1 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG 2 #include <linux/bootmem.h> 3 #endif 4 #include <linux/cpu.h> 5 #include <linux/kexec.h> 6 7 #include <xen/features.h> 8 #include <xen/page.h> 9 #include <xen/interface/memory.h> 10 11 #include <asm/xen/hypercall.h> 12 #include <asm/xen/hypervisor.h> 13 #include <asm/cpu.h> 14 #include <asm/e820/api.h> 15 16 #include "xen-ops.h" 17 #include "smp.h" 18 #include "pmu.h" 19 20 EXPORT_SYMBOL_GPL(hypercall_page); 21 22 /* 23 * Pointer to the xen_vcpu_info structure or 24 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 25 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 26 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 27 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 28 * acknowledge pending events. 29 * Also more subtly it is used by the patched version of irq enable/disable 30 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 31 * 32 * The desire to be able to do those mask/unmask operations as a single 33 * instruction by using the per-cpu offset held in %gs is the real reason 34 * vcpu info is in a per-cpu pointer and the original reason for this 35 * hypercall. 36 * 37 */ 38 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 39 40 /* 41 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 42 * hypercall. This can be used both in PV and PVHVM mode. The structure 43 * overrides the default per_cpu(xen_vcpu, cpu) value. 44 */ 45 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 46 47 /* Linux <-> Xen vCPU id mapping */ 48 DEFINE_PER_CPU(uint32_t, xen_vcpu_id); 49 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); 50 51 enum xen_domain_type xen_domain_type = XEN_NATIVE; 52 EXPORT_SYMBOL_GPL(xen_domain_type); 53 54 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 55 EXPORT_SYMBOL(machine_to_phys_mapping); 56 unsigned long machine_to_phys_nr; 57 EXPORT_SYMBOL(machine_to_phys_nr); 58 59 struct start_info *xen_start_info; 60 EXPORT_SYMBOL_GPL(xen_start_info); 61 62 struct shared_info xen_dummy_shared_info; 63 64 __read_mostly int xen_have_vector_callback; 65 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 66 67 /* 68 * NB: needs to live in .data because it's used by xen_prepare_pvh which runs 69 * before clearing the bss. 70 */ 71 uint32_t xen_start_flags __attribute__((section(".data"))) = 0; 72 EXPORT_SYMBOL(xen_start_flags); 73 74 /* 75 * Point at some empty memory to start with. We map the real shared_info 76 * page as soon as fixmap is up and running. 77 */ 78 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 79 80 /* 81 * Flag to determine whether vcpu info placement is available on all 82 * VCPUs. We assume it is to start with, and then set it to zero on 83 * the first failure. This is because it can succeed on some VCPUs 84 * and not others, since it can involve hypervisor memory allocation, 85 * or because the guest failed to guarantee all the appropriate 86 * constraints on all VCPUs (ie buffer can't cross a page boundary). 87 * 88 * Note that any particular CPU may be using a placed vcpu structure, 89 * but we can only optimise if the all are. 90 * 91 * 0: not available, 1: available 92 */ 93 int xen_have_vcpu_info_placement = 1; 94 95 static int xen_cpu_up_online(unsigned int cpu) 96 { 97 xen_init_lock_cpu(cpu); 98 return 0; 99 } 100 101 int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), 102 int (*cpu_dead_cb)(unsigned int)) 103 { 104 int rc; 105 106 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, 107 "x86/xen/guest:prepare", 108 cpu_up_prepare_cb, cpu_dead_cb); 109 if (rc >= 0) { 110 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 111 "x86/xen/guest:online", 112 xen_cpu_up_online, NULL); 113 if (rc < 0) 114 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); 115 } 116 117 return rc >= 0 ? 0 : rc; 118 } 119 120 static int xen_vcpu_setup_restore(int cpu) 121 { 122 int rc = 0; 123 124 /* Any per_cpu(xen_vcpu) is stale, so reset it */ 125 xen_vcpu_info_reset(cpu); 126 127 /* 128 * For PVH and PVHVM, setup online VCPUs only. The rest will 129 * be handled by hotplug. 