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>
20 #include <linux/tick.h>
22 #include <asm/paravirt.h>
24 #include <asm/pgtable.h>
27 #include <xen/interface/xen.h>
28 #include <xen/interface/vcpu.h>
30 #include <asm/xen/interface.h>
31 #include <asm/xen/hypercall.h>
35 #include <xen/events.h>
37 #include <xen/hvc-console.h>
41 cpumask_var_t xen_cpu_initialized_map
;
43 static DEFINE_PER_CPU(int, xen_resched_irq
);
44 static DEFINE_PER_CPU(int, xen_callfunc_irq
);
45 static DEFINE_PER_CPU(int, xen_callfuncsingle_irq
);
46 static DEFINE_PER_CPU(int, xen_irq_work
);
47 static DEFINE_PER_CPU(int, xen_debug_irq
) = -1;
49 static irqreturn_t
xen_call_function_interrupt(int irq
, void *dev_id
);
50 static irqreturn_t
xen_call_function_single_interrupt(int irq
, void *dev_id
);
51 static irqreturn_t
xen_irq_work_interrupt(int irq
, void *dev_id
);
54 * Reschedule call back.
56 static irqreturn_t
xen_reschedule_interrupt(int irq
, void *dev_id
)
58 inc_irq_stat(irq_resched_count
);
64 static void __cpuinit
cpu_bringup(void)
69 touch_softlockup_watchdog();
72 xen_enable_sysenter();
75 cpu
= smp_processor_id();
76 smp_store_cpu_info(cpu
);
77 cpu_data(cpu
).x86_max_cores
= 1;
78 set_cpu_sibling_map(cpu
);
80 xen_setup_cpu_clockevents();
82 notify_cpu_starting(cpu
);
84 set_cpu_online(cpu
, true);
86 this_cpu_write(cpu_state
, CPU_ONLINE
);
90 /* We can take interrupts now: we're officially "up". */
93 wmb(); /* make sure everything is out */
96 static void __cpuinit
cpu_bringup_and_idle(void)
99 cpu_startup_entry(CPUHP_ONLINE
);
102 static int xen_smp_intr_init(unsigned int cpu
)
105 const char *resched_name
, *callfunc_name
, *debug_name
;
107 resched_name
= kasprintf(GFP_KERNEL
, "resched%d", cpu
);
108 rc
= bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR
,
110 xen_reschedule_interrupt
,
111 IRQF_DISABLED
|IRQF_PERCPU
|IRQF_NOBALANCING
,
116 per_cpu(xen_resched_irq
, cpu
) = rc
;
118 callfunc_name
= kasprintf(GFP_KERNEL
, "callfunc%d", cpu
);
119 rc
= bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR
,
121 xen_call_function_interrupt
,
122 IRQF_DISABLED
|IRQF_PERCPU
|IRQF_NOBALANCING
,
127 per_cpu(xen_callfunc_irq
, cpu
) = rc
;
129 debug_name
= kasprintf(GFP_KERNEL
, "debug%d", cpu
);
130 rc
= bind_virq_to_irqhandler(VIRQ_DEBUG
, cpu
, xen_debug_interrupt
,
131 IRQF_DISABLED
| IRQF_PERCPU
| IRQF_NOBALANCING
,
135 per_cpu(xen_debug_irq
, cpu
) = rc
;
137 callfunc_name
= kasprintf(GFP_KERNEL
, "callfuncsingle%d", cpu
);
138 rc
= bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR
,
140 xen_call_function_single_interrupt
