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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Xen SMP support
4 *
5 * This file implements the Xen versions of smp_ops. SMP under Xen is
6 * very straightforward. Bringing a CPU up is simply a matter of
7 * loading its initial context and setting it running.
8 *
9 * IPIs are handled through the Xen event mechanism.
10 *
11 * Because virtual CPUs can be scheduled onto any real CPU, there's no
12 * useful topology information for the kernel to make use of. As a
13 * result, all CPUs are treated as if they're single-core and
14 * single-threaded.
15 */
16#include <linux/sched.h>
17#include <linux/sched/task_stack.h>
18#include <linux/err.h>
19#include <linux/slab.h>
20#include <linux/smp.h>
21#include <linux/irq_work.h>
22#include <linux/tick.h>
23#include <linux/nmi.h>
24#include <linux/cpuhotplug.h>
25#include <linux/stackprotector.h>
26#include <linux/pgtable.h>
27
28#include <asm/paravirt.h>
29#include <asm/idtentry.h>
30#include <asm/desc.h>
31#include <asm/cpu.h>
32#include <asm/io_apic.h>
33
34#include <xen/interface/xen.h>
35#include <xen/interface/vcpu.h>
36#include <xen/interface/xenpmu.h>
37
38#include <asm/spec-ctrl.h>
39#include <asm/xen/interface.h>
40#include <asm/xen/hypercall.h>
41
42#include <xen/xen.h>
43#include <xen/page.h>
44#include <xen/events.h>
45
46#include <xen/hvc-console.h>
47#include "xen-ops.h"
48#include "mmu.h"
49#include "smp.h"
50#include "pmu.h"
51
52cpumask_var_t xen_cpu_initialized_map;
53
54static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = { .irq = -1 };
55static DEFINE_PER_CPU(struct xen_common_irq, xen_pmu_irq) = { .irq = -1 };
56
57static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id);
58void asm_cpu_bringup_and_idle(void);
59
60static void cpu_bringup(void)
61{
62 int cpu;
63
64 cr4_init();
65 cpu_init();
66 touch_softlockup_watchdog();
67
68 /* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
69 if (!xen_feature(XENFEAT_supervisor_mode_kernel)) {
70 xen_enable_sysenter();
71 xen_enable_syscall();
72 }
73 cpu = smp_processor_id();
74 smp_store_cpu_info(cpu);
75 cpu_data(cpu).x86_max_cores = 1;
76 set_cpu_sibling_map(cpu);
77
78 speculative_store_bypass_ht_init();
79
80 xen_setup_cpu_clockevents();
81
82 notify_cpu_starting(cpu);
83
84 set_cpu_online(cpu, true);
85
86 cpu_set_state_online(cpu); /* Implies full memory barrier. */
87
88 /* We can take interrupts now: we're officially "up". */
89 local_irq_enable();
90}
91
92asmlinkage __visible void cpu_bringup_and_idle(void)
93{
94 cpu_bringup();
95 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
96}
97
98void xen_smp_intr_free_pv(unsigned int cpu)
99{
100 kfree(per_cpu(xen_irq_work, cpu).name);
101 per_cpu(xen_irq_work, cpu).name = NULL;
102 if (per_cpu(xen_irq_work, cpu).irq >= 0) {
103 unbind_from_irqhandler(per_cpu(xen_irq_work, cpu).irq, NULL);
104 per_cpu(xen_irq_work, cpu).irq = -1;
105 }
106
107 kfree(per_cpu(xen_pmu_irq, cpu).name);
