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>
29 #include <xen/interface/xenpmu.h>
31 #include <asm/xen/interface.h>
32 #include <asm/xen/hypercall.h>
36 #include <xen/events.h>
38 #include <xen/hvc-console.h>
44 cpumask_var_t xen_cpu_initialized_map
;
46 struct xen_common_irq
{
50 static DEFINE_PER_CPU(struct xen_common_irq
, xen_resched_irq
) = { .irq
= -1 };
51 static DEFINE_PER_CPU(struct xen_common_irq
, xen_callfunc_irq
) = { .irq
= -1 };
52 static DEFINE_PER_CPU(struct xen_common_irq
, xen_callfuncsingle_irq
) = { .irq
= -1 };
53 static DEFINE_PER_CPU(struct xen_common_irq
, xen_irq_work
) = { .irq
= -1 };
54 static DEFINE_PER_CPU(struct xen_common_irq
, xen_debug_irq
) = { .irq
= -1 };
55 static DEFINE_PER_CPU(struct xen_common_irq
, xen_pmu_irq
) = { .irq
= -1 };
57 static irqreturn_t
xen_call_function_interrupt(int irq
, void *dev_id
);
58 static irqreturn_t
xen_call_function_single_interrupt(int irq
, void *dev_id
);
59 static irqreturn_t
xen_irq_work_interrupt(int irq
, void *dev_id
);
62 * Reschedule call back.
64 static irqreturn_t
xen_reschedule_interrupt(int irq
, void *dev_id
)
66 inc_irq_stat(irq_resched_count
);
72 static void cpu_bringup(void)
77 touch_softlockup_watchdog();
80 /* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
81 if (!xen_feature(XENFEAT_supervisor_mode_kernel
)) {
82 xen_enable_sysenter();
85 cpu
= smp_processor_id();
86 smp_store_cpu_info(cpu
);
87 cpu_data(cpu
).x86_max_cores
= 1;
88 set_cpu_sibling_map(cpu
);
90 xen_setup_cpu_clockevents();
92 notify_cpu_starting(cpu
);
94 set_cpu_online(cpu
, true);
96 cpu_set_state_online(cpu
); /* Implies full memory barrier. */
98 /* We can take interrupts now: we're officially "up". */
102 asmlinkage __visible
void cpu_bringup_and_idle(void)
105 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE
);
108 void xen_smp_intr_free(unsigned int cpu
)
110 if (per_cpu(xen_resched_irq
, cpu
).irq
>= 0) {
111 unbind_from_irqhandler(per_cpu(xen_resched_irq
, cpu
).irq
, NULL
);
112 per_cpu(xen_resched_irq
, cpu
).irq
= -1;
113 kfree(per_cpu(xen_resched_irq
, cpu
).name
);
114 per_cpu(xen_resched_irq
, cpu
).name
= NULL
;
116 if (per_cpu(xen_callfunc_irq
, cpu
).irq
>= 0) {
117 unbind_from_irqhandler(per_cpu(xen_callfunc_irq
, cpu
).irq
, NULL
);
118 per_cpu(xen_callfunc_irq
, cpu
).irq
= -1;
119 kfree(per_cpu(xen_callfunc_irq
, cpu
).name
);
120 per_cpu(xen_callfunc_irq
, cpu
).name
= NULL
;
122 if (per_cpu(xen_debug_irq
, cpu
).irq
>= 0) {
123 unbind_from_irqhandler(per_cpu(xen_debug_irq
, cpu
).irq
, NULL
);
124 per_cpu(xen_debug_irq
, cpu
).irq
= -1;
125 kfree(per_cpu(xen_debug_irq
, cpu
).name
);
126 per_cpu(xen_debug_irq
, cpu
).name
= NULL
;
128 if (per_cpu(xen_callfuncsingle_irq
, cpu
).irq
>= 0) {
129 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq
, cpu
).irq
,
131 per_cpu(xen_callfuncsingle_irq
, cpu
).irq
= -1;
132 kfree(per_cpu(xen_callfuncsingle_irq
, cpu
).name
);
133 per_cpu(xen_callfuncsingle_irq
, cpu
).name
= NULL
;
135 if (xen_hvm_domain())
138 if (per_cpu(xen_irq_work
, cpu
).irq
>= 0) {