,
141 IRQF_DISABLED
|IRQF_PERCPU
|IRQF_NOBALANCING
,
146 per_cpu(xen_callfuncsingle_irq
, cpu
) = rc
;
149 * The IRQ worker on PVHVM goes through the native path and uses the
152 if (xen_hvm_domain())
155 callfunc_name
= kasprintf(GFP_KERNEL
, "irqwork%d", cpu
);
156 rc
= bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR
,
158 xen_irq_work_interrupt
,
159 IRQF_DISABLED
|IRQF_PERCPU
|IRQF_NOBALANCING
,
164 per_cpu(xen_irq_work
, cpu
) = rc
;
169 if (per_cpu(xen_resched_irq
, cpu
) >= 0)
170 unbind_from_irqhandler(per_cpu(xen_resched_irq
, cpu
), NULL
);
171 if (per_cpu(xen_callfunc_irq
, cpu
) >= 0)
172 unbind_from_irqhandler(per_cpu(xen_callfunc_irq
, cpu
), NULL
);
173 if (per_cpu(xen_debug_irq
, cpu
) >= 0)
174 unbind_from_irqhandler(per_cpu(xen_debug_irq
, cpu
), NULL
);
175 if (per_cpu(xen_callfuncsingle_irq
, cpu
) >= 0)
176 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq
, cpu
),
178 if (xen_hvm_domain())
181 if (per_cpu(xen_irq_work
, cpu
) >= 0)
182 unbind_from_irqhandler(per_cpu(xen_irq_work
, cpu
), NULL
);
187 static void __init
xen_fill_possible_map(void)
191 if (xen_initial_domain())
194 for (i
= 0; i
< nr_cpu_ids
; i
++) {
195 rc
= HYPERVISOR_vcpu_op(VCPUOP_is_up
, i
, NULL
);
198 set_cpu_possible(i
, true);
203 static void __init
xen_filter_cpu_maps(void)
206 unsigned int subtract
= 0;
208 if (!xen_initial_domain())
213 for (i
= 0; i
< nr_cpu_ids
; i
++) {
214 rc
= HYPERVISOR_vcpu_op(VCPUOP_is_up
, i
, NULL
);
217 set_cpu_possible(i
, true);
219 set_cpu_possible(i
, false);
220 set_cpu_present(i
, false);
224 #ifdef CONFIG_HOTPLUG_CPU
225 /* This is akin to using 'nr_cpus' on the Linux command line.
226 * Which is OK as when we use 'dom0_max_vcpus=X' we can only
227 * have up to X, while nr_cpu_ids is greater than X. This
228 * normally is not a problem, except when CPU hotplugging
229 * is involved and then there might be more than X CPUs
230 * in the guest - which will not work as there is no
231 * hypercall to expand the max number of VCPUs an already
232 * running guest has. So cap it up to X. */
234 nr_cpu_ids
= nr_cpu_ids
- subtract
;
239 static void __init
xen_smp_prepare_boot_cpu(void)
241 BUG_ON(smp_processor_id() != 0);
242 native_smp_prepare_boot_cpu();
244 /* We've switched to the "real" per-cpu gdt, so make sure the
245 old memory can be recycled */
246 make_lowmem_page_readwrite(xen_initial_gdt
);
248 xen_filter_cpu_maps();
249 xen_setup_vcpu_info_placement();
252 static void __init
xen_smp_prepare_cpus(unsigned int max_cpus
)
257 if (skip_ioapic_setup
) {
258 char *m
= (max_cpus
== 0) ?