108 per_cpu(xen_pmu_irq, cpu).name = NULL;
109 if (per_cpu(xen_pmu_irq, cpu).irq >= 0) {
110 unbind_from_irqhandler(per_cpu(xen_pmu_irq, cpu).irq, NULL);
111 per_cpu(xen_pmu_irq, cpu).irq = -1;
112 }
113}
114
115int xen_smp_intr_init_pv(unsigned int cpu)
116{
117 int rc;
118 char *callfunc_name, *pmu_name;
119
120 callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
121 per_cpu(xen_irq_work, cpu).name = callfunc_name;
122 rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
123 cpu,
124 xen_irq_work_interrupt,
125 IRQF_PERCPU|IRQF_NOBALANCING,
126 callfunc_name,
127 NULL);
128 if (rc < 0)
129 goto fail;
130 per_cpu(xen_irq_work, cpu).irq = rc;
131
132 if (is_xen_pmu) {
133 pmu_name = kasprintf(GFP_KERNEL, "pmu%d", cpu);
134 per_cpu(xen_pmu_irq, cpu).name = pmu_name;
135 rc = bind_virq_to_irqhandler(VIRQ_XENPMU, cpu,
136 xen_pmu_irq_handler,
137 IRQF_PERCPU|IRQF_NOBALANCING,
138 pmu_name, NULL);
139 if (rc < 0)
140 goto fail;
141 per_cpu(xen_pmu_irq, cpu).irq = rc;
142 }
143
144 return 0;
145
146 fail:
147 xen_smp_intr_free_pv(cpu);
148 return rc;
149}
150
151static void __init _get_smp_config(unsigned int early)
152{
153 int i, rc;
154 unsigned int subtract = 0;
155
156 if (early)
157 return;
158
159 num_processors = 0;
160 disabled_cpus = 0;
161 for (i = 0; i < nr_cpu_ids; i++) {
162 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
163 if (rc >= 0) {
164 num_processors++;
165 set_cpu_possible(i, true);
166 } else {
167 set_cpu_possible(i, false);
168 set_cpu_present(i, false);
169 subtract++;
170 }
171 }
172#ifdef CONFIG_HOTPLUG_CPU
173 /* This is akin to using 'nr_cpus' on the Linux command line.
174 * Which is OK as when we use 'dom0_max_vcpus=X' we can only
175 * have up to X, while nr_cpu_ids is greater than X. This
176 * normally is not a problem, except when CPU hotplugging
177 * is involved and then there might be more than X CPUs
178 * in the guest - which will not work as there is no
179 * hypercall to expand the max number of VCPUs an already
180 * running guest has. So cap it up to X. */
181 if (subtract)
182 set_nr_cpu_ids(nr_cpu_ids - subtract);
183#endif
184
185}
186
187static void __init xen_pv_smp_prepare_boot_cpu(void)
188{
189 BUG_ON(smp_processor_id() != 0);
190 native_smp_prepare_boot_cpu();
191
192 if (!xen_feature(XENFEAT_writable_page_tables))
193 /* We've switched to the "real" per-cpu gdt, so make
194 * sure the old memory can be recycled. */
195 make_lowmem_page_readwrite(xen_initial_gdt);
196
197 xen_setup_vcpu_info_placement();
198
199 /*
200 * The alternative logic (which patches the unlock/lock) runs before
201 * the smp bootup up code is activated. Hence we need to set this up
202 * the core kernel is being patched. Otherwise we will have only
203 * modules patched but not core code.
204 */
205 xen_init_spinlocks();
206}
207
208static void __init xen_pv_smp_prepare_cpus(unsigned int max_cpus)
209{
210 unsigned cpu;
211
212 if (skip_ioapic_setup) {
213 char *m = (max_cpus == 0) ?
