KVM: s390: Fix program check on interrupt delivery handling
[linux-2.6.git] / arch / s390 / kvm / interrupt.c
1 /*
2  * interrupt.c - handling kvm guest interrupts
3  *
4  * Copyright IBM Corp. 2008
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License (version 2 only)
8  * as published by the Free Software Foundation.
9  *
10  *    Author(s): Carsten Otte <cotte@de.ibm.com>
11  */
12
13 #include <asm/lowcore.h>
14 #include <asm/uaccess.h>
15 #include <linux/kvm_host.h>
16 #include <linux/signal.h>
17 #include "kvm-s390.h"
18 #include "gaccess.h"
19
20 static int psw_extint_disabled(struct kvm_vcpu *vcpu)
21 {
22         return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT);
23 }
24
25 static int psw_interrupts_disabled(struct kvm_vcpu *vcpu)
26 {
27         if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER) ||
28             (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_IO) ||
29             (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT))
30                 return 0;
31         return 1;
32 }
33
34 static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu,
35                                       struct kvm_s390_interrupt_info *inti)
36 {
37         switch (inti->type) {
38         case KVM_S390_INT_EMERGENCY:
39                 if (psw_extint_disabled(vcpu))
40                         return 0;
41                 if (vcpu->arch.sie_block->gcr[0] & 0x4000ul)
42                         return 1;
43                 return 0;
44         case KVM_S390_INT_SERVICE:
45                 if (psw_extint_disabled(vcpu))
46                         return 0;
47                 if (vcpu->arch.sie_block->gcr[0] & 0x200ul)
48                         return 1;
49                 return 0;
50         case KVM_S390_INT_VIRTIO:
51                 if (psw_extint_disabled(vcpu))
52                         return 0;
53                 if (vcpu->arch.sie_block->gcr[0] & 0x200ul)
54                         return 1;
55                 return 0;
56         case KVM_S390_PROGRAM_INT:
57         case KVM_S390_SIGP_STOP:
58         case KVM_S390_SIGP_SET_PREFIX:
59         case KVM_S390_RESTART:
60                 return 1;
61         default:
62                 BUG();
63         }
64         return 0;
65 }
66
67 static void __set_cpu_idle(struct kvm_vcpu *vcpu)
68 {
69         BUG_ON(vcpu->vcpu_id > KVM_MAX_VCPUS - 1);
70         atomic_set_mask(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
71         set_bit(vcpu->vcpu_id, vcpu->arch.local_int.float_int->idle_mask);
72 }
73
74 static void __unset_cpu_idle(struct kvm_vcpu *vcpu)
75 {
76         BUG_ON(vcpu->vcpu_id > KVM_MAX_VCPUS - 1);
77         atomic_clear_mask(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
78         clear_bit(vcpu->vcpu_id, vcpu->arch.local_int.float_int->idle_mask);
79 }
80
81 static void __reset_intercept_indicators(struct kvm_vcpu *vcpu)
82 {
83         atomic_clear_mask(CPUSTAT_ECALL_PEND |
84                 CPUSTAT_IO_INT | CPUSTAT_EXT_INT | CPUSTAT_STOP_INT,
85                 &vcpu->arch.sie_block->cpuflags);
86         vcpu->arch.sie_block->lctl = 0x0000;
87 }
88
89 static void __set_cpuflag(struct kvm_vcpu *vcpu, u32 flag)
90 {
91         atomic_set_mask(flag, &vcpu->arch.sie_block->cpuflags);
92 }
93
94 static void __set_intercept_indicator(struct kvm_vcpu *vcpu,
95                                       struct kvm_s390_interrupt_info *inti)
96 {
97         switch (inti->type) {
98         case KVM_S390_INT_EMERGENCY:
99         case KVM_S390_INT_SERVICE:
100         case KVM_S390_INT_VIRTIO:
101                 if (psw_extint_disabled(vcpu))
102                         __set_cpuflag(vcpu, CPUSTAT_EXT_INT);
103                 else
104                         vcpu->arch.sie_block->lctl |= LCTL_CR0;
105                 break;
106         case KVM_S390_SIGP_STOP:
107                 __set_cpuflag(vcpu, CPUSTAT_STOP_INT);
108                 break;
109         default:
110                 BUG();
111         }
112 }
113
114 static void __do_deliver_interrupt(struct kvm_vcpu *vcpu,
115                                    struct kvm_s390_interrupt_info *inti)
116 {
117         const unsigned short table[] = { 2, 4, 4, 6 };
118         int rc, exception = 0;
119
120         switch (inti->type) {
121         case KVM_S390_INT_EMERGENCY:
122                 VCPU_EVENT(vcpu, 4, "%s", "interrupt: sigp emerg");
123                 vcpu->stat.deliver_emergency_signal++;
124                 rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1201);
125                 if (rc == -EFAULT)
126                         exception = 1;
127
128                 rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
129                          &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
