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![Paolo Bonzini](/assets/img/avatar_default.png)
ia64 does not need them anymore. Ack notifiers become x86-specific too. Suggested-by: Gleb Natapov <gleb@kernel.org> Reviewed-by: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
925 lines
22 KiB
C
925 lines
22 KiB
C
/*
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* kvm eventfd support - use eventfd objects to signal various KVM events
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*
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* Copyright 2009 Novell. All Rights Reserved.
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* Copyright 2010 Red Hat, Inc. and/or its affiliates.
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*
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* Author:
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* Gregory Haskins <ghaskins@novell.com>
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <linux/kvm_host.h>
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#include <linux/kvm.h>
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#include <linux/workqueue.h>
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#include <linux/syscalls.h>
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#include <linux/wait.h>
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#include <linux/poll.h>
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#include <linux/file.h>
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#include <linux/list.h>
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#include <linux/eventfd.h>
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#include <linux/kernel.h>
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#include <linux/srcu.h>
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#include <linux/slab.h>
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#include <linux/seqlock.h>
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#include <trace/events/kvm.h>
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#include "iodev.h"
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#ifdef CONFIG_HAVE_KVM_IRQFD
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/*
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* --------------------------------------------------------------------
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* irqfd: Allows an fd to be used to inject an interrupt to the guest
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*
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* Credit goes to Avi Kivity for the original idea.
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* --------------------------------------------------------------------
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*/
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/*
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* Resampling irqfds are a special variety of irqfds used to emulate
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* level triggered interrupts. The interrupt is asserted on eventfd
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* trigger. On acknowledgement through the irq ack notifier, the
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* interrupt is de-asserted and userspace is notified through the
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* resamplefd. All resamplers on the same gsi are de-asserted
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* together, so we don't need to track the state of each individual
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* user. We can also therefore share the same irq source ID.
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*/
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struct _irqfd_resampler {
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struct kvm *kvm;
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/*
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* List of resampling struct _irqfd objects sharing this gsi.
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* RCU list modified under kvm->irqfds.resampler_lock
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*/
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struct list_head list;
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struct kvm_irq_ack_notifier notifier;
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/*
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* Entry in list of kvm->irqfd.resampler_list. Use for sharing
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* resamplers among irqfds on the same gsi.
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* Accessed and modified under kvm->irqfds.resampler_lock
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*/
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struct list_head link;
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};
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struct _irqfd {
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/* Used for MSI fast-path */
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struct kvm *kvm;
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wait_queue_t wait;
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/* Update side is protected by irqfds.lock */
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struct kvm_kernel_irq_routing_entry irq_entry;
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seqcount_t irq_entry_sc;
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/* Used for level IRQ fast-path */
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int gsi;
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struct work_struct inject;
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/* The resampler used by this irqfd (resampler-only) */
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struct _irqfd_resampler *resampler;
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/* Eventfd notified on resample (resampler-only) */
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struct eventfd_ctx *resamplefd;
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/* Entry in list of irqfds for a resampler (resampler-only) */
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struct list_head resampler_link;
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/* Used for setup/shutdown */
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struct eventfd_ctx *eventfd;
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struct list_head list;
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poll_table pt;
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struct work_struct shutdown;
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};
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static struct workqueue_struct *irqfd_cleanup_wq;
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static void
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irqfd_inject(struct work_struct *work)
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{
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struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
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struct kvm *kvm = irqfd->kvm;
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if (!irqfd->resampler) {
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kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1,
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false);
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kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0,
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false);
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} else
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kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
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irqfd->gsi, 1, false);
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}
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/*
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* Since resampler irqfds share an IRQ source ID, we de-assert once
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* then notify all of the resampler irqfds using this GSI. We can't
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* do multiple de-asserts or we risk racing with incoming re-asserts.
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*/
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static void
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irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
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{
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struct _irqfd_resampler *resampler;
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struct kvm *kvm;
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struct _irqfd *irqfd;
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int idx;
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resampler = container_of(kian, struct _irqfd_resampler, notifier);
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kvm = resampler->kvm;
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kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
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resampler->notifier.gsi, 0, false);
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idx = srcu_read_lock(&kvm->irq_srcu);
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list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
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eventfd_signal(irqfd->resamplefd, 1);
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srcu_read_unlock(&kvm->irq_srcu, idx);
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}
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static void
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irqfd_resampler_shutdown(struct _irqfd *irqfd)
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{
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struct _irqfd_resampler *resampler = irqfd->resampler;
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struct kvm *kvm = resampler->kvm;
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mutex_lock(&kvm->irqfds.resampler_lock);
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list_del_rcu(&irqfd->resampler_link);
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synchronize_srcu(&kvm->irq_srcu);
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if (list_empty(&resampler->list)) {
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list_del(&resampler->link);
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kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier);
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kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
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resampler->notifier.gsi, 0, false);
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kfree(resampler);
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}
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mutex_unlock(&kvm->irqfds.resampler_lock);
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}
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/*
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* Race-free decouple logic (ordering is critical)
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*/
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static void
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irqfd_shutdown(struct work_struct *work)
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{
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struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
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u64 cnt;
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/*
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* Synchronize with the wait-queue and unhook ourselves to prevent
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* further events.
