#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG #include #endif #include #include #include #include #include #include #include #include #include #include "xen-ops.h" #include "smp.h" #include "pmu.h" EXPORT_SYMBOL_GPL(hypercall_page); /* * Pointer to the xen_vcpu_info structure or * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to * acknowledge pending events. * Also more subtly it is used by the patched version of irq enable/disable * e.g. xen_irq_enable_direct and xen_iret in PV mode. * * The desire to be able to do those mask/unmask operations as a single * instruction by using the per-cpu offset held in %gs is the real reason * vcpu info is in a per-cpu pointer and the original reason for this * hypercall. * */ DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); /* * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info * hypercall. This can be used both in PV and PVHVM mode. The structure * overrides the default per_cpu(xen_vcpu, cpu) value. */ DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); /* Linux <-> Xen vCPU id mapping */ DEFINE_PER_CPU(uint32_t, xen_vcpu_id); EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); enum xen_domain_type xen_domain_type = XEN_NATIVE; EXPORT_SYMBOL_GPL(xen_domain_type); unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; EXPORT_SYMBOL(machine_to_phys_mapping); unsigned long machine_to_phys_nr; EXPORT_SYMBOL(machine_to_phys_nr); struct start_info *xen_start_info; EXPORT_SYMBOL_GPL(xen_start_info); struct shared_info xen_dummy_shared_info; __read_mostly int xen_have_vector_callback; EXPORT_SYMBOL_GPL(xen_have_vector_callback); /* * NB: needs to live in .data because it's used by xen_prepare_pvh which runs * before clearing the bss. */ uint32_t xen_start_flags __attribute__((section(".data"))) = 0; EXPORT_SYMBOL(xen_start_flags); /* * Point at some empty memory to start with. We map the real shared_info * page as soon as fixmap is up and running. */ struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; /* * Flag to determine whether vcpu info placement is available on all * VCPUs. We assume it is to start with, and then set it to zero on * the first failure. This is because it can succeed on some VCPUs * and not others, since it can involve hypervisor memory allocation, * or because the guest failed to guarantee all the appropriate * constraints on all VCPUs (ie buffer can't cross a page boundary). * * Note that any particular CPU may be using a placed vcpu structure, * but we can only optimise if the all are. * * 0: not available, 1: available */ int xen_have_vcpu_info_placement = 1; static int xen_cpu_up_online(unsigned int cpu) { xen_init_lock_cpu(cpu); return 0; } int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), int (*cpu_dead_cb)(unsigned int)) { int rc; rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, "x86/xen/guest:prepare", cpu_up_prepare_cb, cpu_dead_cb); if (rc >= 0) { rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/xen/guest:online", xen_cpu_up_online, NULL); if (rc < 0) cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); } return rc >= 0 ? 0 : rc; } static int xen_vcpu_setup_restore(int cpu) { int rc = 0; /* Any per_cpu(xen_vcpu) is stale, so reset it */ xen_vcpu_info_reset(cpu); /* * For PVH and PVHVM, setup online VCPUs only. The rest will * be handled by hotplug. */ if (xen_pv_domain() || (xen_hvm_domain() && cpu_online(cpu))) { rc = xen_vcpu_setup(cpu); } return rc; } /* * On restore, set the vcpu placement up again. * If it fails, then we're in a bad state, since * we can't back out from using it... */ void xen_vcpu_restore(void) { int cpu, rc; for_each_possible_cpu(cpu) { bool other_cpu = (cpu != smp_processor_id()); bool is_up; if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID) continue; /* Only Xen 4.5 and higher support this. */ is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu), NULL) > 0; if (other_cpu && is_up && HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL)) BUG(); if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) xen_setup_runstate_info(cpu); rc = xen_vcpu_setup_restore(cpu); if (rc) pr_emerg_once("vcpu restore failed for cpu=%d err=%d. " "System will hang.\n", cpu, rc); /* * In case xen_vcpu_setup_restore() fails, do not bring up the * VCPU. This helps us avoid the resulting OOPS when the VCPU * accesses pvclock_vcpu_time via xen_vcpu (which is NULL.) * Note that this does not improve the situation much -- now the * VM hangs instead of OOPSing -- with the VCPUs that did not * fail, spinning in stop_machine(), waiting for the failed * VCPUs to come up. */ if (other_cpu && is_up && (rc == 0) && HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) BUG(); } } void xen_vcpu_info_reset(int cpu) { if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) { per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; } else { /* Set to NULL so that if somebody accesses it we get an OOPS */ per_cpu(xen_vcpu, cpu) = NULL; } } int xen_vcpu_setup(int cpu) { struct vcpu_register_vcpu_info info; int err; struct vcpu_info *vcpup; BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); /* * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu) * and at restore (xen_vcpu_restore). Also called for hotplugged * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm). * However, the hypercall can only be done once (see below) so if a VCPU * is offlined and comes back online then let's not redo the hypercall. * * For PV it is called during restore (xen_vcpu_restore) and bootup * (xen_setup_vcpu_info_placement). The hotplug mechanism does not * use this function. */ if (xen_hvm_domain()) { if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) return 0; } if (xen_have_vcpu_info_placement) { vcpup = &per_cpu(xen_vcpu_info, cpu); info.mfn = arbitrary_virt_to_mfn(vcpup); info.offset = offset_in_page(vcpup); /* * Check to see if the hypervisor will put the vcpu_info * structure where we want it, which allows direct access via * a percpu-variable. * N.B. This hypercall can _only_ be called once per CPU. * Subsequent calls will error out with -EINVAL. This is due to * the fact that hypervisor has no unregister variant and this * hypercall does not allow to over-write info.mfn and * info.offset. */ err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu), &info); if (err) { pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n", cpu, err); xen_have_vcpu_info_placement = 0; } else { /* * This cpu is using the registered vcpu info, even if * later ones fail to. */ per_cpu(xen_vcpu, cpu) = vcpup; } } if (!xen_have_vcpu_info_placement) xen_vcpu_info_reset(cpu); return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0); } void xen_reboot(int reason) { struct sched_shutdown r = { .reason = reason }; int cpu; for_each_online_cpu(cpu) xen_pmu_finish(cpu); if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) BUG(); } static int reboot_reason = SHUTDOWN_reboot; static bool xen_legacy_crash; void xen_emergency_restart(void) { xen_reboot(reboot_reason); } static int xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) { if (!kexec_crash_loaded()) { if (xen_legacy_crash) xen_reboot(SHUTDOWN_crash); reboot_reason = SHUTDOWN_crash; /* * If panic_timeout==0 then we are supposed to wait forever. * However, to preserve original dom0 behavior we have to drop * into hypervisor. (domU behavior is controlled by its * config file) */ if (panic_timeout == 0) panic_timeout = -1; } return NOTIFY_DONE; } static int __init parse_xen_legacy_crash(char *arg) { xen_legacy_crash = true; return 0; } early_param("xen_legacy_crash", parse_xen_legacy_crash); static struct notifier_block xen_panic_block = { .notifier_call = xen_panic_event, .priority = INT_MIN }; int xen_panic_handler_init(void) { atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); return 0; } void xen_pin_vcpu(int cpu) { static bool disable_pinning; struct sched_pin_override pin_override; int ret; if (disable_pinning) return; pin_override.pcpu = cpu; ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); /* Ignore errors when removing override. */ if (cpu < 0) return; switch (ret) { case -ENOSYS: pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", cpu); disable_pinning = true; break; case -EPERM: WARN(1, "Trying to pin vcpu without having privilege to do so\n"); disable_pinning = true; break; case -EINVAL: case -EBUSY: pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", cpu); break; case 0: break; default: WARN(1, "rc %d while trying to pin vcpu\n", ret); disable_pinning = true; } } #ifdef CONFIG_HOTPLUG_CPU void xen_arch_register_cpu(int num) { arch_register_cpu(num); } EXPORT_SYMBOL(xen_arch_register_cpu); void xen_arch_unregister_cpu(int num) { arch_unregister_cpu(num); } EXPORT_SYMBOL(xen_arch_unregister_cpu); #endif