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
  35 /*
  36  * check if there is a pending userspace external interrupt
  37  */
  38 static int pending_userspace_extint(struct kvm_vcpu *v)
  39 {
  40         return v->arch.pending_external_vector != -1;
  41 }
  42
  43 /*
  44  * check if there is pending interrupt from
  45  * non-APIC source without intack.
  46  */
  47 int kvm_cpu_has_extint(struct kvm_vcpu *v)
  48 {
  49         /*
  50          * FIXME: interrupt.injected represents an interrupt whose
  51          * side-effects have already been applied (e.g. bit from IRR
  52          * already moved to ISR). Therefore, it is incorrect to rely
  53          * on interrupt.injected to know if there is a pending
  54          * interrupt in the user-mode LAPIC.
  55          * This leads to nVMX/nSVM not be able to distinguish
  56          * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
  57          * pending interrupt or should re-inject an injected
  58          * interrupt.
  59          */
  60         if (!lapic_in_kernel(v))
  61                 return v->arch.interrupt.injected;
  62
  63         if (kvm_xen_has_interrupt(v))
  64                 return 1;
  65
  66         if (!kvm_apic_accept_pic_intr(v))
  67                 return 0;
  68
  69         if (irqchip_split(v->kvm))
  70                 return pending_userspace_extint(v);
  71         else
  72                 return v->kvm->arch.vpic->output;
  73 }
  74
  75 /*
  76  * check if there is injectable interrupt:
  77  * when virtual interrupt delivery enabled,
  78  * interrupt from apic will handled by hardware,
  79  * we don't need to check it here.
  80  */
  81 int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)
  82 {
  83         if (kvm_cpu_has_extint(v))
  84                 return 1;
  85
  86         if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
  87                 return 0;
  88
  89         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
  90 }
  91 EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
  92
  93 /*
  94  * check if there is pending interrupt without
  95  * intack.
  96  */
  97 int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
  98 {
  99         if (kvm_cpu_has_extint(v))
 100                 return 1;
 101
 102         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
 103 }
 104 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 105
 106 /*
 107  * Read pending interrupt(from non-APIC source)
 108  * vector and intack.
 109  */
 110 static int kvm_cpu_get_extint(struct kvm_vcpu *v)
 111 {
 112         if (!kvm_cpu_has_extint(v)) {
 113                 WARN_ON(!lapic_in_kernel(v));
 114                 return -1;
 115         }
 116
 117         if (!lapic_in_kernel(v))
 118                 return v->arch.interrupt.nr;
 119
 120         if (kvm_xen_has_interrupt(v))
 121                 return v->kvm->arch.xen.upcall_vector;
 122
 123         if (irqchip_split(v->kvm)) {
 124                 int vector = v->arch.pending_external_vector;
 125
 126                 v->arch.pending_external_vector = -1;
 127                 return vector;
 128         } else
 129                 return kvm_pic_read_irq(v->kvm); /* PIC */
 130 }
 131
 132 /*
 133  * Read pending interrupt vector and intack.
 134  */
 135 int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 136 {
 137         int vector = kvm_cpu_get_extint(v);
 138         if (vector != -1)
 139                 return vector;                  /* PIC */
 140
 141         return kvm_get_apic_interrupt(v);       /* APIC */
 142 }
 143 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 144
 145 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 146 {
 147         if (lapic_in_kernel(vcpu))
 148                 kvm_inject_apic_timer_irqs(vcpu);
 149         if (kvm_xen_timer_enabled(vcpu))
 150                 kvm_xen_inject_timer_irqs(vcpu);
 151 }
 152
 153 void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 154 {
 155         __kvm_migrate_apic_timer(vcpu);
 156         __kvm_migrate_pit_timer(vcpu);
 157         static_call_cond(kvm_x86_migrate_timers)(vcpu);
 158 }
 159
 160 bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 161 {
 162         bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
 163
 164         return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
 165 }
 166
 167 bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
 168 {
 169         return irqchip_in_kernel(kvm);
 170 }