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27291e21 DH |
1 | /* |
2 | * kvm guest debug support | |
3 | * | |
4 | * Copyright IBM Corp. 2014 | |
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): David Hildenbrand <dahi@linux.vnet.ibm.com> | |
11 | */ | |
12 | #include <linux/kvm_host.h> | |
13 | #include <linux/errno.h> | |
14 | #include "kvm-s390.h" | |
15 | #include "gaccess.h" | |
16 | ||
17 | /* | |
18 | * Extends the address range given by *start and *stop to include the address | |
19 | * range starting with estart and the length len. Takes care of overflowing | |
20 | * intervals and tries to minimize the overall intervall size. | |
21 | */ | |
22 | static void extend_address_range(u64 *start, u64 *stop, u64 estart, int len) | |
23 | { | |
24 | u64 estop; | |
25 | ||
26 | if (len > 0) | |
27 | len--; | |
28 | else | |
29 | len = 0; | |
30 | ||
31 | estop = estart + len; | |
32 | ||
33 | /* 0-0 range represents "not set" */ | |
34 | if ((*start == 0) && (*stop == 0)) { | |
35 | *start = estart; | |
36 | *stop = estop; | |
37 | } else if (*start <= *stop) { | |
38 | /* increase the existing range */ | |
39 | if (estart < *start) | |
40 | *start = estart; | |
41 | if (estop > *stop) | |
42 | *stop = estop; | |
43 | } else { | |
44 | /* "overflowing" interval, whereby *stop > *start */ | |
45 | if (estart <= *stop) { | |
46 | if (estop > *stop) | |
47 | *stop = estop; | |
48 | } else if (estop > *start) { | |
49 | if (estart < *start) | |
50 | *start = estart; | |
51 | } | |
52 | /* minimize the range */ | |
53 | else if ((estop - *stop) < (*start - estart)) | |
54 | *stop = estop; | |
55 | else | |
56 | *start = estart; | |
57 | } | |
58 | } | |
59 | ||
60 | #define MAX_INST_SIZE 6 | |
61 | ||
62 | static void enable_all_hw_bp(struct kvm_vcpu *vcpu) | |
63 | { | |
64 | unsigned long start, len; | |
65 | u64 *cr9 = &vcpu->arch.sie_block->gcr[9]; | |
66 | u64 *cr10 = &vcpu->arch.sie_block->gcr[10]; | |
67 | u64 *cr11 = &vcpu->arch.sie_block->gcr[11]; | |
68 | int i; | |
69 | ||
70 | if (vcpu->arch.guestdbg.nr_hw_bp <= 0 || | |
71 | vcpu->arch.guestdbg.hw_bp_info == NULL) | |
72 | return; | |
73 | ||
74 | /* | |
75 | * If the guest is not interrested in branching events, we can savely | |
76 | * limit them to the PER address range. | |
77 | */ | |
78 | if (!(*cr9 & PER_EVENT_BRANCH)) | |
79 | *cr9 |= PER_CONTROL_BRANCH_ADDRESS; | |
80 | *cr9 |= PER_EVENT_IFETCH | PER_EVENT_BRANCH; | |
81 | ||
82 | for (i = 0; i < vcpu->arch.guestdbg.nr_hw_bp; i++) { | |
83 | start = vcpu->arch.guestdbg.hw_bp_info[i].addr; | |
84 | len = vcpu->arch.guestdbg.hw_bp_info[i].len; | |
85 | ||
86 | /* | |
87 | * The instruction in front of the desired bp has to | |
88 | * report instruction-fetching events | |
89 | */ | |
90 | if (start < MAX_INST_SIZE) { | |
91 | len += start; | |
92 | start = 0; | |
93 | } else { | |
94 | start -= MAX_INST_SIZE; | |
95 | len += MAX_INST_SIZE; | |
96 | } | |
97 | ||
98 | extend_address_range(cr10, cr11, start, len); | |
99 | } | |
100 | } | |
101 | ||
102 | static void enable_all_hw_wp(struct kvm_vcpu *vcpu) | |
103 | { | |
104 | unsigned long start, len; | |
105 | u64 *cr9 = &vcpu->arch.sie_block->gcr[9]; | |
