1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/cpumask.h>
3#include <linux/kernel.h>
4#include <linux/string.h>
5#include <linux/errno.h>
6#include <linux/msi.h>
7#include <linux/irq.h>
8#include <linux/pci.h>
9#include <linux/irqdomain.h>
10
11#include <asm/hw_irq.h>
12#include <asm/irq_remapping.h>
13#include <asm/processor.h>
14#include <asm/x86_init.h>
15#include <asm/apic.h>
16#include <asm/hpet.h>
17
18#include "irq_remapping.h"
19
20int irq_remapping_enabled;
21int irq_remap_broken;
22int disable_sourceid_checking;
23int no_x2apic_optout;
24
25int disable_irq_post = 0;
26
27static int disable_irq_remap;
28static struct irq_remap_ops *remap_ops;
29
30static void irq_remapping_restore_boot_irq_mode(void)
31{
32 /*
33 * With interrupt-remapping, for now we will use virtual wire A
34 * mode, as virtual wire B is little complex (need to configure
35 * both IOAPIC RTE as well as interrupt-remapping table entry).
36 * As this gets called during crash dump, keep this simple for
37 * now.
38 */
39 if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
40 disconnect_bsp_APIC(virt_wire_setup: 0);
41}
42
43static void __init irq_remapping_modify_x86_ops(void)
44{
45 x86_apic_ops.restore = irq_remapping_restore_boot_irq_mode;
46}
47
48static __init int setup_nointremap(char *str)
49{
50 disable_irq_remap = 1;
51 return 0;
52}
53early_param("nointremap", setup_nointremap);
54
55static __init int setup_irqremap(char *str)
56{
57 if (!str)
58 return -EINVAL;
59
60 while (*str) {
61 if (!strncmp(str, "on", 2)) {
62 disable_irq_remap = 0;
63 disable_irq_post = 0;
64 } else if (!strncmp(str, "off", 3)) {
65 disable_irq_remap = 1;
66 disable_irq_post = 1;
67 } else if (!strncmp(str, "nosid", 5))
68 disable_sourceid_checking = 1;
69 else if (!strncmp(str, "no_x2apic_optout", 16))
70 no_x2apic_optout = 1;
71 else if (!strncmp(str, "nopost", 6))
72 disable_irq_post = 1;
73
74 str += strcspn(str, ",");
75 while (*str == ',')
76 str++;
77 }
78
79 return 0;
80}
81early_param("intremap", setup_irqremap);
82
83void set_irq_remapping_broken(void)
84{
85 irq_remap_broken = 1;
86}
87
88bool irq_remapping_cap(enum irq_remap_cap cap)
89{
90 if (!remap_ops || disable_irq_post)
91 return false;
92
93 return (remap_ops->capability & (1 << cap));
94}
95EXPORT_SYMBOL_GPL(irq_remapping_cap);
96
97int __init irq_remapping_prepare(void)
98{
99 if (disable_irq_remap)
100 return -ENOSYS;
101
102 if (intel_irq_remap_ops.prepare() == 0)
103 remap_ops = &intel_irq_remap_ops;
104 else if (IS_ENABLED(CONFIG_AMD_IOMMU) &&
105 amd_iommu_irq_ops.prepare() == 0)
106 remap_ops = &amd_iommu_irq_ops;
107 else if (IS_ENABLED(CONFIG_HYPERV_IOMMU) &&
108 hyperv_irq_remap_ops.prepare() == 0)
109 remap_ops = &hyperv_irq_remap_ops;
110 else
111 return -ENOSYS;
112
113 return 0;
114}
115
116int __init irq_remapping_enable(void)
117{
118 int ret;
119
120 if (!remap_ops->enable)
121 return -ENODEV;
122
123 ret = remap_ops->enable();
124
125 if (irq_remapping_enabled)
126 irq_remapping_modify_x86_ops();
127
128 return ret;
129}
130
131void irq_remapping_disable(void)
132{
133 if (irq_remapping_enabled && remap_ops->disable)
134 remap_ops->disable();
135}
136
137int irq_remapping_reenable(int mode)
138{
139 if (irq_remapping_enabled && remap_ops->reenable)
140 return remap_ops->reenable(mode);
141
142 return 0;
143}
144
145int __init irq_remap_enable_fault_handling(void)
146{
147 if (!irq_remapping_enabled)
148 return 0;
149
150 if (!remap_ops->enable_faulting)
151 return -ENODEV;
152
153 return remap_ops->enable_faulting();
154}
155
156void panic_if_irq_remap(const char *msg)
157{
158 if (irq_remapping_enabled)
159 panic(fmt: msg);
160}
161

source code of linux/drivers/iommu/irq_remapping.c