Add wrappers and handlers for sending/receiving the postcopy-ram migration messages.

The state of the postcopy process is managed via a series of messages;
   * Add wrappers and handlers for sending/receiving these messages
   * Add state variable that track the current state of postcopy

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2015-11-05 18:10:52 +00:00 committed by Juan Quintela
parent 53dd370ced
commit 093e3c4296
5 changed files with 330 additions and 0 deletions

View File

@ -53,6 +53,29 @@ enum mig_rp_message_type {
};
typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
/* The current postcopy state is read/set by postcopy_state_get/set
* which update it atomically.
* The state is updated as postcopy messages are received, and
* in general only one thread should be writing to the state at any one
* time, initially the main thread and then the listen thread;
* Corner cases are where either thread finishes early and/or errors.
* The state is checked as messages are received to ensure that
* the source is sending us messages in the correct order.
* The state is also used by the RAM reception code to know if it
* has to place pages atomically, and the cleanup code at the end of
* the main thread to know if it has to delay cleanup until the end
* of postcopy.
*/
typedef enum {
POSTCOPY_INCOMING_NONE = 0, /* Initial state - no postcopy */
POSTCOPY_INCOMING_ADVISE,
POSTCOPY_INCOMING_DISCARD,
POSTCOPY_INCOMING_LISTENING,
POSTCOPY_INCOMING_RUNNING,
POSTCOPY_INCOMING_END
} PostcopyState;
/* State for the incoming migration */
struct MigrationIncomingState {
QEMUFile *from_src_file;
@ -240,4 +263,8 @@ void global_state_set_optional(void);
void savevm_skip_configuration(void);
int global_state_store(void);
void global_state_store_running(void);
PostcopyState postcopy_state_get(void);
/* Set the state and return the old state */
PostcopyState postcopy_state_set(PostcopyState new_state);
#endif

View File

@ -89,6 +89,16 @@ enum qemu_vm_cmd {
MIG_CMD_INVALID = 0, /* Must be 0 */
MIG_CMD_OPEN_RETURN_PATH, /* Tell the dest to open the Return path */
MIG_CMD_PING, /* Request a PONG on the RP */
MIG_CMD_POSTCOPY_ADVISE, /* Prior to any page transfers, just
warn we might want to do PC */
MIG_CMD_POSTCOPY_LISTEN, /* Start listening for incoming
pages as it's running. */
MIG_CMD_POSTCOPY_RUN, /* Start execution */
MIG_CMD_POSTCOPY_RAM_DISCARD, /* A list of pages to discard that
were previously sent during
precopy but are dirty. */
MIG_CMD_MAX
};
@ -104,6 +114,15 @@ void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command,
uint16_t len, uint8_t *data);
void qemu_savevm_send_ping(QEMUFile *f, uint32_t value);
void qemu_savevm_send_open_return_path(QEMUFile *f);
void qemu_savevm_send_postcopy_advise(QEMUFile *f);
void qemu_savevm_send_postcopy_listen(QEMUFile *f);
void qemu_savevm_send_postcopy_run(QEMUFile *f);
void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
uint16_t len,
uint64_t *start_list,
uint64_t *length_list);
int qemu_loadvm_state(QEMUFile *f);
typedef enum DisplayType

View File

@ -57,6 +57,13 @@ static NotifierList migration_state_notifiers =
static bool deferred_incoming;
/*
* Current state of incoming postcopy; note this is not part of
* MigrationIncomingState since it's state is used during cleanup
* at the end as MIS is being freed.
*/
static PostcopyState incoming_postcopy_state;
/* When we add fault tolerance, we could have several
migrations at once. For now we don't need to add
dynamic creation of migration */
@ -284,6 +291,7 @@ static void process_incoming_migration_co(void *opaque)
int ret;
migration_incoming_state_new(f);
postcopy_state_set(POSTCOPY_INCOMING_NONE);
migrate_generate_event(MIGRATION_STATUS_ACTIVE);
ret = qemu_loadvm_state(f);
@ -1367,3 +1375,15 @@ void migrate_fd_connect(MigrationState *s)
qemu_thread_create(&s->thread, "migration", migration_thread, s,
QEMU_THREAD_JOINABLE);
}
PostcopyState postcopy_state_get(void)
{
return atomic_mb_read(&incoming_postcopy_state);
}
/* Set the state and return the old state */
PostcopyState postcopy_state_set(PostcopyState new_state)
{
return atomic_xchg(&incoming_postcopy_state, new_state);
}