259 "The nosmp parameter is incompatible with Xen; " \
260 "use Xen dom0_max_vcpus=1 parameter" :
261 "The noapic parameter is incompatible with Xen";
266 xen_init_lock_cpu(0);
268 smp_store_boot_cpu_info();
269 cpu_data(0).x86_max_cores
= 1;
271 for_each_possible_cpu(i
) {
272 zalloc_cpumask_var(&per_cpu(cpu_sibling_map
, i
), GFP_KERNEL
);
273 zalloc_cpumask_var(&per_cpu(cpu_core_map
, i
), GFP_KERNEL
);
274 zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map
, i
), GFP_KERNEL
);
276 set_cpu_sibling_map(0);
278 if (xen_smp_intr_init(0))
281 if (!alloc_cpumask_var(&xen_cpu_initialized_map
, GFP_KERNEL
))
282 panic("could not allocate xen_cpu_initialized_map\n");
284 cpumask_copy(xen_cpu_initialized_map
, cpumask_of(0));
286 /* Restrict the possible_map according to max_cpus. */
287 while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus
)) {
288 for (cpu
= nr_cpu_ids
- 1; !cpu_possible(cpu
); cpu
--)
290 set_cpu_possible(cpu
, false);
293 for_each_possible_cpu(cpu
)
294 set_cpu_present(cpu
, true);
298 cpu_initialize_context(unsigned int cpu
, struct task_struct
*idle
)
300 struct vcpu_guest_context
*ctxt
;
301 struct desc_struct
*gdt
;
302 unsigned long gdt_mfn
;
304 if (cpumask_test_and_set_cpu(cpu
, xen_cpu_initialized_map
))
307 ctxt
= kzalloc(sizeof(*ctxt
), GFP_KERNEL
);
311 gdt
= get_cpu_gdt_table(cpu
);
313 ctxt
->flags
= VGCF_IN_KERNEL
;
314 ctxt
->user_regs
.ss
= __KERNEL_DS
;
316 ctxt
->user_regs
.fs
= __KERNEL_PERCPU
;
317 ctxt
->user_regs
.gs
= __KERNEL_STACK_CANARY
;
319 ctxt
->gs_base_kernel
= per_cpu_offset(cpu
);
321 ctxt
->user_regs
.eip
= (unsigned long)cpu_bringup_and_idle
;
323 memset(&ctxt
->fpu_ctxt
, 0, sizeof(ctxt
->fpu_ctxt
));
326 ctxt
->user_regs
.eflags
= 0x1000; /* IOPL_RING1 */
327 ctxt
->user_regs
.ds
= __USER_DS
;
328 ctxt
->user_regs
.es
= __USER_DS
;
330 xen_copy_trap_info(ctxt
->trap_ctxt
);
334 BUG_ON((unsigned long)gdt
& ~PAGE_MASK
);
336 gdt_mfn
= arbitrary_virt_to_mfn(gdt
);
337 make_lowmem_page_readonly(gdt
);
338 make_lowmem_page_readonly(mfn_to_virt(gdt_mfn
));
340 ctxt
->gdt_frames
[0] = gdt_mfn
;
341 ctxt
->gdt_ents
= GDT_ENTRIES
;
343 ctxt
->kernel_ss
= __KERNEL_DS
;
344 ctxt
->kernel_sp
= idle
->thread
.sp0
;
347 ctxt
->event_callback_cs
= __KERNEL_CS
;
348 ctxt
->failsafe_callback_cs
= __KERNEL_CS
;
350 ctxt
->event_callback_eip
=
351 (unsigned long)xen_hypervisor_callback
;
352 ctxt
->failsafe_callback_eip
=
353 (unsigned long)xen_failsafe_callback
;
355 ctxt
->user_regs
.cs
= __KERNEL_CS
;
356 ctxt
->user_regs
.esp
= idle
->thread
.sp0
- sizeof(struct pt_regs
);
358 per_cpu(xen_cr3
, cpu
) = __pa(swapper_pg_dir
);
359 ctxt
->ctrlreg
[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir
));
361 if (HYPERVISOR_vcpu_op(VCPUOP_initialise
, cpu
, ctxt
))
368 static int __cpuinit
xen_cpu_up(unsigned int cpu
, struct task_struct
*idle
)
372 per_cpu(current_task
, cpu
) = idle
;
376 clear_tsk_thread_flag(idle
, TIF_FORK
);
377 per_cpu(kernel_stack
, cpu
) =
378 (unsigned long)task_stack_page(idle
) -
379 KERNEL_STACK_OFFSET
+ THREAD_SIZE
;
381 xen_setup_runstate_info(cpu
);
382 xen_setup_timer(cpu
