xref: /kernel/linux/linux-5.10/arch/x86/kvm/irq.c (revision 8c2ecf20) 
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
18/*
19 * check if there are pending timer events
20 * to be processed.
21 */
22int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
23{
24	if (lapic_in_kernel(vcpu))
25		return apic_has_pending_timer(vcpu);
26
27	return 0;
28}
29EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
30
31/*
32 * check if there is a pending userspace external interrupt
33 */
34static int pending_userspace_extint(struct kvm_vcpu *v)
35{
36	return v->arch.pending_external_vector != -1;
37}
38
39/*
40 * check if there is pending interrupt from
41 * non-APIC source without intack.
42 */
43int kvm_cpu_has_extint(struct kvm_vcpu *v)
44{
45	/*
46	 * FIXME: interrupt.injected represents an interrupt whose
47	 * side-effects have already been applied (e.g. bit from IRR
48	 * already moved to ISR). Therefore, it is incorrect to rely
49	 * on interrupt.injected to know if there is a pending
50	 * interrupt in the user-mode LAPIC.
51	 * This leads to nVMX/nSVM not be able to distinguish
52	 * if it should exit from L2 to L1 on EXTERNAL_INTERRUPT on
53	 * pending interrupt or should re-inject an injected
54	 * interrupt.
55	 */
56	if (!lapic_in_kernel(v))
57		return v->arch.interrupt.injected;
58
59	if (!kvm_apic_accept_pic_intr(v))
60		return 0;
61
62	if (irqchip_split(v->kvm))
63		return pending_userspace_extint(v);
64	else
65		return v->kvm->arch.vpic->output;
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 */
74int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)
75{
76	if (kvm_cpu_has_extint(v))
77		return 1;
78
79	if (!is_guest_mode(v) && kvm_vcpu_apicv_active(v))
80		return 0;
81
82	return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
83}
84EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);
85
86/*
87 * check if there is pending interrupt without
88 * intack.
89 */
90int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
91{
92	if (kvm_cpu_has_extint(v))
93		return 1;
94
95	return kvm_apic_has_interrupt(v) != -1;	/* LAPIC */
96}
97EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
98
99/*
100 * Read pending interrupt(from non-APIC source)
101 * vector and intack.
102 */
103static int kvm_cpu_get_extint(struct kvm_vcpu *v)
104{
105	if (!kvm_cpu_has_extint(v)) {
106		WARN_ON(!lapic_in_kernel(v));
107		return -1;
108	}
109
110	if (!lapic_in_kernel(v))
111		return v->arch.interrupt.nr;
112
113	if (irqchip_split(v->kvm)) {
114		int vector = v->arch.pending_external_vector;
115
116		v->arch.pending_external_vector = -1;
117		return vector;
118	} else
119		return kvm_pic_read_irq(v->kvm); /* PIC */
120}
121
122/*
123 * Read pending interrupt vector and intack.
124 */
125int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
126{
127	int vector = kvm_cpu_get_extint(v);
128	if (vector != -1)
129		return vector;			/* PIC */
130
131	return kvm_get_apic_interrupt(v);	/* APIC */
132}
133EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
134
135void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
136{
137	if (lapic_in_kernel(vcpu))
138		kvm_inject_apic_timer_irqs(vcpu);
139}
140EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
141
142void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
143{
144	__kvm_migrate_apic_timer(vcpu);
145	__kvm_migrate_pit_timer(vcpu);
146	if (kvm_x86_ops.migrate_timers)
147		kvm_x86_ops.migrate_timers(vcpu);
148}
149
150bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
151{
152	bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
153
154	return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
155}
156