include/linux/kvm_irqfd.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *
   4  * irqfd: Allows an fd to be used to inject an interrupt to the guest
   5  * Credit goes to Avi Kivity for the original idea.
   6  */
   7
   8 #ifndef __LINUX_KVM_IRQFD_H
   9 #define __LINUX_KVM_IRQFD_H
  10
  11 #include <linux/kvm_host.h>
  12 #include <linux/poll.h>
  13
  14 /*
  15  * Resampling irqfds are a special variety of irqfds used to emulate
  16  * level triggered interrupts.  The interrupt is asserted on eventfd
  17  * trigger.  On acknowledgment through the irq ack notifier, the
  18  * interrupt is de-asserted and userspace is notified through the
  19  * resamplefd.  All resamplers on the same gsi are de-asserted
  20  * together, so we don't need to track the state of each individual
  21  * user.  We can also therefore share the same irq source ID.
  22  */
  23 struct kvm_kernel_irqfd_resampler {
  24         struct kvm *kvm;
  25         /*
  26          * List of resampling struct _irqfd objects sharing this gsi.
  27          * RCU list modified under kvm->irqfds.resampler_lock
  28          */
  29         struct list_head list;
  30         struct kvm_irq_ack_notifier notifier;
  31         /*
  32          * Entry in list of kvm->irqfd.resampler_list.  Use for sharing
  33          * resamplers among irqfds on the same gsi.
  34          * Accessed and modified under kvm->irqfds.resampler_lock
  35          */
  36         struct list_head link;
  37 };
  38
  39 struct kvm_kernel_irqfd {
  40         /* Used for MSI fast-path */
  41         struct kvm *kvm;
  42         wait_queue_entry_t wait;
  43         /* Update side is protected by irqfds.lock */
  44         struct kvm_kernel_irq_routing_entry irq_entry;
  45         seqcount_spinlock_t irq_entry_sc;
  46         /* Used for level IRQ fast-path */
  47         int gsi;
  48         struct work_struct inject;
  49         /* The resampler used by this irqfd (resampler-only) */
  50         struct kvm_kernel_irqfd_resampler *resampler;
  51         /* Eventfd notified on resample (resampler-only) */
  52         struct eventfd_ctx *resamplefd;
  53         /* Entry in list of irqfds for a resampler (resampler-only) */
  54         struct list_head resampler_link;
  55         /* Used for setup/shutdown */
  56         struct eventfd_ctx *eventfd;
  57         struct list_head list;
  58         poll_table pt;
  59         struct work_struct shutdown;
  60         struct irq_bypass_consumer consumer;
  61         struct irq_bypass_producer *producer;
  62 };
  63
  64 #endif /* __LINUX_KVM_IRQFD_H */