);
383 xen_init_lock_cpu(cpu
);
385 per_cpu(cpu_state
, cpu
) = CPU_UP_PREPARE
;
387 /* make sure interrupts start blocked */
388 per_cpu(xen_vcpu
, cpu
)->evtchn_upcall_mask
= 1;
390 rc
= cpu_initialize_context(cpu
, idle
);
394 if (num_online_cpus() == 1)
395 /* Just in case we booted with a single CPU. */
396 alternatives_enable_smp();
398 rc
= xen_smp_intr_init(cpu
);
402 rc
= HYPERVISOR_vcpu_op(VCPUOP_up
, cpu
, NULL
);
405 while(per_cpu(cpu_state
, cpu
) != CPU_ONLINE
) {
406 HYPERVISOR_sched_op(SCHEDOP_yield
, NULL
);
413 static void xen_smp_cpus_done(unsigned int max_cpus
)
417 #ifdef CONFIG_HOTPLUG_CPU
418 static int xen_cpu_disable(void)
420 unsigned int cpu
= smp_processor_id();
424 cpu_disable_common();
426 load_cr3(swapper_pg_dir
);
430 static void xen_cpu_die(unsigned int cpu
)
432 while (xen_pv_domain() && HYPERVISOR_vcpu_op(VCPUOP_is_up
, cpu
, NULL
)) {
433 current
->state
= TASK_UNINTERRUPTIBLE
;
434 schedule_timeout(HZ
/10);
436 unbind_from_irqhandler(per_cpu(xen_resched_irq
, cpu
), NULL
);
437 unbind_from_irqhandler(per_cpu(xen_callfunc_irq
, cpu
), NULL
);
438 unbind_from_irqhandler(per_cpu(xen_debug_irq
, cpu
), NULL
);
439 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq
, cpu
), NULL
);
440 if (!xen_hvm_domain())
441 unbind_from_irqhandler(per_cpu(xen_irq_work
, cpu
), NULL
);
442 xen_uninit_lock_cpu(cpu
);
443 xen_teardown_timer(cpu
);
446 static void __cpuinit
xen_play_dead(void) /* used only with HOTPLUG_CPU */
449 HYPERVISOR_vcpu_op(VCPUOP_down
, smp_processor_id(), NULL
);
452 * commit 4b0c0f294 (tick: Cleanup NOHZ per cpu data on cpu down)
453 * clears certain data that the cpu_idle loop (which called us
454 * and that we return from) expects. The only way to get that
455 * data back is to call:
457 tick_nohz_idle_enter();
460 #else /* !CONFIG_HOTPLUG_CPU */
461 static int xen_cpu_disable(void)
466 static void xen_cpu_die(unsigned int cpu
)
471 static void xen_play_dead(void)
477 static void stop_self(void *v
)
479 int cpu
= smp_processor_id();
481 /* make sure we're not pinning something down */
482 load_cr3(swapper_pg_dir
);
483 /* should set up a minimal gdt */
485 set_cpu_online(cpu
, false);
487 HYPERVISOR_vcpu_op(VCPUOP_down
, cpu
, NULL
);
491 static void xen_stop_other_cpus(int wait
)
493 smp_call_function(stop_self
, NULL
, wait
);
496 static void xen_smp_send_reschedule(int cpu
)
498 xen_send_IPI_one(cpu
, XEN_RESCHEDULE_VECTOR
);
501 static void __xen_send_IPI_mask(const struct cpumask
*mask
,
506 for_each_cpu_and(cpu
, mask
, cpu_online_mask
)
507 xen_send_IPI_one(cpu
, vector
);
510 static void xen_smp_send_call_function_ipi(const struct cpumask
*mask
)
514 __xen_send_IPI_mask(mask
, XEN_CALL_FUNCTION_VECTOR
);
516 /* Make sure other vcpus get a chance to run if they need to. */
517 for_each_cpu(cpu
, mask
) {
518 if (xen_vcpu_stolen(cpu
)) {
519 HYPERVISOR_sched_op(SCHEDOP_yield
, NULL
);
525 static void xen_smp_send_call_function_single_ipi(int cpu
)
527 __xen_send_IPI_mask(cpumask_of(cpu
),
528 XEN_CALL_FUNCTION_SINGLE_VECTOR
);
531 static inline int xen_map_vector(int vector
)
536 case RESCHEDULE_VECTOR
