On 27/08/2024 20:54, Maciej S. Szmigiero wrote:
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From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>
Add a basic support for receiving device state via multifd channels -
channels that are shared with RAM transfers.
To differentiate between a device state and a RAM packet the packet
header is read first.
Depending whether MULTIFD_FLAG_DEVICE_STATE flag is present or not in the
packet header either device state (MultiFDPacketDeviceState_t) or RAM
data (existing MultiFDPacket_t) is then read.
The received device state data is provided to
qemu_loadvm_load_state_buffer() function for processing in the
device's load_state_buffer handler.
Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>
---
migration/multifd.c | 127 +++++++++++++++++++++++++++++++++++++-------
migration/multifd.h | 31 ++++++++++-
2 files changed, 138 insertions(+), 20 deletions(-)
diff --git a/migration/multifd.c b/migration/multifd.c
index b06a9fab500e..d5a8e5a9c9b5 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -21,6 +21,7 @@
#include "file.h"
#include "migration.h"
#include "migration-stats.h"
+#include "savevm.h"
#include "socket.h"
#include "tls.h"
#include "qemu-file.h"
@@ -209,10 +210,10 @@ void multifd_send_fill_packet(MultiFDSendParams *p)
memset(packet, 0, p->packet_len);
- packet->magic = cpu_to_be32(MULTIFD_MAGIC);
- packet->version = cpu_to_be32(MULTIFD_VERSION);
+ packet->hdr.magic = cpu_to_be32(MULTIFD_MAGIC);
+ packet->hdr.version = cpu_to_be32(MULTIFD_VERSION);
- packet->flags = cpu_to_be32(p->flags);
+ packet->hdr.flags = cpu_to_be32(p->flags);
packet->next_packet_size = cpu_to_be32(p->next_packet_size);
packet_num = qatomic_fetch_inc(&multifd_send_state->packet_num);
@@ -228,31 +229,49 @@ void multifd_send_fill_packet(MultiFDSendParams *p)
p->flags, p->next_packet_size);
}
-static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
+static int multifd_recv_unfill_packet_header(MultiFDRecvParams *p,
+ MultiFDPacketHdr_t *hdr,
+ Error **errp)
{
- MultiFDPacket_t *packet = p->packet;
- int ret = 0;
-
- packet->magic = be32_to_cpu(packet->magic);
- if (packet->magic != MULTIFD_MAGIC) {
+ hdr->magic = be32_to_cpu(hdr->magic);
+ if (hdr->magic != MULTIFD_MAGIC) {
error_setg(errp, "multifd: received packet "
"magic %x and expected magic %x",
- packet->magic, MULTIFD_MAGIC);
+ hdr->magic, MULTIFD_MAGIC);
return -1;
}
- packet->version = be32_to_cpu(packet->version);
- if (packet->version != MULTIFD_VERSION) {
+ hdr->version = be32_to_cpu(hdr->version);
+ if (hdr->version != MULTIFD_VERSION) {
error_setg(errp, "multifd: received packet "
"version %u and expected version %u",
- packet->version, MULTIFD_VERSION);
+ hdr->version, MULTIFD_VERSION);
return -1;
}
- p->flags = be32_to_cpu(packet->flags);
+ p->flags = be32_to_cpu(hdr->flags);
+
+ return 0;
+}
+
+static int multifd_recv_unfill_packet_device_state(MultiFDRecvParams *p,
+ Error **errp)
+{
+ MultiFDPacketDeviceState_t *packet = p->packet_dev_state;
+
+ packet->instance_id = be32_to_cpu(packet->instance_id);
+ p->next_packet_size = be32_to_cpu(packet->next_packet_size);
+
+ return 0;
+}
+
+static int multifd_recv_unfill_packet_ram(MultiFDRecvParams *p, Error **errp)
+{
+ MultiFDPacket_t *packet = p->packet;
+ int ret = 0;
+
p->next_packet_size = be32_to_cpu(packet->next_packet_size);
p->packet_num = be64_to_cpu(packet->packet_num);
- p->packets_recved++;
if (!(p->flags & MULTIFD_FLAG_SYNC)) {
ret = multifd_ram_unfill_packet(p, errp);
@@ -264,6 +283,19 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams
*p, Error **errp)
return ret;
}
+static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
+{
+ p->packets_recved++;
+
+ if (p->flags & MULTIFD_FLAG_DEVICE_STATE) {
+ return multifd_recv_unfill_packet_device_state(p, errp);
+ } else {
+ return multifd_recv_unfill_packet_ram(p, errp);
+ }
+
+ g_assert_not_reached();
We can drop the assert and the "else":
if (p->flags & MULTIFD_FLAG_DEVICE_STATE) {
return multifd_recv_unfill_packet_device_state(p, errp);
}
return multifd_recv_unfill_packet_ram(p, errp);
+}
+
static bool multifd_send_should_exit(void)
{
return qatomic_read(&multifd_send_state->exiting);
@@ -1014,6 +1046,7 @@ static void
multifd_recv_cleanup_channel(MultiFDRecvParams *p)
p->packet_len = 0;
g_free(p->packet);
p->packet = NULL;
+ g_clear_pointer(&p->packet_dev_state, g_free);
g_free(p->normal);
p->normal = NULL;
g_free(p->zero);