214 "The nosmp parameter is incompatible with Xen; " \
215 "use Xen dom0_max_vcpus=1 parameter" :
216 "The noapic parameter is incompatible with Xen";
217
218 xen_raw_printk(m);
219 panic(m);
220 }
221 xen_init_lock_cpu(0);
222
223 smp_prepare_cpus_common();
224
225 cpu_data(0).x86_max_cores = 1;
226
227 speculative_store_bypass_ht_init();
228
229 xen_pmu_init(0);
230
231 if (xen_smp_intr_init(0) || xen_smp_intr_init_pv(0))
232 BUG();
233
234 if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))
235 panic("could not allocate xen_cpu_initialized_map\n");
236
237 cpumask_copy(xen_cpu_initialized_map, cpumask_of(0));
238
239 /* Restrict the possible_map according to max_cpus. */
240 while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
241 for (cpu = nr_cpu_ids - 1; !cpu_possible(cpu); cpu--)
242 continue;
243 set_cpu_possible(cpu, false);
244 }
245
246 for_each_possible_cpu(cpu)
247 set_cpu_present(cpu, true);
248}
249
250static int
251cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
252{
253 struct vcpu_guest_context *ctxt;
254 struct desc_struct *gdt;
255 unsigned long gdt_mfn;
256
257 /* used to tell cpu_init() that it can proceed with initialization */
258 cpumask_set_cpu(cpu, cpu_callout_mask);
259 if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
260 return 0;
261
262 ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
263 if (ctxt == NULL) {
264 cpumask_clear_cpu(cpu, xen_cpu_initialized_map);
265 cpumask_clear_cpu(cpu, cpu_callout_mask);
266 return -ENOMEM;
267 }
268
269 gdt = get_cpu_gdt_rw(cpu);
270
271 /*
272 * Bring up the CPU in cpu_bringup_and_idle() with the stack
273 * pointing just below where pt_regs would be if it were a normal
274 * kernel entry.
275 */
276 ctxt->user_regs.eip = (unsigned long)asm_cpu_bringup_and_idle;
277 ctxt->flags = VGCF_IN_KERNEL;
278 ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
279 ctxt->user_regs.ds = __USER_DS;
280 ctxt->user_regs.es = __USER_DS;
281 ctxt->user_regs.ss = __KERNEL_DS;
282 ctxt->user_regs.cs = __KERNEL_CS;
283 ctxt->user_regs.esp = (unsigned long)task_pt_regs(idle);
284
285 xen_copy_trap_info(ctxt->trap_ctxt);
286
287 BUG_ON((unsigned long)gdt & ~PAGE_MASK);
288
289 gdt_mfn = arbitrary_virt_to_mfn(gdt);
290 make_lowmem_page_readonly(gdt);
291 make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
292
293 ctxt->gdt_frames[0] = gdt_mfn;
294 ctxt->gdt_ents = GDT_ENTRIES;
295
296 /*
297 * Set SS:SP that Xen will use when entering guest kernel mode
298 * from guest user mode. Subsequent calls to load_sp0() can
299 * change this value.
300 */
301 ctxt->kernel_ss = __KERNEL_DS;
302 ctxt->kernel_sp = task_top_of_stack(idle);
303
304 ctxt->gs_base_kernel = per_cpu_offset(cpu);
305 ctxt->event_callback_eip =
306 (unsigned long)xen_asm_exc_xen_hypervisor_callback;
307 ctxt->failsafe_callback_eip =
308 (unsigned long)xen_failsafe_callback;
309 per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
310
311 ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));
312 if (HYPERVISOR_vcpu_op(VCPUOP_initialise, xen_vcpu_nr(cpu), ctxt))
313 BUG();
314
315 kfree(ctxt);
316 return 0;
317}
318
319static int xen_pv_cpu_up(unsigned int cpu, struct task_struct *idle)
320{
321 int rc;
322
323 rc = common_cpu_up(cpu, idle);
324 if (rc)
325 return rc;
326
327 xen_setup_runstate_info(cpu);
328
329 /*
330 * PV VCPUs are always successfully taken down (see 'while' loop
331 * in xen_cpu_die()), so -EBUSY is an error.
332 */
333 rc = cpu_check_up_prepare(cpu);
334 if (rc)
335 return rc;
336
337 /* make sure interrupts start blocked */
338 per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
339
340 rc = cpu_initialize_context(cpu, idle);
341 if (rc)
342 return rc;
343
344 xen_pmu_init(cpu);
345
346 rc = HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL);
347 BUG_ON(rc);
348
349 while (cpu_report_state(cpu) != CPU_ONLINE)
350 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
351
352 return 0;
353}
354
355#ifdef CONFIG_HOTPLUG_CPU
356static int xen_pv_cpu_disable(void)
357{
358 unsigned int cpu = smp_processor_id();
359 if (cpu == 0)
360 return -EBUSY;
361
362 cpu_disable_common();
363
364 load_cr3(swapper_pg_dir);
365 return 0;
366}
367
368static void xen_pv_cpu_die(unsigned int cpu)
369{
370 while (HYPERVISOR_vcpu_op(VCPUOP_is_up,
371 xen_vcpu_nr(cpu), NULL)) {
372 __set_current_state(TASK_UNINTERRUPTIBLE);
373 schedule_timeout(HZ/10);
374 }
375
376 if (common_cpu_die(cpu) == 0) {
377 xen_smp_intr_free(cpu);
378 xen_uninit_lock_cpu(cpu);
379 xen_teardown_timer(cpu);
380 xen_pmu_finish(cpu);
381 }
382}
383
384static void xen_pv_play_dead(void) /* used only with HOTPLUG_CPU */
385{
386 play_dead_common();
387 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(smp_processor_id()), NULL);
388 cpu_bringup();
389 /*
390 * commit 4b0c0f294 (tick: Cleanup NOHZ per cpu data on cpu down)
391 * clears certain data that the cpu_idle loop (which called us
392 * and that we return from) expects. The only way to get that
393 * data back is to call:
394 */
395 tick_nohz_idle_enter();
396 tick_nohz_idle_stop_tick_protected();
397
398 cpuhp_online_idle(CPUHP_AP_ONLINE_IDLE);
399}
400
401#else /* !CONFIG_HOTPLUG_CPU */
402static int xen_pv_cpu_disable(void)
403{
404 return -ENOSYS;
405}
406
407static void xen_pv_cpu_die(unsigned int cpu)
408{
409 BUG();
410}
411
412static void xen_pv_play_dead(void)
413{
414 BUG();
415}
416
417#endif
418static void stop_self(void *v)
419{
420 int cpu = smp_processor_id();
421
422 /* make sure we're not pinning something down */
423 load_cr3(swapper_pg_dir);
424 /* should set up a minimal gdt */
425
426 set_cpu_online(cpu, false);
427
428 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL);
429 BUG();
430}
431
432static void xen_pv_stop_other_cpus(int wait)
433{
434 smp_call_function(stop_self, NULL, wait);
435}
436
437static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)
438{
439 irq_work_run();
440 inc_irq_stat(apic_irq_work_irqs);
441
442 return IRQ_HANDLED;
443}
444
445static const struct smp_ops xen_smp_ops __initconst = {
446 .smp_prepare_boot_cpu = xen_pv_smp_prepare_boot_cpu,
447 .smp_prepare_cpus = xen_pv_smp_prepare_cpus,
448 .smp_cpus_done = xen_smp_cpus_done,
449
450 .cpu_up = xen_pv_cpu_up,
451 .cpu_die = xen_pv_cpu_die,
452 .cpu_disable = xen_pv_cpu_disable,
453 .play_dead = xen_pv_play_dead,
454
455 .stop_other_cpus = xen_pv_stop_other_cpus,
456 .smp_send_reschedule = xen_smp_send_reschedule,
457
458 .send_call_func_ipi = xen_smp_send_call_function_ipi,
459 .send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
460};
461
462void __init xen_smp_init(void)
463{
464 smp_ops = xen_smp_ops;
465
466 /* Avoid searching for BIOS MP tables */
467 x86_init.mpparse.find_smp_config = x86_init_noop;
468 x86_init.mpparse.get_smp_config = _get_smp_config;
469}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Xen SMP support
4 *
5 * This file implements the Xen versions of smp_ops. SMP under Xen is
6 * very straightforward. Bringing a CPU up is simply a matter of
7 * loading its initial context and setting it running.
8 *
9 * IPIs are handled through the Xen event mechanism.
10 *
11 * Because virtual CPUs can be scheduled onto any real CPU, there's no
12 * useful topology information for the kernel to make use of. As a
13 * result, all CPUs are treated as if they're single-core and
14 * single-threaded.
