1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/console.h> 4 #include <linux/cpu.h> 5 #include <linux/instrumentation.h> 6 #include <linux/kexec.h> 7 #include <linux/memblock.h> 8 #include <linux/slab.h> 9 #include <linux/panic_notifier.h> 10 11 #include <xen/xen.h> 12 #include <xen/features.h> 13 #include <xen/interface/sched.h> 14 #include <xen/interface/version.h> 15 #include <xen/page.h> 16 17 #include <asm/xen/hypercall.h> 18 #include <asm/xen/hypervisor.h> 19 #include <asm/cpu.h> 20 #include <asm/e820/api.h> 21 #include <asm/setup.h> 22 23 #include "xen-ops.h" 24 25 DEFINE_STATIC_CALL(xen_hypercall, xen_hypercall_hvm); 26 EXPORT_STATIC_CALL_TRAMP(xen_hypercall); 27 28 /* 29 * Pointer to the xen_vcpu_info structure or 30 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 31 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 32 * but during boot it is switched to point to xen_vcpu_info. 33 * The pointer is used in xen_evtchn_do_upcall to acknowledge pending events. 34 * Make sure that xen_vcpu_info doesn't cross a page boundary by making it 35 * cache-line aligned (the struct is guaranteed to have a size of 64 bytes, 36 * which matches the cache line size of 64-bit x86 processors). 37 */ 38 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 39 DEFINE_PER_CPU_ALIGNED(struct vcpu_info, xen_vcpu_info); 40 41 /* Linux <-> Xen vCPU id mapping */ 42 DEFINE_PER_CPU(uint32_t, xen_vcpu_id); 43 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); 44 45 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 46 EXPORT_SYMBOL(machine_to_phys_mapping); 47 unsigned long machine_to_phys_nr; 48 EXPORT_SYMBOL(machine_to_phys_nr); 49 50 struct start_info *xen_start_info; 51 EXPORT_SYMBOL_GPL(xen_start_info); 52 53 struct shared_info xen_dummy_shared_info; 54 55 __read_mostly bool xen_have_vector_callback = true; 56 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 57 58 /* 59 * NB: These need to live in .data or alike because they're used by 60 * xen_prepare_pvh() which runs before clearing the bss. 61 */ 62 enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE; 63 EXPORT_SYMBOL_GPL(xen_domain_type); 64 uint32_t __ro_after_init xen_start_flags; 65 EXPORT_SYMBOL(xen_start_flags); 66 67 /* 68 * Point at some empty memory to start with. We map the real shared_info 69 * page as soon as fixmap is up and running. 70 */ 71 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 72 73 /* Number of pages released from the initial allocation. */ 74 unsigned long xen_released_pages; 75 76 static __ref void xen_get_vendor(void) 77 { 78 init_cpu_devs(); 79 cpu_detect(&boot_cpu_data); 80 get_cpu_vendor(&boot_cpu_data); 81 } 82 83 void xen_hypercall_setfunc(void) 84 { 85 if (static_call_query(xen_hypercall) != xen_hypercall_hvm) 86 return; 87 88 if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD || 89 boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)) 90 static_call_update(xen_hypercall, xen_hypercall_amd); 91 else 92 static_call_update(xen_hypercall, xen_hypercall_intel); 93 } 94 95 /* 96 * Evaluate processor vendor in order to select the correct hypercall 97 * function for HVM/PVH guests. 98 * Might be called very early in boot before vendor has been set by 99 * early_cpu_init(). 100 */ 101 noinstr void *__xen_hypercall_setfunc(void) 102 { 103 void (*func)(void); 104 105 /* 106 * Note that __xen_hypercall_setfunc() is noinstr only due to a nasty 107 * dependency chain: it is being called via the xen_hypercall static 108 * call when running as a PVH or HVM guest. Hypercalls need to be 109 * noinstr due to PV guests using hypercalls in noinstr code. So we 110 * can safely tag the function body as "instrumentation ok", since 111 * the PV guest requirement is not of interest here (xen_get_vendor() 112 * calls noinstr functions, and static_call_update_early() might do 113 * so, too). 114 */ 115 instrumentation_begin(); 116 117 xen_get_vendor(); 118 119 if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD || 120 boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)) 121 func = xen_hypercall_amd; 122 else 123 func = xen_hypercall_intel; 124 125 static_call_update_early(xen_hypercall, func); 126 127 instrumentation_end(); 128 129 return func; 130 } 131 132 static int xen_cpu_up_online(unsigned int cpu) 133 { 134 xen_init_lock_cpu(cpu); 135 return 0; 136 } 137 138 int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), 139 int (*cpu_dead_cb)(unsigned int)) 140 { 141 int rc; 142 143 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, 144 "x86/xen/guest:prepare", 145 cpu_up_prepare_cb, cpu_dead_cb); 146 if (rc >= 0) { 147 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 148 "x86/xen/guest:online", 149 xen_cpu_up_online, NULL); 150 if (rc < 0) 151 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); 152 } 153 154 return rc >= 0 ? 