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 #include <asm/mshyperv.h> 24 25 #include "irq_remapping.h" 26 27 #ifdef CONFIG_IRQ_REMAP 28 29 /* 30 * According 82093AA IO-APIC spec , IO APIC has a 24-entry Interrupt 31 * Redirection Table. Hyper-V exposes one single IO-APIC and so define 32 * 24 IO APIC remmapping entries. 33 */ 34 #define IOAPIC_REMAPPING_ENTRY 24 35 36 static cpumask_t ioapic_max_cpumask = { CPU_BITS_NONE }; 37 static struct irq_domain *ioapic_ir_domain; 38 39 static int hyperv_ir_set_affinity(struct irq_data *data, 40 const struct cpumask *mask, bool force) 41 { 42 struct irq_data *parent = data->parent_data; 43 struct irq_cfg *cfg = irqd_cfg(data); 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 vector_schedule_cleanup(cfg); 55 56 return 0; 57 } 58 59 static struct irq_chip hyperv_ir_chip = { 60 .name = "HYPERV-IR", 61 .irq_ack = apic_ack_irq, 62 .irq_set_affinity = hyperv_ir_set_affinity, 63 }; 64 65 static int hyperv_irq_remapping_alloc(struct irq_domain *domain, 66 unsigned int virq, unsigned int nr_irqs, 67 void *arg) 68 { 69 struct irq_alloc_info *info = arg; 70 struct irq_data *irq_data; 71 int ret = 0; 72 73 if (!info || info->type != X86_IRQ_ALLOC_TYPE_IOAPIC || nr_irqs > 1) 74 return -EINVAL; 75 76 ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg); 77 if (ret < 0) 78 return ret; 79 80 irq_data = irq_domain_get_irq_data(domain, virq); 81 if (!irq_data) { 82 irq_domain_free_irqs_common(domain, virq, nr_irqs); 83 return -EINVAL; 84 } 85 86 irq_data->chip = &hyperv_ir_chip; 87 88 /* 89 * Hypver-V IO APIC irq affinity should be in the scope of 90 * ioapic_max_cpumask because no irq remapping support. 91 */ 92 irq_data_update_affinity(irq_data, &ioapic_max_cpumask); 93 94 return 0; 95 } 96 97 static void hyperv_irq_remapping_free(struct irq_domain *domain, 98 unsigned int virq, unsigned int nr_irqs) 99 { 100 irq_domain_free_irqs_common(domain, virq, nr_irqs); 101 } 102 103 static int hyperv_irq_remapping_select(struct irq_domain *d, 104 struct irq_fwspec *fwspec, 105 enum irq_domain_bus_token bus_token) 106 { 107 /* Claim the only I/O APIC emulated by Hyper-V */ 108 return x86_fwspec_is_ioapic(fwspec); 109 } 110 111 static const struct irq_domain_ops hyperv_ir_domain_ops = { 112 .select = hyperv_irq_remapping_select, 113 .alloc = hyperv_irq_remapping_alloc, 114 .free = hyperv_irq_remapping_free, 115 }; 116 117 static const struct irq_domain_ops hyperv_root_ir_domain_ops; 118 static int __init hyperv_prepare_irq_remapping(void) 119 { 120 struct fwnode_handle *fn; 121 int i; 122 const char *name; 123 const struct irq_domain_ops *ops; 124 125 /* 126 * For a Hyper-V root partition, ms_hyperv_msi_ext_dest_id() 127 * will always return false. 128 */ 129 if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) || 130 x86_init.hyper.msi_ext_dest_id()) 131 return -ENODEV; 132 133 if (hv_root_partition) { 134 name = "HYPERV-ROOT-IR"; 135 ops = &hyperv_root_ir_domain_ops; 136 } else { 137 name = "HYPERV-IR"; 138 ops = &hyperv_ir_domain_ops; 139 } 140 141 fn = irq_domain_alloc_named_id_fwnode(name, 0); 142 if (!fn) 143 return -ENOMEM; 144 145 ioapic_ir_domain = 146 irq_domain_create_hierarchy(arch_get_ir_parent_domain(), 147 0, IOAPIC_REMAPPING_ENTRY, fn, ops, NULL); 148 149 if (!ioapic_ir_domain) { 150 irq_domain_free_fwnode(fn); 151 return -ENOMEM; 152 } 153 154 if (hv_root_partition) 155 return 0; /* The rest is only relevant to guests */ 156 157 /* 158 * Hyper-V doesn't provide irq remapping function for 159 * IO-APIC and so IO-APIC only accepts 8-bit APIC ID. 160 * Cpu's APIC ID is read from ACPI MADT table and APIC IDs 161 * in the MADT table on Hyper-v are sorted monotonic increasingly. 162 * APIC ID reflects cpu topology. There maybe some APIC ID 163 * gaps when cpu number in a socket is not power of two. Prepare 164 * max cpu affinity for IOAPIC irqs. Scan cpu 0-255 and set cpu 165 * into ioapic_max_cpumask if its APIC ID is less than 256. 