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KVM: x86: fix LAPIC pending count calculation

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Simplify LAPIC TMCCT calculation by using hrtimer provided
function to query remaining time until expiration.

Fixes host hang with nested ESX.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Marcelo Tosatti
2009-02-10 20:41:41 -02:00
committed by Avi Kivity
parent d7cff1c376
commit b682b814e3
6 changed files with 14 additions and 62 deletions
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64
arch/x86/kvm/lapic.c
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@@ -35,6 +35,12 @@
#include "kvm_cache_regs.h"
#include "irq.h"
#ifndef CONFIG_X86_64
#define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
#else
#define mod_64(x, y) ((x) % (y))
#endif
#define PRId64 "d"
#define PRIx64 "llx"
#define PRIu64 "u"
@@ -511,52 +517,22 @@ static void apic_send_ipi(struct kvm_lapic *apic)
static u32 apic_get_tmcct(struct kvm_lapic *apic)
{
u64 counter_passed;
ktime_t passed, now;
ktime_t remaining;
s64 ns;
u32 tmcct;
ASSERT(apic != NULL);
now = apic->timer.dev.base->get_time();
tmcct = apic_get_reg(apic, APIC_TMICT);
/* if initial count is 0, current count should also be 0 */
if (tmcct == 0)
if (apic_get_reg(apic, APIC_TMICT) == 0)
return 0;
if (unlikely(ktime_to_ns(now) <=
ktime_to_ns(apic->timer.last_update))) {
/* Wrap around */
passed = ktime_add(( {
(ktime_t) {
.tv64 = KTIME_MAX -
(apic->timer.last_update).tv64}; }
), now);
apic_debug("time elapsed\n");
} else
passed = ktime_sub(now, apic->timer.last_update);
remaining = hrtimer_expires_remaining(&apic->timer.dev);
if (ktime_to_ns(remaining) < 0)
remaining = ktime_set(0, 0);
counter_passed = div64_u64(ktime_to_ns(passed),
(APIC_BUS_CYCLE_NS * apic->timer.divide_count));
if (counter_passed > tmcct) {
if (unlikely(!apic_lvtt_period(apic))) {
/* one-shot timers stick at 0 until reset */
tmcct = 0;
} else {
/*
* periodic timers reset to APIC_TMICT when they
* hit 0. The while loop simulates this happening N
* times. (counter_passed %= tmcct) would also work,
* but might be slower or not work on 32-bit??
*/
while (counter_passed > tmcct)
counter_passed -= tmcct;
tmcct -= counter_passed;
}
} else {
tmcct -= counter_passed;
}
ns = mod_64(ktime_to_ns(remaining), apic->timer.period);
tmcct = div64_u64(ns, (APIC_BUS_CYCLE_NS * apic->timer.divide_count));
return tmcct;
}
@@ -653,8 +629,6 @@ static void start_apic_timer(struct kvm_lapic *apic)
{
ktime_t now = apic->timer.dev.base->get_time();
apic->timer.last_update = now;
apic->timer.period = apic_get_reg(apic, APIC_TMICT) *
APIC_BUS_CYCLE_NS * apic->timer.divide_count;
atomic_set(&apic->timer.pending, 0);
@@ -1110,16 +1084,6 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
}
}
void kvm_apic_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
{
struct kvm_lapic *apic = vcpu->arch.apic;
if (apic && apic_lvt_vector(apic, APIC_LVTT) == vec)
apic->timer.last_update = ktime_add_ns(
apic->timer.last_update,
apic->timer.period);
}
int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
{
int vector = kvm_apic_has_interrupt(vcpu);