0 : rc; 155 } 156 157 static void xen_vcpu_setup_restore(int cpu) 158 { 159 /* Any per_cpu(xen_vcpu) is stale, so reset it */ 160 xen_vcpu_info_reset(cpu); 161 162 /* 163 * For PVH and PVHVM, setup online VCPUs only. The rest will 164 * be handled by hotplug. 165 */ 166 if (xen_pv_domain() || 167 (xen_hvm_domain() && cpu_online(cpu))) 168 xen_vcpu_setup(cpu); 169 } 170 171 /* 172 * On restore, set the vcpu placement up again. 173 * If it fails, then we're in a bad state, since 174 * we can't back out from using it... 175 */ 176 void xen_vcpu_restore(void) 177 { 178 int cpu; 179 180 for_each_possible_cpu(cpu) { 181 bool other_cpu = (cpu != smp_processor_id()); 182 bool is_up; 183 184 if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID) 185 continue; 186 187 /* Only Xen 4.5 and higher support this. */ 188 is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, 189 xen_vcpu_nr(cpu), NULL) > 0; 190 191 if (other_cpu && is_up && 192 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL)) 193 BUG(); 194 195 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 196 xen_setup_runstate_info(cpu); 197 198 xen_vcpu_setup_restore(cpu); 199 200 if (other_cpu && is_up && 201 HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) 202 BUG(); 203 } 204 } 205 206 void xen_vcpu_info_reset(int cpu) 207 { 208 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) { 209 per_cpu(xen_vcpu, cpu) = 210 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 211 } else { 212 /* Set to NULL so that if somebody accesses it we get an OOPS */ 213 per_cpu(xen_vcpu, cpu) = NULL; 214 } 215 } 216 217 void xen_vcpu_setup(int cpu) 218 { 219 struct vcpu_register_vcpu_info info; 220 int err; 221 struct vcpu_info *vcpup; 222 223 BUILD_BUG_ON(sizeof(*vcpup) > SMP_CACHE_BYTES); 224 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 225 226 /* 227 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu) 228 * and at restore (xen_vcpu_restore). Also called for hotplugged 229 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm). 230 * However, the hypercall can only be done once (see below) so if a VCPU 231 * is offlined and comes back online then let's not redo the hypercall. 232 * 233 * For PV it is called during restore (xen_vcpu_restore) and bootup 234 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 235 * use this function. 236 */ 237 if (xen_hvm_domain()) { 238 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 239 return; 240 } 241 242 vcpup = &per_cpu(xen_vcpu_info, cpu); 243 info.mfn = arbitrary_virt_to_mfn(vcpup); 244 info.offset = offset_in_page(vcpup); 245 246 /* 247 * N.B. This hypercall can _only_ be called once per CPU. 248 * Subsequent calls will error out with -EINVAL. This is due to 249 * the fact that hypervisor has no unregister variant and this 250 * hypercall does not allow to over-write info.mfn and 251 * info.offset. 252 */ 253 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu), 254 &info); 255 if (err) 256 panic("register_vcpu_info failed: cpu=%d err=%d\n", cpu, err); 257 258 per_cpu(xen_vcpu, cpu) = vcpup; 259 } 260 261 void __init xen_banner(void) 262 { 263 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 264 struct xen_extraversion extra; 265 266 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 267 268 pr_info("Booting kernel on %s\n", pv_info.name); 269 pr_info("Xen version: %u.%u%s%s\n", 270 version >> 16, version & 0xffff, extra.extraversion, 271 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) 272 ? " (preserve-AD)" : ""); 273 } 274 275 /* Check if running on Xen version (major, minor) or later */ 276 bool xen_running_on_version_or_later(unsigned int major, unsigned int minor) 277 { 278 unsigned int version; 279 280 if (!xen_domain()) 281 return false; 282 283 version = HYPERVISOR_xen_version(XENVER_version, NULL); 284 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 285 ((version >> 16) > major)) 286 return true; 287 return false; 288 } 289 290 void __init xen_add_preferred_consoles(void) 291 { 292 add_preferred_console("xenboot", 0, NULL); 293 if (!boot_params.screen_info.orig_video_isVGA) 294 add_preferred_console("tty", 0, NULL); 295 add_preferred_console("hvc", 0, NULL); 296 if (boot_params.screen_info.orig_video_isVGA) 297 add_preferred_console("tty", 0, NULL); 298 } 299 300 void xen_reboot(int reason) 301 { 302 struct sched_shutdown r = { .reason = reason }; 303 int cpu; 304 305 for_each_online_cpu(cpu) 306 xen_pmu_finish(cpu); 307 308 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 309 BUG(); 310 } 311 312 static int reboot_reason = SHUTDOWN_reboot; 313 static bool xen_legacy_crash; 314 void xen_emergency_restart(void) 315 { 316 xen_reboot(reboot_reason); 317 } 318 319 static int 320 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 321 { 322 if (!kexec_crash_loaded()) { 323 if (xen_legacy_crash) 324 xen_reboot(SHUTDOWN_crash); 325 326 reboot_reason = SHUTDOWN_crash; 327 328 /* 329 * If panic_timeout==0 then we are supposed to wait forever. 