include/linux/kvm_irqfd.h

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * irqfd: Allows an fd to be used to inject an interrupt to the guest
  12  * Credit goes to Avi Kivity for the original idea.
  13  */
  14
  15 #ifndef __LINUX_KVM_IRQFD_H
  16 #define __LINUX_KVM_IRQFD_H
  17
  18 #include <linux/kvm_host.h>
  19 #include <linux/poll.h>
  20
  21 /*
  22  * Resampling irqfds are a special variety of irqfds used to emulate
  23  * level triggered interrupts.  The interrupt is asserted on eventfd
  24  * trigger.  On acknowledgment through the irq ack notifier, the
  25  * interrupt is de-asserted and userspace is notified through the
  26  * resamplefd.  All resamplers on the same gsi are de-asserted
  27  * together, so we don't need to track the state of each individual
  28  * user.  We can also therefore share the same irq source ID.
  29  */
  30 struct kvm_kernel_irqfd_resampler {
  31         struct kvm *kvm;
  32         /*
  33          * List of resampling struct _irqfd objects sharing this gsi.
  34          * RCU list modified under kvm->irqfds.resampler_lock
  35          */
  36         struct list_head list;
  37         struct kvm_irq_ack_notifier notifier;
  38         /*
  39          * Entry in list of kvm->irqfd.resampler_list.  Use for sharing
  40          * resamplers among irqfds on the same gsi.
  41          * Accessed and modified under kvm->irqfds.resampler_lock
  42          */
  43         struct list_head link;
  44 };
  45
  46 struct kvm_kernel_irqfd {
  47         /* Used for MSI fast-path */
  48         struct kvm *kvm;
  49         wait_queue_entry_t wait;
  50         /* Update side is protected by irqfds.lock */
  51         struct kvm_kernel_irq_routing_entry irq_entry;
  52         seqcount_t irq_entry_sc;
  53         /* Used for level IRQ fast-path */
  54         int gsi;
  55         struct work_struct inject;
  56         /* The resampler used by this irqfd (resampler-only) */
  57         struct kvm_kernel_irqfd_resampler *resampler;
  58         /* Eventfd notified on resample (resampler-only) */
  59         struct eventfd_ctx *resamplefd;
  60         /* Entry in list of irqfds for a resampler (resampler-only) */
  61         struct list_head resampler_link;
  62         /* Used for setup/shutdown */
  63         struct eventfd_ctx *eventfd;
  64         struct list_head list;
  65         poll_table pt;
  66         struct work_struct shutdown;
  67         struct irq_bypass_consumer consumer;
  68         struct irq_bypass_producer *producer;
  69 };
  70
  71 #endif /* __LINUX_KVM_IRQFD_H */