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  */
  23 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
  24 {
  25         int r = 0;
  26
  27         if (lapic_in_kernel(vcpu))
  28                 r = apic_has_pending_timer(vcpu);
  29         if (kvm_xen_timer_enabled(vcpu))
  30                 r += kvm_xen_has_pending_timer(vcpu);
  31
  32         return r;
  33 }
  34 EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
  35
  36 /*
  37  * check if there is a pending userspace external interrupt
  38  */
  39 static int pending_userspace_extint(struct kvm_vcpu *v)
  40 {
  41         return v->arch.pending_external_vector != -1;
  42 }
  43
  44 /*
  45  * check if there is pending interrupt from
  46  * non-APIC source without intack.
  47  */
  48 int kvm_cpu_has_extint(struct kvm_vcpu *v)
  49 {
  50         /*
  51          * FIXME: interrupt.injected represents an interrupt whose
  52          * side-effects have already been applied (e.g. bit from IRR
  53          * already moved to ISR). Therefore, it is incorrect to rely
  54          * on interrupt.injected to know if there is a pending
  55          * interrupt in the user-mode LAPIC.
  56          * This leads to nVMX/nSVM not be able to distinguish
  57          * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
  58          * pending interrupt or should re-inject an injected
  59          * interrupt.
  60          */
  61         if (!lapic_in_kernel(v))
  62                 return v->arch.interrupt.injected;
  63
  64         if (kvm_xen_has_interrupt(v))
  65                 return 1;
  66
  67         if (!kvm_apic_accept_pic_intr(v))
  68                 return 0;
  69
  70         if (irqchip_split(v->kvm))
  71                 return pending_userspace_extint(v);
  72         else
  73                 return v->kvm->arch.vpic->output;
  74 }
  75
  76 /*
  77  * check if there is injectable interrupt:
  78  * when virtual interrupt delivery enabled,
  79  * interrupt from apic will handled by hardware,
  80  * we don't need to check it here.
  81  */
  82 int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)
  83 {
  84         if (kvm_cpu_has_extint(v))
  85                 return 1;
  86
  87         if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
  88                 return 0;
  89
  90         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
  91 }
  92 EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
  93
  94 /*
  95  * check if there is pending interrupt without
  96  * intack.
  97  */
  98 int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
  99 {
 100         if (kvm_cpu_has_extint(v))
 101                 return 1;
 102
 103         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
 104 }
 105 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 106
 107 /*
 108  * Read pending interrupt(from non-APIC source)
 109  * vector and intack.
 110  */
 111 static int kvm_cpu_get_extint(struct kvm_vcpu *v)
 112 {
 113         if (!kvm_cpu_has_extint(v)) {
 114                 WARN_ON(!lapic_in_kernel(v));
 115                 return -1;
 116         }
 117
 118         if (!lapic_in_kernel(v))
 119                 return v->arch.interrupt.nr;
 120
 121         if (kvm_xen_has_interrupt(v))
 122                 return v->kvm->arch.xen.upcall_vector;
 123
 124         if (irqchip_split(v->kvm)) {
 125                 int vector = v->arch.pending_external_vector;
 126
 127                 v->arch.pending_external_vector = -1;
 128                 return vector;
 129         } else
 130                 return kvm_pic_read_irq(v->kvm); /* PIC */
 131 }
 132
 133 /*
 134  * Read pending interrupt vector and intack.
 135  */
 136 int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 137 {
 138         int vector = kvm_cpu_get_extint(v);
 139         if (vector != -1)
 140                 return vector;                  /* PIC */
 141
 142         return kvm_get_apic_interrupt(v);       /* APIC */
 143 }
 144 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 145
 146 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 147 {
 148         if (lapic_in_kernel(vcpu))
 149                 kvm_inject_apic_timer_irqs(vcpu);
 150         if (kvm_xen_timer_enabled(vcpu))
 151                 kvm_xen_inject_timer_irqs(vcpu);
 152 }
 153 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 154
 155 void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 156 {
 157         __kvm_migrate_apic_timer(vcpu);
 158         __kvm_migrate_pit_timer(vcpu);
 159         static_call_cond(kvm_x86_migrate_timers)(vcpu);
 160 }
 161
 162 bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 163 {
 164         bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
 165
 166         return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
 167 }