330 * However, to preserve original dom0 behavior we have to drop 331 * into hypervisor. (domU behavior is controlled by its 332 * config file) 333 */ 334 if (panic_timeout == 0) 335 panic_timeout = -1; 336 } 337 return NOTIFY_DONE; 338 } 339 340 static int __init parse_xen_legacy_crash(char *arg) 341 { 342 xen_legacy_crash = true; 343 return 0; 344 } 345 early_param("xen_legacy_crash", parse_xen_legacy_crash); 346 347 static struct notifier_block xen_panic_block = { 348 .notifier_call = xen_panic_event, 349 .priority = INT_MIN 350 }; 351 352 int xen_panic_handler_init(void) 353 { 354 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 355 return 0; 356 } 357 358 void xen_pin_vcpu(int cpu) 359 { 360 static bool disable_pinning; 361 struct sched_pin_override pin_override; 362 int ret; 363 364 if (disable_pinning) 365 return; 366 367 pin_override.pcpu = cpu; 368 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); 369 370 /* Ignore errors when removing override. */ 371 if (cpu < 0) 372 return; 373 374 switch (ret) { 375 case -ENOSYS: 376 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", 377 cpu); 378 disable_pinning = true; 379 break; 380 case -EPERM: 381 WARN(1, "Trying to pin vcpu without having privilege to do so\n"); 382 disable_pinning = true; 383 break; 384 case -EINVAL: 385 case -EBUSY: 386 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", 387 cpu); 388 break; 389 case 0: 390 break; 391 default: 392 WARN(1, "rc %d while trying to pin vcpu\n", ret); 393 disable_pinning = true; 394 } 395 } 396 397 #ifdef CONFIG_HOTPLUG_CPU 398 void xen_arch_register_cpu(int num) 399 { 400 arch_register_cpu(num); 401 } 402 EXPORT_SYMBOL(xen_arch_register_cpu); 403 404 void xen_arch_unregister_cpu(int num) 405 { 406 arch_unregister_cpu(num); 407 } 408 EXPORT_SYMBOL(xen_arch_unregister_cpu); 409 #endif 410 411 /* Amount of extra memory space we add to the e820 ranges */ 412 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; 413 414 void __init xen_add_extra_mem(unsigned long start_pfn, unsigned long n_pfns) 415 { 416 unsigned int i; 417 418 /* 419 * No need to check for zero size, should happen rarely and will only 420 * write a new entry regarded to be unused due to zero size. 421 */ 422 for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { 423 /* Add new region. */ 424 if (xen_extra_mem[i].n_pfns == 0) { 425 xen_extra_mem[i].start_pfn = start_pfn; 426 xen_extra_mem[i].n_pfns = n_pfns; 427 break; 428 } 429 /* Append to existing region. */ 430 if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns == 431 start_pfn) { 432 xen_extra_mem[i].n_pfns += n_pfns; 433 break; 434 } 435 } 436 if (i == XEN_EXTRA_MEM_MAX_REGIONS) 437 printk(KERN_WARNING "Warning: not enough extra memory regions\n"); 438 439 memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns)); 440 } 441 442 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC 443 int __init arch_xen_unpopulated_init(struct resource **res) 444 { 445 unsigned int i; 446 447 if (!xen_domain()) 448 return -ENODEV; 449 450 /* Must be set strictly before calling xen_free_unpopulated_pages(). */ 451 *res = &iomem_resource; 452 453 /* 454 * Initialize with pages from the extra memory regions (see 455 * arch/x86/xen/setup.c). 456 */ 457 for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { 458 unsigned int j; 459 460 for (j = 0; j < xen_extra_mem[i].n_pfns; j++) { 461 struct page *pg = 462 pfn_to_page(xen_extra_mem[i].start_pfn + j); 463 464 xen_free_unpopulated_pages(1, &pg); 465 } 466 467 /* 468 * Account for the region being in the physmap but unpopulated. 469 * The value in xen_released_pages is used by the balloon 470 * driver to know how much of the physmap is unpopulated and 471 * set an accurate initial memory target. 472 */ 473 xen_released_pages += xen_extra_mem[i].n_pfns; 474 /* Zero so region is not also added to the balloon driver. */ 475 xen_extra_mem[i].n_pfns = 0; 476 } 477 478 return 0; 479 } 480 #endif 481