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*/
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eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
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/*
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* We know no new events will be scheduled at this point, so block
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* until all previously outstanding events have completed
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*/
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flush_work(&irqfd->inject);
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if (irqfd->resampler) {
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irqfd_resampler_shutdown(irqfd);
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eventfd_ctx_put(irqfd->resamplefd);
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}
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/*
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* It is now safe to release the object's resources
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*/
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eventfd_ctx_put(irqfd->eventfd);
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kfree(irqfd);
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}
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/* assumes kvm->irqfds.lock is held */
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static bool
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irqfd_is_active(struct _irqfd *irqfd)
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{
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return list_empty(&irqfd->list) ? false : true;
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}
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/*
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* Mark the irqfd as inactive and schedule it for removal
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*
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* assumes kvm->irqfds.lock is held
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*/
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static void
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irqfd_deactivate(struct _irqfd *irqfd)
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{
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BUG_ON(!irqfd_is_active(irqfd));
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list_del_init(&irqfd->list);
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queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
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}
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/*
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* Called with wqh->lock held and interrupts disabled
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*/
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static int
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irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
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{
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struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait);
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unsigned long flags = (unsigned long)key;
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struct kvm_kernel_irq_routing_entry irq;
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struct kvm *kvm = irqfd->kvm;
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unsigned seq;
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int idx;
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if (flags & POLLIN) {
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idx = srcu_read_lock(&kvm->irq_srcu);
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do {
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seq = read_seqcount_begin(&irqfd->irq_entry_sc);
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irq = irqfd->irq_entry;
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} while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
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/* An event has been signaled, inject an interrupt */
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if (irq.type == KVM_IRQ_ROUTING_MSI)
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kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1,
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false);
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else
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schedule_work(&irqfd->inject);
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srcu_read_unlock(&kvm->irq_srcu, idx);
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}
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if (flags & POLLHUP) {
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/* The eventfd is closing, detach from KVM */
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unsigned long flags;
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spin_lock_irqsave(&kvm->irqfds.lock, flags);
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/*
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* We must check if someone deactivated the irqfd before
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* we could acquire the irqfds.lock since the item is
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* deactivated from the KVM side before it is unhooked from
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* the wait-queue. If it is already deactivated, we can
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* simply return knowing the other side will cleanup for us.
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* We cannot race against the irqfd going away since the
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* other side is required to acquire wqh->lock, which we hold
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*/
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if (irqfd_is_active(irqfd))
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irqfd_deactivate(irqfd);
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spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
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}
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return 0;
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}
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static void
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irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
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poll_table *pt)
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{
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struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt);
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add_wait_queue(wqh, &irqfd->wait);
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}
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/* Must be called under irqfds.lock */
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static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd)
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{
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struct kvm_kernel_irq_routing_entry *e;
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struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS];
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int i, n_entries;
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n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi);
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write_seqcount_begin(&irqfd->irq_entry_sc);
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irqfd->irq_entry.type = 0;
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e = entries;
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for (i = 0; i < n_entries; ++i, ++e) {
