On 19/02/2025 22:33, Maciej S. Szmigiero wrote:
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From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>
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 <pet...@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>
---
include/migration/misc.h | 4 ++
migration/meson.build | 1 +
migration/multifd-device-state.c | 115 +++++++++++++++++++++++++++++++
migration/multifd-nocomp.c | 14 +++-
migration/multifd.c | 42 +++++++++--
migration/multifd.h | 27 +++++---
6 files changed, 187 insertions(+), 16 deletions(-)
create mode 100644 migration/multifd-device-state.c
diff --git a/include/migration/misc.h b/include/migration/misc.h
index 4c171f4e897e..bd3b725fa0b7 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 d3bfe84d6204..9aa48b290e2a 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 000000000000..ab83773e2d62
--- /dev/null
+++ b/migration/multifd-device-state.c
@@ -0,0 +1,115 @@
+/*
+ * 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.
+ */
+
+#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));
(I think we talked about this in v2):
Looking at idstr creation code, idstr is always NULL terminated. It's
also treated everywhere as a NULL terminated string.
For consistency and to avoid confusion, I'd treat it as a NULL
terminated string here too (use strcpy, remove the QEMU_NONSTRING from
its definition, etc.).
This will also avoid strncpy() unnecessary zeroing of the extra bytes.
Thanks.
+ 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 e46e79d8b272..c00804652383 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 0092547a4f97..3394c2ae12fd 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 20a4bba58ef4..883a43c1d79e 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -137,10 +137,12 @@ typedef struct {
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 {
@@ -153,6 +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)
{
@@ -205,8 +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 */
@@ -365,13 +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);
@@ -396,4 +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
