This will be used in future to start Hyper-V SynIC timer
in several places by one logic in one function.
Changes v2:
* drop stimer->count == 0 check inside stimer_start()
* comment stimer_start() assumptions
Signed-off-by: Andrey Smetanin
Reviewed-by: Roman Kagan
CC: Gleb Natapov
CC: Paolo Bonzini
CC: Roman Kagan
CC: Denis V. Lunev
CC: qemu-devel@nongnu.org
---
arch/x86/kvm/hyperv.c | 43 ---
1 file changed, 20 insertions(+), 23 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 6b2ed93..0dd7d17 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -408,6 +408,7 @@ static void stimer_cleanup(struct kvm_vcpu_hv_stimer
*stimer)
clear_bit(stimer->index,
vcpu_to_hv_vcpu(vcpu)->stimer_pending_bitmap);
stimer->msg_pending = false;
+ stimer->exp_time = 0;
}
static enum hrtimer_restart stimer_timer_callback(struct hrtimer *timer)
@@ -420,24 +421,11 @@ static enum hrtimer_restart stimer_timer_callback(struct
hrtimer *timer)
return HRTIMER_NORESTART;
}
-static void stimer_restart(struct kvm_vcpu_hv_stimer *stimer)
-{
- u64 time_now;
- ktime_t ktime_now;
- u64 remainder;
-
- time_now = get_time_ref_counter(stimer_to_vcpu(stimer)->kvm);
- ktime_now = ktime_get();
-
- div64_u64_rem(time_now - stimer->exp_time, stimer->count, &remainder);
- stimer->exp_time = time_now + (stimer->count - remainder);
-
- hrtimer_start(&stimer->timer,
- ktime_add_ns(ktime_now,
- 100 * (stimer->exp_time - time_now)),
- HRTIMER_MODE_ABS);
-}
-
+/*
+ * stimer_start() assumptions:
+ * a) stimer->count is not equal to 0
+ * b) stimer->config has HV_STIMER_ENABLE flag
+ */
static int stimer_start(struct kvm_vcpu_hv_stimer *stimer)
{
u64 time_now;
@@ -447,12 +435,21 @@ static int stimer_start(struct kvm_vcpu_hv_stimer *stimer)
ktime_now = ktime_get();
if (stimer->config & HV_STIMER_PERIODIC) {
- if (stimer->count == 0)
- return -EINVAL;
+ if (stimer->exp_time) {
+ if (time_now >= stimer->exp_time) {
+ u64 remainder;
+
+ div64_u64_rem(time_now - stimer->exp_time,
+ stimer->count, &remainder);
+ stimer->exp_time =
+ time_now + (stimer->count - remainder);
+ }
+ } else
+ stimer->exp_time = time_now + stimer->count;
- stimer->exp_time = time_now + stimer->count;
hrtimer_start(&stimer->timer,
- ktime_add_ns(ktime_now, 100 * stimer->count),
+ ktime_add_ns(ktime_now,
+ 100 * (stimer->exp_time - time_now)),
HRTIMER_MODE_ABS);
return 0;
}
@@ -580,7 +577,7 @@ static void stimer_expiration(struct kvm_vcpu_hv_stimer
*stimer)
if (!(stimer->config & HV_STIMER_PERIODIC))
stimer->config &= ~HV_STIMER_ENABLE;
else
- stimer_restart(stimer);
+ stimer_start(stimer);
}
void kvm_hv_process_stimers(struct kvm_vcpu *vcpu)
--
2.4.3