139 unbind_from_irqhandler(per_cpu(xen_irq_work
, cpu
).irq
, NULL
);
140 per_cpu(xen_irq_work
, cpu
).irq
= -1;
141 kfree(per_cpu(xen_irq_work
, cpu
).name
);
142 per_cpu(xen_irq_work
, cpu
).name
= NULL
;
145 if (per_cpu(xen_pmu_irq
, cpu
).irq
>= 0) {
146 unbind_from_irqhandler(per_cpu(xen_pmu_irq
, cpu
).irq
, NULL
);
147 per_cpu(xen_pmu_irq
, cpu
).irq
= -1;
148 kfree(per_cpu(xen_pmu_irq
, cpu
).name
);
149 per_cpu(xen_pmu_irq
, cpu
).name
= NULL
;
152 int xen_smp_intr_init(unsigned int cpu
)
155 char *resched_name
, *callfunc_name
, *debug_name
, *pmu_name
;
157 resched_name
= kasprintf(GFP_KERNEL
, "resched%d", cpu
);
158 rc
= bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR
,
160 xen_reschedule_interrupt
,
161 IRQF_PERCPU
|IRQF_NOBALANCING
,
166 per_cpu(xen_resched_irq
, cpu
).irq
= rc
;
167 per_cpu(xen_resched_irq
, cpu
).name
= resched_name
;
169 callfunc_name
= kasprintf(GFP_KERNEL
, "callfunc%d", cpu
);
170 rc
= bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR
,
172 xen_call_function_interrupt
,
173 IRQF_PERCPU
|IRQF_NOBALANCING
,
178 per_cpu(xen_callfunc_irq
, cpu
).irq
= rc
;
179 per_cpu(xen_callfunc_irq
, cpu
).name
= callfunc_name
;
181 debug_name
= kasprintf(GFP_KERNEL
, "debug%d", cpu
);
182 rc
= bind_virq_to_irqhandler(VIRQ_DEBUG
, cpu
, xen_debug_interrupt
,
183 IRQF_PERCPU
| IRQF_NOBALANCING
,
187 per_cpu(xen_debug_irq
, cpu
).irq
= rc
;
188 per_cpu(xen_debug_irq
, cpu
).name
= debug_name
;
190 callfunc_name
= kasprintf(GFP_KERNEL
, "callfuncsingle%d", cpu
);
191 rc
= bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR
,
193 xen_call_function_single_interrupt
,
194 IRQF_PERCPU
|IRQF_NOBALANCING
,
199 per_cpu(xen_callfuncsingle_irq
, cpu
).irq
= rc
;
200 per_cpu(xen_callfuncsingle_irq
, cpu
).name
= callfunc_name
;
203 * The IRQ worker on PVHVM goes through the native path and uses the
206 if (xen_hvm_domain())
209 callfunc_name
= kasprintf(GFP_KERNEL
, "irqwork%d", cpu
);
210 rc
= bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR
,
212 xen_irq_work_interrupt
,
213 IRQF_PERCPU
|IRQF_NOBALANCING
,
218 per_cpu(xen_irq_work
, cpu
).irq
= rc
;
219 per_cpu(xen_irq_work
, cpu
).name
= callfunc_name
;
221 if (is_xen_pmu(cpu
)) {
222 pmu_name
= kasprintf(GFP_KERNEL
, "pmu%d", cpu
);
223 rc
= bind_virq_to_irqhandler(VIRQ_XENPMU
, cpu
,
225 IRQF_PERCPU
|IRQF_NOBALANCING
,
229 per_cpu(xen_pmu_irq
, cpu
).irq
= rc
;
230 per_cpu(xen_pmu_irq
, cpu
).name
= pmu_name
;
236 xen_smp_intr_free(cpu
);
240 static void __init
xen_fill_possible_map(void)
244 if (xen_initial_domain())
247 for (i
= 0; i
< nr_cpu_ids
; i
++) {
248 rc
= HYPERVISOR_vcpu_op(VCPUOP_is_up
, i
, NULL
);
251 set_cpu_possible(i
, true);
256 static void __init
xen_filter_cpu_maps(void)
259 unsigned int subtract
= 0;
261 if (!xen_initial_domain())
266 for (i
= 0; i
< nr_cpu_ids
; i
++) {
267 rc
= HYPERVISOR_vcpu_op(VCPUOP_is_up
, i
, NULL
);
270 set_cpu_possible(i
, true);
272 set_cpu_possible(i
, false);
273 set_cpu_present(i
, false);
277 #ifdef CONFIG_HOTPLUG_CPU
278 /* This is akin to using 'nr_cpus' on the Linux command line.
