From: Li RongQing <lirongqing@xxxxxxxxx>
pit_shutdown() in drivers/clocksource/i8253.c doesn't work because
setting the counter register to zero causes the PIT to start running
again, negating the shutdown.
fix it by stopping pit timer and zeroing channel count
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
---
arch/x86/kvm/i8254.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index e0a7a0e..c8a51f5 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -358,13 +358,15 @@ static void create_pit_timer(struct kvm_pit *pit, u32 val, int is_period)
}
}
- hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
+ if (interval)
+ hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
HRTIMER_MODE_ABS);
}
static void pit_load_count(struct kvm_pit *pit, int channel, u32 val)
{
struct kvm_kpit_state *ps = &pit->pit_state;
+ u32 org = val;
pr_debug("load_count val is %u, channel is %d\n", val, channel);
@@ -386,6 +388,9 @@ static void pit_load_count(struct kvm_pit *pit, int channel, u32 val)
* mode 1 is one shot, mode 2 is period, otherwise del timer */
switch (ps->channels[0].mode) {
case 0:
+ val = org;
+ ps->channels[channel].count = val;
+ fallthrough;
case 1:
/* FIXME: enhance mode 4 precision */
case 4:
--
2.9.4