View File

@ -45,6 +45,7 @@
#include "exec/memory.h"
#include "qmp-commands.h"
#include "trace.h"
#include "qemu/bitops.h"
#include "qemu/iov.h"
#include "block/snapshot.h"
#include "block/qapi.h"
@ -57,6 +58,8 @@
#define ARP_PTYPE_IP 0x0800
#define ARP_OP_REQUEST_REV 0x3
const unsigned int postcopy_ram_discard_version = 0;
static bool skip_section_footers;
static struct mig_cmd_args {
@ -66,6 +69,11 @@ static struct mig_cmd_args {
[MIG_CMD_INVALID] = { .len = -1, .name = "INVALID" },
[MIG_CMD_OPEN_RETURN_PATH] = { .len = 0, .name = "OPEN_RETURN_PATH" },
[MIG_CMD_PING] = { .len = sizeof(uint32_t), .name = "PING" },
[MIG_CMD_POSTCOPY_ADVISE] = { .len = 16, .name = "POSTCOPY_ADVISE" },
[MIG_CMD_POSTCOPY_LISTEN] = { .len = 0, .name = "POSTCOPY_LISTEN" },
[MIG_CMD_POSTCOPY_RUN] = { .len = 0, .name = "POSTCOPY_RUN" },
[MIG_CMD_POSTCOPY_RAM_DISCARD] = {
.len = -1, .name = "POSTCOPY_RAM_DISCARD" },
[MIG_CMD_MAX] = { .len = -1, .name = "MAX" },
};
@ -741,6 +749,77 @@ void qemu_savevm_send_open_return_path(QEMUFile *f)
qemu_savevm_command_send(f, MIG_CMD_OPEN_RETURN_PATH, 0, NULL);
}
/* Send prior to any postcopy transfer */
void qemu_savevm_send_postcopy_advise(QEMUFile *f)
{
uint64_t tmp[2];
tmp[0] = cpu_to_be64(getpagesize());
tmp[1] = cpu_to_be64(1ul << qemu_target_page_bits());
trace_qemu_savevm_send_postcopy_advise();
qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_ADVISE, 16, (uint8_t *)tmp);
}
/* Sent prior to starting the destination running in postcopy, discard pages
* that have already been sent but redirtied on the source.
* CMD_POSTCOPY_RAM_DISCARD consist of:
* byte version (0)
* byte Length of name field (not including 0)
* n x byte RAM block name
* byte 0 terminator (just for safety)
* n x Byte ranges within the named RAMBlock
* be64 Start of the range
* be64 Length
*
* name: RAMBlock name that these entries are part of
* len: Number of page entries
* start_list: 'len' addresses
* length_list: 'len' addresses
*
*/
void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
uint16_t len,
uint64_t *start_list,
uint64_t *length_list)
{
uint8_t *buf;
uint16_t tmplen;
uint16_t t;
size_t name_len = strlen(name);
trace_qemu_savevm_send_postcopy_ram_discard(name, len);
assert(name_len < 256);
buf = g_malloc0(1 + 1 + name_len + 1 + (8 + 8) * len);
buf[0] = postcopy_ram_discard_version;
buf[1] = name_len;
memcpy(buf + 2, name, name_len);
tmplen = 2 + name_len;
buf[tmplen++] = '\0';
for (t = 0; t < len; t++) {
cpu_to_be64w((uint64_t *)(buf + tmplen), start_list[t]);
tmplen += 8;
cpu_to_be64w((uint64_t *)(buf + tmplen), length_list[t]);
tmplen += 8;
}
qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RAM_DISCARD, tmplen, buf);
g_free(buf);
}
/* Get the destination into a state where it can receive postcopy data. */
void qemu_savevm_send_postcopy_listen(QEMUFile *f)
{
trace_savevm_send_postcopy_listen();
qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_LISTEN, 0, NULL);
}
/* Kick the destination into running */
void qemu_savevm_send_postcopy_run(QEMUFile *f)
{
trace_savevm_send_postcopy_run();
qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RUN, 0, NULL);
}
bool qemu_savevm_state_blocked(Error **errp)
{
SaveStateEntry *se;
@ -1057,6 +1136,169 @@ enum LoadVMExitCodes {
};
static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis);
/* ------ incoming postcopy messages ------ */
/* 'advise' arrives before any transfers just to tell us that a postcopy
* *might* happen - it might be skipped if precopy transferred everything
* quickly.
*/
static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis)
{
PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE);
uint64_t remote_hps, remote_tps;
trace_loadvm_postcopy_handle_advise();
if (ps != POSTCOPY_INCOMING_NONE) {
error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps);
return -1;
}
remote_hps = qemu_get_be64(mis->from_src_file);
if (remote_hps != getpagesize()) {
/*
* Some combinations of mismatch are probably possible but it gets
* a bit more complicated. In particular we need to place whole