279 * Which is OK as when we use 'dom0_max_vcpus=X' we can only
280 * have up to X, while nr_cpu_ids is greater than X. This
281 * normally is not a problem, except when CPU hotplugging
282 * is involved and then there might be more than X CPUs
283 * in the guest - which will not work as there is no
284 * hypercall to expand the max number of VCPUs an already
285 * running guest has. So cap it up to X. */
287 nr_cpu_ids
= nr_cpu_ids
- subtract
;
292 static void __init
xen_smp_prepare_boot_cpu(void)
294 BUG_ON(smp_processor_id() != 0);
295 native_smp_prepare_boot_cpu();
297 if (xen_pv_domain()) {
298 if (!xen_feature(XENFEAT_writable_page_tables
))
299 /* We've switched to the "real" per-cpu gdt, so make
300 * sure the old memory can be recycled. */
301 make_lowmem_page_readwrite(xen_initial_gdt
);
305 * Xen starts us with XEN_FLAT_RING1_DS, but linux code
308 loadsegment(ds
, __USER_DS
);
309 loadsegment(es
, __USER_DS
);
312 xen_filter_cpu_maps();
313 xen_setup_vcpu_info_placement();
317 * Setup vcpu_info for boot CPU.
319 if (xen_hvm_domain())
323 * The alternative logic (which patches the unlock/lock) runs before
324 * the smp bootup up code is activated. Hence we need to set this up
325 * the core kernel is being patched. Otherwise we will have only
326 * modules patched but not core code.
328 xen_init_spinlocks();
331 static void __init
xen_smp_prepare_cpus(unsigned int max_cpus
)
336 if (skip_ioapic_setup
) {
337 char *m
= (max_cpus
== 0) ?
