linux/arch/arm/xen/enlighten.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2#include <xen/xen.h>
   3#include <xen/events.h>
   4#include <xen/grant_table.h>
   5#include <xen/hvm.h>
   6#include <xen/interface/vcpu.h>
   7#include <xen/interface/xen.h>
   8#include <xen/interface/memory.h>
   9#include <xen/interface/hvm/params.h>
  10#include <xen/features.h>
  11#include <xen/platform_pci.h>
  12#include <xen/xenbus.h>
  13#include <xen/page.h>
  14#include <xen/interface/sched.h>
  15#include <xen/xen-ops.h>
  16#include <asm/xen/hypervisor.h>
  17#include <asm/xen/hypercall.h>
  18#include <asm/system_misc.h>
  19#include <asm/efi.h>
  20#include <linux/interrupt.h>
  21#include <linux/irqreturn.h>
  22#include <linux/module.h>
  23#include <linux/of.h>
  24#include <linux/of_fdt.h>
  25#include <linux/of_irq.h>
  26#include <linux/of_address.h>
  27#include <linux/cpuidle.h>
  28#include <linux/cpufreq.h>
  29#include <linux/cpu.h>
  30#include <linux/console.h>
  31#include <linux/pvclock_gtod.h>
  32#include <linux/reboot.h>
  33#include <linux/time64.h>
  34#include <linux/timekeeping.h>
  35#include <linux/timekeeper_internal.h>
  36#include <linux/acpi.h>
  37
  38#include <linux/mm.h>
  39
  40static struct start_info _xen_start_info;
  41struct start_info *xen_start_info = &_xen_start_info;
  42EXPORT_SYMBOL(xen_start_info);
  43
  44enum xen_domain_type xen_domain_type = XEN_NATIVE;
  45EXPORT_SYMBOL(xen_domain_type);
  46
  47struct shared_info xen_dummy_shared_info;
  48struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
  49
  50DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
  51static struct vcpu_info __percpu *xen_vcpu_info;
  52
  53/* Linux <-> Xen vCPU id mapping */
  54DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
  55EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
  56
  57/* These are unused until we support booting "pre-ballooned" */
  58unsigned long xen_released_pages;
  59struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
  60
  61static __read_mostly unsigned int xen_events_irq;
  62
  63uint32_t xen_start_flags;
  64EXPORT_SYMBOL(xen_start_flags);
  65
  66int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
  67                               int nr, struct page **pages)
  68{
  69        return xen_xlate_unmap_gfn_range(vma, nr, pages);
  70}
  71EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
  72
  73static void xen_read_wallclock(struct timespec64 *ts)
  74{
  75        u32 version;
  76        struct timespec64 now, ts_monotonic;
  77        struct shared_info *s = HYPERVISOR_shared_info;
  78        struct pvclock_wall_clock *wall_clock = &(s->wc);
  79
  80        /* get wallclock at system boot */
  81        do {
  82                version = wall_clock->version;
  83                rmb();          /* fetch version before time */
  84                now.tv_sec  = ((uint64_t)wall_clock->sec_hi << 32) | wall_clock->sec;
  85                now.tv_nsec = wall_clock->nsec;
  86                rmb();          /* fetch time before checking version */
  87        } while ((wall_clock->version & 1) || (version != wall_clock->version));
  88
  89        /* time since system boot */
  90        ktime_get_ts64(&ts_monotonic);
  91        *ts = timespec64_add(now, ts_monotonic);
  92}
  93
  94static int xen_pvclock_gtod_notify(struct notifier_block *nb,
  95                                   unsigned long was_set, void *priv)
  96{
  97        /* Protected by the calling core code serialization */
  98        static struct timespec64 next_sync;
  99
 100        struct xen_platform_op op;
 101        struct timespec64 now, system_time;
 102        struct timekeeper *tk = priv;
 103
 104        now.tv_sec = tk->xtime_sec;
 105        now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
 106        system_time = timespec64_add(now, tk->wall_to_monotonic);
 107
 108        /*
 109         * We only take the expensive HV call when the clock was set
 110         * or when the 11 minutes RTC synchronization time elapsed.