106 | u64 *cr10 = &vcpu->arch.sie_block->gcr[10]; | |
107 | u64 *cr11 = &vcpu->arch.sie_block->gcr[11]; | |
108 | int i; | |
109 | ||
110 | if (vcpu->arch.guestdbg.nr_hw_wp <= 0 || | |
111 | vcpu->arch.guestdbg.hw_wp_info == NULL) | |
112 | return; | |
113 | ||
114 | /* if host uses storage alternation for special address | |
115 | * spaces, enable all events and give all to the guest */ | |
116 | if (*cr9 & PER_EVENT_STORE && *cr9 & PER_CONTROL_ALTERATION) { | |
117 | *cr9 &= ~PER_CONTROL_ALTERATION; | |
118 | *cr10 = 0; | |
119 | *cr11 = PSW_ADDR_INSN; | |
120 | } else { | |
121 | *cr9 &= ~PER_CONTROL_ALTERATION; | |
122 | *cr9 |= PER_EVENT_STORE; | |
123 | ||
124 | for (i = 0; i < vcpu->arch.guestdbg.nr_hw_wp; i++) { | |
125 | start = vcpu->arch.guestdbg.hw_wp_info[i].addr; | |
126 | len = vcpu->arch.guestdbg.hw_wp_info[i].len; | |
127 | ||
128 | extend_address_range(cr10, cr11, start, len); | |
129 | } | |
130 | } | |
131 | } | |
132 | ||
133 | void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu) | |
134 | { | |
135 | vcpu->arch.guestdbg.cr0 = vcpu->arch.sie_block->gcr[0]; | |
136 | vcpu->arch.guestdbg.cr9 = vcpu->arch.sie_block->gcr[9]; | |
137 | vcpu->arch.guestdbg.cr10 = vcpu->arch.sie_block->gcr[10]; | |
138 | vcpu->arch.guestdbg.cr11 = vcpu->arch.sie_block->gcr[11]; | |
139 | } | |
140 | ||
141 | void kvm_s390_restore_guest_per_regs(struct kvm_vcpu *vcpu) | |
142 | { | |
143 | vcpu->arch.sie_block->gcr[0] = vcpu->arch.guestdbg.cr0; | |
144 | vcpu->arch.sie_block->gcr[9] = vcpu->arch.guestdbg.cr9; | |
145 | vcpu->arch.sie_block->gcr[10] = vcpu->arch.guestdbg.cr10; | |
146 | vcpu->arch.sie_block->gcr[11] = vcpu->arch.guestdbg.cr11; | |
147 | } | |
148 | ||
149 | void kvm_s390_patch_guest_per_regs(struct kvm_vcpu *vcpu) | |
150 | { | |
151 | /* | |
152 | * TODO: if guest psw has per enabled, otherwise 0s! | |
153 | * This reduces the amount of reported events. | |
154 | * Need to intercept all psw changes! | |
155 | */ | |
156 | ||
157 | if (guestdbg_sstep_enabled(vcpu)) { | |
158 | vcpu->arch.sie_block->gcr[9] |= PER_EVENT_IFETCH; | |
159 | vcpu->arch.sie_block->gcr[10] = 0; | |
160 | vcpu->arch.sie_block->gcr[11] = PSW_ADDR_INSN; | |
161 | } | |
162 | ||
163 | if (guestdbg_hw_bp_enabled(vcpu)) { | |
164 | enable_all_hw_bp(vcpu); | |
165 | enable_all_hw_wp(vcpu); | |
166 | } | |
167 | ||
168 | /* TODO: Instruction-fetching-nullification not allowed for now */ | |
169 | if (vcpu->arch.sie_block->gcr[9] & PER_EVENT_NULLIFICATION) | |
170 | vcpu->arch.sie_block->gcr[9] &= ~PER_EVENT_NULLIFICATION; | |
171 | } | |
172 | ||
173 | #define MAX_WP_SIZE 100 | |
174 | ||
175 | static int __import_wp_info(struct kvm_vcpu *vcpu, | |
176 | struct kvm_hw_breakpoint *bp_data, | |
177 | struct kvm_hw_wp_info_arch *wp_info) | |
178 | { | |
179 | int ret = 0; | |
180 | wp_info->len = bp_data->len; | |
181 | wp_info->addr = bp_data->addr; | |
182 | wp_info->phys_addr = bp_data->phys_addr; | |
183 | wp_info->old_data = NULL; | |
184 | ||
185 | if (wp_info->len < 0 || wp_info->len > MAX_WP_SIZE) | |
186 | return -EINVAL; | |
187 | ||
188 | wp_info->old_data = kmalloc(bp_data->len, GFP_KERNEL); | |