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/* Only fast-path MSI. */
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if (e->type == KVM_IRQ_ROUTING_MSI)
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irqfd->irq_entry = *e;
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}
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write_seqcount_end(&irqfd->irq_entry_sc);
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}
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static int
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kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
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{
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struct _irqfd *irqfd, *tmp;
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struct fd f;
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struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
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int ret;
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unsigned int events;
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int idx;
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irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
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if (!irqfd)
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return -ENOMEM;
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irqfd->kvm = kvm;
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irqfd->gsi = args->gsi;
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INIT_LIST_HEAD(&irqfd->list);
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INIT_WORK(&irqfd->inject, irqfd_inject);
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INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
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seqcount_init(&irqfd->irq_entry_sc);
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f = fdget(args->fd);
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if (!f.file) {
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ret = -EBADF;
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goto out;
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}
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eventfd = eventfd_ctx_fileget(f.file);
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if (IS_ERR(eventfd)) {
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ret = PTR_ERR(eventfd);
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goto fail;
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}
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irqfd->eventfd = eventfd;
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if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
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struct _irqfd_resampler *resampler;
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resamplefd = eventfd_ctx_fdget(args->resamplefd);
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if (IS_ERR(resamplefd)) {
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ret = PTR_ERR(resamplefd);
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goto fail;
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}
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irqfd->resamplefd = resamplefd;
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INIT_LIST_HEAD(&irqfd->resampler_link);
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mutex_lock(&kvm->irqfds.resampler_lock);
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list_for_each_entry(resampler,
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&kvm->irqfds.resampler_list, link) {
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if (resampler->notifier.gsi == irqfd->gsi) {
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irqfd->resampler = resampler;
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break;
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}
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}
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if (!irqfd->resampler) {
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resampler = kzalloc(sizeof(*resampler), GFP_KERNEL);
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if (!resampler) {
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ret = -ENOMEM;
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mutex_unlock(&kvm->irqfds.resampler_lock);
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goto fail;
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}
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resampler->kvm = kvm;
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INIT_LIST_HEAD(&resampler->list);
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resampler->notifier.gsi = irqfd->gsi;
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resampler->notifier.irq_acked = irqfd_resampler_ack;
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INIT_LIST_HEAD(&resampler->link);
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list_add(&resampler->link, &kvm->irqfds.resampler_list);
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kvm_register_irq_ack_notifier(kvm,
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&resampler->notifier);
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irqfd->resampler = resampler;
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}
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list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list);
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synchronize_srcu(&kvm->irq_srcu);
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mutex_unlock(&kvm->irqfds.resampler_lock);
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}
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/*
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* Install our own custom wake-up handling so we are notified via
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* a callback whenever someone signals the underlying eventfd
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*/
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init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
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init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
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spin_lock_irq(&kvm->irqfds.lock);
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ret = 0;
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list_for_each_entry(tmp, &kvm->irqfds.items, list) {
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if (irqfd->eventfd != tmp->eventfd)
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continue;
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/* This fd is used for another irq already. */
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ret = -EBUSY;
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spin_unlock_irq(&kvm->irqfds.lock);
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goto fail;
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}
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idx = srcu_read_lock(&kvm->irq_srcu);
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irqfd_update(kvm, irqfd);
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srcu_read_unlock(&kvm->irq_srcu, idx);
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list_add_tail(&irqfd->list, &kvm->irqfds.items);
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spin_unlock_irq(&kvm->irqfds.lock);
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/*
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* Check if there was an event already pending on the eventfd
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* before we registered, and trigger it as if we didn't miss it.
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*/
