On 12/05/2011 10:19 PM, Eric B Munson wrote:

When a host stops or suspends a VM it will set a flag to show this.  The
watchdog will use these functions to determine if a softlockup is real, or the
result of a suspended VM.
 
+bool kvm_check_and_clear_guest_paused(int cpu)
+{
+	bool ret = false;
+	struct pvclock_vcpu_time_info *src;
+
+	/*
+	 * per_cpu() is safe here because this function is only called from
+	 * timer functions where preemption is already disabled.
+	 */
+	WARN_ON(!in_atomic());
+	src = &per_cpu(hv_clock, cpu);

__get_cpu_var(); drop the cpu argument

+	if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
+		src->flags = src->flags & (~PVCLOCK_GUEST_STOPPED);

Isn't this racy?  Between reading and writing src->flags, we can exit to
the hypervisor and add/remove new flags.  The write then overrides those
new flags.

+		ret = true;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_check_and_clear_guest_paused);
+
 static struct clocksource kvm_clock = {
 	.name = "kvm-clock",
 	.read = kvm_clock_get_cycles,

-- 
error compiling committee.c: too many arguments to function