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23#include <linux/module.h>
24#include <linux/kernel.h>
25#include <linux/kvm_para.h>
26#include <linux/cpu.h>
27#include <linux/mm.h>
28#include <linux/highmem.h>
29#include <linux/hardirq.h>
30#include <linux/notifier.h>
31#include <linux/reboot.h>
32#include <linux/hash.h>
33#include <linux/sched.h>
34#include <linux/slab.h>
35#include <linux/kprobes.h>
36#include <asm/timer.h>
37#include <asm/cpu.h>
38#include <asm/traps.h>
39#include <asm/desc.h>
40#include <asm/tlbflush.h>
41
42#define MMU_QUEUE_SIZE 1024
43
44static int kvmapf = 1;
45
46static int parse_no_kvmapf(char *arg)
47{
48 kvmapf = 0;
49 return 0;
50}
51
52early_param("no-kvmapf", parse_no_kvmapf);
53
54struct kvm_para_state {
55 u8 mmu_queue[MMU_QUEUE_SIZE];
56 int mmu_queue_len;
57};
58
59static DEFINE_PER_CPU(struct kvm_para_state, para_state);
60static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
61
62static struct kvm_para_state *kvm_para_state(void)
63{
64 return &per_cpu(para_state, raw_smp_processor_id());
65}
66
67
68
69
70static void kvm_io_delay(void)
71{
72}
73
74#define KVM_TASK_SLEEP_HASHBITS 8
75#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
76
77struct kvm_task_sleep_node {
78 struct hlist_node link;
79 wait_queue_head_t wq;
80 u32 token;
81 int cpu;
82 bool halted;
83 struct mm_struct *mm;
84};
85
86static struct kvm_task_sleep_head {
87 spinlock_t lock;
88 struct hlist_head list;
89} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
90
91static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
92 u32 token)
93{
94 struct hlist_node *p;
95
96 hlist_for_each(p, &b->list) {
97 struct kvm_task_sleep_node *n =
98 hlist_entry(p, typeof(*n), link);
99 if (n->token == token)
100 return n;
101 }
102
103 return NULL;
104}
105
106void kvm_async_pf_task_wait(u32 token)
107{
108 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
109 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
110 struct kvm_task_sleep_node n, *e;
111 DEFINE_WAIT(wait);
112 int cpu, idle;
113
114 cpu = get_cpu();
115 idle = idle_cpu(cpu);
116 put_cpu();
117
118 spin_lock(&b->lock);
119 e = _find_apf_task(b, token);
120 if (e) {
121
122 hlist_del(&e->link);
123 kfree(e);
124 spin_unlock(&b->lock);
125 return;
126 }
127
128 n.token = token;
129 n.cpu = smp_processor_id();
130 n.mm = current->active_mm;
131 n.halted = idle || preempt_count() > 1;
132 atomic_inc(&n.mm->mm_count);
133 init_waitqueue_head(&n.wq);
134 hlist_add_head(&n.link, &b->list);
135 spin_unlock(&b->lock);
136
137 for (;;) {
138 if (!n.halted)
139 prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
140 if (hlist_unhashed(&n.link))
141 break;
142
143 if (!n.halted) {
144 local_irq_enable();
145 schedule();
146 local_irq_disable();
147 } else {
148
149
150
151 native_safe_halt();
152 local_irq_disable();
153 }
154 }
155 if (!n.halted)
156 finish_wait(&n.wq, &wait);
157
158 return;
159}
160EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
161
162static void apf_task_wake_one(struct kvm_task_sleep_node *n)
163{
164 hlist_del_init(&n->link);
165 if (!n->mm)
166 return;
167 mmdrop(n->mm);
168 if (n->halted)
169 smp_send_reschedule(n->cpu);
170 else if (waitqueue_active(&n->wq))
171 wake_up(&n->wq);
172}
173
174static void apf_task_wake_all(void)
175{
176 int i;
177
178 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
179 struct hlist_node *p, *next;
180 struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
181 spin_lock(&b->lock);
182 hlist_for_each_safe(p, next, &b->list) {
183 struct kvm_task_sleep_node *n =
184 hlist_entry(p, typeof(*n), link);
185 if (n->cpu == smp_processor_id())
186 apf_task_wake_one(n);
187 }
188 spin_unlock(&b->lock);
189 }
190}
191
192void kvm_async_pf_task_wake(u32 token)
193{
194 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
195 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
196 struct kvm_task_sleep_node *n;
197
198 if (token == ~0) {
199 apf_task_wake_all();
200 return;
201 }
202
203again:
204 spin_lock(&b->lock);
205 n = _find_apf_task(b, token);
206 if (!n) {
207
208
209
210
211 n = kmalloc(sizeof(*n), GFP_ATOMIC);