189 | if (!wp_info->old_data) | |
190 | return -ENOMEM; | |
191 | /* try to backup the original value */ | |
192 | ret = read_guest(vcpu, wp_info->phys_addr, wp_info->old_data, | |
193 | wp_info->len); | |
194 | if (ret) { | |
195 | kfree(wp_info->old_data); | |
196 | wp_info->old_data = NULL; | |
197 | } | |
198 | ||
199 | return ret; | |
200 | } | |
201 | ||
202 | #define MAX_BP_COUNT 50 | |
203 | ||
204 | int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu, | |
205 | struct kvm_guest_debug *dbg) | |
206 | { | |
207 | int ret = 0, nr_wp = 0, nr_bp = 0, i, size; | |
208 | struct kvm_hw_breakpoint *bp_data = NULL; | |
209 | struct kvm_hw_wp_info_arch *wp_info = NULL; | |
210 | struct kvm_hw_bp_info_arch *bp_info = NULL; | |
211 | ||
212 | if (dbg->arch.nr_hw_bp <= 0 || !dbg->arch.hw_bp) | |
213 | return 0; | |
214 | else if (dbg->arch.nr_hw_bp > MAX_BP_COUNT) | |
215 | return -EINVAL; | |
216 | ||
217 | size = dbg->arch.nr_hw_bp * sizeof(struct kvm_hw_breakpoint); | |
218 | bp_data = kmalloc(size, GFP_KERNEL); | |
219 | if (!bp_data) { | |
220 | ret = -ENOMEM; | |
221 | goto error; | |
222 | } | |
223 | ||
224 | ret = copy_from_user(bp_data, dbg->arch.hw_bp, size); | |
225 | if (ret) | |
226 | goto error; | |
227 | ||
228 | for (i = 0; i < dbg->arch.nr_hw_bp; i++) { | |
229 | switch (bp_data[i].type) { | |
230 | case KVM_HW_WP_WRITE: | |
231 | nr_wp++; | |
232 | break; | |
233 | case KVM_HW_BP: | |
234 | nr_bp++; | |
235 | break; | |
236 | default: | |
237 | break; | |
238 | } | |
239 | } | |
240 | ||
241 | size = nr_wp * sizeof(struct kvm_hw_wp_info_arch); | |
242 | if (size > 0) { | |
243 | wp_info = kmalloc(size, GFP_KERNEL); | |
244 | if (!wp_info) { | |
245 | ret = -ENOMEM; | |
246 | goto error; | |
247 | } | |
248 | } | |
249 | size = nr_bp * sizeof(struct kvm_hw_bp_info_arch); | |
250 | if (size > 0) { | |
251 | bp_info = kmalloc(size, GFP_KERNEL); | |
252 | if (!bp_info) { | |
253 | ret = -ENOMEM; | |
254 | goto error; | |
255 | } | |
256 | } | |
257 | ||
258 | for (nr_wp = 0, nr_bp = 0, i = 0; i < dbg->arch.nr_hw_bp; i++) { | |
259 | switch (bp_data[i].type) { | |
260 | case KVM_HW_WP_WRITE: | |
261 | ret = __import_wp_info(vcpu, &bp_data[i], | |
262 | &wp_info[nr_wp]); | |
263 | if (ret) | |
264 | goto error; | |
265 | nr_wp++; | |
266 | break; | |
267 | case KVM_HW_BP: | |
268 | bp_info[nr_bp].len = bp_data[i].len; | |
269 | bp_info[nr_bp].addr = bp_data[i].addr; | |
270 | nr_bp++; | |
271 | break; | |
272 | } | |
273 | } | |
274 | ||
275 | vcpu->arch.guestdbg.nr_hw_bp = nr_bp; | |
276 | vcpu->arch.guestdbg.hw_bp_info = bp_info; | |
277 | vcpu->arch.guestdbg.nr_hw_wp = nr_wp; | |
278 | vcpu->arch.guestdbg.hw_wp_info = wp_info; | |
279 | return 0; | |
280 | error: | |
281 | kfree(bp_data); | |
282 | kfree(wp_info); | |
283 | kfree(bp_info); | |
284 | return ret; | |
285 | } | |
286 | ||
287 | void kvm_s390_clear_bp_data(struct kvm_vcpu *vcpu) | |
288 | { | |
289 | int i; | |
290 | struct kvm_hw_wp_info_arch *hw_wp_info = NULL; | |
291 | ||
292 | for (i = 0; i < vcpu->arch.guestdbg.nr_hw_wp; i++) { | |
293 | hw_wp_info = &vcpu->arch.guestdbg.hw_wp_info[i]; | |
294 | kfree(hw_wp_info->old_data); | |