130                 if (rc == -EFAULT)
131                         exception = 1;
132
133                 rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
134                         __LC_EXT_NEW_PSW, sizeof(psw_t));
135                 if (rc == -EFAULT)
136                         exception = 1;
137                 break;
138
139         case KVM_S390_INT_SERVICE:
140                 VCPU_EVENT(vcpu, 4, "interrupt: sclp parm:%x",
141                            inti->ext.ext_params);
142                 vcpu->stat.deliver_service_signal++;
143                 rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2401);
144                 if (rc == -EFAULT)
145                         exception = 1;
146
147                 rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
148                          &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
149                 if (rc == -EFAULT)
150                         exception = 1;
151
152                 rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
153                         __LC_EXT_NEW_PSW, sizeof(psw_t));
154                 if (rc == -EFAULT)
155                         exception = 1;
156
157                 rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
158                 if (rc == -EFAULT)
159                         exception = 1;
160                 break;
161
162         case KVM_S390_INT_VIRTIO:
163                 VCPU_EVENT(vcpu, 4, "interrupt: virtio parm:%x,parm64:%lx",
164                            inti->ext.ext_params, inti->ext.ext_params2);
165                 vcpu->stat.deliver_virtio_interrupt++;
166                 rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2603);
167                 if (rc == -EFAULT)
168                         exception = 1;
169
170                 rc = put_guest_u16(vcpu, __LC_CPU_ADDRESS, 0x0d00);
171                 if (rc == -EFAULT)
172                         exception = 1;
173
174                 rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
175                          &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
176                 if (rc == -EFAULT)
177                         exception = 1;
178
179                 rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
180                         __LC_EXT_NEW_PSW, sizeof(psw_t));
181                 if (rc == -EFAULT)
182                         exception = 1;
183
184                 rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
185                 if (rc == -EFAULT)
186                         exception = 1;
187
188                 rc = put_guest_u64(vcpu, __LC_PFAULT_INTPARM,
189                         inti->ext.ext_params2);
190                 if (rc == -EFAULT)
191                         exception = 1;
192                 break;
193
194         case KVM_S390_SIGP_STOP:
195                 VCPU_EVENT(vcpu, 4, "%s", "interrupt: cpu stop");
196                 vcpu->stat.deliver_stop_signal++;
197                 __set_intercept_indicator(vcpu, inti);
198                 break;
199
200         case KVM_S390_SIGP_SET_PREFIX:
201                 VCPU_EVENT(vcpu, 4, "interrupt: set prefix to %x",
202                            inti->prefix.address);
203                 vcpu->stat.deliver_prefix_signal++;
204                 vcpu->arch.sie_block->prefix = inti->prefix.address;
205                 vcpu->arch.sie_block->ihcpu = 0xffff;
206                 break;
207
208         case KVM_S390_RESTART:
209                 VCPU_EVENT(vcpu, 4, "%s", "interrupt: cpu restart");
210                 vcpu->stat.deliver_restart_signal++;
211                 rc = copy_to_guest(vcpu, offsetof(struct _lowcore,
212                   restart_old_psw), &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
213                 if (rc == -EFAULT)
214                         exception = 1;
215
216                 rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
217                         offsetof(struct _lowcore, restart_psw), sizeof(psw_t));
218                 if (rc == -EFAULT)
219                         exception = 1;
220                 break;
221
222         case KVM_S390_PROGRAM_INT:
223                 VCPU_EVENT(vcpu, 4, "interrupt: pgm check code:%x, ilc:%x",
224                            inti->pgm.code,
225                            table[vcpu->arch.sie_block->ipa >> 14]);
226                 vcpu->stat.deliver_program_int++;
227                 rc = put_guest_u16(vcpu, __LC_PGM_INT_CODE, inti->pgm.code);
228                 if (rc == -EFAULT)
229                         exception = 1;
230
231                 rc = put_guest_u16(vcpu, __LC_PGM_ILC,
232                         table[vcpu->arch.sie_block->ipa >> 14]);
