1 // SPDX-License-Identifier: GPL-2.0 2 3 /* 4 * Hyper-V stub IOMMU driver. 5 * 6 * Copyright (C) 2019, Microsoft, Inc. 7 * 8 * Author : Lan Tianyu <Tianyu.Lan@microsoft.com> 9 */ 10 11 #include <linux/types.h> 12 #include <linux/interrupt.h> 13 #include <linux/irq.h> 14 #include <linux/iommu.h> 15 #include <linux/module.h> 16 17 #include <asm/apic.h> 18 #include <asm/cpu.h> 19 #include <asm/hw_irq.h> 20 #include <asm/io_apic.h> 21 #include <asm/irq_remapping.h> 22 #include <asm/hypervisor.h> 23 24 #include "irq_remapping.h" 25 26 #ifdef CONFIG_IRQ_REMAP 27 28 /* 29 * According 82093AA IO-APIC spec , IO APIC has a 24-entry Interrupt 30 * Redirection Table. Hyper-V exposes one single IO-APIC and so define 31 * 24 IO APIC remmapping entries. 32 */ 33 #define IOAPIC_REMAPPING_ENTRY 24 34 35 static cpumask_t ioapic_max_cpumask = { CPU_BITS_NONE }; 36 static struct irq_domain *ioapic_ir_domain; 37 38 static int hyperv_ir_set_affinity(struct irq_data *data, 39 const struct cpumask *mask, bool force) 40 { 41 struct irq_data *parent = data->parent_data; 42 struct irq_cfg *cfg = irqd_cfg(data); 43 struct IO_APIC_route_entry *entry; 44 int ret; 45 46 /* Return error If new irq affinity is out of ioapic_max_cpumask. */ 47 if (!cpumask_subset(mask, &ioapic_max_cpumask)) 48 return -EINVAL; 49 50 ret = parent->chip->irq_set_affinity(parent, mask, force); 51 if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE) 52 return ret; 53 54 entry = data->chip_data; 55 entry->dest = cfg->dest_apicid; 56 entry->vector = cfg->vector; 57 send_cleanup_vector(cfg); 58 59 return 0; 60 } 61 62 static struct irq_chip hyperv_ir_chip = { 63 .name = "HYPERV-IR", 64 .irq_ack = apic_ack_irq, 65 .irq_set_affinity = hyperv_ir_set_affinity, 66 }; 67 68 static int hyperv_irq_remapping_alloc(struct irq_domain *domain, 69 unsigned int virq, unsigned int nr_irqs, 70 void *arg) 71 { 72 struct irq_alloc_info *info = arg; 73 struct irq_data *irq_data; 74 struct irq_desc *desc; 75 int ret = 0; 76 77 if (!info || info->type != X86_IRQ_ALLOC_TYPE_IOAPIC || nr_irqs > 1) 78 return -EINVAL; 79 80 ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg); 81 if (ret < 0) 82 return ret; 83 84 irq_data = irq_domain_get_irq_data(domain, virq); 85 if (!irq_data) { 86 irq_domain_free_irqs_common(domain, virq, nr_irqs); 87 return -EINVAL; 88 } 89 90 irq_data->chip = &hyperv_ir_chip; 91 92 /* 93 * If there is interrupt remapping function of IOMMU, setting irq 94 * affinity only needs to change IRTE of IOMMU. But Hyper-V doesn't 95 * support interrupt remapping function, setting irq affinity of IO-APIC 96 * interrupts still needs to change IO-APIC registers. But ioapic_ 97 * configure_entry() will ignore value of cfg->vector and cfg-> 98 * dest_apicid when IO-APIC's parent irq domain is not the vector 99 * domain.(See ioapic_configure_entry()) In order to setting vector 100 * and dest_apicid to IO-APIC register, IO-APIC entry pointer is saved 101 * in the chip_data and hyperv_irq_remapping_activate()/hyperv_ir_set_ 102 * affinity() set vector and dest_apicid directly into IO-APIC entry. 103 */ 104 irq_data->chip_data = info->ioapic_entry; 105 106 /* 107 * Hypver-V IO APIC irq affinity should be in the scope of 108 * ioapic_max_cpumask because no irq remapping support. 109 */ 110 desc = irq_data_to_desc(irq_data); 111 cpumask_copy(desc->irq_common_data.affinity, &ioapic_max_cpumask); 112 113 return 0; 114 } 115 116 static void hyperv_irq_remapping_free(struct irq_domain *domain, 117 unsigned int virq, unsigned int nr_irqs) 118 { 119 irq_domain_free_irqs_common(domain, virq, nr_irqs); 120 } 121 122 static int hyperv_irq_remapping_activate(struct irq_domain *domain, 123 struct irq_data *irq_data, bool reserve) 124 { 125 struct irq_cfg *cfg = irqd_cfg(irq_data); 126 struct IO_APIC_route_entry *entry = irq_data->chip_data; 127 128 entry->dest = cfg->dest_apicid; 129 entry->vector = cfg->vector; 130 131 return 0; 132 } 133 134 static const struct irq_domain_ops hyperv_ir_domain_ops = { 135 .alloc = hyperv_irq_remapping_alloc, 136 .free = hyperv_irq_remapping_free, 137 .activate = hyperv_irq_remapping_activate, 138 }; 139 140 static int __init hyperv_prepare_irq_remapping(void) 141 { 142 struct fwnode_handle *fn; 143 int i; 144 145 if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) || 146 !x2apic_supported()) 147 return -ENODEV; 148 149 fn = irq_domain_alloc_named_id_fwnode("HYPERV-IR", 0); 150 if (!fn) 151 return -ENOMEM; 152 153 ioapic_ir_domain = 154 irq_domain_create_hierarchy(arch_get_ir_parent_domain(), 155 0, IOAPIC_REMAPPING_ENTRY, fn, 156 &hyperv_ir_domain_ops, NULL); 157 158 irq_domain_free_fwnode(fn); 159 160 /* 161 * Hyper-V doesn't provide irq remapping function for 162 * IO-APIC and so IO-APIC only accepts 8-bit APIC ID. 163 * Cpu's APIC ID is read from ACPI MADT table and APIC IDs 164 * in the MADT table on Hyper-v are sorted monotonic increasingly. 165 * APIC ID reflects cpu topology. There maybe some APIC ID 166 * gaps when cpu number in a socket is not power of two. Prepare 167 * max cpu affinity for IOAPIC irqs. Scan cpu 0-255 and set cpu 168 * into ioapic_max_cpumask if its APIC ID is less than 256. 169 */ 170 for (i = min_t(unsigned int, num_possible_cpus() - 1, 255); i >= 0; i--) 171 if (cpu_physical_id(i) < 256) 172 cpumask_set_cpu(i, &ioapic_max_cpumask); 173 174 return 0; 175 } 176 177 static int __init hyperv_enable_irq_remapping(void) 178 { 179 return IRQ_REMAP_X2APIC_MODE; 180 } 181 182 static struct irq_domain *hyperv_get_ir_irq_domain(struct irq_alloc_info *info) 183 { 184 if (info->type == X86_IRQ_ALLOC_TYPE_IOAPIC) 185 return ioapic_ir_domain; 186 else 187 return NULL; 188 } 189 190 struct irq_remap_ops hyperv_irq_remap_ops = { 191 .prepare = hyperv_prepare_irq_remapping, 192 .enable = hyperv_enable_irq_remapping, 193 .get_ir_irq_domain = hyperv_get_ir_irq_domain, 194 }; 195 196 #endif 197