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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/export.h>
13 #include <linux/kvm_host.h>
14
15 #include "irq.h"
16 #include "i8254.h"
17 #include "x86.h"
18 #include "xen.h"
19
20 /*
21 * check if there are pending timer events
22 * to be processed.
23 */
24 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
25 {
26 int r = 0;
27
28 if (lapic_in_kernel(vcpu))
29 r = apic_has_pending_timer(vcpu);
30 if (kvm_xen_timer_enabled(vcpu))
31 r += kvm_xen_has_pending_timer(vcpu);
32
33 return r;
34 }
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 #ifdef CONFIG_KVM_XEN
122 if (kvm_xen_has_interrupt(v))
123 return v->kvm->arch.xen.upcall_vector;
124 #endif
125
126 if (irqchip_split(v->kvm)) {
127 int vector = v->arch.pending_external_vector;
128
129 v->arch.pending_external_vector = -1;
130 return vector;
131 } else
132 return kvm_pic_read_irq(v->kvm); /* PIC */
133 }
134
135 /*
136 * Read pending interrupt vector and intack.
137 */
138 int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
139 {
140 int vector = kvm_cpu_get_extint(v);
141 if (vector != -1)
142 return vector; /* PIC */
143
144 return kvm_get_apic_interrupt(v); /* APIC */
145 }
146 EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
147
148 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
149 {
150 if (lapic_in_kernel(vcpu))
151 kvm_inject_apic_timer_irqs(vcpu);
152 if (kvm_xen_timer_enabled(vcpu))
153 kvm_xen_inject_timer_irqs(vcpu);
154 }
155
156 void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
157 {
158 __kvm_migrate_apic_timer(vcpu);
159 __kvm_migrate_pit_timer(vcpu);
160 kvm_x86_call(migrate_timers)(vcpu);
161 }
162
163 bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
164 {
165 bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
166
167 return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
168 }
169
170 bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
171 {
172 return irqchip_in_kernel(kvm);
173 }
174
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