irq.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
 * irq.c: API for in kernel interrupt controller
 * Copyright (c) 2007, Intel Corporation.
 * Copyright 2009 Red Hat, Inc. and/or its affiliates.
 *
 * Authors:
 *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
#include <linux/export.h>
#include <linux/kvm_host.h>
 
#include "irq.h"
#include "i8254.h"
#include "x86.h"
#include "xen.h"
 
/*
 * check if there are pending timer events
 * to be processed.
 */
int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
    int r = 0;
 
    if (lapic_in_kernel(vcpu))
        r = apic_has_pending_timer(vcpu);
    if (kvm_xen_timer_enabled(vcpu))
        r += kvm_xen_has_pending_timer(vcpu);
 
    return r;
}
 
/*
 * check if there is a pending userspace external interrupt
 */
static int pending_userspace_extint(struct kvm_vcpu *v)
{
    return v->arch.pending_external_vector != -1;
}
 
/*
 * check if there is pending interrupt from
 * non-APIC source without intack.
 */
int kvm_cpu_has_extint(struct kvm_vcpu *v)
{
    /*
     * FIXME: interrupt.injected represents an interrupt whose
     * side-effects have already been applied (e.g. bit from IRR
     * already moved to ISR). Therefore, it is incorrect to rely
     * on interrupt.injected to know if there is a pending
     * interrupt in the user-mode LAPIC.
     * This leads to nVMX/nSVM not be able to distinguish
     * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
     * pending interrupt or should re-inject an injected
     * interrupt.
     */
    if (!lapic_in_kernel(v))
        return v->arch.interrupt.injected;
 
    if (kvm_xen_has_interrupt(v))
        return 1;
 
    if (!kvm_apic_accept_pic_intr(v))
        return 0;
 
    if (irqchip_split(v->kvm))
        return pending_userspace_extint(v);
    else
        return v->kvm->arch.vpic->output;
}
 
/*
 * check if there is injectable interrupt:
 * when virtual interrupt delivery enabled,
 * interrupt from apic will handled by hardware,
 * we don't need to check it here.
 */
int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)
{
    if (kvm_cpu_has_extint(v))
        return 1;
 
    if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
        return 0;
 
    return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
}
EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
 
/*
 * check if there is pending interrupt without
 * intack.
 */
int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
{
    if (kvm_cpu_has_extint(v))
        return 1;
 
    return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
}
EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 
/*
 * Read pending interrupt(from non-APIC source)
 * vector and intack.
 */
static int kvm_cpu_get_extint(struct kvm_vcpu *v)
{
    if (!kvm_cpu_has_extint(v)) {
        WARN_ON(!lapic_in_kernel(v));
        return -1;
    }
 
    if (!lapic_in_kernel(v))
        return v->arch.interrupt.nr;
 
#ifdef CONFIG_KVM_XEN
    if (kvm_xen_has_interrupt(v))
        return v->kvm->arch.xen.upcall_vector;
#endif
 
    if (irqchip_split(v->kvm)) {
        int vector = v->arch.pending_external_vector;
 
        v->arch.pending_external_vector = -1;
        return vector;
    } else
        return kvm_pic_read_irq(v->kvm); /* PIC */
}
 
/*
 * Read pending interrupt vector and intack.
 */
int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
{
    int vector = kvm_cpu_get_extint(v);
    if (vector != -1)
        return vector;          /* PIC */
 
    return kvm_get_apic_interrupt(v);   /* APIC */
}
EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 
void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
{
    if (lapic_in_kernel(vcpu))
        kvm_inject_apic_timer_irqs(vcpu);
    if (kvm_xen_timer_enabled(vcpu))
        kvm_xen_inject_timer_irqs(vcpu);
}
 
void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
{
    __kvm_migrate_apic_timer(vcpu);
    __kvm_migrate_pit_timer(vcpu);
    static_call_cond(kvm_x86_migrate_timers)(vcpu);
}
 
bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
{
    bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
 
    return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
}
 
bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
{
    return irqchip_in_kernel(kvm);
}