233                 if (rc == -EFAULT)
234                         exception = 1;
235
236                 rc = copy_to_guest(vcpu, __LC_PGM_OLD_PSW,
237                          &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
238                 if (rc == -EFAULT)
239                         exception = 1;
240
241                 rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
242                         __LC_PGM_NEW_PSW, sizeof(psw_t));
243                 if (rc == -EFAULT)
244                         exception = 1;
245                 break;
246
247         default:
248                 BUG();
249         }
250         if (exception) {
251                 printk("kvm: The guest lowcore is not mapped during interrupt "
252                         "delivery, killing userspace\n");
253                 do_exit(SIGKILL);
254         }
255 }
256
257 static int __try_deliver_ckc_interrupt(struct kvm_vcpu *vcpu)
258 {
259         int rc, exception = 0;
260
261         if (psw_extint_disabled(vcpu))
262                 return 0;
263         if (!(vcpu->arch.sie_block->gcr[0] & 0x800ul))
264                 return 0;
265         rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1004);
266         if (rc == -EFAULT)
267                 exception = 1;
268         rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
269                  &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
270         if (rc == -EFAULT)
271                 exception = 1;
272         rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
273                 __LC_EXT_NEW_PSW, sizeof(psw_t));
274         if (rc == -EFAULT)
275                 exception = 1;
276         if (exception) {
277                 printk("kvm: The guest lowcore is not mapped during interrupt "
278                         "delivery, killing userspace\n");
279                 do_exit(SIGKILL);
280         }
281         return 1;
282 }
283
284 int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu)
285 {
286         struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
287         struct kvm_s390_float_interrupt *fi = vcpu->arch.local_int.float_int;
288         struct kvm_s390_interrupt_info  *inti;
289         int rc = 0;
290
291         if (atomic_read(&li->active)) {
292                 spin_lock_bh(&li->lock);
293                 list_for_each_entry(inti, &li->list, list)
294                         if (__interrupt_is_deliverable(vcpu, inti)) {
295                                 rc = 1;
296                                 break;
297                         }
298                 spin_unlock_bh(&li->lock);
299         }
300
301         if ((!rc) && atomic_read(&fi->active)) {
302                 spin_lock_bh(&fi->lock);
303                 list_for_each_entry(inti, &fi->list, list)
304                         if (__interrupt_is_deliverable(vcpu, inti)) {
305                                 rc = 1;
306                                 break;
307                         }
308                 spin_unlock_bh(&fi->lock);
309         }
310
311         if ((!rc) && (vcpu->arch.sie_block->ckc <
312                 get_clock() + vcpu->arch.sie_block->epoch)) {
313                 if ((!psw_extint_disabled(vcpu)) &&
314                         (vcpu->arch.sie_block->gcr[0] & 0x800ul))
315                         rc = 1;
316         }
317
318         return rc;
319 }
320
321 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
322 {
323         return 0;
324 }
325
326 int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
327 {
328         u64 now, sltime;
329         DECLARE_WAITQUEUE(wait, current);
330
331         vcpu->stat.exit_wait_state++;
332         if (kvm_cpu_has_interrupt(vcpu))
333                 return 0;
334
335         __set_cpu_idle(vcpu);
336         spin_lock_bh(&vcpu->arch.local_int.lock);
337         vcpu->arch.local_int.timer_due = 0;
338         spin_unlock_bh(&vcpu->arch.local_int.lock);
339
340         if (psw_interrupts_disabled(vcpu)) {
341                 VCPU_EVENT(vcpu, 3, "%s", "disabled wait");
342                 __unset_cpu_idle(vcpu);
343                 return -ENOTSUPP; /* disabled wait */
344         }
345
346         if (psw_extint_disabled(vcpu) ||
347             (!(vcpu->arch.sie_block->gcr[0] & 0x800ul))) {
348                 VCPU_EVENT(vcpu, 3, "%s", "enabled wait w/o timer");
349                 goto no_timer;
350         }
351
352         now = get_clock() + vcpu->arch.sie_block->epoch;
353         if (vcpu->arch.sie_block->ckc < now) {
354                 __unset_cpu_idle(vcpu);
355                 return 0;
356         }
357
358         sltime = (vcpu->arch.sie_block->ckc - now) / (0xf4240000ul / HZ) + 1;
359
360         vcpu->arch.ckc_timer.expires = jiffies + sltime;
