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 #include <linux/slab.h> 7 8 #include <xen/features.h> 9 #include <xen/page.h> 10 #include <xen/interface/memory.h> 11 12 #include <asm/xen/hypercall.h> 13 #include <asm/xen/hypervisor.h> 14 #include <asm/cpu.h> 15 #include <asm/e820/api.h> 16 17 #include "xen-ops.h" 18 #include "smp.h" 19 #include "pmu.h" 20 21 EXPORT_SYMBOL_GPL(hypercall_page); 22 23 /* 24 * Pointer to the xen_vcpu_info structure or 25 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 26 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 27 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 28 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 29 * acknowledge pending events. 30 * Also more subtly it is used by the patched version of irq enable/disable 31 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 32 * 33 * The desire to be able to do those mask/unmask operations as a single 34 * instruction by using the per-cpu offset held in %gs is the real reason 35 * vcpu info is in a per-cpu pointer and the original reason for this 36 * hypercall. 37 * 38 */ 39 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 40 41 /* 42 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 43 * hypercall. This can be used both in PV and PVHVM mode. The structure 44 * overrides the default per_cpu(xen_vcpu, cpu) value. 45 */ 46 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 47 48 /* Linux <-> Xen vCPU id mapping */ 49 DEFINE_PER_CPU(uint32_t, xen_vcpu_id); 50 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); 51 52 enum xen_domain_type xen_domain_type = XEN_NATIVE; 53 EXPORT_SYMBOL_GPL(xen_domain_type); 54 55 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 56 EXPORT_SYMBOL(machine_to_phys_mapping); 57 unsigned long machine_to_phys_nr; 58 EXPORT_SYMBOL(machine_to_phys_nr); 59 60 struct start_info *xen_start_info; 61 EXPORT_SYMBOL_GPL(xen_start_info); 62 63 struct shared_info xen_dummy_shared_info; 64 65 __read_mostly int xen_have_vector_callback; 66 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 67 68 /* 69 * NB: needs to live in .data because it's used by xen_prepare_pvh which runs 70 * before clearing the bss. 71 */ 72 uint32_t xen_start_flags __attribute__((section(".data"))) = 0; 73 EXPORT_SYMBOL(xen_start_flags); 74 75 /* 76 * Point at some empty memory to start with. We map the real shared_info 77 * page as soon as fixmap is up and running. 78 */ 79 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 80 81 /* 82 * Flag to determine whether vcpu info placement is available on all 83 * VCPUs. We assume it is to start with, and then set it to zero on 84 * the first failure. This is because it can succeed on some VCPUs 85 * and not others, since it can involve hypervisor memory allocation, 86 * or because the guest failed to guarantee all the appropriate 87 * constraints on all VCPUs (ie buffer can't cross a page boundary). 88 * 89 * Note that any particular CPU may be using a placed vcpu structure, 90 * but we can only optimise if the all are. 91 * 92 * 0: not available, 1: available 93 */ 94 int xen_have_vcpu_info_placement = 1; 95 96 static int xen_cpu_up_online(unsigned int cpu) 97 { 98 xen_init_lock_cpu(cpu); 99 return 0; 100 } 101 102 int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), 103 int (*cpu_dead_cb)(unsigned int)) 104 { 105 int rc; 106 107 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, 108 "x86/xen/guest:prepare", 109 cpu_up_prepare_cb, cpu_dead_cb); 110 if (rc >= 0) { 111 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 112 "x86/xen/guest:online", 113 xen_cpu_up_online, NULL); 114 if (rc < 0) 115 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); 116 } 117 118 return rc >= 0 ? 0 : rc; 119 } 120 121 static int xen_vcpu_setup_restore(int cpu) 122 { 123 int rc = 0; 124 125 /* Any per_cpu(xen_vcpu) is stale, so reset it */ 126 xen_vcpu_info_reset(cpu); 127 128 /* 129 * For PVH and PVHVM, setup online VCPUs only. The rest will 130 * be handled by hotplug. 