130 */ 131 if (xen_pv_domain() || 132 (xen_hvm_domain() && cpu_online(cpu))) { 133 rc = xen_vcpu_setup(cpu); 134 } 135 136 return rc; 137 } 138 139 /* 140 * On restore, set the vcpu placement up again. 141 * If it fails, then we're in a bad state, since 142 * we can't back out from using it... 143 */ 144 void xen_vcpu_restore(void) 145 { 146 int cpu, rc; 147 148 for_each_possible_cpu(cpu) { 149 bool other_cpu = (cpu != smp_processor_id()); 150 bool is_up; 151 152 if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID) 153 continue; 154 155 /* Only Xen 4.5 and higher support this. */ 156 is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, 157 xen_vcpu_nr(cpu), NULL) > 0; 158 159 if (other_cpu && is_up && 160 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL)) 161 BUG(); 162 163 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 164 xen_setup_runstate_info(cpu); 165 166 rc = xen_vcpu_setup_restore(cpu); 167 if (rc) 168 pr_emerg_once("vcpu restore failed for cpu=%d err=%d. " 169 "System will hang.\n", cpu, rc); 170 /* 171 * In case xen_vcpu_setup_restore() fails, do not bring up the 172 * VCPU. This helps us avoid the resulting OOPS when the VCPU 173 * accesses pvclock_vcpu_time via xen_vcpu (which is NULL.) 174 * Note that this does not improve the situation much -- now the 175 * VM hangs instead of OOPSing -- with the VCPUs that did not 176 * fail, spinning in stop_machine(), waiting for the failed 177 * VCPUs to come up. 178 */ 179 if (other_cpu && is_up && (rc == 0) && 180 HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) 181 BUG(); 182 } 183 } 184 185 void xen_vcpu_info_reset(int cpu) 186 { 187 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) { 188 per_cpu(xen_vcpu, cpu) = 189 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 190 } else { 191 /* Set to NULL so that if somebody accesses it we get an OOPS */ 192 per_cpu(xen_vcpu, cpu) = NULL; 193 } 194 } 195 196 int xen_vcpu_setup(int cpu) 197 { 198 struct vcpu_register_vcpu_info info; 199 int err; 200 struct vcpu_info *vcpup; 201 202 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 203 204 /* 205 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu) 206 * and at restore (xen_vcpu_restore). Also called for hotplugged 207 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm). 208 * However, the hypercall can only be done once (see below) so if a VCPU 209 * is offlined and comes back online then let's not redo the hypercall. 210 * 211 * For PV it is called during restore (xen_vcpu_restore) and bootup 212 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 213 * use this function. 214 */ 215 if (xen_hvm_domain()) { 216 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 217 return 0; 218 } 219 220 if (xen_have_vcpu_info_placement) { 221 vcpup = &per_cpu(xen_vcpu_info, cpu); 222 info.mfn = arbitrary_virt_to_mfn(vcpup); 223 info.offset = offset_in_page(vcpup); 224 225 /* 226 * Check to see if the hypervisor will put the vcpu_info 227 * structure where we want it, which allows direct access via 228 * a percpu-variable. 229 * N.B. This hypercall can _only_ be called once per CPU. 230 * Subsequent calls will error out with -EINVAL. This is due to 231 * the fact that hypervisor has no unregister variant and this 232 * hypercall does not allow to over-write info.mfn and 233 * info.offset. 234 */ 235 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, 236 xen_vcpu_nr(cpu), &info); 237 238 if (err) { 239 pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n", 240 cpu, err); 241 xen_have_vcpu_info_placement = 0; 242 } else { 243 /* 244 * This cpu is using the registered vcpu info, even if 245 * later ones fail to. 246 */ 247 per_cpu(xen_vcpu, cpu) = vcpup; 248 } 249 } 250 251 if (!xen_have_vcpu_info_placement) 252 xen_vcpu_info_reset(cpu); 253 254 return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0); 255 } 256 257 void xen_reboot(int reason) 258 { 259 struct sched_shutdown r = { .reason = reason }; 260 int cpu; 261 262 for_each_online_cpu(cpu) 