4 * This file implements the Xen versions of smp_ops. SMP under Xen is
5 * very straightforward. Bringing a CPU up is simply a matter of
6 * loading its initial context and setting it running.
8 * IPIs are handled through the Xen event mechanism.
10 * Because virtual CPUs can be scheduled onto any real CPU, there's no
11 * useful topology information for the kernel to make use of. As a
12 * result, all CPUs are treated as if they're single-core and
15 #include <linux/sched.h>
16 #include <linux/err.h>
17 #include <linux/slab.h>
18 #include <linux/smp.h>
19 #include <linux/irq_work.h>
21 #include <asm/paravirt.h>
23 #include <asm/pgtable.h>
26 #include <xen/interface/xen.h>
27 #include <xen/interface/vcpu.h>
29 #include <asm/xen/interface.h>
30 #include <asm/xen/hypercall.h>
34 #include <xen/events.h>
36 #include <xen/hvc-console.h>
40 cpumask_var_t xen_cpu_initialized_map;
42 static DEFINE_PER_CPU(int, xen_resched_irq);
43 static DEFINE_PER_CPU(int, xen_callfunc_irq);
44 static DEFINE_PER_CPU(int, xen_callfuncsingle_irq);
45 static DEFINE_PER_CPU(int, xen_irq_work);
46 static DEFINE_PER_CPU(int, xen_debug_irq) = -1;
48 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
49 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
50 static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id);
53 * Reschedule call back.
55 static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
57 inc_irq_stat(irq_resched_count);
63 static void __cpuinit cpu_bringup(void)
68 touch_softlockup_watchdog();
71 xen_enable_sysenter();
74 cpu = smp_processor_id();
75 smp_store_cpu_info(cpu);
76 cpu_data(cpu).x86_max_cores = 1;
77 set_cpu_sibling_map(cpu);
79 xen_setup_cpu_clockevents();
81 notify_cpu_starting(cpu);
84 set_cpu_online(cpu, true);
87 this_cpu_write(cpu_state, CPU_ONLINE);
91 /* We can take interrupts now: we're officially "up". */
94 wmb(); /* make sure everything is out */
97 static void __cpuinit cpu_bringup_and_idle(void)
103 static int xen_smp_intr_init(unsigned int cpu)
106 const char *resched_name, *callfunc_name, *debug_name;
108 resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
109 rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
111 xen_reschedule_interrupt,
112 IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
117 per_cpu(xen_resched_irq, cpu) = rc;
119 callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
120 rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
122 xen_call_function_interrupt,
123 IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
128 per_cpu(xen_callfunc_irq, cpu) = rc;
130 debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
131 rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
132 IRQF_DISABLED | IRQF_PERCPU | IRQF_NOBALANCING,
136 per_cpu(xen_debug_irq, cpu) = rc;
138 callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
139 rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
141 xen_call_function_single_interrupt,
142 IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
147 per_cpu(xen_callfuncsingle_irq, cpu) = rc;
149 callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
150 rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
152 xen_irq_work_interrupt,
153 IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
158 per_cpu(xen_irq_work, cpu) = rc;
163 if (per_cpu(xen_resched_irq, cpu) >= 0)
164 unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
165 if (per_cpu(xen_callfunc_irq, cpu) >= 0)
166 unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
167 if (per_cpu(xen_debug_irq, cpu) >= 0)
168 unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
169 if (per_cpu(xen_callfuncsingle_irq, cpu) >= 0)
170 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu),
172 if (per_cpu(xen_irq_work, cpu) >= 0)
173 unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL);
178 static void __init xen_fill_possible_map(void)
182 if (xen_initial_domain())
185 for (i = 0; i < nr_cpu_ids; i++) {
186 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
189 set_cpu_possible(i, true);
194 static void __init xen_filter_cpu_maps(void)
197 unsigned int subtract = 0;
199 if (!xen_initial_domain())
204 for (i = 0; i < nr_cpu_ids; i++) {
205 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
208 set_cpu_possible(i, true);
210 set_cpu_possible(i, false);
211 set_cpu_present(i, false);
215 #ifdef CONFIG_HOTPLUG_CPU
216 /* This is akin to using 'nr_cpus' on the Linux command line.
217 * Which is OK as when we use 'dom0_max_vcpus=X' we can only
218 * have up to X, while nr_cpu_ids is greater than X. This
219 * normally is not a problem, except when CPU hotplugging
220 * is involved and then there might be more than X CPUs
221 * in the guest - which will not work as there is no
222 * hypercall to expand the max number of VCPUs an already
223 * running guest has. So cap it up to X. */
225 nr_cpu_ids = nr_cpu_ids - subtract;
230 static void __init xen_smp_prepare_boot_cpu(void)
232 BUG_ON(smp_processor_id() != 0);
233 native_smp_prepare_boot_cpu();
235 /* We've switched to the "real" per-cpu gdt, so make sure the
236 old memory can be recycled */
237 make_lowmem_page_readwrite(xen_initial_gdt);
239 xen_filter_cpu_maps();
240 xen_setup_vcpu_info_placement();
243 static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
248 if (skip_ioapic_setup) {
249 char *m = (max_cpus == 0) ?
