1 // SPDX-License-Identifier: GPL-2.0 2 3 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG 4 #include <linux/memblock.h> 5 #endif 6 #include <linux/console.h> 7 #include <linux/cpu.h> 8 #include <linux/kexec.h> 9 #include <linux/slab.h> 10 #include <linux/panic_notifier.h> 11 12 #include <xen/xen.h> 13 #include <xen/features.h> 14 #include <xen/interface/sched.h> 15 #include <xen/interface/version.h> 16 #include <xen/page.h> 17 18 #include <asm/xen/hypercall.h> 19 #include <asm/xen/hypervisor.h> 20 #include <asm/cpu.h> 21 #include <asm/e820/api.h> 22 #include <asm/setup.h> 23 24 #include "xen-ops.h" 25 #include "smp.h" 26 #include "pmu.h" 27 28 EXPORT_SYMBOL_GPL(hypercall_page); 29 30 /* 31 * Pointer to the xen_vcpu_info structure or 32 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 33 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 34 * but during boot it is switched to point to xen_vcpu_info. 35 * The pointer is used in __xen_evtchn_do_upcall to acknowledge pending events. 36 */ 37 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 38 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 39 40 /* Linux <-> Xen vCPU id mapping */ 41 DEFINE_PER_CPU(uint32_t, xen_vcpu_id); 42 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); 43 44 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 45 EXPORT_SYMBOL(machine_to_phys_mapping); 46 unsigned long machine_to_phys_nr; 47 EXPORT_SYMBOL(machine_to_phys_nr); 48 49 struct start_info *xen_start_info; 50 EXPORT_SYMBOL_GPL(xen_start_info); 51 52 struct shared_info xen_dummy_shared_info; 53 54 __read_mostly bool xen_have_vector_callback = true; 55 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 56 57 /* 58 * NB: These need to live in .data or alike because they're used by 59 * xen_prepare_pvh() which runs before clearing the bss. 60 */ 61 enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE; 62 EXPORT_SYMBOL_GPL(xen_domain_type); 63 uint32_t __ro_after_init xen_start_flags; 64 EXPORT_SYMBOL(xen_start_flags); 65 66 /* 67 * Point at some empty memory to start with. We map the real shared_info 68 * page as soon as fixmap is up and running. 69 */ 70 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 71 72 static int xen_cpu_up_online(unsigned int cpu) 73 { 74 xen_init_lock_cpu(cpu); 75 return 0; 76 } 77 78 int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), 79 int (*cpu_dead_cb)(unsigned int)) 80 { 81 int rc; 82 83 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, 84 "x86/xen/guest:prepare", 85 cpu_up_prepare_cb, cpu_dead_cb); 86 if (rc >= 0) { 87 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 88 "x86/xen/guest:online", 89 xen_cpu_up_online, NULL); 90 if (rc < 0) 91 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); 92 } 93 94 return rc >= 0 ? 0 : rc; 95 } 96 97 static void xen_vcpu_setup_restore(int cpu) 98 { 99 /* Any per_cpu(xen_vcpu) is stale, so reset it */ 100 xen_vcpu_info_reset(cpu); 101 102 /* 103 * For PVH and PVHVM, setup online VCPUs only. The rest will 104 * be handled by hotplug. 105 */ 106 if (xen_pv_domain() || 107 (xen_hvm_domain() && cpu_online(cpu))) 108 xen_vcpu_setup(cpu); 109 } 110 111 /* 112 * On restore, set the vcpu placement up again. 113 * If it fails, then we're in a bad state, since 114 * we can't back out from using it... 115 */ 116 void xen_vcpu_restore(void) 117 { 118 int cpu; 119 120 for_each_possible_cpu(cpu) { 121 bool other_cpu = (cpu != smp_processor_id()); 122 bool is_up; 123 124 if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID) 125 continue; 126 127 /* Only Xen 4.5 and higher support this. */ 128 is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, 129 xen_vcpu_nr(cpu), NULL) > 0; 130 131 if (other_cpu && is_up && 132 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL)) 133 BUG(); 134 135 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 136 xen_setup_runstate_info(cpu); 137 138 xen_vcpu_setup_restore(cpu); 139 140 if (other_cpu && is_up && 141 HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) 142 BUG(); 143 } 144 } 145 146 void xen_vcpu_info_reset(int cpu) 147 { 148 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) { 149 per_cpu(xen_vcpu, cpu) = 150 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 151 } else { 152 /* Set to NULL so that if somebody accesses it we get an OOPS */ 153 per_cpu(xen_vcpu, cpu) = NULL; 154 } 155 } 156 157 void xen_vcpu_setup(int cpu) 158 { 159 struct vcpu_register_vcpu_info info; 160 int err; 161 struct vcpu_info *vcpup; 162 163 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 164 165 /* 166 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu) 167 * and at restore (xen_vcpu_restore). Also called for hotplugged 168 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm). 