/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *
 * irqfd: Allows an fd to be used to inject an interrupt to the guest
 * Credit goes to Avi Kivity for the original idea.
 */

#ifndef __LINUX_KVM_IRQFD_H
#define __LINUX_KVM_IRQFD_H

#include <linux/kvm_host.h>
#include <linux/poll.h>

/*
 * Resampling irqfds are a special variety of irqfds used to emulate
 * level triggered interrupts.  The interrupt is asserted on eventfd
 * trigger.  On acknowledgment through the irq ack notifier, the
 * interrupt is de-asserted and userspace is notified through the
 * resamplefd.  All resamplers on the same gsi are de-asserted
 * together, so we don't need to track the state of each individual
 * user.  We can also therefore share the same irq source ID.
 */
struct kvm_kernel_irqfd_resampler {
        struct kvm *kvm;
        /*
         * List of resampling struct _irqfd objects sharing this gsi.
         * RCU list modified under kvm->irqfds.resampler_lock
         */
        struct list_head list;
        struct kvm_irq_ack_notifier notifier;
        /*
         * Entry in list of kvm->irqfd.resampler_list.  Use for sharing
         * resamplers among irqfds on the same gsi.
         * RCU list modified under kvm->irqfds.resampler_lock
         */
        struct list_head link;
};

struct kvm_kernel_irqfd {
        /* Used for MSI fast-path */
        struct kvm *kvm;
        wait_queue_entry_t wait;
        /* Update side is protected by irqfds.lock */
        struct kvm_kernel_irq_routing_entry irq_entry;
        seqcount_spinlock_t irq_entry_sc;
        /* Used for level IRQ fast-path */
        int gsi;
        struct work_struct inject;
        /* The resampler used by this irqfd (resampler-only) */
        struct kvm_kernel_irqfd_resampler *resampler;
        /* Eventfd notified on resample (resampler-only) */
        struct eventfd_ctx *resamplefd;
        /* Entry in list of irqfds for a resampler (resampler-only) */
        struct list_head resampler_link;
        /* Used for setup/shutdown */
        struct eventfd_ctx *eventfd;
        struct list_head list;
        struct work_struct shutdown;
        struct irq_bypass_consumer consumer;
        struct irq_bypass_producer *producer;

        struct kvm_vcpu *irq_bypass_vcpu;
        struct list_head vcpu_list;
        void *irq_bypass_data;
};

#endif /* __LINUX_KVM_IRQFD_H */