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