timer.c
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/*
* Kernel-based Virtual Machine driver for Linux
*
* This module enables machines with Intel VT-x extensions to run virtual
* machines without emulation or binary translation.
*
* timer support
*
* Copyright 2010 Red Hat, Inc. and/or its affiliates.
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*/
#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/hrtimer.h>
#include <linux/atomic.h>
#include "kvm_timer.h"
enum hrtimer_restart kvm_timer_fn(struct hrtimer *data)
{
struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
struct kvm_vcpu *vcpu = ktimer->vcpu;
wait_queue_head_t *q = &vcpu->wq;
/*
* There is a race window between reading and incrementing, but we do
* not care about potentially losing timer events in the !reinject
* case anyway. Note: KVM_REQ_PENDING_TIMER is implicitly checked
* in vcpu_enter_guest.
*/
if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
atomic_inc(&ktimer->pending);
/* FIXME: this code should not know anything about vcpus */
kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
}
if (waitqueue_active(q))
wake_up_interruptible(q);
if (ktimer->t_ops->is_periodic(ktimer)) {
hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
return HRTIMER_RESTART;
} else
return HRTIMER_NORESTART;
}