSendParams *p, Error **errp) return; } +static void multifd_ram_prepare_header(MultiFDSendParams *p) +{ + p->iov[0].iov_len = p->packet_len; + p->iov[0].iov_base = p->packet; + p->iovs_num++; +} + static void multifd_send_prepare_iovs(MultiFDSendParams *p) { MultiFDPages_t *pages = &p->data->u.ram; @@ -118,7 +126,7 @@ static int multifd_nocomp_send_prepare(MultiFDSendParams *p, Error **errp) * Only !zerocopy needs the header in IOV; zerocopy will * send it separately. */ - multifd_send_prepare_header(p); + multifd_ram_prepare_header(p); } multifd_send_prepare_iovs(p); @@ -133,6 +141,8 @@ static int multifd_nocomp_send_prepare(MultiFDSendParams *p, Error **errp) if (ret != 0) { return -1; } + + stat64_add(&mig_stats.multifd_bytes, p->packet_len); } return 0; @@ -431,7 +441,7 @@ int multifd_ram_flush_and_sync(QEMUFile *f) bool multifd_send_prepare_common(MultiFDSendParams *p) { MultiFDPages_t *pages = &p->data->u.ram; - multifd_send_prepare_header(p); + multifd_ram_prepare_header(p); multifd_send_zero_page_detect(p); if (!pages->normal_num) { diff --git a/migration/multifd.c b/migration/multifd.c index c8508cadab..3625c9a37c 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -12,6 +12,7 @@ #include "qemu/osdep.h" #include "qemu/cutils.h" +#include "qemu/iov.h" #include "qemu/rcu.h" #include "exec/target_page.h" #include "system/system.h" @@ -19,6 +20,7 @@ #include "qemu/error-report.h" #include "qapi/error.h" #include "file.h" +#include "migration/misc.h" #include "migration.h" #include "migration-stats.h" #include "savevm.h" @@ -111,7 +113,9 @@ MultiFDSendData *multifd_send_data_alloc(void) * added to the union in the future are larger than * (MultiFDPages_t + flex array). */ - max_payload_size = MAX(multifd_ram_payload_size(), sizeof(MultiFDPayload)); + max_payload_size = MAX(multifd_ram_payload_size(), + multifd_device_state_payload_size()); + max_payload_size = MAX(max_payload_size, sizeof(MultiFDPayload)); /* * Account for any holes the compiler might insert. We can't pack @@ -130,6 +134,9 @@ void multifd_send_data_clear(MultiFDSendData *data) } switch (data->type) { + case MULTIFD_PAYLOAD_DEVICE_STATE: + multifd_send_data_clear_device_state(&data->u.device_state); + break; default: /* Nothing to do */ break; @@ -232,6 +239,7 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp) return msg.id; } +/* Fills a RAM multifd packet */ void multifd_send_fill_packet(MultiFDSendParams *p) { MultiFDPacket_t *packet = p->packet; @@ -524,6 +532,7 @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp) p->name = NULL; g_clear_pointer(&p->data, multifd_send_data_free); p->packet_len = 0; + g_clear_pointer(&p->packet_device_state, g_free); g_free(p->packet); p->packet = NULL; multifd_send_state->ops->send_cleanup(p, errp); @@ -536,6 +545,7 @@ static void multifd_send_cleanup_state(void) { file_cleanup_outgoing_migration(); socket_cleanup_outgoing_migration(); + multifd_device_state_send_cleanup(); qemu_sem_destroy(&multifd_send_state->channels_created); qemu_sem_destroy(&multifd_send_state->channels_ready); qemu_mutex_destroy(&multifd_send_state->multifd_send_mutex); @@ -694,16 +704,32 @@ static void *multifd_send_thread(void *opaque) * qatomic_store_release() in multifd_send(). */ if (qatomic_load_acquire(&p->pending_job)) { + bool is_device_state = multifd_payload_device_state(p->data); + size_t total_size; + p->flags = 0; p->iovs_num = 0; assert(!multifd_payload_empty(p->data)); - ret = multifd_send_state->ops->send_prepare(p, &local_err); - if (ret != 0) { - break; + if (is_device_state) { + multifd_device_state_send_prepare(p); + } else { + ret = multifd_send_state->ops->send_prepare(p, &local_err); + if (ret != 0) { + break; + } } + /* + * The packet header in the zerocopy RAM case is accounted for + * in multifd_nocomp_send_prepare() - where it is actually + * being sent. + */ + total_size = iov_size(p->iov, p->iovs_num); + if (migrate_mapped_ram()) { + assert(!is_device_state); + ret = file_write_ramblock_iov(p->c, p->iov, p->iovs_num, &p->data->u.ram, &local_err); } else { @@ -716,8 +742,7 @@ static void *multifd_send_thread(void *opaque) break; } - stat64_add(&mig_stats.multifd_bytes, - (uint64_t)p->next_packet_size + p->packet_len); + stat64_add(&mig_stats.multifd_bytes, total_size); p->next_packet_size = 0; multifd_send_data_clear(p->data); @@ -938,6 +963,9 @@ bool multifd_send_setup(void) p->packet_len = sizeof(MultiFDPacket_t) + sizeof(uint64_t) * page_count; p->packet = g_malloc0(p->packet_len); + p->packet_device_state = g_malloc0(sizeof(*p->packet_device_state)); + p->packet_device_state->hdr.magic = cpu_to_be32(MULTIFD_MAGIC); + p->packet_device_state->hdr.version = cpu_to_be32(MULTIFD_VERSION); } p->name = g_strdup_printf(MIGRATION_THREAD_SRC_MULTIFD, i); p->write_flags = 0; @@ -973,6 +1001,8 @@ bool multifd_send_setup(void) assert(p->iov); } + multifd_device_state_send_setup(); + return true; err: diff --git a/migration/multifd.h b/migration/multifd.h index 8d639eec69..aa679d8bbe 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -127,13 +127,22 @@ struct MultiFDRecvData { off_t file_offset; }; +typedef struct { + char *idstr; + uint32_t instance_id; + char *buf; + size_t buf_len; +} MultiFDDeviceState_t; + typedef enum { MULTIFD_PAYLOAD_NONE, MULTIFD_PAYLOAD_RAM, + MULTIFD_PAYLOAD_DEVICE_STATE, } MultiFDPayloadType; typedef union MultiFDPayload { MultiFDPages_t ram; + MultiFDDeviceState_t device_state; } MultiFDPayload; struct MultiFDSendData { @@ -146,6 +155,11 @@ static inline bool multifd_payload_empty(MultiFDSendData *data) return data->type == MULTIFD_PAYLOAD_NONE; } +static inline bool multifd_payload_device_state(MultiFDSendData *data) +{ + return data->type == MULTIFD_PAYLOAD_DEVICE_STATE; +} + static inline void multifd_set_payload_type(MultiFDSendData *data, MultiFDPayloadType type) { @@ -198,8 +212,9 @@ typedef struct { /* thread local variables. No locking required */ - /* pointer to the packet */ + /* pointers to the possible packet types */ MultiFDPacket_t *packet; + MultiFDPacketDeviceState_t *packet_device_state; /* size of the next packet that contains pages */ uint32_t next_packet_size; /* packets sent through this channel */ @@ -358,13 +373,6 @@ bool multifd_send_prepare_common(MultiFDSendParams *p); void multifd_send_zero_page_detect(MultiFDSendParams *p); void multifd_recv_zero_page_process(MultiFDRecvParams *p); -static inline void multifd_send_prepare_header(MultiFDSendParams *p) -{ - p->iov[0].iov_len = p->packet_len; - p->iov[0].iov_base = p->packet; - p->iovs_num++; -} - void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc); bool multifd_send(MultiFDSendData **send_data); MultiFDSendData *multifd_send_data_alloc(void); @@ -389,4 +397,14 @@ bool multifd_ram_sync_per_section(void); size_t multifd_ram_payload_size(void); void multifd_ram_fill_packet(MultiFDSendParams *p); int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp); + +size_t multifd_device_state_payload_size(void); + +void multifd_send_data_clear_device_state(MultiFDDeviceState_t *device_state); + +void multifd_device_state_send_setup(void); +void multifd_device_state_send_cleanup(void); + +void multifd_device_state_send_prepare(MultiFDSendParams *p); + #endif -- 2.30.2