338 "The nosmp parameter is incompatible with Xen; " \
339 "use Xen dom0_max_vcpus=1 parameter" :
340 "The noapic parameter is incompatible with Xen";
345 xen_init_lock_cpu(0);
347 smp_store_boot_cpu_info();
348 cpu_data(0).x86_max_cores
= 1;
350 for_each_possible_cpu(i
) {
351 zalloc_cpumask_var(&per_cpu(cpu_sibling_map
, i
), GFP_KERNEL
);
352 zalloc_cpumask_var(&per_cpu(cpu_core_map
, i
), GFP_KERNEL
);
353 zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map
, i
), GFP_KERNEL
);
355 set_cpu_sibling_map(0);
359 if (xen_smp_intr_init(0))
362 if (!alloc_cpumask_var(&xen_cpu_initialized_map
, GFP_KERNEL
))
363 panic("could not allocate xen_cpu_initialized_map\n");
365 cpumask_copy(xen_cpu_initialized_map
, cpumask_of(0));
367 /* Restrict the possible_map according to max_cpus. */
368 while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus
)) {
369 for (cpu
= nr_cpu_ids
- 1; !cpu_possible(cpu
); cpu
--)
371 set_cpu_possible(cpu
, false);
374 for_each_possible_cpu(cpu
)
375 set_cpu_present(cpu
, true);
379 cpu_initialize_context(unsigned int cpu
, struct task_struct
*idle
)
381 struct vcpu_guest_context
*ctxt
;
382 struct desc_struct
*gdt
;
383 unsigned long gdt_mfn
;
385 /* used to tell cpu_init() that it can proceed with initialization */
386 cpumask_set_cpu(cpu
, cpu_callout_mask
);
387 if (cpumask_test_and_set_cpu(cpu
, xen_cpu_initialized_map
))
390 ctxt
= kzalloc(sizeof(*ctxt
), GFP_KERNEL
);
394 gdt
= get_cpu_gdt_table(cpu
);
397 ctxt
->user_regs
.fs
= __KERNEL_PERCPU
;
398 ctxt
->user_regs
.gs
= __KERNEL_STACK_CANARY
;
400 memset(&ctxt
->fpu_ctxt
, 0, sizeof(ctxt
->fpu_ctxt
));
402 ctxt
->user_regs
.eip
= (unsigned long)cpu_bringup_and_idle
;
403 ctxt
->flags
= VGCF_IN_KERNEL
;
404 ctxt
->user_regs
.eflags
= 0x1000; /* IOPL_RING1 */
405 ctxt
->user_regs
.ds
= __USER_DS
;
406 ctxt
->user_regs
.es
= __USER_DS
;
407 ctxt
->user_regs
.ss
= __KERNEL_DS
;
409 xen_copy_trap_info(ctxt
->trap_ctxt
);
413 BUG_ON((unsigned long)gdt
& ~PAGE_MASK
);
415 gdt_mfn
= arbitrary_virt_to_mfn(gdt
);
416 make_lowmem_page_readonly(gdt
);
417 make_lowmem_page_readonly(mfn_to_virt(gdt_mfn
));
419 ctxt
->gdt_frames
[0] = gdt_mfn
;
420 ctxt
->gdt_ents
= GDT_ENTRIES
;
422 ctxt
->kernel_ss
= __KERNEL_DS
;
423 ctxt
->kernel_sp
= idle
->thread
.sp0
;
426 ctxt
->event_callback_cs
= __KERNEL_CS
;
427 ctxt
->failsafe_callback_cs
= __KERNEL_CS
;
429 ctxt
->gs_base_kernel
= per_cpu_offset(cpu
);
431 ctxt
->event_callback_eip
=
432 (unsigned long)xen_hypervisor_callback
;
433 ctxt
->failsafe_callback_eip
=
434 (unsigned long)xen_failsafe_callback
;
435 ctxt
->user_regs
.cs
= __KERNEL_CS
;
436 per_cpu(xen_cr3
, cpu
) = __pa(swapper_pg_dir
);
438 ctxt
->user_regs
.esp
= idle
->thread
.sp0
- sizeof(struct pt_regs
);
439 ctxt
->ctrlreg
[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir
));
440 if (HYPERVISOR_vcpu_op(VCPUOP_initialise
, xen_vcpu_nr(cpu
), ctxt
))
447 static int xen_cpu_up(unsigned int cpu
, struct task_struct
*idle
)
451 common_cpu_up(cpu
, idle
);
453 xen_setup_runstate_info(cpu
);
456 * PV VCPUs are always successfully taken down (see 'while' loop
457 * in xen_cpu_die()), so -EBUSY is an error.
