KVM: PIT: support mode 3
The in-kernel PIT emulation ignores pending timers if operating
under mode 3, which for example Hurd uses.
This mode should output a square wave, high for (N+1)/2 counts and low
for (N-1)/2 counts. As we only care about the resulting interrupts, the
period is N, and mode 3 is the same as mode 2 with regard to
interrupts.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 735ec9a..60074dc 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -308,6 +308,7 @@
create_pit_timer(&ps->pit_timer, val, 0);
break;
case 2:
+ case 3:
create_pit_timer(&ps->pit_timer, val, 1);
break;
default: