1 #include <linux/cpu.h> 2 #include <linux/kexec.h> 3 4 #include <xen/features.h> 5 #include <xen/page.h> 6 7 #include <asm/xen/hypercall.h> 8 #include <asm/xen/hypervisor.h> 9 #include <asm/cpu.h> 10 #include <asm/e820/api.h> 11 12 #include "xen-ops.h" 13 #include "smp.h" 14 #include "pmu.h" 15 16 EXPORT_SYMBOL_GPL(hypercall_page); 17 18 /* 19 * Pointer to the xen_vcpu_info structure or 20 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 21 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 22 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 23 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 24 * acknowledge pending events. 25 * Also more subtly it is used by the patched version of irq enable/disable 26 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 27 * 28 * The desire to be able to do those mask/unmask operations as a single 29 * instruction by using the per-cpu offset held in %gs is the real reason 30 * vcpu info is in a per-cpu pointer and the original reason for this 31 * hypercall. 32 * 33 */ 34 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 35 36 /* 37 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 38 * hypercall. This can be used both in PV and PVHVM mode. The structure 39 * overrides the default per_cpu(xen_vcpu, cpu) value. 40 */ 41 DEFINE_PER_CPU(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 enum xen_domain_type xen_domain_type = XEN_NATIVE; 48 EXPORT_SYMBOL_GPL(xen_domain_type); 49 50 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 51 EXPORT_SYMBOL(machine_to_phys_mapping); 52 unsigned long machine_to_phys_nr; 53 EXPORT_SYMBOL(machine_to_phys_nr); 54 55 struct start_info *xen_start_info; 56 EXPORT_SYMBOL_GPL(xen_start_info); 57 58 struct shared_info xen_dummy_shared_info; 59 60 __read_mostly int xen_have_vector_callback; 61 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 62 63 /* 64 * Point at some empty memory to start with. We map the real shared_info 65 * page as soon as fixmap is up and running. 66 */ 67 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 68 69 /* 70 * Flag to determine whether vcpu info placement is available on all 71 * VCPUs. We assume it is to start with, and then set it to zero on 72 * the first failure. This is because it can succeed on some VCPUs 73 * and not others, since it can involve hypervisor memory allocation, 74 * or because the guest failed to guarantee all the appropriate 75 * constraints on all VCPUs (ie buffer can't cross a page boundary). 76 * 77 * Note that any particular CPU may be using a placed vcpu structure, 78 * but we can only optimise if the all are. 79 * 80 * 0: not available, 1: available 81 */ 82 int xen_have_vcpu_info_placement = 1; 83 84 static int xen_cpu_up_online(unsigned int cpu) 85 { 86 xen_init_lock_cpu(cpu); 87 return 0; 88 } 89 90 int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), 91 int (*cpu_dead_cb)(unsigned int)) 92 { 93 int rc; 94 95 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, 96 "x86/xen/hvm_guest:prepare", 97 cpu_up_prepare_cb, cpu_dead_cb); 98 if (rc >= 0) { 99 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 100 "x86/xen/hvm_guest:online", 101 xen_cpu_up_online, NULL); 102 if (rc < 0) 103 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); 104 } 105 106 return rc >= 0 ? 0 : rc; 107 } 108 109 static void clamp_max_cpus(void) 110 { 111 #ifdef CONFIG_SMP 112 if (setup_max_cpus > MAX_VIRT_CPUS) 113 setup_max_cpus = MAX_VIRT_CPUS; 114 #endif 115 } 116 117 void xen_vcpu_setup(int cpu) 118 { 119 struct vcpu_register_vcpu_info info; 120 int err; 121 struct vcpu_info *vcpup; 122 123 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 124 125 /* 126 * This path is called twice on PVHVM - first during bootup via 127 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being 128 * hotplugged: cpu_up -> xen_hvm_cpu_notify. 129 * As we can only do the VCPUOP_register_vcpu_info once lets 130 * not over-write its result. 131 * 132 * For PV it is called during restore (xen_vcpu_restore) and bootup 133 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 134 * use this function. 135 */ 136 if (xen_hvm_domain()) { 137 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 138 return; 139 } 140 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) 141 per_cpu(xen_vcpu, cpu) = 142 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 143 144 if (!xen_have_vcpu_info_placement) { 145 if (cpu >= MAX_VIRT_CPUS) 146 clamp_max_cpus(); 147 return; 148 } 149 150 vcpup = &per_cpu(xen_vcpu_info, cpu); 151 info.mfn = arbitrary_virt_to_mfn(vcpup); 152 info.offset = offset_in_page(vcpup); 153 154 /* Check to see if the hypervisor will put the vcpu_info 155 structure where we want it, which allows direct access via 156 a percpu-variable. 157 N.B. This hypercall can _only_ be called once per CPU. Subsequent 158 calls will error out with -EINVAL. This is due to the fact that 159 hypervisor has no unregister variant and this hypercall does not 160 allow to over-write info.mfn and info.offset. 161 */ 162 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu), 163 &info); 164 165 if (err) { 166 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 167 xen_have_vcpu_info_placement = 0; 168 clamp_max_cpus(); 169 } else { 170 /* This cpu is using the registered vcpu info, even if 171 later ones fail to. */ 172 per_cpu(xen_vcpu, cpu) = vcpup; 173 } 174 } 175 176 void xen_reboot(int reason) 177 { 178 struct sched_shutdown r = { .reason = reason }; 179 int cpu; 180 181 for_each_online_cpu(cpu) 182 xen_pmu_finish(cpu); 183 184 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 185 BUG(); 186 } 187 188 void xen_emergency_restart(void) 189 { 190 xen_reboot(SHUTDOWN_reboot); 191 } 192 193 static int 194 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 195 { 196 if (!kexec_crash_loaded()) 197 xen_reboot(SHUTDOWN_crash); 198 return NOTIFY_DONE; 199 } 200 201 static struct notifier_block xen_panic_block = { 202 .notifier_call = xen_panic_event, 203 .priority = INT_MIN 204 }; 205 206 int xen_panic_handler_init(void) 207 { 208 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 209 return 0; 210 } 211 212 void xen_pin_vcpu(int cpu) 213 { 214 static bool disable_pinning; 215 struct sched_pin_override pin_override; 216 int ret; 217 218 if (disable_pinning) 219 return; 220 221 pin_override.pcpu = cpu; 222 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); 223 224 /* Ignore errors when removing override. */ 225 if (cpu < 0) 226 return; 227 228 switch (ret) { 229 case -ENOSYS: 230 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", 231 cpu); 232 disable_pinning = true; 233 break; 234 case -EPERM: 235 WARN(1, "Trying to pin vcpu without having privilege to do so\n"); 236 disable_pinning = true; 237 break; 238 case -EINVAL: 239 case -EBUSY: 240 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", 241 cpu); 242 break; 243 case 0: 244 break; 245 default: 246 WARN(1, "rc %d while trying to pin vcpu\n", ret); 247 disable_pinning = true; 248 } 249 } 250 251 #ifdef CONFIG_HOTPLUG_CPU 252 void xen_arch_register_cpu(int num) 253 { 254 arch_register_cpu(num); 255 } 256 EXPORT_SYMBOL(xen_arch_register_cpu); 257 258 void xen_arch_unregister_cpu(int num) 259 { 260 arch_unregister_cpu(num); 261 } 262 EXPORT_SYMBOL(xen_arch_unregister_cpu); 263 #endif 264