xref: /openbmc/linux/drivers/iommu/irq_remapping.c (revision 0c6dfa75)
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 
20 int irq_remapping_enabled;
21 int irq_remap_broken;
22 int disable_sourceid_checking;
23 int no_x2apic_optout;
24 
25 int disable_irq_post = 0;
26 
27 static int disable_irq_remap;
28 static struct irq_remap_ops *remap_ops;
29 
30 static 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(0);
41 }
42 
43 static void __init irq_remapping_modify_x86_ops(void)
44 {
45 	x86_apic_ops.restore = irq_remapping_restore_boot_irq_mode;
46 }
47 
48 static __init int setup_nointremap(char *str)
49 {
50 	disable_irq_remap = 1;
51 	return 0;
52 }
53 early_param("nointremap", setup_nointremap);
54 
55 static __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 }
81 early_param("intremap", setup_irqremap);
82 
83 void set_irq_remapping_broken(void)
84 {
85 	irq_remap_broken = 1;
86 }
87 
88 bool 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 }
95 EXPORT_SYMBOL_GPL(irq_remapping_cap);
96 
97 int __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 
116 int __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 
131 void irq_remapping_disable(void)
132 {
133 	if (irq_remapping_enabled && remap_ops->disable)
134 		remap_ops->disable();
135 }
136 
137 int 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 
145 int __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 
156 void panic_if_irq_remap(const char *msg)
157 {
158 	if (irq_remapping_enabled)
159 		panic(msg);
160 }
161