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[Qemu-devel] [PULL 26/57] MIG_CMD_PACKAGED: Send a packaged chunk of mig
From: |
Juan Quintela |
Subject: |
[Qemu-devel] [PULL 26/57] MIG_CMD_PACKAGED: Send a packaged chunk of migration stream |
Date: |
Mon, 9 Nov 2015 18:28:30 +0100 |
From: "Dr. David Alan Gilbert" <address@hidden>
MIG_CMD_PACKAGED is a migration command that wraps a chunk of migration
stream inside a package whose length can be determined purely by reading
its header. The destination guarantees that the whole MIG_CMD_PACKAGED
is read off the stream prior to parsing the contents.
This is used by postcopy to load device state (from the package)
while leaving the main stream free to receive memory pages.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Reviewed-by: Amit Shah <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Signed-off-by: Juan Quintela <address@hidden>
---
include/sysemu/sysemu.h | 4 ++
migration/savevm.c | 104 +++++++++++++++++++++++++++++++++++++++++++++---
trace-events | 4 ++
3 files changed, 107 insertions(+), 5 deletions(-)
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 6225e00..c27b926 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -99,9 +99,12 @@ enum qemu_vm_cmd {
MIG_CMD_POSTCOPY_RAM_DISCARD, /* A list of pages to discard that
were previously sent during
precopy but are dirty. */
+ MIG_CMD_PACKAGED, /* Send a wrapped stream within this stream */
MIG_CMD_MAX
};
+#define MAX_VM_CMD_PACKAGED_SIZE (1ul << 24)
+
bool qemu_savevm_state_blocked(Error **errp);
void qemu_savevm_state_begin(QEMUFile *f,
const MigrationParams *params);
@@ -114,6 +117,7 @@ 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);
+int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb);
void qemu_savevm_send_postcopy_advise(QEMUFile *f);
void qemu_savevm_send_postcopy_listen(QEMUFile *f);
void qemu_savevm_send_postcopy_run(QEMUFile *f);
diff --git a/migration/savevm.c b/migration/savevm.c
index a7a958c..01fdc72 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -74,6 +74,7 @@ static struct mig_cmd_args {
[MIG_CMD_POSTCOPY_RUN] = { .len = 0, .name = "POSTCOPY_RUN" },
[MIG_CMD_POSTCOPY_RAM_DISCARD] = {
.len = -1, .name = "POSTCOPY_RAM_DISCARD" },
+ [MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" },
[MIG_CMD_MAX] = { .len = -1, .name = "MAX" },
};
@@ -749,6 +750,48 @@ void qemu_savevm_send_open_return_path(QEMUFile *f)
qemu_savevm_command_send(f, MIG_CMD_OPEN_RETURN_PATH, 0, NULL);
}
+/* We have a buffer of data to send; we don't want that all to be loaded
+ * by the command itself, so the command contains just the length of the
+ * extra buffer that we then send straight after it.
+ * TODO: Must be a better way to organise that
+ *
+ * Returns:
+ * 0 on success
+ * -ve on error
+ */
+int qemu_savevm_send_packaged(QEMUFile *f, const QEMUSizedBuffer *qsb)
+{
+ size_t cur_iov;
+ size_t len = qsb_get_length(qsb);
+ uint32_t tmp;
+
+ if (len > MAX_VM_CMD_PACKAGED_SIZE) {
+ error_report("%s: Unreasonably large packaged state: %zu",
+ __func__, len);
+ return -1;
+ }
+
+ tmp = cpu_to_be32(len);
+
+ trace_qemu_savevm_send_packaged();
+ qemu_savevm_command_send(f, MIG_CMD_PACKAGED, 4, (uint8_t *)&tmp);
+
+ /* all the data follows (concatinating the iov's) */
+ for (cur_iov = 0; cur_iov < qsb->n_iov; cur_iov++) {
+ /* The iov entries are partially filled */
+ size_t towrite = MIN(qsb->iov[cur_iov].iov_len, len);
+ len -= towrite;
+
+ if (!towrite) {
+ break;
+ }
+
+ qemu_put_buffer(f, qsb->iov[cur_iov].iov_base, towrite);
+ }
+
+ return 0;
+}
+
/* Send prior to any postcopy transfer */
void qemu_savevm_send_postcopy_advise(QEMUFile *f)
{
@@ -1300,12 +1343,60 @@ static int
loadvm_postcopy_handle_run(MigrationIncomingState *mis)
}
/**
- * loadvm_process_command: Process an incoming 'QEMU_VM_COMMAND'
+ * Immediately following this command is a blob of data containing an embedded
+ * chunk of migration stream; read it and load it.
