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