x86/xen/enlighten.c

0001 // SPDX-License-Identifier: GPL-2.0
0002
0003 #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
0004 #include <linux/memblock.h>
0005 #endif
0006 #include <linux/console.h>
0007 #include <linux/cpu.h>
0008 #include <linux/kexec.h>
0009 #include <linux/slab.h>
0010 #include <linux/panic_notifier.h>
0011
0012 #include <xen/xen.h>
0013 #include <xen/features.h>
0014 #include <xen/interface/sched.h>
0015 #include <xen/interface/version.h>
0016 #include <xen/page.h>
0017
0018 #include <asm/xen/hypercall.h>
0019 #include <asm/xen/hypervisor.h>
0020 #include <asm/cpu.h>
0021 #include <asm/e820/api.h>
0022 #include <asm/setup.h>
0023
0024 #include "xen-ops.h"
0025 #include "smp.h"
0026 #include "pmu.h"
0027
0028 EXPORT_SYMBOL_GPL(hypercall_page);
0029
0030 /*
0031  * Pointer to the xen_vcpu_info structure or
0032  * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
0033  * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
0034  * but during boot it is switched to point to xen_vcpu_info.
0035  * The pointer is used in __xen_evtchn_do_upcall to acknowledge pending events.
0036  */
0037 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
0038 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
0039
0040 /* Linux <-> Xen vCPU id mapping */
0041 DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
0042 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
0043
0044 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
0045 EXPORT_SYMBOL(machine_to_phys_mapping);
0046 unsigned long  machine_to_phys_nr;
0047 EXPORT_SYMBOL(machine_to_phys_nr);
0048
0049 struct start_info *xen_start_info;
0050 EXPORT_SYMBOL_GPL(xen_start_info);
0051
0052 struct shared_info xen_dummy_shared_info;
0053
0054 __read_mostly bool xen_have_vector_callback = true;
0055 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
0056
0057 /*
0058  * NB: These need to live in .data or alike because they're used by
0059  * xen_prepare_pvh() which runs before clearing the bss.
0060  */
0061 enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE;
0062 EXPORT_SYMBOL_GPL(xen_domain_type);
0063 uint32_t __ro_after_init xen_start_flags;
0064 EXPORT_SYMBOL(xen_start_flags);
0065
0066 /*
0067  * Point at some empty memory to start with. We map the real shared_info
0068  * page as soon as fixmap is up and running.
0069  */
0070 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
0071
0072 static int xen_cpu_up_online(unsigned int cpu)
0073 {
0074     xen_init_lock_cpu(cpu);
0075     return 0;
0076 }
0077
0078 int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
0079             int (*cpu_dead_cb)(unsigned int))
0080 {
0081     int rc;
0082
0083     rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
0084                        "x86/xen/guest:prepare",
0085                        cpu_up_prepare_cb, cpu_dead_cb);
0086     if (rc >= 0) {
0087         rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
0088                            "x86/xen/guest:online",
0089                            xen_cpu_up_online, NULL);
0090         if (rc < 0)
0091             cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE);
0092     }
0093
0094     return rc >= 0 ? 0 : rc;
0095 }
0096
0097 static void xen_vcpu_setup_restore(int cpu)
0098 {
0099     /* Any per_cpu(xen_vcpu) is stale, so reset it */
0100     xen_vcpu_info_reset(cpu);
0101
0102     /*
0103      * For PVH and PVHVM, setup online VCPUs only. The rest will
0104      * be handled by hotplug.
0105      */
0106     if (xen_pv_domain() ||
0107         (xen_hvm_domain() && cpu_online(cpu)))
0108         xen_vcpu_setup(cpu);
0109 }
0110
0111 /*
0112  * On restore, set the vcpu placement up again.
0113  * If it fails, then we're in a bad state, since
0114  * we can't back out from using it...
0115  */
0116 void xen_vcpu_restore(void)
0117 {
0118     int cpu;
0119
0120     for_each_possible_cpu(cpu) {
0121         bool other_cpu = (cpu != smp_processor_id());
0122         bool is_up;
0123
0124         if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID)
0125             continue;
0126
0127         /* Only Xen 4.5 and higher support this. */
0128         is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up,
0129                        xen_vcpu_nr(cpu), NULL) > 0;
0130
0131         if (other_cpu && is_up &&
0132             HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
0133             BUG();
0134
0135         if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
0136             xen_setup_runstate_info(cpu);
0137
0138         xen_vcpu_setup_restore(cpu);
0139
0140         if (other_cpu && is_up &&
0141             HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
0142             BUG();
0143     }
0144 }
0145
0146 void xen_vcpu_info_reset(int cpu)
0147 {
0148     if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) {
0149         per_cpu(xen_vcpu, cpu) =
0150             &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
0151     } else {
0152         /* Set to NULL so that if somebody accesses it we get an OOPS */
0153         per_cpu(xen_vcpu, cpu) = NULL;
0154     }
0155 }
0156
0157 void xen_vcpu_setup(int cpu)
0158 {
0159     struct vcpu_register_vcpu_info info;
0160     int err;
0161     struct vcpu_info *vcpup;
0162
0163     BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
0164
0165     /*
0166      * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu)
0167      * and at restore (xen_vcpu_restore). Also called for hotplugged
0168      * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm).
0169      * However, the hypercall can only be done once (see below) so if a VCPU
0170      * is offlined and comes back online then let's not redo the hypercall.
0171      *
0172      * For PV it is called during restore (xen_vcpu_restore) and bootup
0173      * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
0174      * use this function.