361
362         add_timer(&vcpu->arch.ckc_timer);
363         VCPU_EVENT(vcpu, 5, "enabled wait timer:%lx jiffies", sltime);
364 no_timer:
365         spin_lock_bh(&vcpu->arch.local_int.float_int->lock);
366         spin_lock_bh(&vcpu->arch.local_int.lock);
367         add_wait_queue(&vcpu->arch.local_int.wq, &wait);
368         while (list_empty(&vcpu->arch.local_int.list) &&
369                 list_empty(&vcpu->arch.local_int.float_int->list) &&
370                 (!vcpu->arch.local_int.timer_due) &&
371                 !signal_pending(current)) {
372                 set_current_state(TASK_INTERRUPTIBLE);
373                 spin_unlock_bh(&vcpu->arch.local_int.lock);
374                 spin_unlock_bh(&vcpu->arch.local_int.float_int->lock);
375                 vcpu_put(vcpu);
376                 schedule();
377                 vcpu_load(vcpu);
378                 spin_lock_bh(&vcpu->arch.local_int.float_int->lock);
379                 spin_lock_bh(&vcpu->arch.local_int.lock);
380         }
381         __unset_cpu_idle(vcpu);
382         __set_current_state(TASK_RUNNING);
383         remove_wait_queue(&vcpu->wq, &wait);
384         spin_unlock_bh(&vcpu->arch.local_int.lock);
385         spin_unlock_bh(&vcpu->arch.local_int.float_int->lock);
386         del_timer(&vcpu->arch.ckc_timer);
387         return 0;
388 }
389
390 void kvm_s390_idle_wakeup(unsigned long data)
391 {
392         struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data;
393
394         spin_lock_bh(&vcpu->arch.local_int.lock);
395         vcpu->arch.local_int.timer_due = 1;
396         if (waitqueue_active(&vcpu->arch.local_int.wq))
397                 wake_up_interruptible(&vcpu->arch.local_int.wq);
398         spin_unlock_bh(&vcpu->arch.local_int.lock);
399 }
400
401
402 void kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu)
403 {
404         struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
405         struct kvm_s390_float_interrupt *fi = vcpu->arch.local_int.float_int;
406         struct kvm_s390_interrupt_info  *n, *inti = NULL;
407         int deliver;
408
409         __reset_intercept_indicators(vcpu);
410         if (atomic_read(&li->active)) {
411                 do {
412                         deliver = 0;
413                         spin_lock_bh(&li->lock);
414                         list_for_each_entry_safe(inti, n, &li->list, list) {
415                                 if (__interrupt_is_deliverable(vcpu, inti)) {
416                                         list_del(&inti->list);
417                                         deliver = 1;
418                                         break;
419                                 }
420                                 __set_intercept_indicator(vcpu, inti);
421                         }
422                         if (list_empty(&li->list))
423                                 atomic_set(&li->active, 0);
424                         spin_unlock_bh(&li->lock);
425                         if (deliver) {
426                                 __do_deliver_interrupt(vcpu, inti);
427                                 kfree(inti);
428                         }
429                 } while (deliver);
430         }
431
432         if ((vcpu->arch.sie_block->ckc <
433                 get_clock() + vcpu->arch.sie_block->epoch))
434                 __try_deliver_ckc_interrupt(vcpu);
435
436         if (atomic_read(&fi->active)) {
437                 do {
438                         deliver = 0;
439                         spin_lock_bh(&fi->lock);
440                         list_for_each_entry_safe(inti, n, &fi->list, list) {
441                                 if (__interrupt_is_deliverable(vcpu, inti)) {
442                                         list_del(&inti->list);
443                                         deliver = 1;
444                                         break;
445                                 }
446                                 __set_intercept_indicator(vcpu, inti);
447                         }
448                         if (list_empty(&fi->list))
449                                 atomic_set(&fi->active, 0);
450                         spin_unlock_bh(&fi->lock);
451                         if (deliver) {
452                                 __do_deliver_interrupt(vcpu, inti);
453                                 kfree(inti);
454                         }
455                 } while (deliver);
456         }
457 }
458
459 int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code)
460 {
461         struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
462         struct kvm_s390_interrupt_info *inti;
463
464         inti = kzalloc(sizeof(*inti), GFP_KERNEL);
465         if (!inti)
466                 return -ENOMEM;
