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#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 */
138int 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}
146EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
147
148void 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
156void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
157{
158	__kvm_migrate_apic_timer(vcpu);
159	__kvm_migrate_pit_timer(vcpu);
160	static_call_cond(kvm_x86_migrate_timers)(vcpu);
161}
162
163bool 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
170bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
171{
172	return irqchip_in_kernel(kvm);
173}
174