15 */
16#include <linux/sched.h>
17#include <linux/sched/task_stack.h>
18#include <linux/err.h>
19#include <linux/slab.h>
20#include <linux/smp.h>
21#include <linux/irq_work.h>
22#include <linux/tick.h>
23#include <linux/nmi.h>
24#include <linux/cpuhotplug.h>
25#include <linux/stackprotector.h>
26
27#include <asm/paravirt.h>
28#include <asm/desc.h>
29#include <asm/pgtable.h>
30#include <asm/cpu.h>
31
32#include <xen/interface/xen.h>
33#include <xen/interface/vcpu.h>
34#include <xen/interface/xenpmu.h>
35
36#include <asm/spec-ctrl.h>
37#include <asm/xen/interface.h>
38#include <asm/xen/hypercall.h>
39
40#include <xen/xen.h>
41#include <xen/page.h>
42#include <xen/events.h>
43
44#include <xen/hvc-console.h>
45#include "xen-ops.h"
46#include "mmu.h"
47#include "smp.h"
48#include "pmu.h"
49
50cpumask_var_t xen_cpu_initialized_map;
51
52static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = { .irq = -1 };
53static DEFINE_PER_CPU(struct xen_common_irq, xen_pmu_irq) = { .irq = -1 };
54
55static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id);
56
57static void cpu_bringup(void)
58{
59 int cpu;
60
61 cr4_init();
62 cpu_init();
63 touch_softlockup_watchdog();
64 preempt_disable();
65
66 /* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
67 if (!xen_feature(XENFEAT_supervisor_mode_kernel)) {
68 xen_enable_sysenter();
69 xen_enable_syscall();
70 }
71 cpu = smp_processor_id();
72 smp_store_cpu_info(cpu);
73 cpu_data(cpu).x86_max_cores = 1;
74 set_cpu_sibling_map(cpu);
75
76 speculative_store_bypass_ht_init();
77
78 xen_setup_cpu_clockevents();
79
80 notify_cpu_starting(cpu);
81
82 set_cpu_online(cpu, true);
83
84 cpu_set_state_online(cpu); /* Implies full memory barrier. */
85
86 /* We can take interrupts now: we're officially "up". */
87 local_irq_enable();
88}
89
90asmlinkage __visible void cpu_bringup_and_idle(void)
91{
92 cpu_bringup();
93 boot_init_stack_canary();
94 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
95}
96
97void xen_smp_intr_free_pv(unsigned int cpu)
98{
99 if (per_cpu(xen_irq_work, cpu).irq >= 0) {
100 unbind_from_irqhandler(per_cpu(xen_irq_work, cpu).irq, NULL);
101 per_cpu(xen_irq_work, cpu).irq = -1;
102 kfree(per_cpu(xen_irq_work, cpu).name);
103 per_cpu(xen_irq_work, cpu).name = NULL;
104 }
105
106 if (per_cpu(xen_pmu_irq, cpu).irq >= 0) {
107 unbind_from_irqhandler(per_cpu(xen_pmu_irq, cpu).irq, NULL);
108 per_cpu(xen_pmu_irq, cpu).irq = -1;
109 kfree(per_cpu(xen_pmu_irq, cpu).name);
110 per_cpu(xen_pmu_irq, cpu).name = NULL;
111 }
112}
113
114int xen_smp_intr_init_pv(unsigned int cpu)
115{
116 int rc;
117 char *callfunc_name, *pmu_name;
118
119 callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
120 rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
121 cpu,
122 xen_irq_work_interrupt,
123 IRQF_PERCPU|IRQF_NOBALANCING,
124 callfunc_name,
125 NULL);
126 if (rc < 0)
127 goto fail;
128 per_cpu(xen_irq_work, cpu).irq = rc;
