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Diffstat (limited to 'hw/kvm/i8254.c')
-rw-r--r--hw/kvm/i8254.c52
1 files changed, 34 insertions, 18 deletions
diff --git a/hw/kvm/i8254.c b/hw/kvm/i8254.c
index c5d3711a0..53d13e312 100644
--- a/hw/kvm/i8254.c
+++ b/hw/kvm/i8254.c
@@ -35,7 +35,8 @@
typedef struct KVMPITState {
PITCommonState pit;
LostTickPolicy lost_tick_policy;
- bool state_valid;
+ bool vm_stopped;
+ int64_t kernel_clock_offset;
} KVMPITState;
static int64_t abs64(int64_t v)
@@ -43,19 +44,11 @@ static int64_t abs64(int64_t v)
return v < 0 ? -v : v;
}
-static void kvm_pit_get(PITCommonState *pit)
+static void kvm_pit_update_clock_offset(KVMPITState *s)
{
- KVMPITState *s = DO_UPCAST(KVMPITState, pit, pit);
- struct kvm_pit_state2 kpit;
- struct kvm_pit_channel_state *kchan;
- struct PITChannelState *sc;
int64_t offset, clock_offset;
struct timespec ts;
- int i, ret;
-
- if (s->state_valid) {
- return;
- }
+ int i;
/*
* Measure the delta between CLOCK_MONOTONIC, the base used for
@@ -72,6 +65,21 @@ static void kvm_pit_get(PITCommonState *pit)
clock_offset = offset;
}
}
+ s->kernel_clock_offset = clock_offset;
+}
+
+static void kvm_pit_get(PITCommonState *pit)
+{
+ KVMPITState *s = DO_UPCAST(KVMPITState, pit, pit);
+ struct kvm_pit_state2 kpit;
+ struct kvm_pit_channel_state *kchan;
+ struct PITChannelState *sc;
+ int i, ret;
+
+ /* No need to re-read the state if VM is stopped. */
+ if (s->vm_stopped) {
+ return;
+ }
if (kvm_has_pit_state2()) {
ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit);
@@ -106,7 +114,7 @@ static void kvm_pit_get(PITCommonState *pit)
sc->mode = kchan->mode;
sc->bcd = kchan->bcd;
sc->gate = kchan->gate;
- sc->count_load_time = kchan->count_load_time + clock_offset;
+ sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset;
}
sc = &pit->channels[0];
@@ -114,17 +122,23 @@ static void kvm_pit_get(PITCommonState *pit)
pit_get_next_transition_time(sc, sc->count_load_time);
}
-static void kvm_pit_put(PITCommonState *s)
+static void kvm_pit_put(PITCommonState *pit)
{
+ KVMPITState *s = DO_UPCAST(KVMPITState, pit, pit);
struct kvm_pit_state2 kpit;
struct kvm_pit_channel_state *kchan;
struct PITChannelState *sc;
int i, ret;
- kpit.flags = s->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0;
+ /* The offset keeps changing as long as the VM is stopped. */
+ if (s->vm_stopped) {
+ kvm_pit_update_clock_offset(s);
+ }
+
+ kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0;
for (i = 0; i < 3; i++) {
kchan = &kpit.channels[i];
- sc = &s->channels[i];
+ sc = &pit->channels[i];
kchan->count = sc->count;
kchan->latched_count = sc->latched_count;
kchan->count_latched = sc->count_latched;
@@ -137,7 +151,7 @@ static void kvm_pit_put(PITCommonState *s)
kchan->mode = sc->mode;
kchan->bcd = sc->bcd;
kchan->gate = sc->gate;
- kchan->count_load_time = sc->count_load_time;
+ kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset;
}
ret = kvm_vm_ioctl(kvm_state,
@@ -211,10 +225,12 @@ static void kvm_pit_vm_state_change(void *opaque, int running,
KVMPITState *s = opaque;
if (running) {
- s->state_valid = false;
+ kvm_pit_update_clock_offset(s);
+ s->vm_stopped = false;
} else {
+ kvm_pit_update_clock_offset(s);
kvm_pit_get(&s->pit);
- s->state_valid = true;
+ s->vm_stopped = true;
}
}