459 rc
= cpu_check_up_prepare(cpu
);
463 /* make sure interrupts start blocked */
464 per_cpu(xen_vcpu
, cpu
)->evtchn_upcall_mask
= 1;
466 rc
= cpu_initialize_context(cpu
, idle
);
472 rc
= HYPERVISOR_vcpu_op(VCPUOP_up
, xen_vcpu_nr(cpu
), NULL
);
475 while (cpu_report_state(cpu
) != CPU_ONLINE
)
476 HYPERVISOR_sched_op(SCHEDOP_yield
, NULL
);
481 static void xen_smp_cpus_done(unsigned int max_cpus
)
485 #ifdef CONFIG_HOTPLUG_CPU
486 static int xen_cpu_disable(void)
488 unsigned int cpu
= smp_processor_id();
492 cpu_disable_common();
494 load_cr3(swapper_pg_dir
);
498 static void xen_cpu_die(unsigned int cpu
)
500 while (xen_pv_domain() && HYPERVISOR_vcpu_op(VCPUOP_is_up
,
501 xen_vcpu_nr(cpu
), NULL
)) {
502 __set_current_state(TASK_UNINTERRUPTIBLE
);
503 schedule_timeout(HZ
/10);
506 if (common_cpu_die(cpu
) == 0) {
507 xen_smp_intr_free(cpu
);
508 xen_uninit_lock_cpu(cpu
);
509 xen_teardown_timer(cpu
);
514 static void xen_play_dead(void) /* used only with HOTPLUG_CPU */
517 HYPERVISOR_vcpu_op(VCPUOP_down
, xen_vcpu_nr(smp_processor_id()), NULL
);
520 * commit 4b0c0f294 (tick: Cleanup NOHZ per cpu data on cpu down)
521 * clears certain data that the cpu_idle loop (which called us
522 * and that we return from) expects. The only way to get that
523 * data back is to call:
525 tick_nohz_idle_enter();
527 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE
);
530 #else /* !CONFIG_HOTPLUG_CPU */
531 static int xen_cpu_disable(void)
536 static void xen_cpu_die(unsigned int cpu
)
541 static void xen_play_dead(void)
547 static void stop_self(void *v
)
549 int cpu
= smp_processor_id();
551 /* make sure we're not pinning something down */
552 load_cr3(swapper_pg_dir
);
553 /* should set up a minimal gdt */
555 set_cpu_online(cpu
, false);
557 HYPERVISOR_vcpu_op(VCPUOP_down
, xen_vcpu_nr(cpu
), NULL
);
561 static void xen_stop_other_cpus(int wait
)
563 smp_call_function(stop_self
, NULL
, wait
);
566 static void xen_smp_send_reschedule(int cpu
)
568 xen_send_IPI_one(cpu
, XEN_RESCHEDULE_VECTOR
);
571 static void __xen_send_IPI_mask(const struct cpumask
*mask
,
576 for_each_cpu_and(cpu
, mask
, cpu_online_mask
)
577 xen_send_IPI_one(cpu
, vector
);
580 static void xen_smp_send_call_function_ipi(const struct cpumask
*mask
)
584 __xen_send_IPI_mask(mask
, XEN_CALL_FUNCTION_VECTOR
);
586 /* Make sure other vcpus get a chance to run if they need to. */
587 for_each_cpu(cpu
, mask
) {
588 if (xen_vcpu_stolen(cpu
)) {
589 HYPERVISOR_sched_op(SCHEDOP_yield
, NULL
);
595 static void xen_smp_send_call_function_single_ipi(int cpu
)
597 __xen_send_IPI_mask(cpumask_of(cpu
),
598 XEN_CALL_FUNCTION_SINGLE_VECTOR
);
601 static inline int xen_map_vector(int vector
)
606 case RESCHEDULE_VECTOR
:
607 xen_vector
= XEN_RESCHEDULE_VECTOR
;
609 case CALL_FUNCTION_VECTOR
:
610 xen_vector
= XEN_CALL_FUNCTION_VECTOR
