drivers/iommu/irq_remapping.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 #include <linux/cpumask.h>
0003 #include <linux/kernel.h>
0004 #include <linux/string.h>
0005 #include <linux/errno.h>
0006 #include <linux/msi.h>
0007 #include <linux/irq.h>
0008 #include <linux/pci.h>
0009 #include <linux/irqdomain.h>
0010
0011 #include <asm/hw_irq.h>
0012 #include <asm/irq_remapping.h>
0013 #include <asm/processor.h>
0014 #include <asm/x86_init.h>
0015 #include <asm/apic.h>
0016 #include <asm/hpet.h>
0017
0018 #include "irq_remapping.h"
0019
0020 int irq_remapping_enabled;
0021 int irq_remap_broken;
0022 int disable_sourceid_checking;
0023 int no_x2apic_optout;
0024
0025 int disable_irq_post = 0;
0026
0027 static int disable_irq_remap;
0028 static struct irq_remap_ops *remap_ops;
0029
0030 static void irq_remapping_restore_boot_irq_mode(void)
0031 {
0032     /*
0033      * With interrupt-remapping, for now we will use virtual wire A
0034      * mode, as virtual wire B is little complex (need to configure
0035      * both IOAPIC RTE as well as interrupt-remapping table entry).
0036      * As this gets called during crash dump, keep this simple for
0037      * now.
0038      */
0039     if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
0040         disconnect_bsp_APIC(0);
0041 }
0042
0043 static void __init irq_remapping_modify_x86_ops(void)
0044 {
0045     x86_apic_ops.restore = irq_remapping_restore_boot_irq_mode;
0046 }
0047
0048 static __init int setup_nointremap(char *str)
0049 {
0050     disable_irq_remap = 1;
0051     return 0;
0052 }
0053 early_param("nointremap", setup_nointremap);
0054
0055 static __init int setup_irqremap(char *str)
0056 {
0057     if (!str)
0058         return -EINVAL;
0059
0060     while (*str) {
0061         if (!strncmp(str, "on", 2)) {
0062             disable_irq_remap = 0;
0063             disable_irq_post = 0;
0064         } else if (!strncmp(str, "off", 3)) {
0065             disable_irq_remap = 1;
0066             disable_irq_post = 1;
0067         } else if (!strncmp(str, "nosid", 5))
0068             disable_sourceid_checking = 1;
0069         else if (!strncmp(str, "no_x2apic_optout", 16))
0070             no_x2apic_optout = 1;
0071         else if (!strncmp(str, "nopost", 6))
0072             disable_irq_post = 1;
0073
0074         str += strcspn(str, ",");
0075         while (*str == ',')
0076             str++;
0077     }
0078
0079     return 0;
0080 }
0081 early_param("intremap", setup_irqremap);
0082
0083 void set_irq_remapping_broken(void)
0084 {
0085     irq_remap_broken = 1;
0086 }
0087
0088 bool irq_remapping_cap(enum irq_remap_cap cap)
0089 {
0090     if (!remap_ops || disable_irq_post)
0091         return false;
0092
0093     return (remap_ops->capability & (1 << cap));
0094 }
0095 EXPORT_SYMBOL_GPL(irq_remapping_cap);
0096
0097 int __init irq_remapping_prepare(void)
0098 {
0099     if (disable_irq_remap)
0100         return -ENOSYS;
0101
0102     if (intel_irq_remap_ops.prepare() == 0)
0103         remap_ops = &intel_irq_remap_ops;
0104     else if (IS_ENABLED(CONFIG_AMD_IOMMU) &&
0105          amd_iommu_irq_ops.prepare() == 0)
0106         remap_ops = &amd_iommu_irq_ops;
0107     else if (IS_ENABLED(CONFIG_HYPERV_IOMMU) &&
0108          hyperv_irq_remap_ops.prepare() == 0)
0109         remap_ops = &hyperv_irq_remap_ops;
0110     else
0111         return -ENOSYS;
0112
0113     return 0;
0114 }
0115
0116 int __init irq_remapping_enable(void)
0117 {
0118     int ret;
0119
0120     if (!remap_ops->enable)
0121         return -ENODEV;
0122
0123     ret = remap_ops->enable();
0124
0125     if (irq_remapping_enabled)
0126         irq_remapping_modify_x86_ops();
0127
0128     return ret;
0129 }
0130
0131 void irq_remapping_disable(void)
0132 {
0133     if (irq_remapping_enabled && remap_ops->disable)
0134         remap_ops->disable();
0135 }
0136
0137 int irq_remapping_reenable(int mode)
0138 {
0139     if (irq_remapping_enabled && remap_ops->reenable)
0140         return remap_ops->reenable(mode);
0141
0142     return 0;
0143 }
0144
0145 int __init irq_remap_enable_fault_handling(void)
0146 {
0147     if (!irq_remapping_enabled)
0148         return 0;
0149
0150     if (!remap_ops->enable_faulting)
0151         return -ENODEV;
0152
0153     return remap_ops->enable_faulting();
0154 }
0155
0156 void panic_if_irq_remap(const char *msg)
0157 {
0158     if (irq_remapping_enabled)
0159         panic(msg);
0160 }