*
- * Returns: 0 on just a normal return
- * LOADVM_QUIT All good, but exit the loop
- * <0 error (in which case it will issue an error message).
- * @f: The stream to read the command data from.
+ * @mis: Incoming state
+ * @length: Length of packaged data to read
+ *
+ * Returns: Negative values on error
+ *
+ */
+static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis)
+{
+ int ret;
+ uint8_t *buffer;
+ uint32_t length;
+ QEMUSizedBuffer *qsb;
+
+ length = qemu_get_be32(mis->from_src_file);
+ trace_loadvm_handle_cmd_packaged(length);
+
+ if (length > MAX_VM_CMD_PACKAGED_SIZE) {
+ error_report("Unreasonably large packaged state: %u", length);
+ return -1;
+ }
+ buffer = g_malloc0(length);
+ ret = qemu_get_buffer(mis->from_src_file, buffer, (int)length);
+ if (ret != length) {
+ g_free(buffer);
+ error_report("CMD_PACKAGED: Buffer receive fail ret=%d length=%d\n",
+ ret, length);
+ return (ret < 0) ? ret : -EAGAIN;
+ }
+ trace_loadvm_handle_cmd_packaged_received(ret);
+
+ /* Setup a dummy QEMUFile that actually reads from the buffer */
+ qsb = qsb_create(buffer, length);
+ g_free(buffer); /* Because qsb_create copies */
+ if (!qsb) {
+ error_report("Unable to create qsb");
+ }
+ QEMUFile *packf = qemu_bufopen("r", qsb);
+
+ ret = qemu_loadvm_state_main(packf, mis);
+ trace_loadvm_handle_cmd_packaged_main(ret);
+ qemu_fclose(packf);
+ qsb_free(qsb);
+
+ return ret;
+}
+
+/*
+ * Process an incoming 'QEMU_VM_COMMAND'
+ * 0 just a normal return
+ * LOADVM_QUIT All good, but exit the loop
+ * <0 Error
*/
static int loadvm_process_command(QEMUFile *f)
{
@@ -1354,6 +1445,9 @@ static int loadvm_process_command(QEMUFile *f)
migrate_send_rp_pong(mis, tmp32);
break;
+ case MIG_CMD_PACKAGED:
+ return loadvm_handle_cmd_packaged(mis);
+
case MIG_CMD_POSTCOPY_ADVISE:
return loadvm_postcopy_handle_advise(mis);
diff --git a/trace-events b/trace-events
index 5359235..b908c19 100644
--- a/trace-events
+++ b/trace-events
@@ -1208,6 +1208,10 @@ 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"
+qemu_savevm_send_packaged(void) ""
+loadvm_handle_cmd_packaged(unsigned int length) "%u"
+loadvm_handle_cmd_packaged_main(int ret) "%d"
+loadvm_handle_cmd_packaged_received(int ret) "%d"
loadvm_postcopy_handle_advise(void) ""
loadvm_postcopy_handle_listen(void) ""
loadvm_postcopy_handle_run(void) ""
--
2.5.0
- [Qemu-devel] [PULL 13/57] migrate_init: Call from savevm, (continued)
- [Qemu-devel] [PULL 13/57] migrate_init: Call from savevm, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 16/57] Return path: Open a return path on QEMUFile for sockets, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 17/57] Return path: socket_writev_buffer: Block even on non-blocking fd's, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 20/57] Return path: Send responses from destination to source, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 18/57] Migration commands, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 21/57] migration_is_setup_or_active, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 19/57] Return path: Control commands, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 24/57] Add migration-capability boolean for postcopy-ram., Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 22/57] Return path: Source handling of return path, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 25/57] Add wrappers and handlers for sending/receiving the postcopy-ram migration messages., Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 26/57] MIG_CMD_PACKAGED: Send a packaged chunk of migration stream,
Juan Quintela <=
- [Qemu-devel] [PULL 23/57] Rework loadvm path for subloops, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 27/57] Modify save_live_pending for postcopy, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 31/57] MIGRATION_STATUS_POSTCOPY_ACTIVE: Add new migration state, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 28/57] postcopy: OS support test, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 30/57] migration_completion: Take current state, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 32/57] Avoid sending vmdescription during postcopy, Juan Quintela, 2015/11/09
- [Qemu-devel] [PULL 29/57] migrate_start_postcopy: Command to trigger transition to postcopy, Juan Quintela, 2015/11/09