 111         */
 112        if (!was_set && timespec64_compare(&now, &next_sync) < 0)
 113                return NOTIFY_OK;
 114
 115        op.cmd = XENPF_settime64;
 116        op.u.settime64.mbz = 0;
 117        op.u.settime64.secs = now.tv_sec;
 118        op.u.settime64.nsecs = now.tv_nsec;
 119        op.u.settime64.system_time = timespec64_to_ns(&system_time);
 120        (void)HYPERVISOR_platform_op(&op);
 121
 122        /*
 123         * Move the next drift compensation time 11 minutes
 124         * ahead. That's emulating the sync_cmos_clock() update for
 125         * the hardware RTC.
 126         */
 127        next_sync = now;
 128        next_sync.tv_sec += 11 * 60;
 129
 130        return NOTIFY_OK;
 131}
 132
 133static struct notifier_block xen_pvclock_gtod_notifier = {
 134        .notifier_call = xen_pvclock_gtod_notify,
 135};
 136
 137static int xen_starting_cpu(unsigned int cpu)
 138{
 139        struct vcpu_register_vcpu_info info;
 140        struct vcpu_info *vcpup;
 141        int err;
 142
 143        /* 
 144         * VCPUOP_register_vcpu_info cannot be called twice for the same
 145         * vcpu, so if vcpu_info is already registered, just get out. This
 146         * can happen with cpu-hotplug.
 147         */
 148        if (per_cpu(xen_vcpu, cpu) != NULL)
 149                goto after_register_vcpu_info;
 150
 151        pr_info("Xen: initializing cpu%d\n", cpu);
 152        vcpup = per_cpu_ptr(xen_vcpu_info, cpu);
 153
 154        info.mfn = percpu_to_gfn(vcpup);
 155        info.offset = xen_offset_in_page(vcpup);
 156
 157        err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
 158                                 &info);
 159        BUG_ON(err);
 160        per_cpu(xen_vcpu, cpu) = vcpup;
 161
 162        if (!xen_kernel_unmapped_at_usr())
 163                xen_setup_runstate_info(cpu);
 164
 165after_register_vcpu_info:
 166        enable_percpu_irq(xen_events_irq, 0);
 167        return 0;
 168}
 169
 170static int xen_dying_cpu(unsigned int cpu)
 171{
 172        disable_percpu_irq(xen_events_irq);
 173        return 0;
 174}
 175
 176void xen_reboot(int reason)
 177{
 178        struct sched_shutdown r = { .reason = reason };
 179        int rc;
 180
 181        rc = HYPERVISOR_sched_op(SCHEDOP_shutdown, &r);
 182        BUG_ON(rc);
 183}
 184
 185static int xen_restart(struct notifier_block *nb, unsigned long action,
 186                       void *data)
 187{
 188        xen_reboot(SHUTDOWN_reboot);
 189
 190        return NOTIFY_DONE;
 191}
 192
 193static struct notifier_block xen_restart_nb = {
 194        .notifier_call = xen_restart,
 195        .priority = 192,
 196};
 197
 198static void xen_power_off(void)
 199{
 200        xen_reboot(SHUTDOWN_poweroff);
 201}
 202
 203static irqreturn_t xen_arm_callback(int irq, void *arg)
 204{
 205        xen_hvm_evtchn_do_upcall();
 206        return IRQ_HANDLED;
 207}
 208
 209static __initdata struct {
 210        const char *compat;
 211        const char *prefix;
 212        const char *version;
 213        bool found;
 214} hyper_node = {"xen,xen", "xen,xen-", NULL, false};
 215
 216static int __init fdt_find_hyper_node(unsigned long node, const char *uname,
 217                                      int depth, void *data)
 218{
 219        const void *s = NULL;
 220        int len;
 221
 222        if (depth != 1 || strcmp(uname, "hypervisor") != 0)
 223                return 0;
 224
 225        if (of_flat_dt_is_compatible(node, hyper_node.compat))
 226                hyper_node.found = true;
 227
 228        s = of_get_flat_dt_prop(node, "compatible", &len);
 229        if (strlen(hyper_node.prefix) + 3  < len &&
 230            !strncmp(hyper_node.prefix, s, strlen(hyper_node.prefix)))
 231                hyper_node.version = s + strlen(hyper_node.prefix);
 232
 233        /*
 234         * Check if Xen supports EFI by checking whether there is the
 235         * "/hypervisor/uefi" node in DT. If so, runtime services are available
 236         * through proxy functions (e.g. in case of Xen dom0 EFI implementation
 237         * they call special hypercall which executes relevant EFI functions)
 238         * and that is why they are always enabled.
