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681405bfc7
The current code tries to optimize the setting of KVM_REQ_PENDING_TIMER but used atomic_inc_and_test - which always returns true unless pending had the invalid value of -1 on entry. This patch drops the test part preserving the original semantic but expressing it less confusingly. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
51 lines
1.2 KiB
C
51 lines
1.2 KiB
C
#include <linux/kvm_host.h>
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#include <linux/kvm.h>
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#include <linux/hrtimer.h>
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#include <asm/atomic.h>
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#include "kvm_timer.h"
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static int __kvm_timer_fn(struct kvm_vcpu *vcpu, struct kvm_timer *ktimer)
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{
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int restart_timer = 0;
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wait_queue_head_t *q = &vcpu->wq;
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/*
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* There is a race window between reading and incrementing, but we do
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* not care about potentially loosing timer events in the !reinject
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* case anyway.
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*/
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if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
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atomic_inc(&ktimer->pending);
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/* FIXME: this code should not know anything about vcpus */
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set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
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}
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if (waitqueue_active(q))
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wake_up_interruptible(q);
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if (ktimer->t_ops->is_periodic(ktimer)) {
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hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
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restart_timer = 1;
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}
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return restart_timer;
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}
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enum hrtimer_restart kvm_timer_fn(struct hrtimer *data)
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{
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int restart_timer;
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struct kvm_vcpu *vcpu;
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struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
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vcpu = ktimer->vcpu;
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if (!vcpu)
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return HRTIMER_NORESTART;
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restart_timer = __kvm_timer_fn(vcpu, ktimer);
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if (restart_timer)
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return HRTIMER_RESTART;
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else
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return HRTIMER_NORESTART;
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}
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