131 */ 132 if (xen_pv_domain() || 133 (xen_hvm_domain() && cpu_online(cpu))) { 134 rc = xen_vcpu_setup(cpu); 135 } 136 137 return rc; 138 } 139 140 /* 141 * On restore, set the vcpu placement up again. 142 * If it fails, then we're in a bad state, since 143 * we can't back out from using it... 144 */ 145 void xen_vcpu_restore(void) 146 { 147 int cpu, rc; 148 149 for_each_possible_cpu(cpu) { 150 bool other_cpu = (cpu != smp_processor_id()); 151 bool is_up; 152 153 if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID) 154 continue; 155 156 /* Only Xen 4.5 and higher support this. */ 157 is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, 158 xen_vcpu_nr(cpu), NULL) > 0; 159 160 if (other_cpu && is_up && 161 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL)) 162 BUG(); 163 164 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 165 xen_setup_runstate_info(cpu); 166 167 rc = xen_vcpu_setup_restore(cpu); 168 if (rc) 169 pr_emerg_once("vcpu restore failed for cpu=%d err=%d. " 170 "System will hang.\n", cpu, rc); 171 /* 172 * In case xen_vcpu_setup_restore() fails, do not bring up the 173 * VCPU. This helps us avoid the resulting OOPS when the VCPU 174 * accesses pvclock_vcpu_time via xen_vcpu (which is NULL.) 175 * Note that this does not improve the situation much -- now the 176 * VM hangs instead of OOPSing -- with the VCPUs that did not 177 * fail, spinning in stop_machine(), waiting for the failed 178 * VCPUs to come up. 179 */ 180 if (other_cpu && is_up && (rc == 0) && 181 HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) 182 BUG(); 183 } 184 } 185 186 void xen_vcpu_info_reset(int cpu) 187 { 188 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) { 189 per_cpu(xen_vcpu, cpu) = 190 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 191 } else { 192 /* Set to NULL so that if somebody accesses it we get an OOPS */ 193 per_cpu(xen_vcpu, cpu) = NULL; 194 } 195 } 196 197 int xen_vcpu_setup(int cpu) 198 { 199 struct vcpu_register_vcpu_info info; 200 int err; 201 struct vcpu_info *vcpup; 202 203 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 204 205 /* 206 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu) 207 * and at restore (xen_vcpu_restore). Also called for hotplugged 208 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm). 209 * However, the hypercall can only be done once (see below) so if a VCPU 210 * is offlined and comes back online then let's not redo the hypercall. 211 * 212 * For PV it is called during restore (xen_vcpu_restore) and bootup 213 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 214 * use this function. 215 */ 216 if (xen_hvm_domain()) { 217 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 218 return 0; 219 } 220 221 if (xen_have_vcpu_info_placement) { 222 vcpup = &per_cpu(xen_vcpu_info, cpu); 223 info.mfn = arbitrary_virt_to_mfn(vcpup); 224 info.offset = offset_in_page(vcpup); 225 226 /* 227 * Check to see if the hypervisor will put the vcpu_info 228 * structure where we want it, which allows direct access via 229 * a percpu-variable. 230 * N.B. This hypercall can _only_ be called once per CPU. 231 * Subsequent calls will error out with -EINVAL. This is due to 232 * the fact that hypervisor has no unregister variant and this 233 * hypercall does not allow to over-write info.mfn and 234 * info.offset. 235 */ 236 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, 237 xen_vcpu_nr(cpu), &info); 238 239 if (err) { 240 pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n", 241 cpu, err); 242 xen_have_vcpu_info_placement = 0; 243 } else { 244 /* 245 * This cpu is using the registered vcpu info, even if 246 * later ones fail to. 247 */ 248 per_cpu(xen_vcpu, cpu) = vcpup; 249 } 250 } 251 252 if (!xen_have_vcpu_info_placement) 253 xen_vcpu_info_reset(cpu); 254 255 return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0); 256 } 257 258 void xen_reboot(int reason) 259 { 260 struct sched_shutdown r = { .reason = reason }; 261 int cpu; 262 263 for_each_online_cpu(cpu) 264 xen_pmu_finish(cpu); 