 239         */
 240        if (IS_ENABLED(CONFIG_XEN_EFI)) {
 241                if ((of_get_flat_dt_subnode_by_name(node, "uefi") > 0) &&
 242                    !efi_runtime_disabled())
 243                        set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 244        }
 245
 246        return 0;
 247}
 248
 249/*
 250 * see Documentation/devicetree/bindings/arm/xen.txt for the
 251 * documentation of the Xen Device Tree format.
 252 */
 253void __init xen_early_init(void)
 254{
 255        of_scan_flat_dt(fdt_find_hyper_node, NULL);
 256        if (!hyper_node.found) {
 257                pr_debug("No Xen support\n");
 258                return;
 259        }
 260
 261        if (hyper_node.version == NULL) {
 262                pr_debug("Xen version not found\n");
 263                return;
 264        }
 265
 266        pr_info("Xen %s support found\n", hyper_node.version);
 267
 268        xen_domain_type = XEN_HVM_DOMAIN;
 269
 270        xen_setup_features();
 271
 272        if (xen_feature(XENFEAT_dom0))
 273                xen_start_flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
 274
 275        if (!console_set_on_cmdline && !xen_initial_domain())
 276                add_preferred_console("hvc", 0, NULL);
 277}
 278
 279static void __init xen_acpi_guest_init(void)
 280{
 281#ifdef CONFIG_ACPI
 282        struct xen_hvm_param a;
 283        int interrupt, trigger, polarity;
 284
 285        a.domid = DOMID_SELF;
 286        a.index = HVM_PARAM_CALLBACK_IRQ;
 287
 288        if (HYPERVISOR_hvm_op(HVMOP_get_param, &a)
 289            || (a.value >> 56) != HVM_PARAM_CALLBACK_TYPE_PPI) {
 290                xen_events_irq = 0;
 291                return;
 292        }
 293
 294        interrupt = a.value & 0xff;
 295        trigger = ((a.value >> 8) & 0x1) ? ACPI_EDGE_SENSITIVE
 296                                         : ACPI_LEVEL_SENSITIVE;
 297        polarity = ((a.value >> 8) & 0x2) ? ACPI_ACTIVE_LOW
 298                                          : ACPI_ACTIVE_HIGH;
 299        xen_events_irq = acpi_register_gsi(NULL, interrupt, trigger, polarity);
 300#endif
 301}
 302
 303static void __init xen_dt_guest_init(void)
 304{
 305        struct device_node *xen_node;
 306
 307        xen_node = of_find_compatible_node(NULL, NULL, "xen,xen");
 308        if (!xen_node) {
 309                pr_err("Xen support was detected before, but it has disappeared\n");
 310                return;
 311        }
 312
 313        xen_events_irq = irq_of_parse_and_map(xen_node, 0);
 314}
 315
 316static int __init xen_guest_init(void)
 317{
 318        struct xen_add_to_physmap xatp;
 319        struct shared_info *shared_info_page = NULL;
 320        int cpu;
 321
 322        if (!xen_domain())
 323                return 0;
 324
 325        if (!acpi_disabled)
 326                xen_acpi_guest_init();
 327        else
 328                xen_dt_guest_init();
 329
 330        if (!xen_events_irq) {
 331                pr_err("Xen event channel interrupt not found\n");
 332                return -ENODEV;
 333        }
 334
 335        /*
 336         * The fdt parsing codes have set EFI_RUNTIME_SERVICES if Xen EFI
 337         * parameters are found. Force enable runtime services.
 338         */
 339        if (efi_enabled(EFI_RUNTIME_SERVICES))
 340                xen_efi_runtime_setup();
 341
 342        shared_info_page = (struct shared_info *)get_zeroed_page(GFP_KERNEL);
 343
 344        if (!shared_info_page) {
 345                pr_err("not enough memory\n");
 346                return -ENOMEM;
 347        }
 348        xatp.domid = DOMID_SELF;
 349        xatp.idx = 0;
 350        xatp.space = XENMAPSPACE_shared_info;
 351        xatp.gpfn = virt_to_gfn(shared_info_page);
 352        if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
 353                BUG();
 354
 355        HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
 356
 357        /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
 358         * page, we use it in the event channel upcall and in some pvclock
 359         * related functions. 