212 if (!n) {
213
214
215
216
217 spin_unlock(&b->lock);
218 cpu_relax();
219 goto again;
220 }
221 n->token = token;
222 n->cpu = smp_processor_id();
223 n->mm = NULL;
224 init_waitqueue_head(&n->wq);
225 hlist_add_head(&n->link, &b->list);
226 } else
227 apf_task_wake_one(n);
228 spin_unlock(&b->lock);
229 return;
230}
231EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
232
233u32 kvm_read_and_reset_pf_reason(void)
234{
235 u32 reason = 0;
236
237 if (__get_cpu_var(apf_reason).enabled) {
238 reason = __get_cpu_var(apf_reason).reason;
239 __get_cpu_var(apf_reason).reason = 0;
240 }
241
242 return reason;
243}
244EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
245
246dotraplinkage void __kprobes
247do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
248{
249 switch (kvm_read_and_reset_pf_reason()) {
250 default:
251 do_page_fault(regs, error_code);
252 break;
253 case KVM_PV_REASON_PAGE_NOT_PRESENT:
254
255 kvm_async_pf_task_wait((u32)read_cr2());
256 break;
257 case KVM_PV_REASON_PAGE_READY:
258 kvm_async_pf_task_wake((u32)read_cr2());
259 break;
260 }
261}
262
263static void kvm_mmu_op(void *buffer, unsigned len)
264{
265 int r;
266 unsigned long a1, a2;
267
268 do {
269 a1 = __pa(buffer);
270 a2 = 0;
271 r = kvm_hypercall3(KVM_HC_MMU_OP, len, a1, a2);
272 buffer += r;
273 len -= r;
274 } while (len);
275}
276
277static void mmu_queue_flush(struct kvm_para_state *state)
278{
279 if (state->mmu_queue_len) {
280 kvm_mmu_op(state->mmu_queue, state->mmu_queue_len);
281 state->mmu_queue_len = 0;
282 }
283}
284
285static void kvm_deferred_mmu_op(void *buffer, int len)
286{
287 struct kvm_para_state *state = kvm_para_state();
288
289 if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU) {
290 kvm_mmu_op(buffer, len);
291 return;
292 }
293 if (state->mmu_queue_len + len > sizeof state->mmu_queue)
294 mmu_queue_flush(state);
295 memcpy(state->mmu_queue + state->mmu_queue_len, buffer, len);
296 state->mmu_queue_len += len;
297}
298
299static void kvm_mmu_write(void *dest, u64 val)
300{
301 __u64 pte_phys;
302 struct kvm_mmu_op_write_pte wpte;
303
304#ifdef CONFIG_HIGHPTE
305 struct page *page;
306 unsigned long dst = (unsigned long) dest;
307
308 page = kmap_atomic_to_page(dest);
309 pte_phys = page_to_pfn(page);
310 pte_phys <<= PAGE_SHIFT;
311 pte_phys += (dst & ~(PAGE_MASK));
312#else
313 pte_phys = (unsigned long)__pa(dest);
314#endif
315 wpte.header.op = KVM_MMU_OP_WRITE_PTE;
316 wpte.pte_val = val;
317 wpte.pte_phys = pte_phys;
318
319 kvm_deferred_mmu_op(&wpte, sizeof wpte);
320}
321
322
323
324
325
326
327
328static void kvm_set_pte(pte_t *ptep, pte_t pte)
329{
330 kvm_mmu_write(ptep, pte_val(pte));
331}
332
333static void kvm_set_pte_at(struct mm_struct *mm, unsigned long addr,
334 pte_t *ptep, pte_t pte)
335{
336 kvm_mmu_write(ptep, pte_val(pte));
337}
338
339static void kvm_set_pmd(pmd_t *pmdp, pmd_t pmd)
340{
341 kvm_mmu_write(pmdp, pmd_val(pmd));
342}
343
344#if PAGETABLE_LEVELS >= 3
345#ifdef CONFIG_X86_PAE
346static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte)
347{
348 kvm_mmu_write(ptep, pte_val(pte));
349}
350
351static void kvm_pte_clear(struct mm_struct *mm,
352 unsigned long addr, pte_t *ptep)
353{
354 kvm_mmu_write(ptep, 0);
355}
356
357static void kvm_pmd_clear(pmd_t *pmdp)
358{
359 kvm_mmu_write(pmdp, 0);
360}
361#endif
362
363static void kvm_set_pud(pud_t *pudp, pud_t pud)
364{
365 kvm_mmu_write(pudp, pud_val(pud));
366}
367
368#if PAGETABLE_LEVELS == 4
369static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
370{
371 kvm_mmu_write(pgdp, pgd_val(pgd));
372}
373#endif
374#endif
375
376static void kvm_flush_tlb(void)
377{
378 struct kvm_mmu_op_flush_tlb ftlb = {
379 .header.op = KVM_MMU_OP_FLUSH_TLB,
380 };
381
382 kvm_deferred_mmu_op(&ftlb, sizeof ftlb);
383}
384
385static void kvm_release_pt(unsigned long pfn)
386{
387 struct kvm_mmu_op_release_pt rpt = {
388 .header.op = KVM_MMU_OP_RELEASE_PT,
389 .pt_phys = (u64)pfn << PAGE_SHIFT,
390 };
391
392 kvm_mmu_op(&rpt, sizeof rpt);
393}
394
395static void kvm_enter_lazy_mmu(void)
396{
397 paravirt_enter_lazy_mmu();
398}
399