265 266 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 267 BUG(); 268 } 269 270 void xen_emergency_restart(void) 271 { 272 xen_reboot(SHUTDOWN_reboot); 273 } 274 275 static int 276 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 277 { 278 if (!kexec_crash_loaded()) 279 xen_reboot(SHUTDOWN_crash); 280 return NOTIFY_DONE; 281 } 282 283 static struct notifier_block xen_panic_block = { 284 .notifier_call = xen_panic_event, 285 .priority = INT_MIN 286 }; 287 288 int xen_panic_handler_init(void) 289 { 290 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 291 return 0; 292 } 293 294 void xen_pin_vcpu(int cpu) 295 { 296 static bool disable_pinning; 297 struct sched_pin_override pin_override; 298 int ret; 299 300 if (disable_pinning) 301 return; 302 303 pin_override.pcpu = cpu; 304 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); 305 306 /* Ignore errors when removing override. */ 307 if (cpu < 0) 308 return; 309 310 switch (ret) { 311 case -ENOSYS: 312 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", 313 cpu); 314 disable_pinning = true; 315 break; 316 case -EPERM: 317 WARN(1, "Trying to pin vcpu without having privilege to do so\n"); 318 disable_pinning = true; 319 break; 320 case -EINVAL: 321 case -EBUSY: 322 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", 323 cpu); 324 break; 325 case 0: 326 break; 327 default: 328 WARN(1, "rc %d while trying to pin vcpu\n", ret); 329 disable_pinning = true; 330 } 331 } 332 333 #ifdef CONFIG_HOTPLUG_CPU 334 void xen_arch_register_cpu(int num) 335 { 336 arch_register_cpu(num); 337 } 338 EXPORT_SYMBOL(xen_arch_register_cpu); 339 340 void xen_arch_unregister_cpu(int num) 341 { 342 arch_unregister_cpu(num); 343 } 344 EXPORT_SYMBOL(xen_arch_unregister_cpu); 345 #endif 346 347 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG 348 void __init arch_xen_balloon_init(struct resource *hostmem_resource) 349 { 350 struct xen_memory_map memmap; 351 int rc; 352 unsigned int i, last_guest_ram; 353 phys_addr_t max_addr = PFN_PHYS(max_pfn); 354 struct e820_table *xen_e820_table; 355 const struct e820_entry *entry; 356 struct resource *res; 357 358 if (!xen_initial_domain()) 359 return; 360 361 xen_e820_table = kmalloc(sizeof(*xen_e820_table), GFP_KERNEL); 362 if (!xen_e820_table) 363 return; 364 365 memmap.nr_entries = ARRAY_SIZE(xen_e820_table->entries); 366 set_xen_guest_handle(memmap.buffer, xen_e820_table->entries); 367 rc = HYPERVISOR_memory_op(XENMEM_machine_memory_map, &memmap); 368 if (rc) { 369 pr_warn("%s: Can't read host e820 (%d)\n", __func__, rc); 370 goto out; 371 } 372 373 last_guest_ram = 0; 374 for (i = 0; i < memmap.nr_entries; i++) { 375 if (xen_e820_table->entries[i].addr >= max_addr) 376 break; 377 if (xen_e820_table->entries[i].type == E820_TYPE_RAM) 378 last_guest_ram = i; 379 } 380 381 entry = &xen_e820_table->entries[last_guest_ram]; 382 if (max_addr >= entry->addr + entry->size) 383 goto out; /* No unallocated host RAM. */ 384 385 hostmem_resource->start = max_addr; 386 hostmem_resource->end = entry->addr + entry->size; 387 388 /* 389 * Mark non-RAM regions between the end of dom0 RAM and end of host RAM 390 * as unavailable. The rest of that region can be used for hotplug-based 391 * ballooning. 392 */ 393 for (; i < memmap.nr_entries; i++) { 394 entry = &xen_e820_table->entries[i]; 395 396 if (entry->type == E820_TYPE_RAM) 397 continue; 398 399 if (entry->addr >= hostmem_resource->end) 400 break; 401 402 res = kzalloc(sizeof(*res), GFP_KERNEL); 403 if (!res) 404 goto out; 405 406 res->name = "Unavailable host RAM"; 407 res->start = entry->addr; 408 res->end = (entry->addr + entry->size < hostmem_resource->end) ? 409 entry->addr + entry->size : hostmem_resource->end; 410 rc = insert_resource(hostmem_resource, res); 411 if (rc) { 412 pr_warn("%s: Can't insert [%llx - %llx) (%d)\n", 413 __func__, res->start, res->end, rc); 414 kfree(res); 415 goto out; 416 } 417 } 418 419 out: 420 kfree(xen_e820_table); 421 } 422 #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ 423