295 | hw_wp_info->old_data = NULL; | |
296 | } | |
297 | kfree(vcpu->arch.guestdbg.hw_wp_info); | |
298 | vcpu->arch.guestdbg.hw_wp_info = NULL; | |
299 | ||
300 | kfree(vcpu->arch.guestdbg.hw_bp_info); | |
301 | vcpu->arch.guestdbg.hw_bp_info = NULL; | |
302 | ||
303 | vcpu->arch.guestdbg.nr_hw_wp = 0; | |
304 | vcpu->arch.guestdbg.nr_hw_bp = 0; | |
305 | } | |
306 | ||
307 | static inline int in_addr_range(u64 addr, u64 a, u64 b) | |
308 | { | |
309 | if (a <= b) | |
310 | return (addr >= a) && (addr <= b); | |
311 | else | |
312 | /* "overflowing" interval */ | |
313 | return (addr <= a) && (addr >= b); | |
314 | } | |
315 | ||
316 | #define end_of_range(bp_info) (bp_info->addr + bp_info->len - 1) | |
317 | ||
318 | static struct kvm_hw_bp_info_arch *find_hw_bp(struct kvm_vcpu *vcpu, | |
319 | unsigned long addr) | |
320 | { | |
321 | struct kvm_hw_bp_info_arch *bp_info = vcpu->arch.guestdbg.hw_bp_info; | |
322 | int i; | |
323 | ||
324 | if (vcpu->arch.guestdbg.nr_hw_bp == 0) | |
325 | return NULL; | |
326 | ||
327 | for (i = 0; i < vcpu->arch.guestdbg.nr_hw_bp; i++) { | |
328 | /* addr is directly the start or in the range of a bp */ | |
329 | if (addr == bp_info->addr) | |
330 | goto found; | |
331 | if (bp_info->len > 0 && | |
332 | in_addr_range(addr, bp_info->addr, end_of_range(bp_info))) | |
333 | goto found; | |
334 | ||
335 | bp_info++; | |
336 | } | |
337 | ||
338 | return NULL; | |
339 | found: | |
340 | return bp_info; | |
341 | } | |
342 | ||
343 | static struct kvm_hw_wp_info_arch *any_wp_changed(struct kvm_vcpu *vcpu) | |
344 | { | |
345 | int i; | |
346 | struct kvm_hw_wp_info_arch *wp_info = NULL; | |
347 | void *temp = NULL; | |
348 | ||
349 | if (vcpu->arch.guestdbg.nr_hw_wp == 0) | |
350 | return NULL; | |
351 | ||
352 | for (i = 0; i < vcpu->arch.guestdbg.nr_hw_wp; i++) { | |
353 | wp_info = &vcpu->arch.guestdbg.hw_wp_info[i]; | |
354 | if (!wp_info || !wp_info->old_data || wp_info->len <= 0) | |
355 | continue; | |
356 | ||
357 | temp = kmalloc(wp_info->len, GFP_KERNEL); | |
358 | if (!temp) | |
359 | continue; | |
360 | ||
361 | /* refetch the wp data and compare it to the old value */ | |
362 | if (!read_guest(vcpu, wp_info->phys_addr, temp, | |
363 | wp_info->len)) { | |
364 | if (memcmp(temp, wp_info->old_data, wp_info->len)) { | |
365 | kfree(temp); | |
366 | return wp_info; | |
367 | } | |
368 | } | |
369 | kfree(temp); | |
370 | temp = NULL; | |
371 | } | |
372 | ||
373 | return NULL; | |
374 | } | |
375 | ||
376 | void kvm_s390_prepare_debug_exit(struct kvm_vcpu *vcpu) | |
377 | { | |
378 | vcpu->run->exit_reason = KVM_EXIT_DEBUG; | |
379 | vcpu->guest_debug &= ~KVM_GUESTDBG_EXIT_PENDING; | |
380 | } | |
381 | ||
382 | #define per_bp_event(code) \ | |
383 | (code & (PER_EVENT_IFETCH | PER_EVENT_BRANCH)) | |
384 | #define per_write_wp_event(code) \ | |
385 | (code & (PER_EVENT_STORE | PER_EVENT_STORE_REAL)) | |
386 | ||
387 | static int debug_exit_required(struct kvm_vcpu *vcpu) | |
388 | { | |
389 | u32 perc = (vcpu->arch.sie_block->perc << 24); | |
390 | struct kvm_debug_exit_arch *debug_exit = &vcpu->run->debug.arch; | |
391 | struct kvm_hw_wp_info_arch *wp_info = NULL; | |
