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Linux kernel mirror (for testing)
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kernel
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linux
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 */
24int 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 */
39static 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 */
48int 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 */
82int 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}
92EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
93
94/*
95 * check if there is pending interrupt without
96 * intack.
97 */
98int 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}
105EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
106
107/*
108 * Read pending interrupt(from non-APIC source)
109 * vector and intack.
110 */
111static 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 */
136int 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}
144EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
145
146void 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
154void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
155{
156 __kvm_migrate_apic_timer(vcpu);
157 __kvm_migrate_pit_timer(vcpu);
158 static_call_cond(kvm_x86_migrate_timers)(vcpu);
159}
160
161bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
162{
163 bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
164
165 return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
166}
167
168bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
169{
170 return irqchip_in_kernel(kvm);
171}