166 */ 167 for (i = min_t(unsigned int, num_possible_cpus() - 1, 255); i >= 0; i--) 168 if (cpu_physical_id(i) < 256) 169 cpumask_set_cpu(i, &ioapic_max_cpumask); 170 171 return 0; 172 } 173 174 static int __init hyperv_enable_irq_remapping(void) 175 { 176 if (x2apic_supported()) 177 return IRQ_REMAP_X2APIC_MODE; 178 return IRQ_REMAP_XAPIC_MODE; 179 } 180 181 struct irq_remap_ops hyperv_irq_remap_ops = { 182 .prepare = hyperv_prepare_irq_remapping, 183 .enable = hyperv_enable_irq_remapping, 184 }; 185 186 /* IRQ remapping domain when Linux runs as the root partition */ 187 struct hyperv_root_ir_data { 188 u8 ioapic_id; 189 bool is_level; 190 struct hv_interrupt_entry entry; 191 }; 192 193 static void 194 hyperv_root_ir_compose_msi_msg(struct irq_data *irq_data, struct msi_msg *msg) 195 { 196 u64 status; 197 u32 vector; 198 struct irq_cfg *cfg; 199 int ioapic_id; 200 const struct cpumask *affinity; 201 int cpu; 202 struct hv_interrupt_entry entry; 203 struct hyperv_root_ir_data *data = irq_data->chip_data; 204 struct IO_APIC_route_entry e; 205 206 cfg = irqd_cfg(irq_data); 207 affinity = irq_data_get_effective_affinity_mask(irq_data); 208 cpu = cpumask_first_and(affinity, cpu_online_mask); 209 210 vector = cfg->vector; 211 ioapic_id = data->ioapic_id; 212 213 if (data->entry.source == HV_DEVICE_TYPE_IOAPIC 214 && data->entry.ioapic_rte.as_uint64) { 215 entry = data->entry; 216 217 status = hv_unmap_ioapic_interrupt(ioapic_id, &entry); 218 219 if (status != HV_STATUS_SUCCESS) 220 pr_debug("%s: unexpected unmap status %lld\n", __func__, status); 221 222 data->entry.ioapic_rte.as_uint64 = 0; 223 data->entry.source = 0; /* Invalid source */ 224 } 225 226 227 status = hv_map_ioapic_interrupt(ioapic_id, data->is_level, cpu, 228 vector, &entry); 229 230 if (status != HV_STATUS_SUCCESS) { 231 pr_err("%s: map hypercall failed, status %lld\n", __func__, status); 232 return; 233 } 234 235 data->entry = entry; 236 237 /* Turn it into an IO_APIC_route_entry, and generate MSI MSG. */ 238 e.w1 = entry.ioapic_rte.low_uint32; 239 e.w2 = entry.ioapic_rte.high_uint32; 240 241 memset(msg, 0, sizeof(*msg)); 242 msg->arch_data.vector = e.vector; 243 msg->arch_data.delivery_mode = e.delivery_mode; 244 msg->arch_addr_lo.dest_mode_logical = e.dest_mode_logical; 245 msg->arch_addr_lo.dmar_format = e.ir_format; 246 msg->arch_addr_lo.dmar_index_0_14 = e.ir_index_0_14; 247 } 248 249 static int hyperv_root_ir_set_affinity(struct irq_data *data, 250 const struct cpumask *mask, bool force) 251 { 252 struct irq_data *parent = data->parent_data; 253 struct irq_cfg *cfg = irqd_cfg(data); 254 int ret; 255 256 ret = parent->chip->irq_set_affinity(parent, mask, force); 257 if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE) 258 return ret; 259 260 vector_schedule_cleanup(cfg); 261 262 return 0; 263 } 264 265 static struct irq_chip hyperv_root_ir_chip = { 266 .name = "HYPERV-ROOT-IR", 267 .irq_ack = apic_ack_irq, 268 .irq_set_affinity = hyperv_root_ir_set_affinity, 269 .irq_compose_msi_msg = hyperv_root_ir_compose_msi_msg, 270 }; 271 272 static int hyperv_root_irq_remapping_alloc(struct irq_domain *domain, 273 unsigned int virq, unsigned int nr_irqs, 274 void *arg) 275 { 276 struct irq_alloc_info *info = arg; 277 struct irq_data *irq_data; 278 struct hyperv_root_ir_data *data; 279 int ret = 0; 280 281 if (!info || info->type != X86_IRQ_ALLOC_TYPE_IOAPIC || nr_irqs > 1) 282 return -EINVAL; 283 284 ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg); 285 if (ret < 0) 286 return ret; 287 288 data = kzalloc(sizeof(*data), GFP_KERNEL); 289 if (!data) { 290 irq_domain_free_irqs_common(domain, virq, nr_irqs); 291 return -ENOMEM; 292 } 293 294 irq_data = irq_domain_get_irq_data(domain, virq); 295 if (!irq_data) { 296 kfree(data); 297 irq_domain_free_irqs_common(domain, virq, nr_irqs); 298 return -EINVAL; 299 } 300 301 data->ioapic_id = info->devid; 302 data->is_level = info->ioapic.is_level; 303 304 irq_data->chip = &hyperv_root_ir_chip; 305 irq_data->chip_data = data; 306 307 return 0; 308 } 309 310 static void hyperv_root_irq_remapping_free(struct irq_domain *domain, 311 unsigned int virq, unsigned int nr_irqs) 312 { 313 struct irq_data *irq_data; 314 struct hyperv_root_ir_data *data; 315 struct hv_interrupt_entry *e; 316 int i; 317 318 for (i = 0; i < nr_irqs; i++) { 319 irq_data = irq_domain_get_irq_data(domain, virq + i); 320 321 if (irq_data && irq_data->chip_data) { 322 data = irq_data->chip_data; 323 e = &data->entry; 324 325 if (e->source == HV_DEVICE_TYPE_IOAPIC 326 && e->ioapic_rte.as_uint64) 327 hv_unmap_ioapic_interrupt(data->ioapic_id, 328 &data->entry); 329 330 kfree(data); 331 } 332 } 333 334 irq_domain_free_irqs_common(domain, virq, nr_irqs); 335 } 336 337 static const struct irq_domain_ops hyperv_root_ir_domain_ops = { 338 .select = hyperv_irq_remapping_select, 339 .alloc = hyperv_root_irq_remapping_alloc, 340 .free = hyperv_root_irq_remapping_free, 341 }; 342 343 #endif 344