 360         * The shared info contains exactly 1 CPU (the boot CPU). The guest
 361         * is required to use VCPUOP_register_vcpu_info to place vcpu info
 362         * for secondary CPUs as they are brought up.
 363         * For uniformity we use VCPUOP_register_vcpu_info even on cpu0.
 364         */
 365        xen_vcpu_info = alloc_percpu(struct vcpu_info);
 366        if (xen_vcpu_info == NULL)
 367                return -ENOMEM;
 368
 369        /* Direct vCPU id mapping for ARM guests. */
 370        for_each_possible_cpu(cpu)
 371                per_cpu(xen_vcpu_id, cpu) = cpu;
 372
 373        xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
 374        if (xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
 375                                          &xen_auto_xlat_grant_frames.vaddr,
 376                                          xen_auto_xlat_grant_frames.count)) {
 377                free_percpu(xen_vcpu_info);
 378                return -ENOMEM;
 379        }
 380        gnttab_init();
 381
 382        /*
 383         * Making sure board specific code will not set up ops for
 384         * cpu idle and cpu freq.
 385         */
 386        disable_cpuidle();
 387        disable_cpufreq();
 388
 389        xen_init_IRQ();
 390
 391        if (request_percpu_irq(xen_events_irq, xen_arm_callback,
 392                               "events", &xen_vcpu)) {
 393                pr_err("Error request IRQ %d\n", xen_events_irq);
 394                return -EINVAL;
 395        }
 396
 397        if (!xen_kernel_unmapped_at_usr())
 398                xen_time_setup_guest();
 399
 400        if (xen_initial_domain())
 401                pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
 402
 403        return cpuhp_setup_state(CPUHP_AP_ARM_XEN_STARTING,
 404                                 "arm/xen:starting", xen_starting_cpu,
 405                                 xen_dying_cpu);
 406}
 407early_initcall(xen_guest_init);
 408
 409static int __init xen_pm_init(void)
 410{
 411        if (!xen_domain())
 412                return -ENODEV;
 413
 414        pm_power_off = xen_power_off;
 415        register_restart_handler(&xen_restart_nb);
 416        if (!xen_initial_domain()) {
 417                struct timespec64 ts;
 418                xen_read_wallclock(&ts);
 419                do_settimeofday64(&ts);
 420        }
 421
 422        return 0;
 423}
 424late_initcall(xen_pm_init);
 425
 426
 427/* empty stubs */
 428void xen_arch_pre_suspend(void) { }
 429void xen_arch_post_suspend(int suspend_cancelled) { }
 430void xen_timer_resume(void) { }
 431void xen_arch_resume(void) { }
 432void xen_arch_suspend(void) { }
 433
 434
 435/* In the hypercall.S file. */
 436EXPORT_SYMBOL_GPL(HYPERVISOR_event_channel_op);
 437EXPORT_SYMBOL_GPL(HYPERVISOR_grant_table_op);
 438EXPORT_SYMBOL_GPL(HYPERVISOR_xen_version);
 439EXPORT_SYMBOL_GPL(HYPERVISOR_console_io);
 440EXPORT_SYMBOL_GPL(HYPERVISOR_sched_op);
 441EXPORT_SYMBOL_GPL(HYPERVISOR_hvm_op);
 442EXPORT_SYMBOL_GPL(HYPERVISOR_memory_op);
 443EXPORT_SYMBOL_GPL(HYPERVISOR_physdev_op);
 444EXPORT_SYMBOL_GPL(HYPERVISOR_vcpu_op);
 445EXPORT_SYMBOL_GPL(HYPERVISOR_tmem_op);
 446EXPORT_SYMBOL_GPL(HYPERVISOR_platform_op_raw);
 447EXPORT_SYMBOL_GPL(HYPERVISOR_multicall);
 448EXPORT_SYMBOL_GPL(HYPERVISOR_vm_assist);
 449EXPORT_SYMBOL_GPL(HYPERVISOR_dm_op);
 450EXPORT_SYMBOL_GPL(privcmd_call);
 451