drivers/iommu/irq_remapping.c

   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 bool enable_posted_msi __ro_after_init;
  28
  29 static int disable_irq_remap;
  30 static struct irq_remap_ops *remap_ops;
  31
  32 static void irq_remapping_restore_boot_irq_mode(void)
  33 {
  34         /*
  35          * With interrupt-remapping, for now we will use virtual wire A
  36          * mode, as virtual wire B is little complex (need to configure
  37          * both IOAPIC RTE as well as interrupt-remapping table entry).
  38          * As this gets called during crash dump, keep this simple for
  39          * now.
  40          */
  41         if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
  42                 disconnect_bsp_APIC(0);
  43 }
  44
  45 static void __init irq_remapping_modify_x86_ops(void)
  46 {
  47         x86_apic_ops.restore = irq_remapping_restore_boot_irq_mode;
  48 }
  49
  50 static __init int setup_nointremap(char *str)
  51 {
  52         disable_irq_remap = 1;
  53         return 0;
  54 }
  55 early_param("nointremap", setup_nointremap);
  56
  57 static __init int setup_irqremap(char *str)
  58 {
  59         if (!str)
  60                 return -EINVAL;
  61
  62         while (*str) {
  63                 if (!strncmp(str, "on", 2)) {
  64                         disable_irq_remap = 0;
  65                         disable_irq_post = 0;
  66                 } else if (!strncmp(str, "off", 3)) {
  67                         disable_irq_remap = 1;
  68                         disable_irq_post = 1;
  69                 } else if (!strncmp(str, "nosid", 5))
  70                         disable_sourceid_checking = 1;
  71                 else if (!strncmp(str, "no_x2apic_optout", 16))
  72                         no_x2apic_optout = 1;
  73                 else if (!strncmp(str, "nopost", 6))
  74                         disable_irq_post = 1;
  75                 else if (IS_ENABLED(CONFIG_X86_POSTED_MSI) && !strncmp(str, "posted_msi", 10))
  76                         enable_posted_msi = true;
  77                 str += strcspn(str, ",");
  78                 while (*str == ',')
  79                         str++;
  80         }
  81
  82         return 0;
  83 }
  84 early_param("intremap", setup_irqremap);
  85
  86 void set_irq_remapping_broken(void)
  87 {
  88         irq_remap_broken = 1;
  89 }
  90
  91 bool irq_remapping_cap(enum irq_remap_cap cap)
  92 {
  93         if (!remap_ops || disable_irq_post)
  94                 return false;
  95
  96         return (remap_ops->capability & (1 << cap));
  97 }
  98 EXPORT_SYMBOL_GPL(irq_remapping_cap);
  99
 100 int __init irq_remapping_prepare(void)
 101 {
 102         if (disable_irq_remap)
 103                 return -ENOSYS;
 104
 105         if (IS_ENABLED(CONFIG_INTEL_IOMMU) &&
 106             intel_irq_remap_ops.prepare() == 0)
 107                 remap_ops = &intel_irq_remap_ops;
 108         else if (IS_ENABLED(CONFIG_AMD_IOMMU) &&
 109                  amd_iommu_irq_ops.prepare() == 0)
 110                 remap_ops = &amd_iommu_irq_ops;
 111         else if (IS_ENABLED(CONFIG_HYPERV_IOMMU) &&
 112                  hyperv_irq_remap_ops.prepare() == 0)
 113                 remap_ops = &hyperv_irq_remap_ops;
 114         else
 115                 return -ENOSYS;
 116
 117         return 0;
 118 }
 119
 120 int __init irq_remapping_enable(void)
 121 {
 122         int ret;
 123
 124         if (!remap_ops->enable)
 125                 return -ENODEV;
 126
 127         ret = remap_ops->enable();
 128
 129         if (irq_remapping_enabled)
 130                 irq_remapping_modify_x86_ops();
 131
 132         return ret;
 133 }
 134
 135 void irq_remapping_disable(void)
 136 {
 137         if (irq_remapping_enabled && remap_ops->disable)
 138                 remap_ops->disable();
 139 }
 140
 141 int irq_remapping_reenable(int mode)
 142 {
 143         if (irq_remapping_enabled && remap_ops->reenable)
 144                 return remap_ops->reenable(mode);
 145
 146         return 0;
 147 }
 148
 149 int __init irq_remap_enable_fault_handling(void)
 150 {
 151         if (!irq_remapping_enabled)
 152                 return 0;
 153
 154         if (!remap_ops->enable_faulting)
 155                 return -ENODEV;
 156
 157         cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dmar:enable_fault_handling",
 158                           remap_ops->enable_faulting, NULL);
 159
 160         return remap_ops->enable_faulting(smp_processor_id());
 161 }
 162
 163 void panic_if_irq_remap(const char *msg)
 164 {
 165         if (irq_remapping_enabled)
 166                 panic(msg);
 167 }