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events = f.file->f_op->poll(f.file, &irqfd->pt);
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if (events & POLLIN)
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schedule_work(&irqfd->inject);
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/*
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* do not drop the file until the irqfd is fully initialized, otherwise
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* we might race against the POLLHUP
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*/
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fdput(f);
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return 0;
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fail:
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if (irqfd->resampler)
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irqfd_resampler_shutdown(irqfd);
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if (resamplefd && !IS_ERR(resamplefd))
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eventfd_ctx_put(resamplefd);
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if (eventfd && !IS_ERR(eventfd))
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eventfd_ctx_put(eventfd);
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fdput(f);
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out:
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kfree(irqfd);
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return ret;
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}
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bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
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{
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struct kvm_irq_ack_notifier *kian;
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int gsi, idx;
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idx = srcu_read_lock(&kvm->irq_srcu);
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gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
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if (gsi != -1)
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hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
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link)
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if (kian->gsi == gsi) {
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srcu_read_unlock(&kvm->irq_srcu, idx);
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return true;
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}
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srcu_read_unlock(&kvm->irq_srcu, idx);
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return false;
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}
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EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
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void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
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{
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struct kvm_irq_ack_notifier *kian;
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int gsi, idx;
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trace_kvm_ack_irq(irqchip, pin);
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idx = srcu_read_lock(&kvm->irq_srcu);
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gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
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if (gsi != -1)
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hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
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link)
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if (kian->gsi == gsi)
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kian->irq_acked(kian);
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srcu_read_unlock(&kvm->irq_srcu, idx);
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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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mutex_lock(&kvm->irq_lock);
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hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
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mutex_unlock(&kvm->irq_lock);
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kvm_vcpu_request_scan_ioapic(kvm);
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}
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|
void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
|
|
struct kvm_irq_ack_notifier *kian)
|
|
{
|
|
mutex_lock(&kvm->irq_lock);
|
|
hlist_del_init_rcu(&kian->link);
|
|
mutex_unlock(&kvm->irq_lock);
|
|
synchronize_srcu(&kvm->irq_srcu);
|
|
kvm_vcpu_request_scan_ioapic(kvm);
|
|
}
|
|
#endif
|
|
|
|
void
|
|
kvm_eventfd_init(struct kvm *kvm)
|
|
{
|
|
#ifdef CONFIG_HAVE_KVM_IRQFD
|
|
spin_lock_init(&kvm->irqfds.lock);
|
|
INIT_LIST_HEAD(&kvm->irqfds.items);
|
|
INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
|
|
mutex_init(&kvm->irqfds.resampler_lock);
|
|
#endif
|
|
INIT_LIST_HEAD(&kvm->ioeventfds);
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_KVM_IRQFD
|
|
/*
|
|
* shutdown any irqfd's that match fd+gsi
|
|
*/
|
|
static int
|
|
kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
|
|
{
|
|
struct _irqfd *irqfd, *tmp;
|
|
struct eventfd_ctx *eventfd;
|
|
|
|
eventfd = eventfd_ctx_fdget(args->fd);
|
|
if (IS_ERR(eventfd))
|
|
return PTR_ERR(eventfd);
|
|
|
|
spin_lock_irq(&kvm->irqfds.lock);
|
|
|
|
list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
|
|
if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
|
|
/*
|
|
* This clearing of irq_entry.type is needed for when
|
|
* another thread calls kvm_irq_routing_update before
|
|
* we flush workqueue below (we synchronize with
|
|
* kvm_irq_routing_update using irqfds.lock).
|
|
*/
|
|
write_seqcount_begin(&irqfd->irq_entry_sc);
|
|
irqfd->irq_entry.type = 0;
|
|
write_seqcount_end(&irqfd->irq_entry_sc);
|
|
irqfd_deactivate(irqfd);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irq(&kvm->irqfds.lock);
|
|
eventfd_ctx_put(eventfd);
|
|
|
|
/*
|
|
* Block until we know all outstanding shutdown jobs have completed
|
|
* so that we guarantee there will not be any more interrupts on this
|
|
* gsi once this deassign function returns.
|
|
*/
|
|
flush_workqueue(irqfd_cleanup_wq);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
|
|
{
|
|
if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
|
|
return -EINVAL;
|
|
|
|
if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
|
|
return kvm_irqfd_deassign(kvm, args);
|
|
|
|
return kvm_irqfd_assign(kvm, args);
|
|
}
|
|
|
|
/*
|
|
* This function is called as the kvm VM fd is being released. Shutdown all
|
|
* irqfds that still remain open
|
|
*/
|
|
void
|
|
kvm_irqfd_release(struct kvm *kvm)
|
|
{
|
|
struct _irqfd *irqfd, *tmp;
|
|
|
|
spin_lock_irq(&kvm->irqfds.lock);
|
|
|
|
list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
|
|
irqfd_deactivate(irqfd);
|
|
|
|
spin_unlock_irq(&kvm->irqfds.lock);
|
|
|
|
/*
|
|
* Block until we know all outstanding shutdown jobs have completed
|
|
* since we do not take a kvm* reference.
|
|
*/
|
|
flush_workqueue(irqfd_cleanup_wq);
|
|
|
|
}
|
|
|
|
/*
|
|
* Take note of a change in irq routing.
|
|
* Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards.
|
|
*/
|
|
void kvm_irq_routing_update(struct kvm *kvm)
|
|
{
|
|
struct _irqfd *irqfd;
|
|
|
|
spin_lock_irq(&kvm->irqfds.lock);
|
|
|
|
list_for_each_entry(irqfd, &kvm->irqfds.items, list)
|
|
irqfd_update(kvm, irqfd);
|
|
|
|
spin_unlock_irq(&kvm->irqfds.lock);
|
|
}
|
|
|
|
/*
|
|
* create a host-wide workqueue for issuing deferred shutdown requests
|
|
* aggregated from all vm* instances. We need our own isolated single-thread
|
|
* queue to prevent deadlock against flushing the normal work-queue.
