arch/x86/xen/enlighten.c

   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 int xen_have_vector_callback;
  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