runqemu: display host uptime when starting

In order to be able to debug issues on the host that have an impact on the
guest, it is useful to get the uptime of the host while starting so we can
match with the events in dmesg. Also include the uptime when cleaning up.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/runqemu

@@ -1505,6 +1505,9 @@ class BaseConfig(object):
         cmd = "%s %s" % (self.qemu_opt, kernel_opts)
         cmds = shlex.split(cmd)
         logger.info('Running %s\n' % cmd)
+        with open('/proc/uptime', 'r') as f:
+            uptime_seconds = f.readline().split()[0]
+        logger.info('Host uptime: %s\n' % uptime_seconds)
         pass_fds = []
         if self.taplock_descriptor:
             pass_fds = [self.taplock_descriptor.fileno()]
@@ -1528,6 +1531,9 @@ class BaseConfig(object):
         signal.signal(signal.SIGTERM, signal.SIG_IGN)
 
         logger.info("Cleaning up")
+        with open('/proc/uptime', 'r') as f:
+            uptime_seconds = f.readline().split()[0]
+        logger.info('Host uptime: %s\n' % uptime_seconds)
         if self.cleantap:
             cmd = ('sudo', self.qemuifdown, self.tap, self.bindir_native)
             logger.debug('Running %s' % str(cmd))