@@ -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
@@ -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
@@ -53,6 +53,13 @@ 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 */
@@ -276,6 +283,7 @@ 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);
@@ -1286,3 +1294,15 @@ 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);
+}
+
@@ -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" },
};
@@ -739,6 +747,77 @@ 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;
@@ -1055,6 +1134,167 @@ 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,
+ uint64_t remote_hps,
+ uint64_t remote_tps)
+{
+ PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE);
+ trace_loadvm_postcopy_handle_advise();
+ if (ps != POSTCOPY_INCOMING_NONE) {
+ error_report("CMD_POSTCOPY_ADVISE in wrong postcopy state (%d)", ps);
+ return -1;
+ }
+
+ 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;
+ }
+
+ 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'
*
@@ -1069,6 +1309,7 @@ static int loadvm_process_command(QEMUFile *f)
uint16_t cmd;
uint16_t len;
uint32_t tmp32;
+ uint64_t tmp64a, tmp64b;
cmd = qemu_get_be16(f);
len = qemu_get_be16(f);
@@ -1109,6 +1350,20 @@ static int loadvm_process_command(QEMUFile *f)
}
migrate_send_rp_pong(mis, tmp32);
break;
+
+ case MIG_CMD_POSTCOPY_ADVISE:
+ tmp64a = qemu_get_be64(f); /* hps */
+ tmp64b = qemu_get_be64(f); /* tps */
+ return loadvm_postcopy_handle_advise(mis, tmp64a, tmp64b);
+
+ 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;
@@ -1201,13 +1201,23 @@ 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_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) ""