:
537 xen_vector
= XEN_RESCHEDULE_VECTOR
;
539 case CALL_FUNCTION_VECTOR
:
540 xen_vector
= XEN_CALL_FUNCTION_VECTOR
;
542 case CALL_FUNCTION_SINGLE_VECTOR
:
543 xen_vector
= XEN_CALL_FUNCTION_SINGLE_VECTOR
;
545 case IRQ_WORK_VECTOR
:
546 xen_vector
= XEN_IRQ_WORK_VECTOR
;
550 printk(KERN_ERR
"xen: vector 0x%x is not implemented\n",
557 void xen_send_IPI_mask(const struct cpumask
*mask
,
560 int xen_vector
= xen_map_vector(vector
);
563 __xen_send_IPI_mask(mask
, xen_vector
);
566 void xen_send_IPI_all(int vector
)
568 int xen_vector
= xen_map_vector(vector
);
571 __xen_send_IPI_mask(cpu_online_mask
, xen_vector
);
574 void xen_send_IPI_self(int vector
)
576 int xen_vector
= xen_map_vector(vector
);
579 xen_send_IPI_one(smp_processor_id(), xen_vector
);
582 void xen_send_IPI_mask_allbutself(const struct cpumask
*mask
,
586 unsigned int this_cpu
= smp_processor_id();
587 int xen_vector
= xen_map_vector(vector
);
589 if (!(num_online_cpus() > 1) || (xen_vector
< 0))
592 for_each_cpu_and(cpu
, mask
, cpu_online_mask
) {
596 xen_send_IPI_one(cpu
, xen_vector
);
600 void xen_send_IPI_allbutself(int vector
)
602 xen_send_IPI_mask_allbutself(cpu_online_mask
, vector
);
605 static irqreturn_t
xen_call_function_interrupt(int irq
, void *dev_id
)
608 generic_smp_call_function_interrupt();
609 inc_irq_stat(irq_call_count
);
615 static irqreturn_t
xen_call_function_single_interrupt(int irq
, void *dev_id
)
618 generic_smp_call_function_single_interrupt();
619 inc_irq_stat(irq_call_count
);
625 static irqreturn_t
xen_irq_work_interrupt(int irq
, void *dev_id
)
629 inc_irq_stat(apic_irq_work_irqs
);
635 static const struct smp_ops xen_smp_ops __initconst
= {
636 .smp_prepare_boot_cpu
= xen_smp_prepare_boot_cpu
,
637 .smp_prepare_cpus
= xen_smp_prepare_cpus
,
638 .smp_cpus_done
= xen_smp_cpus_done
,
640 .cpu_up
= xen_cpu_up
,
641 .cpu_die
= xen_cpu_die
,
642 .cpu_disable
= xen_cpu_disable
,
643 .play_dead
= xen_play_dead
,
645 .stop_other_cpus
= xen_stop_other_cpus
,
646 .smp_send_reschedule
= xen_smp_send_reschedule
,
648 .send_call_func_ipi
= xen_smp_send_call_function_ipi
,
649 .send_call_func_single_ipi
= xen_smp_send_call_function_single_ipi
,
652 void __init
xen_smp_init(void)
654 smp_ops
= xen_smp_ops
;
655 xen_fill_possible_map();
656 xen_init_spinlocks();
659 static void __init
xen_hvm_smp_prepare_cpus(unsigned int max_cpus
)
661 native_smp_prepare_cpus(max_cpus
);
662 WARN_ON(xen_smp_intr_init(0));
664 xen_init_lock_cpu(0);
667 static int __cpuinit
xen_hvm_cpu_up(unsigned int cpu
, struct task_struct
*tidle
)
670 rc
= native_cpu_up(cpu
, tidle
);
671 WARN_ON (xen_smp_intr_init(cpu
));
675 static void xen_hvm_cpu_die(unsigned int cpu
)
681 void __init
xen_hvm_smp_init(void)
683 if (!xen_have_vector_callback
)
685 smp_ops
.smp_prepare_cpus
= xen_hvm_smp_prepare_cpus
;
686 smp_ops
.smp_send_reschedule
= xen_smp_send_reschedule
;
687 smp_ops
.cpu_up
= xen_hvm_cpu_up
;
688 smp_ops
.cpu_die
= xen_hvm_cpu_die
;
689 smp_ops
.send_call_func_ipi
= xen_smp_send_call_function_ipi
;
690 smp_ops
.send_call_func_single_ipi
= xen_smp_send_call_function_single_ipi
;