* host pages on the dest at once, and we need to ensure that we
* handle dirtying to make sure we never end up sending part of
* a hostpage on it's own.
*/
error_report("Postcopy needs matching host page sizes (s=%d d=%d)",
(int)remote_hps, getpagesize());
return -1;
}
remote_tps = qemu_get_be64(mis->from_src_file);
if (remote_tps != (1ul << qemu_target_page_bits())) {
/*
* Again, some differences could be dealt with, but for now keep it
* simple.
*/
error_report("Postcopy needs matching target page sizes (s=%d d=%d)",
(int)remote_tps, 1 << qemu_target_page_bits());
return -1;
}
return 0;
}
/* After postcopy we will be told to throw some pages away since they're
* dirty and will have to be demand fetched. Must happen before CPU is
* started.
* There can be 0..many of these messages, each encoding multiple pages.
*/
static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis,
uint16_t len)
{
int tmp;
char ramid[256];
PostcopyState ps = postcopy_state_get();
trace_loadvm_postcopy_ram_handle_discard();
switch (ps) {
case POSTCOPY_INCOMING_ADVISE:
/* 1st discard */
tmp = 0; /* TODO: later patch postcopy_ram_prepare_discard(mis); */
if (tmp) {
return tmp;
}
break;
case POSTCOPY_INCOMING_DISCARD:
/* Expected state */
break;
default:
error_report("CMD_POSTCOPY_RAM_DISCARD in wrong postcopy state (%d)",
ps);
return -1;
}
/* We're expecting a
* Version (0)
* a RAM ID string (length byte, name, 0 term)
* then at least 1 16 byte chunk
*/
if (len < (1 + 1 + 1 + 1 + 2 * 8)) {
error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
return -1;
}
tmp = qemu_get_byte(mis->from_src_file);
if (tmp != postcopy_ram_discard_version) {
error_report("CMD_POSTCOPY_RAM_DISCARD invalid version (%d)", tmp);
return -1;
}
if (!qemu_get_counted_string(mis->from_src_file, ramid)) {
error_report("CMD_POSTCOPY_RAM_DISCARD Failed to read RAMBlock ID");
return -1;
}
tmp = qemu_get_byte(mis->from_src_file);
if (tmp != 0) {
error_report("CMD_POSTCOPY_RAM_DISCARD missing nil (%d)", tmp);
return -1;
}
len -= 3 + strlen(ramid);
if (len % 16) {
error_report("CMD_POSTCOPY_RAM_DISCARD invalid length (%d)", len);
return -1;
}
trace_loadvm_postcopy_ram_handle_discard_header(ramid, len);
while (len) {
/* TODO - ram_discard_range gets added in a later patch
uint64_t start_addr, block_length;
start_addr = qemu_get_be64(mis->from_src_file);
block_length = qemu_get_be64(mis->from_src_file);
len -= 16;
int ret = ram_discard_range(mis, ramid, start_addr,
block_length);
if (ret) {
return ret;
}
*/
}
trace_loadvm_postcopy_ram_handle_discard_end();
return 0;
}
/* After this message we must be able to immediately receive postcopy data */
static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis)
{
PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_LISTENING);
trace_loadvm_postcopy_handle_listen();
if (ps != POSTCOPY_INCOMING_ADVISE && ps != POSTCOPY_INCOMING_DISCARD) {
error_report("CMD_POSTCOPY_LISTEN in wrong postcopy state (%d)", ps);
return -1;
}
/* TODO start up the postcopy listening thread */
return 0;
}
/* After all discards we can start running and asking for pages */
static int loadvm_postcopy_handle_run(MigrationIncomingState *mis)
{
PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_RUNNING);
trace_loadvm_postcopy_handle_run();
if (ps != POSTCOPY_INCOMING_LISTENING) {
error_report("CMD_POSTCOPY_RUN in wrong postcopy state (%d)", ps);
return -1;
}
if (autostart) {
/* Hold onto your hats, starting the CPU */
vm_start();
} else {
/* leave it paused and let management decide when to start the CPU */
runstate_set(RUN_STATE_PAUSED);
}
return 0;
}
/**
* loadvm_process_command: Process an incoming 'QEMU_VM_COMMAND'
*
@ -1112,6 +1354,18 @@ static int loadvm_process_command(QEMUFile *f)
}
migrate_send_rp_pong(mis, tmp32);
break;
case MIG_CMD_POSTCOPY_ADVISE:
return loadvm_postcopy_handle_advise(mis);
case MIG_CMD_POSTCOPY_LISTEN:
return loadvm_postcopy_handle_listen(mis);
case MIG_CMD_POSTCOPY_RUN:
return loadvm_postcopy_handle_run(mis);
case MIG_CMD_POSTCOPY_RAM_DISCARD:
return loadvm_postcopy_ram_handle_discard(mis, len);
}
return 0;