129 per_cpu(xen_irq_work, cpu).name = callfunc_name;
130
131 if (is_xen_pmu(cpu)) {
132 pmu_name = kasprintf(GFP_KERNEL, "pmu%d", cpu);
133 rc = bind_virq_to_irqhandler(VIRQ_XENPMU, cpu,
134 xen_pmu_irq_handler,
135 IRQF_PERCPU|IRQF_NOBALANCING,
136 pmu_name, NULL);
137 if (rc < 0)
138 goto fail;
139 per_cpu(xen_pmu_irq, cpu).irq = rc;
140 per_cpu(xen_pmu_irq, cpu).name = pmu_name;
141 }
142
143 return 0;
144
145 fail:
146 xen_smp_intr_free_pv(cpu);
147 return rc;
148}
149
150static void __init xen_fill_possible_map(void)
151{
152 int i, rc;
153
154 if (xen_initial_domain())
155 return;
156
157 for (i = 0; i < nr_cpu_ids; i++) {
158 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
159 if (rc >= 0) {
160 num_processors++;
161 set_cpu_possible(i, true);
162 }
163 }
164}
165
166static void __init xen_filter_cpu_maps(void)
167{
168 int i, rc;
169 unsigned int subtract = 0;
170
171 if (!xen_initial_domain())
172 return;
173
174 num_processors = 0;
175 disabled_cpus = 0;
176 for (i = 0; i < nr_cpu_ids; i++) {
177 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
178 if (rc >= 0) {
179 num_processors++;
180 set_cpu_possible(i, true);
181 } else {
182 set_cpu_possible(i, false);
183 set_cpu_present(i, false);
184 subtract++;
185 }
186 }
187#ifdef CONFIG_HOTPLUG_CPU
188 /* This is akin to using 'nr_cpus' on the Linux command line.
189 * Which is OK as when we use 'dom0_max_vcpus=X' we can only
190 * have up to X, while nr_cpu_ids is greater than X. This
191 * normally is not a problem, except when CPU hotplugging
192 * is involved and then there might be more than X CPUs
193 * in the guest - which will not work as there is no
194 * hypercall to expand the max number of VCPUs an already
195 * running guest has. So cap it up to X. */
196 if (subtract)
197 nr_cpu_ids = nr_cpu_ids - subtract;
198#endif
199
200}
201
202static void __init xen_pv_smp_prepare_boot_cpu(void)
203{
204 BUG_ON(smp_processor_id() != 0);
205 native_smp_prepare_boot_cpu();
206
207 if (!xen_feature(XENFEAT_writable_page_tables))
208 /* We've switched to the "real" per-cpu gdt, so make
209 * sure the old memory can be recycled. */
210 make_lowmem_page_readwrite(xen_initial_gdt);
211
212#ifdef CONFIG_X86_32
213 /*
214 * Xen starts us with XEN_FLAT_RING1_DS, but linux code
215 * expects __USER_DS
216 */
217 loadsegment(ds, __USER_DS);
218 loadsegment(es, __USER_DS);
219#endif
220
221 xen_filter_cpu_maps();
222 xen_setup_vcpu_info_placement();
223
224 /*
225 * The alternative logic (which patches the unlock/lock) runs before
226 * the smp bootup up code is activated. Hence we need to set this up
227 * the core kernel is being patched. Otherwise we will have only
228 * modules patched but not core code.
229 */
230 xen_init_spinlocks();
231}
232
233static void __init xen_pv_smp_prepare_cpus(unsigned int max_cpus)
234{
235 unsigned cpu;
236 unsigned int i;
237
238 if (skip_ioapic_setup) {
239 char *m = (max_cpus == 0) ?