|
|
*/
|
|
int kvm_irqfd_init(void)
|
|
{
|
|
irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup");
|
|
if (!irqfd_cleanup_wq)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void kvm_irqfd_exit(void)
|
|
{
|
|
destroy_workqueue(irqfd_cleanup_wq);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* --------------------------------------------------------------------
|
|
* ioeventfd: translate a PIO/MMIO memory write to an eventfd signal.
|
|
*
|
|
* userspace can register a PIO/MMIO address with an eventfd for receiving
|
|
* notification when the memory has been touched.
|
|
* --------------------------------------------------------------------
|
|
*/
|
|
|
|
struct _ioeventfd {
|
|
struct list_head list;
|
|
u64 addr;
|
|
int length;
|
|
struct eventfd_ctx *eventfd;
|
|
u64 datamatch;
|
|
struct kvm_io_device dev;
|
|
u8 bus_idx;
|
|
bool wildcard;
|
|
};
|
|
|
|
static inline struct _ioeventfd *
|
|
to_ioeventfd(struct kvm_io_device *dev)
|
|
{
|
|
return container_of(dev, struct _ioeventfd, dev);
|
|
}
|
|
|
|
static void
|
|
ioeventfd_release(struct _ioeventfd *p)
|
|
{
|
|
eventfd_ctx_put(p->eventfd);
|
|
list_del(&p->list);
|
|
kfree(p);
|
|
}
|
|
|
|
static bool
|
|
ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
|
|
{
|
|
u64 _val;
|
|
|
|
if (addr != p->addr)
|
|
/* address must be precise for a hit */
|
|
return false;
|
|
|
|
if (!p->length)
|
|
/* length = 0 means only look at the address, so always a hit */
|
|
return true;
|
|
|
|
if (len != p->length)
|
|
/* address-range must be precise for a hit */
|
|
return false;
|
|
|
|
if (p->wildcard)
|
|
/* all else equal, wildcard is always a hit */
|
|
return true;
|
|
|
|
/* otherwise, we have to actually compare the data */
|
|
|
|
BUG_ON(!IS_ALIGNED((unsigned long)val, len));
|
|
|
|
switch (len) {
|
|
case 1:
|
|
_val = *(u8 *)val;
|
|
break;
|
|
case 2:
|
|
_val = *(u16 *)val;
|
|
break;
|
|
case 4:
|
|
_val = *(u32 *)val;
|
|
break;
|
|
case 8:
|
|
_val = *(u64 *)val;
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
return _val == p->datamatch ? true : false;
|
|
}
|
|
|
|
/* MMIO/PIO writes trigger an event if the addr/val match */
|
|
static int
|
|
ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len,
|
|
const void *val)
|
|
{
|
|
struct _ioeventfd *p = to_ioeventfd(this);
|
|
|
|
if (!ioeventfd_in_range(p, addr, len, val))
|
|
return -EOPNOTSUPP;
|
|
|
|
eventfd_signal(p->eventfd, 1);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function is called as KVM is completely shutting down. We do not
|
|
* need to worry about locking just nuke anything we have as quickly as possible
|
|
*/
|
|
static void
|
|
ioeventfd_destructor(struct kvm_io_device *this)
|
|
{
|
|
struct _ioeventfd *p = to_ioeventfd(this);
|
|
|
|
ioeventfd_release(p);
|
|
}
|
|
|
|
static const struct kvm_io_device_ops ioeventfd_ops = {
|
|
.write = ioeventfd_write,
|
|
.destructor = ioeventfd_destructor,
|
|
};
|
|
|
|
/* assumes kvm->slots_lock held */
|
|
static bool
|
|
ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
|
|
{
|
|
struct _ioeventfd *_p;
|
|
|
|
list_for_each_entry(_p, &kvm->ioeventfds, list)
|
|
if (_p->bus_idx == p->bus_idx &&
|
|
_p->addr == p->addr &&
|
|
(!_p->length || !p->length ||
|
|
(_p->length == p->length &&
|
|
(_p->wildcard || p->wildcard ||
|
|
_p->datamatch == p->datamatch))))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
|
|
{
|
|
if (flags & KVM_IOEVENTFD_FLAG_PIO)
|
|
return KVM_PIO_BUS;
|
|
if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY)
|
|
return KVM_VIRTIO_CCW_NOTIFY_BUS;
|
|
return KVM_MMIO_BUS;
|
|
}
|
|
|
|
static int
|
|
kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
|
|
{
|
|
enum kvm_bus bus_idx;
|
|
struct _ioeventfd *p;
|
|
struct eventfd_ctx *eventfd;
|
|
int ret;
|
|
|
|
bus_idx = ioeventfd_bus_from_flags(args->flags);
|
|
/* must be natural-word sized, or 0 to ignore length */
|
|
switch (args->len) {
|
|
case 0:
|
|
case 1:
|
|
case 2:
|
|
case 4:
|
|
case 8:
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* check for range overflow */
|
|
if (args->addr + args->len < args->addr)
|
|
return -EINVAL;
|
|
|
|
/* check for extra flags that we don't understand */
|
|
if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
|
|
return -EINVAL;
|
|
|
|
/* ioeventfd with no length can't be combined with DATAMATCH */
|
|
if (!args->len &&
|
|
args->flags & (KVM_IOEVENTFD_FLAG_PIO |
|
|
KVM_IOEVENTFD_FLAG_DATAMATCH))
|
|
return -EINVAL;
|
|
|
|
eventfd = eventfd_ctx_fdget(args->fd);
|
|
if (IS_ERR(eventfd))
|
|
return PTR_ERR(eventfd);
|
|
|
|
p = kzalloc(sizeof(*p), GFP_KERNEL);
|
|
if (!p) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&p->list);
|
|
p->addr = args->addr;
|
|
p->bus_idx = bus_idx;
|
|
p->length = args->len;
|
|
p->eventfd = eventfd;
|
|
|
|
/* The datamatch feature is optional, otherwise this is a wildcard */
|
|
if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
|
|
p->datamatch = args->datamatch;
|
|
else
|
|
p->wildcard = true;
|
|
|
|
mutex_lock(&kvm->slots_lock);
|
|
|
|
/* Verify that there isn't a match already */
|
|
if (ioeventfd_check_collision(kvm, p)) {
|
|
ret = -EEXIST;
|
|
goto unlock_fail;
|
|
}
|
|
|
|
kvm_iodevice_init(&p->dev, &ioeventfd_ops);
|
|
|
|
ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
|
|
&p->dev);
|
|
if (ret < 0)
|
|
goto unlock_fail;
|
|
|
|
/* When length is ignored, MMIO is also put on a separate bus, for
|
|
* faster lookups.
|
|
*/
|
|
if (!args->len && !(args->flags & KVM_IOEVENTFD_FLAG_PIO)) {
|
|
ret = kvm_io_bus_register_dev(kvm, KVM_FAST_MMIO_BUS,
|
|
p->addr, 0, &p->dev);
|
|
if (ret < 0)
|
|
goto register_fail;
|
|
}
|
|
|
|
kvm->buses[bus_idx]->ioeventfd_count++;
|
|
list_add_tail(&p->list, &kvm->ioeventfds);
|
|
|
|
mutex_unlock(&kvm->slots_lock);
|
|
|
|
return 0;
|
|
|
|
register_fail:
|
|
kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
|
|
unlock_fail:
|
|
mutex_unlock(&kvm->slots_lock);
|
|
|
|
fail:
|
|
kfree(p);
|
|
eventfd_ctx_put(eventfd);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
|
|
{
|
|
enum kvm_bus bus_idx;
|
|
struct _ioeventfd *p, *tmp;
|
|
struct eventfd_ctx *eventfd;
|
|
int ret = -ENOENT;
|
|
|
|
bus_idx = ioeventfd_bus_from_flags(args->flags);
|
|
eventfd = eventfd_ctx_fdget(args->fd);
|
|
if (IS_ERR(eventfd))
|
|
return PTR_ERR(eventfd);
|
|
|
|
mutex_lock(&kvm->slots_lock);
|
|
|
|
list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
|
|
bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
|
|
|
|
if (p->bus_idx != bus_idx ||
|
|
p->eventfd != eventfd ||
|
|
p->addr != args->addr ||
|
|
p->length != args->len ||
|
|
p->wildcard != wildcard)
|
|
continue;
|
|
|
|
if (!p->wildcard && p->datamatch != args->datamatch)
|
|
continue;
|
|
|
|
kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
|
|
if (!p->length) {
|
|
kvm_io_bus_unregister_dev(kvm, KVM_FAST_MMIO_BUS,
|
|
&p->dev);
|
|
}
|
|
kvm->buses[bus_idx]->ioeventfd_count--;
|
|
ioeventfd_release(p);
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
mutex_unlock(&kvm->slots_lock);
|
|
|
|
eventfd_ctx_put(eventfd);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
|
|
{
|
|
if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
|
|
return kvm_deassign_ioeventfd(kvm, args);
|
|
|
|
return kvm_assign_ioeventfd(kvm, args);
|
|
}
|