View File

@ -1208,14 +1208,24 @@ qemu_loadvm_state_main(void) ""
qemu_loadvm_state_main_quit_parent(void) ""
qemu_loadvm_state_post_main(int ret) "%d"
qemu_loadvm_state_section_startfull(uint32_t section_id, const char *idstr, uint32_t instance_id, uint32_t version_id) "%u(%s) %u %u"
loadvm_postcopy_handle_advise(void) ""
loadvm_postcopy_handle_listen(void) ""
loadvm_postcopy_handle_run(void) ""
loadvm_postcopy_ram_handle_discard(void) ""
loadvm_postcopy_ram_handle_discard_end(void) ""
loadvm_postcopy_ram_handle_discard_header(const char *ramid, uint16_t len) "%s: %ud"
loadvm_process_command(uint16_t com, uint16_t len) "com=0x%x len=%d"
loadvm_process_command_ping(uint32_t val) "%x"
qemu_savevm_send_postcopy_advise(void) ""
qemu_savevm_send_postcopy_ram_discard(const char *id, uint16_t len) "%s: %ud"
savevm_command_send(uint16_t command, uint16_t len) "com=0x%x len=%d"
savevm_section_start(const char *id, unsigned int section_id) "%s, section_id %u"
savevm_section_end(const char *id, unsigned int section_id, int ret) "%s, section_id %u -> %d"
savevm_section_skip(const char *id, unsigned int section_id) "%s, section_id %u"
savevm_send_open_return_path(void) ""
savevm_send_ping(uint32_t val) "%x"
savevm_send_postcopy_listen(void) ""
savevm_send_postcopy_run(void) ""
savevm_state_begin(void) ""
savevm_state_header(void) ""
savevm_state_iterate(void) ""