0175      */
0176     if (xen_hvm_domain()) {
0177         if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
0178             return;
0179     }
0180
0181     vcpup = &per_cpu(xen_vcpu_info, cpu);
0182     info.mfn = arbitrary_virt_to_mfn(vcpup);
0183     info.offset = offset_in_page(vcpup);
0184
0185     /*
0186      * N.B. This hypercall can _only_ be called once per CPU.
0187      * Subsequent calls will error out with -EINVAL. This is due to
0188      * the fact that hypervisor has no unregister variant and this
0189      * hypercall does not allow to over-write info.mfn and
0190      * info.offset.
0191      */
0192     err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
0193                  &info);
0194     if (err)
0195         panic("register_vcpu_info failed: cpu=%d err=%d\n", cpu, err);
0196
0197     per_cpu(xen_vcpu, cpu) = vcpup;
0198 }
0199
0200 void __init xen_banner(void)
0201 {
0202     unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
0203     struct xen_extraversion extra;
0204
0205     HYPERVISOR_xen_version(XENVER_extraversion, &extra);
0206
0207     pr_info("Booting kernel on %s\n", pv_info.name);
0208     pr_info("Xen version: %u.%u%s%s\n",
0209         version >> 16, version & 0xffff, extra.extraversion,
0210         xen_feature(XENFEAT_mmu_pt_update_preserve_ad)
0211         ? " (preserve-AD)" : "");
0212 }
0213
0214 /* Check if running on Xen version (major, minor) or later */
0215 bool xen_running_on_version_or_later(unsigned int major, unsigned int minor)
0216 {
0217     unsigned int version;
0218
0219     if (!xen_domain())
0220         return false;
0221
0222     version = HYPERVISOR_xen_version(XENVER_version, NULL);
0223     if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
0224         ((version >> 16) > major))
0225         return true;
0226     return false;
0227 }
0228
0229 void __init xen_add_preferred_consoles(void)
0230 {
0231     add_preferred_console("xenboot", 0, NULL);
0232     if (!boot_params.screen_info.orig_video_isVGA)
0233         add_preferred_console("tty", 0, NULL);
0234     add_preferred_console("hvc", 0, NULL);
0235     if (boot_params.screen_info.orig_video_isVGA)
0236         add_preferred_console("tty", 0, NULL);
0237 }
0238
0239 void xen_reboot(int reason)
0240 {
0241     struct sched_shutdown r = { .reason = reason };
0242     int cpu;
0243
0244     for_each_online_cpu(cpu)
0245         xen_pmu_finish(cpu);
0246
0247     if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
0248         BUG();
0249 }
0250
0251 static int reboot_reason = SHUTDOWN_reboot;
0252 static bool xen_legacy_crash;
0253 void xen_emergency_restart(void)
0254 {
0255     xen_reboot(reboot_reason);
0256 }
0257
0258 static int
0259 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
0260 {
0261     if (!kexec_crash_loaded()) {
0262         if (xen_legacy_crash)
0263             xen_reboot(SHUTDOWN_crash);
0264
0265         reboot_reason = SHUTDOWN_crash;
0266
0267         /*
0268          * If panic_timeout==0 then we are supposed to wait forever.
0269          * However, to preserve original dom0 behavior we have to drop
0270          * into hypervisor. (domU behavior is controlled by its
0271          * config file)
0272          */
0273         if (panic_timeout == 0)
0274             panic_timeout = -1;
0275     }
0276     return NOTIFY_DONE;
0277 }
0278
0279 static int __init parse_xen_legacy_crash(char *arg)
0280 {
0281     xen_legacy_crash = true;
0282     return 0;
0283 }
0284 early_param("xen_legacy_crash", parse_xen_legacy_crash);
0285
0286 static struct notifier_block xen_panic_block = {
0287     .notifier_call = xen_panic_event,
0288     .priority = INT_MIN
0289 };
0290
0291 int xen_panic_handler_init(void)
0292 {
0293     atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
0294     return 0;
0295 }
0296
0297 void xen_pin_vcpu(int cpu)
0298 {
0299     static bool disable_pinning;
0300     struct sched_pin_override pin_override;
0301     int ret;
0302
0303     if (disable_pinning)
0304         return;
0305
0306     pin_override.pcpu = cpu;
0307     ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override);
0308
0309     /* Ignore errors when removing override. */
0310     if (cpu < 0)
0311         return;
0312
0313     switch (ret) {
0314     case -ENOSYS:
0315         pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
0316             cpu);
0317         disable_pinning = true;
0318         break;
0319     case -EPERM:
0320         WARN(1, "Trying to pin vcpu without having privilege to do so\n");
0321         disable_pinning = true;
0322         break;
0323     case -EINVAL:
0324     case -EBUSY:
0325         pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
0326             cpu);
0327         break;
0328     case 0:
0329         break;
0330     default:
0331         WARN(1, "rc %d while trying to pin vcpu\n", ret);
0332         disable_pinning = true;
0333     }
0334 }
0335
0336 #ifdef CONFIG_HOTPLUG_CPU
0337 void xen_arch_register_cpu(int num)
0338 {
0339     arch_register_cpu(num);
0340 }
0341 EXPORT_SYMBOL(xen_arch_register_cpu);
0342
0343 void xen_arch_unregister_cpu(int num)
0344 {
0345     arch_unregister_cpu(num);
0346 }
0347 EXPORT_SYMBOL(xen_arch_unregister_cpu);
0348 #endif