400static void kvm_leave_lazy_mmu(void)
401{
402 struct kvm_para_state *state = kvm_para_state();
403
404 mmu_queue_flush(state);
405 paravirt_leave_lazy_mmu();
406}
407
408static void __init paravirt_ops_setup(void)
409{
410 pv_info.name = "KVM";
411 pv_info.paravirt_enabled = 1;
412
413 if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
414 pv_cpu_ops.io_delay = kvm_io_delay;
415
416 if (kvm_para_has_feature(KVM_FEATURE_MMU_OP)) {
417 pv_mmu_ops.set_pte = kvm_set_pte;
418 pv_mmu_ops.set_pte_at = kvm_set_pte_at;
419 pv_mmu_ops.set_pmd = kvm_set_pmd;
420#if PAGETABLE_LEVELS >= 3
421#ifdef CONFIG_X86_PAE
422 pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic;
423 pv_mmu_ops.pte_clear = kvm_pte_clear;
424 pv_mmu_ops.pmd_clear = kvm_pmd_clear;
425#endif
426 pv_mmu_ops.set_pud = kvm_set_pud;
427#if PAGETABLE_LEVELS == 4
428 pv_mmu_ops.set_pgd = kvm_set_pgd;
429#endif
430#endif
431 pv_mmu_ops.flush_tlb_user = kvm_flush_tlb;
432 pv_mmu_ops.release_pte = kvm_release_pt;
433 pv_mmu_ops.release_pmd = kvm_release_pt;
434 pv_mmu_ops.release_pud = kvm_release_pt;
435
436 pv_mmu_ops.lazy_mode.enter = kvm_enter_lazy_mmu;
437 pv_mmu_ops.lazy_mode.leave = kvm_leave_lazy_mmu;
438 }
439#ifdef CONFIG_X86_IO_APIC
440 no_timer_check = 1;
441#endif
442}
443
444void __cpuinit kvm_guest_cpu_init(void)
445{
446 if (!kvm_para_available())
447 return;
448
449 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
450 u64 pa = __pa(&__get_cpu_var(apf_reason));
451
452#ifdef CONFIG_PREEMPT
453 pa |= KVM_ASYNC_PF_SEND_ALWAYS;
454#endif
455 wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
456 __get_cpu_var(apf_reason).enabled = 1;
457 printk(KERN_INFO"KVM setup async PF for cpu %d\n",
458 smp_processor_id());
459 }
460}
461
462static void kvm_pv_disable_apf(void *unused)
463{
464 if (!__get_cpu_var(apf_reason).enabled)
465 return;
466
467 wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
468 __get_cpu_var(apf_reason).enabled = 0;
469
470 printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
471 smp_processor_id());
472}
473
474static int kvm_pv_reboot_notify(struct notifier_block *nb,
475 unsigned long code, void *unused)
476{
477 if (code == SYS_RESTART)
478 on_each_cpu(kvm_pv_disable_apf, NULL, 1);
479 return NOTIFY_DONE;
480}
481
482static struct notifier_block kvm_pv_reboot_nb = {
483 .notifier_call = kvm_pv_reboot_notify,
484};
485
486#ifdef CONFIG_SMP
487static void __init kvm_smp_prepare_boot_cpu(void)
488{
489#ifdef CONFIG_KVM_CLOCK
490 WARN_ON(kvm_register_clock("primary cpu clock"));
491#endif
492 kvm_guest_cpu_init();
493 native_smp_prepare_boot_cpu();
494}
495
496static void kvm_guest_cpu_online(void *dummy)
497{
498 kvm_guest_cpu_init();
499}
500
501static void kvm_guest_cpu_offline(void *dummy)
502{
503 kvm_pv_disable_apf(NULL);
504 apf_task_wake_all();
505}
506
507static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
508 unsigned long action, void *hcpu)
509{
510 int cpu = (unsigned long)hcpu;
511 switch (action) {
512 case CPU_ONLINE:
513 case CPU_DOWN_FAILED:
514 case CPU_ONLINE_FROZEN:
515 smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
516 break;
517 case CPU_DOWN_PREPARE:
518 case CPU_DOWN_PREPARE_FROZEN:
519 smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
520 break;
521 default:
522 break;
523 }
524 return NOTIFY_OK;
525}
526
527static struct notifier_block __cpuinitdata kvm_cpu_notifier = {
528 .notifier_call = kvm_cpu_notify,
529};
530#endif
531
532static void __init kvm_apf_trap_init(void)
533{
534 set_intr_gate(14, &async_page_fault);
535}
536
537void __init kvm_guest_init(void)
538{
539 int i;
540
541 if (!kvm_para_available())
542 return;
543
544 paravirt_ops_setup();
545 register_reboot_notifier(&kvm_pv_reboot_nb);
546 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
547 spin_lock_init(&async_pf_sleepers[i].lock);
548 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
549 x86_init.irqs.trap_init = kvm_apf_trap_init;
550
551#ifdef CONFIG_SMP
552 smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
553 register_cpu_notifier(&kvm_cpu_notifier);
554#else
555 kvm_guest_cpu_init();
556#endif
557}
558