250 "The nosmp parameter is incompatible with Xen; " \
251 "use Xen dom0_max_vcpus=1 parameter" :
252 "The noapic parameter is incompatible with Xen";
257 xen_init_lock_cpu(0);
259 smp_store_cpu_info(0);
260 cpu_data(0).x86_max_cores = 1;
262 for_each_possible_cpu(i) {
263 zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
264 zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
265 zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
267 set_cpu_sibling_map(0);
269 if (xen_smp_intr_init(0))
272 if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))
273 panic("could not allocate xen_cpu_initialized_map\n");
275 cpumask_copy(xen_cpu_initialized_map, cpumask_of(0));
277 /* Restrict the possible_map according to max_cpus. */
278 while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
279 for (cpu = nr_cpu_ids - 1; !cpu_possible(cpu); cpu--)
281 set_cpu_possible(cpu, false);
284 for_each_possible_cpu(cpu)
285 set_cpu_present(cpu, true);
289 cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
291 struct vcpu_guest_context *ctxt;
292 struct desc_struct *gdt;
293 unsigned long gdt_mfn;
295 if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
298 ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
302 gdt = get_cpu_gdt_table(cpu);
304 ctxt->flags = VGCF_IN_KERNEL;
305 ctxt->user_regs.ds = __USER_DS;
306 ctxt->user_regs.es = __USER_DS;
307 ctxt->user_regs.ss = __KERNEL_DS;
309 ctxt->user_regs.fs = __KERNEL_PERCPU;
310 ctxt->user_regs.gs = __KERNEL_STACK_CANARY;
312 ctxt->gs_base_kernel = per_cpu_offset(cpu);
314 ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
315 ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
317 memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
319 xen_copy_trap_info(ctxt->trap_ctxt);
323 BUG_ON((unsigned long)gdt & ~PAGE_MASK);
325 gdt_mfn = arbitrary_virt_to_mfn(gdt);
326 make_lowmem_page_readonly(gdt);
327 make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
329 ctxt->gdt_frames[0] = gdt_mfn;
330 ctxt->gdt_ents = GDT_ENTRIES;
332 ctxt->user_regs.cs = __KERNEL_CS;
333 ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
335 ctxt->kernel_ss = __KERNEL_DS;
336 ctxt->kernel_sp = idle->thread.sp0;
339 ctxt->event_callback_cs = __KERNEL_CS;
340 ctxt->failsafe_callback_cs = __KERNEL_CS;
342 ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback;
343 ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
345 per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
346 ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
348 if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
355 static int __cpuinit xen_cpu_up(unsigned int cpu, struct task_struct *idle)
359 per_cpu(current_task, cpu) = idle;
363 clear_tsk_thread_flag(idle, TIF_FORK);
364 per_cpu(kernel_stack, cpu) =
365 (unsigned long)task_stack_page(idle) -
366 KERNEL_STACK_OFFSET + THREAD_SIZE;
368 xen_setup_runstate_info(cpu);
369 xen_setup_timer(cpu);
370 xen_init_lock_cpu(cpu);
372 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
374 /* make sure interrupts start blocked */
375 per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
377 rc = cpu_initialize_context(cpu, idle);
381 if (num_online_cpus() == 1)
382 alternatives_smp_switch(1);
384 rc = xen_smp_intr_init(cpu);
388 rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
391 while(per_cpu(cpu_state, cpu) != CPU_ONLINE) {
392 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
399 static void xen_smp_cpus_done(unsigned int max_cpus)
403 #ifdef CONFIG_HOTPLUG_CPU
404 static int xen_cpu_disable(void)
406 unsigned int cpu = smp_processor_id();
410 cpu_disable_common();
412 load_cr3(swapper_pg_dir);
416 static void xen_cpu_die(unsigned int cpu)
418 while (HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL)) {
419 current->state = TASK_UNINTERRUPTIBLE;
420 schedule_timeout(HZ/10);
422 unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
423 unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
424 unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
425 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL);
426 unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL);
427 xen_uninit_lock_cpu(cpu);
428 xen_teardown_timer(cpu);
430 if (num_online_cpus() == 1)
431 alternatives_smp_switch(0);
434 static void __cpuinit xen_play_dead(void) /* used only with HOTPLUG_CPU */
437 HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
440 * Balance out the preempt calls - as we are running in cpu_idle
441 * loop which has been called at bootup from cpu_bringup_and_idle.
442 * The cpucpu_bringup_and_idle called cpu_bringup which made a
443 * preempt_disable() So this preempt_enable will balance it out.
