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#include "xen.h"
  18
  19/*
  20 * check if there are pending timer events
  21 * to be processed.
  22 */
  23int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
  24{
  25        if (lapic_in_kernel(vcpu))
  26                return apic_has_pending_timer(vcpu);
  27
  28        return 0;
  29}
  30EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
  31
  32/*
  33 * check if there is a pending userspace external interrupt
  34 */
  35static int pending_userspace_extint(struct kvm_vcpu *v)
  36{
  37        return v->arch.pending_external_vector != -1;
  38}
  39
  40/*
  41 * check if there is pending interrupt from
  42 * non-APIC source without intack.
  43 */
  44int kvm_cpu_has_extint(struct kvm_vcpu *v)
  45{
  46        /*
  47         * FIXME: interrupt.injected represents an interrupt whose
  48         * side-effects have already been applied (e.g. bit from IRR
  49         * already moved to ISR). Therefore, it is incorrect to rely
  50         * on interrupt.injected to know if there is a pending
  51         * interrupt in the user-mode LAPIC.
  52         * This leads to nVMX/nSVM not be able to distinguish
  53         * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
  54         * pending interrupt or should re-inject an injected
  55         * interrupt.
  56         */
  57        if (!lapic_in_kernel(v))
  58                return v->arch.interrupt.injected;
  59
  60        if (kvm_xen_has_interrupt(v))
  61                return 1;
  62
  63        if (!kvm_apic_accept_pic_intr(v))
  64                return 0;
  65
  66        if (irqchip_split(v->kvm))
  67                return pending_userspace_extint(v);
  68        else
  69                return v->kvm->arch.vpic->output;
  70}
  71
  72/*
  73 * check if there is injectable interrupt:
  74 * when virtual interrupt delivery enabled,
  75 * interrupt from apic will handled by hardware,
  76 * we don't need to check it here.
  77 */
  78int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)
  79{
  80        if (kvm_cpu_has_extint(v))
  81                return 1;
  82
  83        if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
  84                return 0;
  85
  86        return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
  87}
  88EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
  89
  90/*
  91 * check if there is pending interrupt without
  92 * intack.
  93 */
  94int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
  95{
  96        if (kvm_cpu_has_extint(v))
  97                return 1;
  98
  99        return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
 100}
 101EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 102
 103/*
 104 * Read pending interrupt(from non-APIC source)
 105 * vector and intack.
 106 */
 107static int kvm_cpu_get_extint(struct kvm_vcpu *v)
 108{
 109        if (!kvm_cpu_has_extint(v)) {
 110                WARN_ON(!lapic_in_kernel(v));
 111                return -1;
 112        }
 113
 114        if (!lapic_in_kernel(v))
 115                return v->arch.interrupt.nr;
 116
 117        if (kvm_xen_has_interrupt(v))
 118                return v->kvm->arch.xen.upcall_vector;
 119
 120        if (irqchip_split(v->kvm)) {
 121                int vector = v->arch.pending_external_vector;
 122
 123                v->arch.pending_external_vector = -1;
 124                return vector;
 125        } else
 126                return kvm_pic_read_irq(v->kvm); /* PIC */
 127}
 128
 129/*
 130 * Read pending interrupt vector and intack.
 131 */
 132int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 133{
 134        int vector = kvm_cpu_get_extint(v);
 135        if (vector != -1)
 136                return vector;                  /* PIC */
 137
 138        return kvm_get_apic_interrupt(v);       /* APIC */
 139}
 140EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 141
 142void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 143{
 144        if (lapic_in_kernel(vcpu))
 145                kvm_inject_apic_timer_irqs(vcpu);
 146}
 147EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 148
 149void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 150{
 151        __kvm_migrate_apic_timer(vcpu);
 152        __kvm_migrate_pit_timer(vcpu);
 153        static_call_cond(kvm_x86_migrate_timers)(vcpu);
 154}
 155
 156bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 157{
 158        bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
 159
 160        return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
 161}
 162