;
612 case CALL_FUNCTION_SINGLE_VECTOR
:
613 xen_vector
= XEN_CALL_FUNCTION_SINGLE_VECTOR
;
615 case IRQ_WORK_VECTOR
:
616 xen_vector
= XEN_IRQ_WORK_VECTOR
;
620 case APIC_DM_NMI
: /* Some use that instead of NMI_VECTOR */
621 xen_vector
= XEN_NMI_VECTOR
;
626 printk(KERN_ERR
"xen: vector 0x%x is not implemented\n",
633 void xen_send_IPI_mask(const struct cpumask
*mask
,
636 int xen_vector
= xen_map_vector(vector
);
639 __xen_send_IPI_mask(mask
, xen_vector
);
642 void xen_send_IPI_all(int vector
)
644 int xen_vector
= xen_map_vector(vector
);
647 __xen_send_IPI_mask(cpu_online_mask
, xen_vector
);
650 void xen_send_IPI_self(int vector
)
652 int xen_vector
= xen_map_vector(vector
);
655 xen_send_IPI_one(smp_processor_id(), xen_vector
);
658 void xen_send_IPI_mask_allbutself(const struct cpumask
*mask
,
662 unsigned int this_cpu
= smp_processor_id();
663 int xen_vector
= xen_map_vector(vector
);
665 if (!(num_online_cpus() > 1) || (xen_vector
< 0))
668 for_each_cpu_and(cpu
, mask
, cpu_online_mask
) {
672 xen_send_IPI_one(cpu
, xen_vector
);
676 void xen_send_IPI_allbutself(int vector
)
678 xen_send_IPI_mask_allbutself(cpu_online_mask
, vector
);
681 static irqreturn_t
xen_call_function_interrupt(int irq
, void *dev_id
)
684 generic_smp_call_function_interrupt();
685 inc_irq_stat(irq_call_count
);
691 static irqreturn_t
xen_call_function_single_interrupt(int irq
, void *dev_id
)
694 generic_smp_call_function_single_interrupt();
695 inc_irq_stat(irq_call_count
);
701 static irqreturn_t
xen_irq_work_interrupt(int irq
, void *dev_id
)
705 inc_irq_stat(apic_irq_work_irqs
);
711 static const struct smp_ops xen_smp_ops __initconst
= {
712 .smp_prepare_boot_cpu
= xen_smp_prepare_boot_cpu
,
713 .smp_prepare_cpus
= xen_smp_prepare_cpus
,
714 .smp_cpus_done
= xen_smp_cpus_done
,
716 .cpu_up
= xen_cpu_up
,
717 .cpu_die
= xen_cpu_die
,
718 .cpu_disable
= xen_cpu_disable
,
719 .play_dead
= xen_play_dead
,
721 .stop_other_cpus
= xen_stop_other_cpus
,
722 .smp_send_reschedule
= xen_smp_send_reschedule
,
724 .send_call_func_ipi
= xen_smp_send_call_function_ipi
,
725 .send_call_func_single_ipi
= xen_smp_send_call_function_single_ipi
,
728 void __init
xen_smp_init(void)
730 smp_ops
= xen_smp_ops
;
731 xen_fill_possible_map();
734 static void __init
xen_hvm_smp_prepare_cpus(unsigned int max_cpus
)
736 native_smp_prepare_cpus(max_cpus
);
737 WARN_ON(xen_smp_intr_init(0));
739 xen_init_lock_cpu(0);
742 void __init
xen_hvm_smp_init(void)
744 smp_ops
.smp_prepare_cpus
= xen_hvm_smp_prepare_cpus
;
745 smp_ops
.smp_send_reschedule
= xen_smp_send_reschedule
;
746 smp_ops
.cpu_die
= xen_cpu_die
;
747 smp_ops
.send_call_func_ipi
= xen_smp_send_call_function_ipi
;
748 smp_ops
.send_call_func_single_ipi
= xen_smp_send_call_function_single_ipi
;
749 smp_ops
.smp_prepare_boot_cpu
= xen_smp_prepare_boot_cpu
;