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