392 | struct kvm_hw_bp_info_arch *bp_info = NULL; | |
393 | unsigned long addr = vcpu->arch.sie_block->gpsw.addr; | |
394 | unsigned long peraddr = vcpu->arch.sie_block->peraddr; | |
395 | ||
396 | if (guestdbg_hw_bp_enabled(vcpu)) { | |
397 | if (per_write_wp_event(perc) && | |
398 | vcpu->arch.guestdbg.nr_hw_wp > 0) { | |
399 | wp_info = any_wp_changed(vcpu); | |
400 | if (wp_info) { | |
401 | debug_exit->addr = wp_info->addr; | |
402 | debug_exit->type = KVM_HW_WP_WRITE; | |
403 | goto exit_required; | |
404 | } | |
405 | } | |
406 | if (per_bp_event(perc) && | |
407 | vcpu->arch.guestdbg.nr_hw_bp > 0) { | |
408 | bp_info = find_hw_bp(vcpu, addr); | |
409 | /* remove duplicate events if PC==PER address */ | |
410 | if (bp_info && (addr != peraddr)) { | |
411 | debug_exit->addr = addr; | |
412 | debug_exit->type = KVM_HW_BP; | |
413 | vcpu->arch.guestdbg.last_bp = addr; | |
414 | goto exit_required; | |
415 | } | |
416 | /* breakpoint missed */ | |
417 | bp_info = find_hw_bp(vcpu, peraddr); | |
418 | if (bp_info && vcpu->arch.guestdbg.last_bp != peraddr) { | |
419 | debug_exit->addr = peraddr; | |
420 | debug_exit->type = KVM_HW_BP; | |
421 | goto exit_required; | |
422 | } | |
423 | } | |
424 | } | |
425 | if (guestdbg_sstep_enabled(vcpu) && per_bp_event(perc)) { | |
426 | debug_exit->addr = addr; | |
427 | debug_exit->type = KVM_SINGLESTEP; | |
428 | goto exit_required; | |
429 | } | |
430 | ||
431 | return 0; | |
432 | exit_required: | |
433 | return 1; | |
434 | } | |
435 | ||
436 | #define guest_per_enabled(vcpu) \ | |
437 | (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER) | |
438 | ||
439 | static void filter_guest_per_event(struct kvm_vcpu *vcpu) | |
440 | { | |
441 | u32 perc = vcpu->arch.sie_block->perc << 24; | |
442 | u64 peraddr = vcpu->arch.sie_block->peraddr; | |
443 | u64 addr = vcpu->arch.sie_block->gpsw.addr; | |
444 | u64 cr9 = vcpu->arch.sie_block->gcr[9]; | |
445 | u64 cr10 = vcpu->arch.sie_block->gcr[10]; | |
446 | u64 cr11 = vcpu->arch.sie_block->gcr[11]; | |
447 | /* filter all events, demanded by the guest */ | |
448 | u32 guest_perc = perc & cr9 & PER_EVENT_MASK; | |
449 | ||
450 | if (!guest_per_enabled(vcpu)) | |
451 | guest_perc = 0; | |
452 | ||
453 | /* filter "successful-branching" events */ | |
454 | if (guest_perc & PER_EVENT_BRANCH && | |
455 | cr9 & PER_CONTROL_BRANCH_ADDRESS && | |
456 | !in_addr_range(addr, cr10, cr11)) | |
457 | guest_perc &= ~PER_EVENT_BRANCH; | |
458 | ||
459 | /* filter "instruction-fetching" events */ | |
460 | if (guest_perc & PER_EVENT_IFETCH && | |
461 | !in_addr_range(peraddr, cr10, cr11)) | |
462 | guest_perc &= ~PER_EVENT_IFETCH; | |
463 | ||
464 | /* All other PER events will be given to the guest */ | |
465 | /* TODO: Check alterated address/address space */ | |
466 | ||
467 | vcpu->arch.sie_block->perc = guest_perc >> 24; | |
468 | ||
469 | if (!guest_perc) | |
470 | vcpu->arch.sie_block->iprcc &= ~PGM_PER; | |
471 | } | |
472 | ||
473 | void kvm_s390_handle_per_event(struct kvm_vcpu *vcpu) | |
474 | { | |
475 | if (debug_exit_required(vcpu)) | |
476 | vcpu->guest_debug |= KVM_GUESTDBG_EXIT_PENDING; | |
477 | ||
478 | filter_guest_per_event(vcpu); | |
479 | } |