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https://gitlab.com/qemu-project/qemu
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8a43b1ea7f
All,
I've recently been playing around with migration via exec. Unfortunately,
when starting the incoming qemu process with "-incoming exec:cmd", it suffers
the same problem that -incoming tcp used to suffer; namely, that you can't
interact with the monitor until after the migration has happened. This causes
problems for libvirt usage of -incoming exec, since libvirt expects to be able
to access the monitor ahead of time. This fairly simple patch allows you to
access the monitor both before and after the migration has completed using exec.
(note: developed/tested with qemu-kvm, but applies perfectly fine to qemu)
Signed-off-by: Chris Lalancette <clalance@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
144 lines
3.2 KiB
C
144 lines
3.2 KiB
C
/*
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* QEMU live migration
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*
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* Copyright IBM, Corp. 2008
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* Copyright Dell MessageOne 2008
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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* Charles Duffy <charles_duffy@messageone.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "qemu-common.h"
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#include "qemu_socket.h"
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#include "migration.h"
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#include "qemu-char.h"
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#include "sysemu.h"
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#include "buffered_file.h"
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#include "block.h"
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//#define DEBUG_MIGRATION_EXEC
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#ifdef DEBUG_MIGRATION_EXEC
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#define dprintf(fmt, ...) \
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do { printf("migration-exec: " fmt, ## __VA_ARGS__); } while (0)
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#else
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#define dprintf(fmt, ...) \
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do { } while (0)
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#endif
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static int file_errno(FdMigrationState *s)
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{
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return errno;
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}
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static int file_write(FdMigrationState *s, const void * buf, size_t size)
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{
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return write(s->fd, buf, size);
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}
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static int exec_close(FdMigrationState *s)
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{
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dprintf("exec_close\n");
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if (s->opaque) {
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qemu_fclose(s->opaque);
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s->opaque = NULL;
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s->fd = -1;
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}
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return 0;
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}
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MigrationState *exec_start_outgoing_migration(const char *command,
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int64_t bandwidth_limit,
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int detach)
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{
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FdMigrationState *s;
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FILE *f;
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s = qemu_mallocz(sizeof(*s));
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f = popen(command, "w");
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if (f == NULL) {
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dprintf("Unable to popen exec target\n");
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goto err_after_alloc;
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}
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s->fd = fileno(f);
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if (s->fd == -1) {
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dprintf("Unable to retrieve file descriptor for popen'd handle\n");
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goto err_after_open;
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}
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if (fcntl(s->fd, F_SETFD, O_NONBLOCK) == -1) {
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dprintf("Unable to set nonblocking mode on file descriptor\n");
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goto err_after_open;
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}
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s->opaque = qemu_popen(f, "w");
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s->close = exec_close;
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s->get_error = file_errno;
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s->write = file_write;
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s->mig_state.cancel = migrate_fd_cancel;
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s->mig_state.get_status = migrate_fd_get_status;
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s->mig_state.release = migrate_fd_release;
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s->state = MIG_STATE_ACTIVE;
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s->mon_resume = NULL;
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s->bandwidth_limit = bandwidth_limit;
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if (!detach)
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migrate_fd_monitor_suspend(s);
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migrate_fd_connect(s);
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return &s->mig_state;
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err_after_open:
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pclose(f);
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err_after_alloc:
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qemu_free(s);
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return NULL;
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}
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static void exec_accept_incoming_migration(void *opaque)
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{
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QEMUFile *f = opaque;
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int ret;
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vm_stop(0); /* just in case */
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ret = qemu_loadvm_state(f);
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if (ret < 0) {
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fprintf(stderr, "load of migration failed\n");
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goto err;
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}
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qemu_announce_self();
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dprintf("successfully loaded vm state\n");
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/* we've successfully migrated, close the fd */
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qemu_set_fd_handler2(qemu_popen_fd(f), NULL, NULL, NULL, NULL);
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vm_start();
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err:
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qemu_fclose(f);
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}
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int exec_start_incoming_migration(const char *command)
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{
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QEMUFile *f;
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dprintf("Attempting to start an incoming migration\n");
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f = qemu_popen_cmd(command, "r");
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if(f == NULL) {
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dprintf("Unable to apply qemu wrapper to popen file\n");
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return -errno;
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}
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qemu_set_fd_handler2(qemu_popen_fd(f), NULL,
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exec_accept_incoming_migration, NULL,
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(void *)(unsigned long)f);
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return 0;
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}
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