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