169 * However, the hypercall can only be done once (see below) so if a VCPU 170 * is offlined and comes back online then let's not redo the hypercall. 171 * 172 * For PV it is called during restore (xen_vcpu_restore) and bootup 173 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 174 * use this function. 175 */ 176 if (xen_hvm_domain()) { 177 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 178 return; 179 } 180 181 vcpup = &per_cpu(xen_vcpu_info, cpu); 182 info.mfn = arbitrary_virt_to_mfn(vcpup); 183 info.offset = offset_in_page(vcpup); 184 185 /* 186 * N.B. This hypercall can _only_ be called once per CPU. 187 * Subsequent calls will error out with -EINVAL. This is due to 188 * the fact that hypervisor has no unregister variant and this 189 * hypercall does not allow to over-write info.mfn and 190 * info.offset. 191 */ 192 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu), 193 &info); 194 if (err) 195 panic("register_vcpu_info failed: cpu=%d err=%d\n", cpu, err); 196 197 per_cpu(xen_vcpu, cpu) = vcpup; 198 } 199 200 void __init xen_banner(void) 201 { 202 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 203 struct xen_extraversion extra; 204 205 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 206 207 pr_info("Booting kernel on %s\n", pv_info.name); 208 pr_info("Xen version: %u.%u%s%s\n", 209 version >> 16, version & 0xffff, extra.extraversion, 210 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) 211 ? " (preserve-AD)" : ""); 212 } 213 214 /* Check if running on Xen version (major, minor) or later */ 215 bool xen_running_on_version_or_later(unsigned int major, unsigned int minor) 216 { 217 unsigned int version; 218 219 if (!xen_domain()) 220 return false; 221 222 version = HYPERVISOR_xen_version(XENVER_version, NULL); 223 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 224 ((version >> 16) > major)) 225 return true; 226 return false; 227 } 228 229 void __init xen_add_preferred_consoles(void) 230 { 231 add_preferred_console("xenboot", 0, NULL); 232 if (!boot_params.screen_info.orig_video_isVGA) 233 add_preferred_console("tty", 0, NULL); 234 add_preferred_console("hvc", 0, NULL); 235 if (boot_params.screen_info.orig_video_isVGA) 236 add_preferred_console("tty", 0, NULL); 237 } 238 239 void xen_reboot(int reason) 240 { 241 struct sched_shutdown r = { .reason = reason }; 242 int cpu; 243 244 for_each_online_cpu(cpu) 245 xen_pmu_finish(cpu); 246 247 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 248 BUG(); 249 } 250 251 static int reboot_reason = SHUTDOWN_reboot; 252 static bool xen_legacy_crash; 253 void xen_emergency_restart(void) 254 { 255 xen_reboot(reboot_reason); 256 } 257 258 static int 259 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 260 { 261 if (!kexec_crash_loaded()) { 262 if (xen_legacy_crash) 263 xen_reboot(SHUTDOWN_crash); 264 265 reboot_reason = SHUTDOWN_crash; 266 267 /* 268 * If panic_timeout==0 then we are supposed to wait forever. 269 * However, to preserve original dom0 behavior we have to drop 270 * into hypervisor. (domU behavior is controlled by its 271 * config file) 272 */ 273 if (panic_timeout == 0) 274 panic_timeout = -1; 275 } 276 return NOTIFY_DONE; 277 } 278 279 static int __init parse_xen_legacy_crash(char *arg) 280 { 281 xen_legacy_crash = true; 282 return 0; 283 } 284 early_param("xen_legacy_crash", parse_xen_legacy_crash); 285 286 static struct notifier_block xen_panic_block = { 287 .notifier_call = xen_panic_event, 288 .priority = INT_MIN 289 }; 290 291 int xen_panic_handler_init(void) 292 { 293 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 294 return 0; 295 } 296 297 void xen_pin_vcpu(int cpu) 298 { 299 static bool disable_pinning; 300 struct sched_pin_override pin_override; 301 int ret; 302 303 if (disable_pinning) 304 return; 305 306 pin_override.pcpu = cpu; 307 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); 308 309 /* Ignore errors when removing override. */ 310 if (cpu < 0) 311 return; 312 313 switch (ret) { 314 case -ENOSYS: 315 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", 316 cpu); 317 disable_pinning = true; 318 break; 319 case -EPERM: 320 WARN(1, "Trying to pin vcpu without having privilege to do so\n"); 321 disable_pinning = true; 322 break; 323 case -EINVAL: 324 case -EBUSY: 325 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", 326 cpu); 327 break; 328 case 0: 329 break; 330 default: 331 WARN(1, "rc %d while trying to pin vcpu\n", ret); 332 disable_pinning = true; 333 } 334 } 335 336 #ifdef CONFIG_HOTPLUG_CPU 337 void xen_arch_register_cpu(int num) 338 { 339 arch_register_cpu(num); 340 } 341 EXPORT_SYMBOL(xen_arch_register_cpu); 342 343 void xen_arch_unregister_cpu(int num) 344 { 345 arch_unregister_cpu(num); 346 } 347 EXPORT_SYMBOL(xen_arch_unregister_cpu); 348 #endif 349