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 static 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 EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
  85
  86 /*
  87  * check if there is pending interrupt without
  88  * intack.
  89  */
  90 int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
  91 {
  92         if (kvm_cpu_has_extint(v))
  93                 return 1;
  94
  95         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
  96 }
  97 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
  98
  99 /*
 100  * Read pending interrupt(from non-APIC source)
 101  * vector and intack.
 102  */
 103 static int kvm_cpu_get_extint(struct kvm_vcpu *v)
 104 {
 105         if (!kvm_cpu_has_extint(v)) {
 106                 WARN_ON(!lapic_in_kernel(v));
 107                 return -1;
 108         }
 109
 110         if (!lapic_in_kernel(v))
 111                 return v->arch.interrupt.nr;
 112
 113         if (irqchip_split(v->kvm)) {
 114                 int vector = v->arch.pending_external_vector;
 115
 116                 v->arch.pending_external_vector = -1;
 117                 return vector;
 118         } else
 119                 return kvm_pic_read_irq(v->kvm); /* PIC */
 120 }
 121
 122 /*
 123  * Read pending interrupt vector and intack.
 124  */
 125 int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 126 {
 127         int vector = kvm_cpu_get_extint(v);
 128         if (vector != -1)
 129                 return vector;                  /* PIC */
 130
 131         return kvm_get_apic_interrupt(v);       /* APIC */
 132 }
 133 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 134
 135 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 136 {
 137         if (lapic_in_kernel(vcpu))
 138                 kvm_inject_apic_timer_irqs(vcpu);
 139 }
 140 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 141
 142 void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 143 {
 144         __kvm_migrate_apic_timer(vcpu);
 145         __kvm_migrate_pit_timer(vcpu);
 146         if (kvm_x86_ops.migrate_timers)
 147                 kvm_x86_ops.migrate_timers(vcpu);
 148 }
 149
 150 bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 151 {
 152         bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
 153
 154         return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
 155 }