return success ? p2m : NULL;
}
+#define SUSPEND_LOCK_FILE "/var/lib/xen/suspend_evtchn_lock.d"
+static int lock_suspend_event(void)
+{
+ int fd;
+ mode_t mask;
+ char buf[128];
+
+ mask = umask(022);
+ fd = open(SUSPEND_LOCK_FILE, O_CREAT | O_EXCL | O_RDWR, 0666);
+ if (fd < 0)
+ {
+ ERROR("Can't create lock file for suspend event channel\n");
+ return -EINVAL;
+ }
+ umask(mask);
+ snprintf(buf, sizeof(buf), "%10ld", (long)getpid());
+
+ write(fd, buf, strlen(buf));
+ close(fd);
+
+ return 0;
+}
+
+static int unlock_suspend_event(void)
+{
+ int fd, pid, n;
+ char buf[128];
+
+ fd = open(SUSPEND_LOCK_FILE, O_RDWR);
+
+ if (fd < 0)
+ return -EINVAL;
+
+ n = read(fd, buf, 127);
+
+ close(fd);
+
+ if (n > 0)
+ {
+ sscanf(buf, "%d", &pid);
+ /* We are the owner, so we can simply delete the file */
+ if (pid == getpid())
+ {
+ unlink(SUSPEND_LOCK_FILE);
+ return 0;
+ }
+ }
+
+ return -EPERM;
+}
+
+int xc_await_suspend(int xce, int suspend_evtchn)
+{
+ int rc;
+ do {
+ rc = xc_evtchn_pending(xce);
+ if (rc < 0) {
+ ERROR("error polling suspend notification channel: %d", rc);
+ return -1;
+ }
+ } while (rc != suspend_evtchn);
+
+ /* harmless for one-off suspend */
+ if (xc_evtchn_unmask(xce, suspend_evtchn) < 0)
+ ERROR("failed to unmask suspend notification channel: %d", rc);
+
+ return 0;
+}
+
+int xc_suspend_evtchn_release(int xce, int suspend_evtchn)
+{
+ if (suspend_evtchn >= 0)
+ xc_evtchn_unbind(xce, suspend_evtchn);
+
+ return unlock_suspend_event();
+}
+
+int xc_suspend_evtchn_init(int xc, int xce, int domid, int port)
+{
+ int rc, suspend_evtchn = -1;
+
+ if (lock_suspend_event())
+ return -EINVAL;
+
+ suspend_evtchn = xc_evtchn_bind_interdomain(xce, domid, port);
+ if (suspend_evtchn < 0) {
+ ERROR("failed to bind suspend event channel: %d", suspend_evtchn);
+ goto cleanup;
+ }
+
+ rc = xc_domain_subscribe_for_suspend(xc, domid, port);
+ if (rc < 0) {
+ ERROR("failed to subscribe to domain: %d", rc);
+ goto cleanup;
+ }
+
+ /* event channel is pending immediately after binding */
+ xc_await_suspend(xce, suspend_evtchn);
+
+ return suspend_evtchn;
+
+cleanup:
+ if (suspend_evtchn > 0)
+ xc_suspend_evtchn_release(xce, suspend_evtchn);
+
+ return -1;
+}
int xc_domain_save(int xc_handle, int io_fd, uint32_t dom, uint32_t max_iters,
uint32_t max_factor, uint32_t flags, int (*suspend)(void),
!strncmp(ans, "done\n", 5));
}
-static int suspend_evtchn_release(int xce, int suspend_evtchn)
-{
- if (suspend_evtchn >= 0)
- xc_evtchn_unbind(xce, suspend_evtchn);
-
- return 0;
-}
-
-static int await_suspend(int xce, int suspend_evtchn)
-{
- int rc;
-
- do {
- rc = xc_evtchn_pending(xce);
- if (rc < 0) {
- warnx("error polling suspend notification channel: %d", rc);
- return -1;
- }
- } while (rc != suspend_evtchn);
-
- /* harmless for one-off suspend */
- if (xc_evtchn_unmask(xce, suspend_evtchn) < 0)