467
468         inti->type = KVM_S390_PROGRAM_INT;;
469         inti->pgm.code = code;
470
471         VCPU_EVENT(vcpu, 3, "inject: program check %d (from kernel)", code);
472         spin_lock_bh(&li->lock);
473         list_add(&inti->list, &li->list);
474         atomic_set(&li->active, 1);
475         BUG_ON(waitqueue_active(&li->wq));
476         spin_unlock_bh(&li->lock);
477         return 0;
478 }
479
480 int kvm_s390_inject_vm(struct kvm *kvm,
481                        struct kvm_s390_interrupt *s390int)
482 {
483         struct kvm_s390_local_interrupt *li;
484         struct kvm_s390_float_interrupt *fi;
485         struct kvm_s390_interrupt_info *inti;
486         int sigcpu;
487
488         inti = kzalloc(sizeof(*inti), GFP_KERNEL);
489         if (!inti)
490                 return -ENOMEM;
491
492         switch (s390int->type) {
493         case KVM_S390_INT_VIRTIO:
494                 VM_EVENT(kvm, 5, "inject: virtio parm:%x,parm64:%lx",
495                          s390int->parm, s390int->parm64);
496                 inti->type = s390int->type;
497                 inti->ext.ext_params = s390int->parm;
498                 inti->ext.ext_params2 = s390int->parm64;
499                 break;
500         case KVM_S390_INT_SERVICE:
501                 VM_EVENT(kvm, 5, "inject: sclp parm:%x", s390int->parm);
502                 inti->type = s390int->type;
503                 inti->ext.ext_params = s390int->parm;
504                 break;
505         case KVM_S390_PROGRAM_INT:
506         case KVM_S390_SIGP_STOP:
507         case KVM_S390_INT_EMERGENCY:
508         default:
509                 kfree(inti);
510                 return -EINVAL;
511         }
512
513         mutex_lock(&kvm->lock);
514         fi = &kvm->arch.float_int;
515         spin_lock_bh(&fi->lock);
516         list_add_tail(&inti->list, &fi->list);
517         atomic_set(&fi->active, 1);
518         sigcpu = find_first_bit(fi->idle_mask, KVM_MAX_VCPUS);
519         if (sigcpu == KVM_MAX_VCPUS) {
520                 do {
521                         sigcpu = fi->next_rr_cpu++;
522                         if (sigcpu == KVM_MAX_VCPUS)
523                                 sigcpu = fi->next_rr_cpu = 0;
524                 } while (fi->local_int[sigcpu] == NULL);
525         }
526         li = fi->local_int[sigcpu];
527         spin_lock_bh(&li->lock);
528         atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
529         if (waitqueue_active(&li->wq))
530                 wake_up_interruptible(&li->wq);
531         spin_unlock_bh(&li->lock);
532         spin_unlock_bh(&fi->lock);
533         mutex_unlock(&kvm->lock);
534         return 0;
535 }
536
537 int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
538                          struct kvm_s390_interrupt *s390int)
539 {
540         struct kvm_s390_local_interrupt *li;
541         struct kvm_s390_interrupt_info *inti;
542
543         inti = kzalloc(sizeof(*inti), GFP_KERNEL);
544         if (!inti)
545                 return -ENOMEM;
546
547         switch (s390int->type) {
548         case KVM_S390_PROGRAM_INT:
549                 if (s390int->parm & 0xffff0000) {
550                         kfree(inti);
551                         return -EINVAL;
552                 }
553                 inti->type = s390int->type;
554                 inti->pgm.code = s390int->parm;
555                 VCPU_EVENT(vcpu, 3, "inject: program check %d (from user)",
556                            s390int->parm);
557                 break;
558         case KVM_S390_SIGP_STOP:
559         case KVM_S390_RESTART:
560         case KVM_S390_SIGP_SET_PREFIX:
561         case KVM_S390_INT_EMERGENCY:
562                 VCPU_EVENT(vcpu, 3, "inject: type %x", s390int->type);
563                 inti->type = s390int->type;
564                 break;
565         case KVM_S390_INT_VIRTIO:
566         case KVM_S390_INT_SERVICE:
567         default:
568                 kfree(inti);
569                 return -EINVAL;
570         }
571
572         mutex_lock(&vcpu->kvm->lock);
573         li = &vcpu->arch.local_int;
574         spin_lock_bh(&li->lock);
575         if (inti->type == KVM_S390_PROGRAM_INT)
576                 list_add(&inti->list, &li->list);
577         else
578                 list_add_tail(&inti->list, &li->list);
579         atomic_set(&li->active, 1);
580         if (inti->type == KVM_S390_SIGP_STOP)
581                 li->action_bits |= ACTION_STOP_ON_STOP;
582         atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
583         if (waitqueue_active(&li->wq))
584                 wake_up_interruptible(&vcpu->arch.local_int.wq);
585         spin_unlock_bh(&li->lock);
586         mutex_unlock(&vcpu->kvm->lock);
587         return 0;
588 }