diff options
| -rw-r--r-- | arch/x86/kvm/lapic.c | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index f7ad11255557..2c9e88a82738 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1456,6 +1456,30 @@ static void start_sw_period(struct kvm_lapic *apic) HRTIMER_MODE_ABS_PINNED); } +static void update_target_expiration(struct kvm_lapic *apic, uint32_t old_divisor) +{ + ktime_t now, remaining; + u64 ns_remaining_old, ns_remaining_new; + + apic->lapic_timer.period = (u64)kvm_lapic_get_reg(apic, APIC_TMICT) + * APIC_BUS_CYCLE_NS * apic->divide_count; + limit_periodic_timer_frequency(apic); + + now = ktime_get(); + remaining = ktime_sub(apic->lapic_timer.target_expiration, now); + if (ktime_to_ns(remaining) < 0) + remaining = 0; + + ns_remaining_old = ktime_to_ns(remaining); + ns_remaining_new = mul_u64_u32_div(ns_remaining_old, + apic->divide_count, old_divisor); + + apic->lapic_timer.tscdeadline += + nsec_to_cycles(apic->vcpu, ns_remaining_new) - + nsec_to_cycles(apic->vcpu, ns_remaining_old); + apic->lapic_timer.target_expiration = ktime_add_ns(now, ns_remaining_new); +} + static bool set_target_expiration(struct kvm_lapic *apic) { ktime_t now; @@ -1748,13 +1772,21 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) start_apic_timer(apic); break; - case APIC_TDCR: + case APIC_TDCR: { + uint32_t old_divisor = apic->divide_count; + if (val & 4) apic_debug("KVM_WRITE:TDCR %x\n", val); kvm_lapic_set_reg(apic, APIC_TDCR, val); update_divide_count(apic); + if (apic->divide_count != old_divisor && + apic->lapic_timer.period) { + hrtimer_cancel(&apic->lapic_timer.timer); + update_target_expiration(apic, old_divisor); + restart_apic_timer(apic); + } break; - + } case APIC_ESR: if (apic_x2apic_mode(apic) && val != 0) { apic_debug("KVM_WRITE:ESR not zero %x\n", val); |