- warnx("failed to unmask suspend notification channel: %d", rc);
-
- return 0;
-}
-
-static int suspend_evtchn_init(int xc, int xce, int domid)
-{
- struct xs_handle *xs;
- char path[128];
- char *portstr;
- unsigned int plen;
- int port;
- int rc, suspend_evtchn = -1;
-
- xs = xs_daemon_open();
- if (!xs) {
- warnx("failed to get xenstore handle");
- return -1;
- }
- sprintf(path, "/local/domain/%d/device/suspend/event-channel", domid);
- portstr = xs_read(xs, XBT_NULL, path, &plen);
- xs_daemon_close(xs);
-
- if (!portstr || !plen) {
- warnx("could not read suspend event channel");
- return -1;
- }
-
- port = atoi(portstr);
- free(portstr);
-
- suspend_evtchn = xc_evtchn_bind_interdomain(xce, domid, port);
- if (suspend_evtchn < 0) {
- warnx("failed to bind suspend event channel: %d", si.suspend_evtchn);
- goto cleanup;
- }
-
- rc = xc_domain_subscribe_for_suspend(xc, domid, port);
- if (rc < 0) {
- warnx("failed to subscribe to domain: %d", rc);
- goto cleanup;
- }
-
- /* event channel is pending immediately after binding */
- await_suspend(xce, suspend_evtchn);
-
- return suspend_evtchn;
-
-cleanup:
- if (suspend_evtchn > 0)
- suspend_evtchn_release(xce, suspend_evtchn);
-
- return -1;
-}
-
/**
* Issue a suspend request to a dedicated event channel in the guest, and
* receive the acknowledgement from the subscribe event channel. */
return 0;
}
- if (await_suspend(si.xce, si.suspend_evtchn) < 0) {
+ if (xc_await_suspend(si.xce, si.suspend_evtchn) < 0) {
warnx("suspend failed");
return 0;
}
return seg;
}
-
int
main(int argc, char **argv)
{
unsigned int maxit, max_f;
- int io_fd, ret;
+ int io_fd, ret, port;
if (argc != 6)
errx(1, "usage: %s iofd domid maxit maxf flags", argv[0]);
max_f = atoi(argv[4]);
si.flags = atoi(argv[5]);
+ si.suspend_evtchn = si.xce = -1;
si.xce = xc_evtchn_open();
if (si.xce < 0)
- errx(1, "failed to open event channel handle");
-
- si.suspend_evtchn = suspend_evtchn_init(si.xc_fd, si.xce, si.domid);
-
- if (si.suspend_evtchn < 0)
- warnx("suspend event channel initialization failed, using slow path");
-
+ warnx("failed to open event channel handle");
+
+ if (si.xce > 0)
+ {
+ port = xs_suspend_evtchn_port(si.domid);
+
+ if (port < 0)
+ warnx("faield to get the suspend evtchn port\n");
+ else
+ {
+ si.suspend_evtchn =
+ xc_suspend_evtchn_init(si.xc_fd, si.xce, si.domid, port);
+
+ if (si.suspend_evtchn < 0)
+ warnx("suspend event channel initialization failed"
+ "using slow path");
+ }
+ }
ret = xc_domain_save(si.xc_fd, io_fd, si.domid, maxit, max_f, si.flags,
&suspend, !!(si.flags & XCFLAGS_HVM),
&init_qemu_maps, &qemu_flip_buffer);
- suspend_evtchn_release(si.xce, si.suspend_evtchn);
+ if (si.suspend_evtchn > 0)
+ xc_suspend_evtchn_release(si.xce, si.suspend_evtchn);
- xc_evtchn_close(si.xce);
+ if (si.xce > 0)
+ xc_evtchn_close(si.xce);
xc_interface_close(si.xc_fd);
projects / xen.git / commitdiff