arch/x86/kvm/irq.c

   1 /*
   2  * irq.c: API for in kernel interrupt controller
   3  * Copyright (c) 2007, Intel Corporation.
   4  * Copyright 2009 Red Hat, Inc. and/or its affiliates.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  17  * Place - Suite 330, Boston, MA 02111-1307 USA.
  18  * Authors:
  19  *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
  20  *
  21  */
  22
  23 #include <linux/export.h>
  24 #include <linux/kvm_host.h>
  25
  26 #include "irq.h"
  27 #include "i8254.h"
  28 #include "x86.h"
  29
  30 /*
  31  * check if there are pending timer events
  32  * to be processed.
  33  */
  34 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
  35 {
  36         if (lapic_in_kernel(vcpu))
  37                 return apic_has_pending_timer(vcpu);
  38
  39         return 0;
  40 }
  41 EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
  42
  43 /*
  44  * check if there is a pending userspace external interrupt
  45  */
  46 static int pending_userspace_extint(struct kvm_vcpu *v)
  47 {
  48         return v->arch.pending_external_vector != -1;
  49 }
  50
  51 /*
  52  * check if there is pending interrupt from
  53  * non-APIC source without intack.
  54  */
  55 static int kvm_cpu_has_extint(struct kvm_vcpu *v)
  56 {
  57         u8 accept = kvm_apic_accept_pic_intr(v);
  58
  59         if (accept) {
  60                 if (irqchip_split(v->kvm))
  61                         return pending_userspace_extint(v);
  62                 else
  63                         return v->kvm->arch.vpic->output;
  64         } else
  65                 return 0;
  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         /*
  77          * FIXME: interrupt.injected represents an interrupt that it's
  78          * side-effects have already been applied (e.g. bit from IRR
  79          * already moved to ISR). Therefore, it is incorrect to rely
  80          * on interrupt.injected to know if there is a pending
  81          * interrupt in the user-mode LAPIC.
  82          * This leads to nVMX/nSVM not be able to distinguish
  83          * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
  84          * pending interrupt or should re-inject an injected
  85          * interrupt.
  86          */
  87         if (!lapic_in_kernel(v))
  88                 return v->arch.interrupt.injected;
  89
  90         if (kvm_cpu_has_extint(v))
  91                 return 1;
  92
  93         if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
  94                 return 0;
  95
  96         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
  97 }
  98
  99 /*
 100  * check if there is pending interrupt without
 101  * intack.
 102  */
 103 int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
 104 {
 105         /*
 106          * FIXME: interrupt.injected represents an interrupt that it's
 107          * side-effects have already been applied (e.g. bit from IRR
 108          * already moved to ISR). Therefore, it is incorrect to rely
 109          * on interrupt.injected to know if there is a pending
 110          * interrupt in the user-mode LAPIC.
 111          * This leads to nVMX/nSVM not be able to distinguish
 112          * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
 113          * pending interrupt or should re-inject an injected
 114          * interrupt.
 115          */
 116         if (!lapic_in_kernel(v))
 117                 return v->arch.interrupt.injected;
 118
 119         if (kvm_cpu_has_extint(v))
 120                 return 1;
 121
 122         return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
 123 }
 124 EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
 125
 126 /*
 127  * Read pending interrupt(from non-APIC source)
 128  * vector and intack.
 129  */
 130 static int kvm_cpu_get_extint(struct kvm_vcpu *v)
 131 {
 132         if (kvm_cpu_has_extint(v)) {
 133                 if (irqchip_split(v->kvm)) {
 134                         int vector = v->arch.pending_external_vector;
 135
 136                         v->arch.pending_external_vector = -1;
 137                         return vector;
 138                 } else
 139                         return kvm_pic_read_irq(v->kvm); /* PIC */
 140         } else
 141                 return -1;
 142 }
 143
 144 /*
 145  * Read pending interrupt vector and intack.
 146  */
 147 int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
 148 {
 149         int vector;
 150
 151         if (!lapic_in_kernel(v))
 152                 return v->arch.interrupt.nr;
 153
 154         vector = kvm_cpu_get_extint(v);
 155
 156         if (vector != -1)
 157                 return vector;                  /* PIC */
 158
 159         return kvm_get_apic_interrupt(v);       /* APIC */
 160 }
 161 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
 162
 163 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
 164 {
 165         if (lapic_in_kernel(vcpu))
 166                 kvm_inject_apic_timer_irqs(vcpu);
 167 }
 168 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 169
 170 void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 171 {
 172         __kvm_migrate_apic_timer(vcpu);
 173         __kvm_migrate_pit_timer(vcpu);
 174 }