/* * 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; }