3cf57fed21
The PIT injection logic is problematic under the following cases: 1) If there is a higher priority vector to be delivered by the time kvm_pit_timer_intr_post is invoked ps->inject_pending won't be set. This opens the possibility for missing many PIT event injections (say if guest executes hlt at this point). 2) ps->inject_pending is racy with more than two vcpus. Since there's no locking around read/dec of pt->pending, two vcpu's can inject two interrupts for a single pt->pending count. Fix 1 by using an irq ack notifier: only reinject when the previous irq has been acked. Fix 2 with appropriate locking around manipulation of pending count and irq_ack by the injection / ack paths. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
134 lines
3.3 KiB
C
134 lines
3.3 KiB
C
/*
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* irq.c: API for in kernel interrupt controller
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* Copyright (c) 2007, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place - Suite 330, Boston, MA 02111-1307 USA.
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* Authors:
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* Yaozu (Eddie) Dong <Eddie.dong@intel.com>
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*
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*/
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#include <linux/module.h>
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#include <linux/kvm_host.h>
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#include "irq.h"
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#include "i8254.h"
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/*
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* check if there are pending timer events
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* to be processed.
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*/
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int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
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{
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int ret;
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ret = pit_has_pending_timer(vcpu);
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ret |= apic_has_pending_timer(vcpu);
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return ret;
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}
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EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
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/*
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* check if there is pending interrupt without
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* intack.
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*/
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int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
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{
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struct kvm_pic *s;
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if (kvm_apic_has_interrupt(v) == -1) { /* LAPIC */
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if (kvm_apic_accept_pic_intr(v)) {
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s = pic_irqchip(v->kvm); /* PIC */
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return s->output;
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} else
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return 0;
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}
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return 1;
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}
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EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
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/*
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* Read pending interrupt vector and intack.
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*/
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int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
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{
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struct kvm_pic *s;
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int vector;
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vector = kvm_get_apic_interrupt(v); /* APIC */
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if (vector == -1) {
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if (kvm_apic_accept_pic_intr(v)) {
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s = pic_irqchip(v->kvm);
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s->output = 0; /* PIC */
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vector = kvm_pic_read_irq(v->kvm);
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}
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}
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return vector;
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}
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EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
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void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
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{
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kvm_inject_apic_timer_irqs(vcpu);
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kvm_inject_pit_timer_irqs(vcpu);
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/* TODO: PIT, RTC etc. */
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}
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EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
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void kvm_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
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{
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kvm_apic_timer_intr_post(vcpu, vec);
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/* TODO: PIT, RTC etc. */
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}
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EXPORT_SYMBOL_GPL(kvm_timer_intr_post);
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void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
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{
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__kvm_migrate_apic_timer(vcpu);
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__kvm_migrate_pit_timer(vcpu);
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}
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/* This should be called with the kvm->lock mutex held */
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void kvm_set_irq(struct kvm *kvm, int irq, int level)
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{
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/* Not possible to detect if the guest uses the PIC or the
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* IOAPIC. So set the bit in both. The guest will ignore
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* writes to the unused one.
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*/
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kvm_ioapic_set_irq(kvm->arch.vioapic, irq, level);
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kvm_pic_set_irq(pic_irqchip(kvm), irq, level);
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}
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void kvm_notify_acked_irq(struct kvm *kvm, unsigned gsi)
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{
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struct kvm_irq_ack_notifier *kian;
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struct hlist_node *n;
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hlist_for_each_entry(kian, n, &kvm->arch.irq_ack_notifier_list, link)
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if (kian->gsi == gsi)
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kian->irq_acked(kian);
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}
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void kvm_register_irq_ack_notifier(struct kvm *kvm,
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struct kvm_irq_ack_notifier *kian)
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{
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hlist_add_head(&kian->link, &kvm->arch.irq_ack_notifier_list);
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}
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void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
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struct kvm_irq_ack_notifier *kian)
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{
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hlist_del(&kian->link);
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}
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