240 "The nosmp parameter is incompatible with Xen; " \
241 "use Xen dom0_max_vcpus=1 parameter" :
242 "The noapic parameter is incompatible with Xen";
243
244 xen_raw_printk(m);
245 panic(m);
246 }
247 xen_init_lock_cpu(0);
248
249 smp_store_boot_cpu_info();
250 cpu_data(0).x86_max_cores = 1;
251
252 for_each_possible_cpu(i) {
253 zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
254 zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
255 zalloc_cpumask_var(&per_cpu(cpu_die_map, i), GFP_KERNEL);
256 zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
257 }
258 set_cpu_sibling_map(0);
259
260 speculative_store_bypass_ht_init();
261
262 xen_pmu_init(0);
263
264 if (xen_smp_intr_init(0) || xen_smp_intr_init_pv(0))
265 BUG();
266
267 if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))
268 panic("could not allocate xen_cpu_initialized_map\n");
269
270 cpumask_copy(xen_cpu_initialized_map, cpumask_of(0));
271
272 /* Restrict the possible_map according to max_cpus. */
273 while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
274 for (cpu = nr_cpu_ids - 1; !cpu_possible(cpu); cpu--)
275 continue;
276 set_cpu_possible(cpu, false);
277 }
278
279 for_each_possible_cpu(cpu)
280 set_cpu_present(cpu, true);
281}
282
283static int
284cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
285{
286 struct vcpu_guest_context *ctxt;
287 struct desc_struct *gdt;
288 unsigned long gdt_mfn;
289
290 /* used to tell cpu_init() that it can proceed with initialization */
291 cpumask_set_cpu(cpu, cpu_callout_mask);
292 if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
293 return 0;
294
295 ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
296 if (ctxt == NULL)
297 return -ENOMEM;
298
299 gdt = get_cpu_gdt_rw(cpu);
300
301#ifdef CONFIG_X86_32
302 ctxt->user_regs.fs = __KERNEL_PERCPU;
303 ctxt->user_regs.gs = __KERNEL_STACK_CANARY;
304#endif
305 memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
306
307 /*
308 * Bring up the CPU in cpu_bringup_and_idle() with the stack
309 * pointing just below where pt_regs would be if it were a normal
310 * kernel entry.
311 */
312 ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
313 ctxt->flags = VGCF_IN_KERNEL;
314 ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
315 ctxt->user_regs.ds = __USER_DS;
316 ctxt->user_regs.es = __USER_DS;
317 ctxt->user_regs.ss = __KERNEL_DS;
318 ctxt->user_regs.cs = __KERNEL_CS;
319 ctxt->user_regs.esp = (unsigned long)task_pt_regs(idle);
320
321 xen_copy_trap_info(ctxt->trap_ctxt);
322
323 ctxt->ldt_ents = 0;
324
325 BUG_ON((unsigned long)gdt & ~PAGE_MASK);
326
327 gdt_mfn = arbitrary_virt_to_mfn(gdt);
328 make_lowmem_page_readonly(gdt);
329 make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
330
331 ctxt->gdt_frames[0] = gdt_mfn;
332 ctxt->gdt_ents = GDT_ENTRIES;
333
334 /*
335 * Set SS:SP that Xen will use when entering guest kernel mode
336 * from guest user mode. Subsequent calls to load_sp0() can
337 * change this value.
338 */
339 ctxt->kernel_ss = __KERNEL_DS;
340 ctxt->kernel_sp = task_top_of_stack(idle);
341
342#ifdef CONFIG_X86_32
343 ctxt->event_callback_cs = __KERNEL_CS;
344 ctxt->failsafe_callback_cs = __KERNEL_CS;
345#else
346 ctxt->gs_base_kernel = per_cpu_offset(cpu);
347#endif
348 ctxt->event_callback_eip =
349 (unsigned long)xen_hypervisor_callback;
350 ctxt->failsafe_callback_eip =
351 (unsigned long)xen_failsafe_callback;
352 per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
353
354 ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));
355 if (HYPERVISOR_vcpu_op(VCPUOP_initialise, xen_vcpu_nr(cpu), ctxt))
356 BUG();
357
358 kfree(ctxt);
359 return 0;
360}
361
362static int xen_pv_cpu_up(unsigned int cpu, struct task_struct *idle)
363{
364 int rc;
365
366 rc = common_cpu_up(cpu, idle);
367 if (rc)
368 return rc;
369
370 xen_setup_runstate_info(cpu);
371
372 /*
373 * PV VCPUs are always successfully taken down (see 'while' loop
374 * in xen_cpu_die()), so -EBUSY is an error.