@@ -1126,8 +1159,13 @@ static void *multifd_recv_thread(void *opaque)
rcu_register_thread();
while (true) {
+ MultiFDPacketHdr_t hdr;
uint32_t flags = 0;
+ bool is_device_state = false;
bool has_data = false;
+ uint8_t *pkt_buf;
+ size_t pkt_len;
+
p->normal_num = 0;
if (use_packets) {
@@ -1135,8 +1173,28 @@ static void *multifd_recv_thread(void *opaque)
break;
}
- ret = qio_channel_read_all_eof(p->c, (void *)p->packet,
- p->packet_len, &local_err);
+ ret = qio_channel_read_all_eof(p->c, (void *)&hdr,
+ sizeof(hdr), &local_err);
+ if (ret == 0 || ret == -1) { /* 0: EOF -1: Error */
+ break;
+ }
+
+ ret = multifd_recv_unfill_packet_header(p, &hdr, &local_err);
+ if (ret) {
+ break;
+ }
+
+ is_device_state = p->flags & MULTIFD_FLAG_DEVICE_STATE;
+ if (is_device_state) {
+ pkt_buf = (uint8_t *)p->packet_dev_state + sizeof(hdr);
+ pkt_len = sizeof(*p->packet_dev_state) - sizeof(hdr);
+ } else {
+ pkt_buf = (uint8_t *)p->packet + sizeof(hdr);
+ pkt_len = p->packet_len - sizeof(hdr);
+ }
+
+ ret = qio_channel_read_all_eof(p->c, (char *)pkt_buf, pkt_len,
+ &local_err);
if (ret == 0 || ret == -1) { /* 0: EOF -1: Error */
break;
}
@@ -1181,8 +1239,33 @@ static void *multifd_recv_thread(void *opaque)
has_data = !!p->data->size;
}
- if (has_data) {
- ret = multifd_recv_state->ops->recv(p, &local_err);
+ if (!is_device_state) {
+ if (has_data) {
+ ret = multifd_recv_state->ops->recv(p, &local_err);
+ if (ret != 0) {
+ break;
+ }
+ }
+ } else {
+ g_autofree char *idstr = NULL;
+ g_autofree char *dev_state_buf = NULL;
+
+ assert(use_packets);
+
+ if (p->next_packet_size > 0) {
+ dev_state_buf = g_malloc(p->next_packet_size);
+
+ ret = qio_channel_read_all(p->c, dev_state_buf,
p->next_packet_size, &local_err);
+ if (ret != 0) {
+ break;
+ }
+ }
+
+ idstr = g_strndup(p->packet_dev_state->idstr,
sizeof(p->packet_dev_state->idstr));
+ ret = qemu_loadvm_load_state_buffer(idstr,
+
p->packet_dev_state->instance_id,
+ dev_state_buf,
p->next_packet_size,
+ &local_err);
if (ret != 0) {
break;
}
@@ -1190,6 +1273,11 @@ static void *multifd_recv_thread(void *opaque)
if (use_packets) {
if (flags & MULTIFD_FLAG_SYNC) {
+ if (is_device_state) {
+ error_setg(&local_err, "multifd: received SYNC device state
packet");
+ break;
+ }
+
qemu_sem_post(&multifd_recv_state->sem_sync);
qemu_sem_wait(&p->sem_sync);
}
@@ -1258,6 +1346,7 @@ int multifd_recv_setup(Error **errp)
p->packet_len = sizeof(MultiFDPacket_t)
+ sizeof(uint64_t) * page_count;
p->packet = g_malloc0(p->packet_len);
+ p->packet_dev_state = g_malloc0(sizeof(*p->packet_dev_state));
}
p->name = g_strdup_printf("mig/dst/recv_%d", i);
p->normal = g_new0(ram_addr_t, page_count);
diff --git a/migration/multifd.h b/migration/multifd.h
index a3e35196d179..a8f3e4838c01 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -45,6 +45,12 @@ MultiFDRecvData *multifd_get_recv_data(void);
#define MULTIFD_FLAG_QPL (4 << 1)
#define MULTIFD_FLAG_UADK (8 << 1)
+/*
+ * If set it means that this packet contains device state
+ * (MultiFDPacketDeviceState_t), not RAM data (MultiFDPacket_t).
+ */
+#define MULTIFD_FLAG_DEVICE_STATE (1 << 4)
+
/* This value needs to be a multiple of qemu_target_page_size() */
#define MULTIFD_PACKET_SIZE (512 * 1024)
@@ -52,6 +58,11 @@ typedef struct {
uint32_t magic;
uint32_t version;
uint32_t flags;
+} __attribute__((packed)) MultiFDPacketHdr_t;
Maybe split this patch into two: one that adds the packet header concept
and another that adds the new device packet?
+
+typedef struct {
+ MultiFDPacketHdr_t hdr;
+
/* maximum number of allocated pages */
uint32_t pages_alloc;
/* non zero pages */
@@ -72,6 +83,16 @@ typedef struct {
uint64_t offset[];
} __attribute__((packed)) MultiFDPacket_t;
+typedef struct {
+ MultiFDPacketHdr_t hdr;
+
+ char idstr[256] QEMU_NONSTRING;
idstr should be null terminated, or am I missing something?
Thanks.
+ uint32_t instance_id;
+
+ /* size of the next packet that contains the actual data */
+ uint32_t next_packet_size;
+} __attribute__((packed)) MultiFDPacketDeviceState_t;
+
typedef struct {
/* number of used pages */
uint32_t num;
@@ -89,6 +110,13 @@ 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,
@@ -204,8 +232,9 @@ typedef struct {
/* thread local variables. No locking required */
- /* pointer to the packet */
+ /* pointers to the possible packet types */
MultiFDPacket_t *packet;
+ MultiFDPacketDeviceState_t *packet_dev_state;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
/* packets received through this channel */
