linux-loongson/include/linux/kvm_irqfd.h
Sean Christopherson 283ed5001d KVM: Use a local struct to do the initial vfs_poll() on an irqfd
Use a function-local struct for the poll_table passed to vfs_poll(), as
nothing in the vfs_poll() callchain grabs a long-term reference to the
structure, i.e. its lifetime doesn't need to be tied to the irqfd.  Using
a local structure will also allow propagating failures out of the polling
callback without further polluting kvm_kernel_irqfd.

Opportunstically rename irqfd_ptable_queue_proc() to kvm_irqfd_register()
to capture what it actually does.

Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250522235223.3178519-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-06-23 09:50:53 -07:00

68 lines
2.1 KiB
C

/* 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 */