LXR linux/arch/x86/kvm/irq.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * irq.c: API for in kernel interrupt controller
   4 * Copyright (c) 2007, Intel Corporation.
   5 * Copyright 2009 Red Hat, Inc. and/or its affiliates.
   6 *
   7 * Authors:
   8 *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
   9 */
  10
  11#include <linux/export.h>
  12#include <linux/kvm_host.h>
  13
  14#include "irq.h"
  15#include "i8254.h"
  16#include "x86.h"
  17
  18/*
  19 * check if there are pending timer events
  20 * to be processed.
  21 */
  22int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
  23{
  24        if (lapic_in_kernel(vcpu))
  25                return apic_has_pending_timer(vcpu);
  26
  27        return 0;
  28}
  29EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
  30
  31/*
  32 * check if there is a pending userspace external interrupt
  33 */
  34static int pending_userspace_extint(struct kvm_vcpu *v)
  35{
  36        return v->arch.pending_external_vector != -1;
  37}
  38
  39/*
  40 * check if there is pending interrupt from
  41 * non-APIC source without intack.
  42 */
  43static int kvm_cpu_has_extint(struct kvm_vcpu *v)
  44{
  45        u8 accept = kvm_apic_accept_pic_intr(v);
  46
  47        if (accept) {
  48                if (irqchip_split(v->kvm))
  49                        return pending_userspace_extint(v);
  50                else
  51                        return v->kvm->arch.vpic->output;
  52        } else
  53                return 0;
  54}
  55
  56/*
  57 * check if there is injectable interrupt:
  58 * when virtual interrupt delivery enabled,
  59 * interrupt from apic will handled by hardware,
  60 * we don't need to check it here.
  61 */
  62int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)
  63{
  64        /*
  65         * FIXME: interrupt.injected represents an interrupt that it's
  66         * side-effects have already been applied (e.g. bit from IRR
  67         * already moved to ISR). Therefore, it is incorrect to rely
  68         * on interrupt.injected to know if there is a pending
  69         * interrupt in the user-mode LAPIC.
  70         * This leads to nVMX/nSVM not be able to distinguish
  71         * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
  72         * pending interrupt or should re-inject an injected
  73         * interrupt.
  74         */
  75        if (!lapic_in_kernel(v))
  76                return v->arch.interrupt.injected;
  77
  78        if (kvm_cpu_has_extint(v))
  79                return 1;
  80
  81        if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
  82                return 0;
  83
  84        return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
  85}
  86
  87/*
  88 * check if there is pending interrupt without
  89 * intack.
  90 */
  91int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
  92{
  93        /*
  94         * FIXME: interrupt.injected represents an interrupt that it's
  95         * side-effects have already been applied (e.g. bit from IRR
  96         * already moved to ISR). Therefore, it is incorrect to rely
  97         * on interrupt.injected to know if there is a pending
  98         * interrupt in the user-mode LAPIC.
  99         * This leads to nVMX/nSVM not be able to distinguish
 100         * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
 101         * pending interrupt or should re-inject an injected
 102         * interrupt.
 103         */
 104        if (!lapic_in_kernel(v))
 105                return v->arch.interrupt.injected;
 106
 107        if (kvm_cpu_has_extint(v))
 108                return 1;
 109
 110        return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
 111}
 112EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 113
 114/*
 115 * Read pending interrupt(from non-APIC source)
 116 * vector and intack.
 117 */
 118static int kvm_cpu_get_extint(struct kvm_vcpu *v)
 119{
 120        if (kvm_cpu_has_extint(v)) {
 121                if (irqchip_split(v->kvm)) {
 122                        int vector = v->arch.pending_external_vector;
 123
 124                        v->arch.pending_external_vector = -1;
 125                        return vector;
 126                } else
 127                        return kvm_pic_read_irq(v->kvm); /* PIC */
 128        } else
 129                return -1;
 130}
 131
 132/*
 133 * Read pending interrupt vector and intack.
 134 */
 135int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 136{
 137        int vector;
 138
 139        if (!lapic_in_kernel(v))
 140                return v->arch.interrupt.nr;
 141
 142        vector = kvm_cpu_get_extint(v);
 143
 144        if (vector != -1)
 145                return vector;                  /* PIC */
 146
 147        return kvm_get_apic_interrupt(v);       /* APIC */
 148}
 149EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 150
 151void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 152{
 153        if (lapic_in_kernel(vcpu))
 154                kvm_inject_apic_timer_irqs(vcpu);
 155}
 156EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 157
 158void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 159{
 160        __kvm_migrate_apic_timer(vcpu);
 161        __kvm_migrate_pit_timer(vcpu);
 162}
 163
 164bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 165{
 166        bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
 167
 168        return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
 169}
 170