263 xen_pmu_finish(cpu); 264 265 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 266 BUG(); 267 } 268 269 void xen_emergency_restart(void) 270 { 271 xen_reboot(SHUTDOWN_reboot); 272 } 273 274 static int 275 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 276 { 277 if (!kexec_crash_loaded()) 278 xen_reboot(SHUTDOWN_crash); 279 return NOTIFY_DONE; 280 } 281 282 static struct notifier_block xen_panic_block = { 283 .notifier_call = xen_panic_event, 284 .priority = INT_MIN 285 }; 286 287 int xen_panic_handler_init(void) 288 { 289 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 290 return 0; 291 } 292 293 void xen_pin_vcpu(int cpu) 294 { 295 static bool disable_pinning; 296 struct sched_pin_override pin_override; 297 int ret; 298 299 if (disable_pinning) 300 return; 301 302 pin_override.pcpu = cpu; 303 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); 304 305 /* Ignore errors when removing override. */ 306 if (cpu < 0) 307 return; 308 309 switch (ret) { 310 case -ENOSYS: 311 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", 312 cpu); 313 disable_pinning = true; 314 break; 315 case -EPERM: 316 WARN(1, "Trying to pin vcpu without having privilege to do so\n"); 317 disable_pinning = true; 318 break; 319 case -EINVAL: 320 case -EBUSY: 321 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", 322 cpu); 323 break; 324 case 0: 325 break; 326 default: 327 WARN(1, "rc %d while trying to pin vcpu\n", ret); 328 disable_pinning = true; 329 } 330 } 331 332 #ifdef CONFIG_HOTPLUG_CPU 333 void xen_arch_register_cpu(int num) 334 { 335 arch_register_cpu(num); 336 } 337 EXPORT_SYMBOL(xen_arch_register_cpu); 338 339 void xen_arch_unregister_cpu(int num) 340 { 341 arch_unregister_cpu(num); 342 } 343 EXPORT_SYMBOL(xen_arch_unregister_cpu); 344 #endif 345 346 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG 347 void __init arch_xen_balloon_init(struct resource *hostmem_resource) 348 { 349 struct xen_memory_map memmap; 350 int rc; 351 unsigned int i, last_guest_ram; 352 phys_addr_t max_addr = PFN_PHYS(max_pfn); 353 struct e820_table *xen_e820_table; 354 const struct e820_entry *entry; 355 struct resource *res; 356 357 if (!xen_initial_domain()) 358 return; 359 360 xen_e820_table = kmalloc(sizeof(*xen_e820_table), GFP_KERNEL); 361 if (!xen_e820_table) 362 return; 363 364 memmap.nr_entries = ARRAY_SIZE(xen_e820_table->entries); 365 set_xen_guest_handle(memmap.buffer, xen_e820_table->entries); 366 rc = HYPERVISOR_memory_op(XENMEM_machine_memory_map, &memmap); 367 if (rc) { 368 pr_warn("%s: Can't read host e820 (%d)\n", __func__, rc); 369 goto out; 370 } 371 372 last_guest_ram = 0; 373 for (i = 0; i < memmap.nr_entries; i++) { 374 if (xen_e820_table->entries[i].addr >= max_addr) 375 break; 376 if (xen_e820_table->entries[i].type == E820_TYPE_RAM) 377 last_guest_ram = i; 378 } 379 380 entry = &xen_e820_table->entries[last_guest_ram]; 381 if (max_addr >= entry->addr + entry->size) 382 goto out; /* No unallocated host RAM. */ 383 384 hostmem_resource->start = max_addr; 385 hostmem_resource->end = entry->addr + entry->size; 386 387 /* 388 * Mark non-RAM regions between the end of dom0 RAM and end of host RAM 389 * as unavailable. The rest of that region can be used for hotplug-based 390 * ballooning. 391 */ 392 for (; i < memmap.nr_entries; i++) { 393 entry = &xen_e820_table->entries[i]; 394 395 if (entry->type == E820_TYPE_RAM) 396 continue; 397 398 if (entry->addr >= hostmem_resource->end) 399 break; 400 401 res = kzalloc(sizeof(*res), GFP_KERNEL); 402 if (!res) 403 goto out; 404 405 res->name = "Unavailable host RAM"; 406 res->start = entry->addr; 407 res->end = (entry->addr + entry->size < hostmem_resource->end) ? 408 entry->addr + entry->size : hostmem_resource->end; 409 rc = insert_resource(hostmem_resource, res); 410 if (rc) { 411 pr_warn("%s: Can't insert [%llx - %llx) (%d)\n", 412 __func__, res->start, res->end, rc); 413 kfree(res); 414 goto out; 415 } 416 } 417 418 out: 419 kfree(xen_e820_table); 420 } 421 #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ 422