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         if (lapic_in_kernel(vcpu))
  26                 return apic_has_pending_timer(vcpu);
  27
  28         return 0;
  29 }
  30 EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
  31
  32 /*
  33  * check if there is a pending userspace external interrupt
  34  */
  35 static 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  */
  44 int 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  */
  78 int 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 }
  88 EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
  89
  90 /*
  91  * check if there is pending interrupt without
  92  * intack.
  93  */
  94 int 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 }
 101 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 102
 103 /*
 104  * Read pending interrupt(from non-APIC source)
 105  * vector and intack.
 106  */
 107 static 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  */
 132 int 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 }
 140 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 141
 142 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 143 {
 144         if (lapic_in_kernel(vcpu))
 145                 kvm_inject_apic_timer_irqs(vcpu);
 146 }
 147 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 148
 149 void __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
 156 bool 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 }