375 */
376 rc = cpu_check_up_prepare(cpu);
377 if (rc)
378 return rc;
379
380 /* make sure interrupts start blocked */
381 per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
382
383 rc = cpu_initialize_context(cpu, idle);
384 if (rc)
385 return rc;
386
387 xen_pmu_init(cpu);
388
389 rc = HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL);
390 BUG_ON(rc);
391
392 while (cpu_report_state(cpu) != CPU_ONLINE)
393 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
394
395 return 0;
396}
397
398#ifdef CONFIG_HOTPLUG_CPU
399static int xen_pv_cpu_disable(void)
400{
401 unsigned int cpu = smp_processor_id();
402 if (cpu == 0)
403 return -EBUSY;
404
405 cpu_disable_common();
406
407 load_cr3(swapper_pg_dir);
408 return 0;
409}
410
411static void xen_pv_cpu_die(unsigned int cpu)
412{
413 while (HYPERVISOR_vcpu_op(VCPUOP_is_up,
414 xen_vcpu_nr(cpu), NULL)) {
415 __set_current_state(TASK_UNINTERRUPTIBLE);
416 schedule_timeout(HZ/10);
417 }
418
419 if (common_cpu_die(cpu) == 0) {
420 xen_smp_intr_free(cpu);
421 xen_uninit_lock_cpu(cpu);
422 xen_teardown_timer(cpu);
423 xen_pmu_finish(cpu);
424 }
425}
426
427static void xen_pv_play_dead(void) /* used only with HOTPLUG_CPU */
428{
429 play_dead_common();
430 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(smp_processor_id()), NULL);
431 cpu_bringup();
432 /*
433 * commit 4b0c0f294 (tick: Cleanup NOHZ per cpu data on cpu down)
434 * clears certain data that the cpu_idle loop (which called us
435 * and that we return from) expects. The only way to get that
436 * data back is to call:
437 */
438 tick_nohz_idle_enter();
439 tick_nohz_idle_stop_tick_protected();
440
441 cpuhp_online_idle(CPUHP_AP_ONLINE_IDLE);
442}
443
444#else /* !CONFIG_HOTPLUG_CPU */
445static int xen_pv_cpu_disable(void)
446{
447 return -ENOSYS;
448}
449
450static void xen_pv_cpu_die(unsigned int cpu)
451{
452 BUG();
453}
454
455static void xen_pv_play_dead(void)
456{
457 BUG();
458}
459
460#endif
461static void stop_self(void *v)
462{
463 int cpu = smp_processor_id();
464
465 /* make sure we're not pinning something down */
466 load_cr3(swapper_pg_dir);
467 /* should set up a minimal gdt */
468
469 set_cpu_online(cpu, false);
470
471 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL);
472 BUG();
473}
474
475static void xen_pv_stop_other_cpus(int wait)
476{
477 smp_call_function(stop_self, NULL, wait);
478}
479
480static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)
481{
482 irq_enter();
483 irq_work_run();
484 inc_irq_stat(apic_irq_work_irqs);
485 irq_exit();
486
487 return IRQ_HANDLED;
488}
489
490static const struct smp_ops xen_smp_ops __initconst = {
491 .smp_prepare_boot_cpu = xen_pv_smp_prepare_boot_cpu,
492 .smp_prepare_cpus = xen_pv_smp_prepare_cpus,
493 .smp_cpus_done = xen_smp_cpus_done,
494
495 .cpu_up = xen_pv_cpu_up,
496 .cpu_die = xen_pv_cpu_die,
497 .cpu_disable = xen_pv_cpu_disable,
498 .play_dead = xen_pv_play_dead,
499
500 .stop_other_cpus = xen_pv_stop_other_cpus,
501 .smp_send_reschedule = xen_smp_send_reschedule,
502
503 .send_call_func_ipi = xen_smp_send_call_function_ipi,
504 .send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
505};
506
507void __init xen_smp_init(void)
508{
509 smp_ops = xen_smp_ops;
510 xen_fill_possible_map();
511}