448 #else /* !CONFIG_HOTPLUG_CPU */
449 static int xen_cpu_disable(void)
454 static void xen_cpu_die(unsigned int cpu)
459 static void xen_play_dead(void)
465 static void stop_self(void *v)
467 int cpu = smp_processor_id();
469 /* make sure we're not pinning something down */
470 load_cr3(swapper_pg_dir);
471 /* should set up a minimal gdt */
473 set_cpu_online(cpu, false);
475 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
479 static void xen_stop_other_cpus(int wait)
481 smp_call_function(stop_self, NULL, wait);
484 static void xen_smp_send_reschedule(int cpu)
486 xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
489 static void __xen_send_IPI_mask(const struct cpumask *mask,
494 for_each_cpu_and(cpu, mask, cpu_online_mask)
495 xen_send_IPI_one(cpu, vector);
498 static void xen_smp_send_call_function_ipi(const struct cpumask *mask)
502 __xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
504 /* Make sure other vcpus get a chance to run if they need to. */
505 for_each_cpu(cpu, mask) {
506 if (xen_vcpu_stolen(cpu)) {
507 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
513 static void xen_smp_send_call_function_single_ipi(int cpu)
515 __xen_send_IPI_mask(cpumask_of(cpu),
516 XEN_CALL_FUNCTION_SINGLE_VECTOR);
519 static inline int xen_map_vector(int vector)
524 case RESCHEDULE_VECTOR:
525 xen_vector = XEN_RESCHEDULE_VECTOR;
527 case CALL_FUNCTION_VECTOR:
528 xen_vector = XEN_CALL_FUNCTION_VECTOR;
530 case CALL_FUNCTION_SINGLE_VECTOR:
531 xen_vector = XEN_CALL_FUNCTION_SINGLE_VECTOR;
533 case IRQ_WORK_VECTOR:
534 xen_vector = XEN_IRQ_WORK_VECTOR;
538 printk(KERN_ERR "xen: vector 0x%x is not implemented\n",
545 void xen_send_IPI_mask(const struct cpumask *mask,
548 int xen_vector = xen_map_vector(vector);
551 __xen_send_IPI_mask(mask, xen_vector);
554 void xen_send_IPI_all(int vector)
556 int xen_vector = xen_map_vector(vector);
559 __xen_send_IPI_mask(cpu_online_mask, xen_vector);
562 void xen_send_IPI_self(int vector)
564 int xen_vector = xen_map_vector(vector);
567 xen_send_IPI_one(smp_processor_id(), xen_vector);
570 void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
574 unsigned int this_cpu = smp_processor_id();
576 if (!(num_online_cpus() > 1))
579 for_each_cpu_and(cpu, mask, cpu_online_mask) {
583 xen_smp_send_call_function_single_ipi(cpu);
587 void xen_send_IPI_allbutself(int vector)
589 int xen_vector = xen_map_vector(vector);
592 xen_send_IPI_mask_allbutself(cpu_online_mask, xen_vector);
595 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
598 generic_smp_call_function_interrupt();
599 inc_irq_stat(irq_call_count);
605 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
608 generic_smp_call_function_single_interrupt();
609 inc_irq_stat(irq_call_count);
615 static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)
619 inc_irq_stat(apic_irq_work_irqs);
625 static const struct smp_ops xen_smp_ops __initconst = {
626 .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
627 .smp_prepare_cpus = xen_smp_prepare_cpus,
628 .smp_cpus_done = xen_smp_cpus_done,
630 .cpu_up = xen_cpu_up,
631 .cpu_die = xen_cpu_die,
632 .cpu_disable = xen_cpu_disable,
633 .play_dead = xen_play_dead,
635 .stop_other_cpus = xen_stop_other_cpus,
636 .smp_send_reschedule = xen_smp_send_reschedule,
638 .send_call_func_ipi = xen_smp_send_call_function_ipi,
639 .send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
642 void __init xen_smp_init(void)
644 smp_ops = xen_smp_ops;
645 xen_fill_possible_map();
646 xen_init_spinlocks();
649 static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
651 native_smp_prepare_cpus(max_cpus);
652 WARN_ON(xen_smp_intr_init(0));
654 xen_init_lock_cpu(0);
657 static int __cpuinit xen_hvm_cpu_up(unsigned int cpu, struct task_struct *tidle)
660 rc = native_cpu_up(cpu, tidle);
661 WARN_ON (xen_smp_intr_init(cpu));
665 static void xen_hvm_cpu_die(unsigned int cpu)
667 unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
668 unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
669 unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
670 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL);
671 unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL);
675 void __init xen_hvm_smp_init(void)
677 if (!xen_have_vector_callback)
679 smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus;
680 smp_ops.smp_send_reschedule = xen_smp_send_reschedule;
681 smp_ops.cpu_up = xen_hvm_cpu_up;
682 smp_ops.cpu_die = xen_hvm_cpu_die;
683 smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi;
684 smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi;