xref: /openbmc/linux/arch/powerpc/kvm/emulate.c (revision 63dc02bd)
1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License, version 2, as
4  * published by the Free Software Foundation.
5  *
6  * This program is distributed in the hope that it will be useful,
7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
9  * GNU General Public License for more details.
10  *
11  * You should have received a copy of the GNU General Public License
12  * along with this program; if not, write to the Free Software
13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
14  *
15  * Copyright IBM Corp. 2007
16  * Copyright 2011 Freescale Semiconductor, Inc.
17  *
18  * Authors: Hollis Blanchard <hollisb@us.ibm.com>
19  */
20 
21 #include <linux/jiffies.h>
22 #include <linux/hrtimer.h>
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/kvm_host.h>
26 
27 #include <asm/reg.h>
28 #include <asm/time.h>
29 #include <asm/byteorder.h>
30 #include <asm/kvm_ppc.h>
31 #include <asm/disassemble.h>
32 #include "timing.h"
33 #include "trace.h"
34 
35 #define OP_TRAP 3
36 #define OP_TRAP_64 2
37 
38 #define OP_31_XOP_LWZX      23
39 #define OP_31_XOP_LBZX      87
40 #define OP_31_XOP_STWX      151
41 #define OP_31_XOP_STBX      215
42 #define OP_31_XOP_LBZUX     119
43 #define OP_31_XOP_STBUX     247
44 #define OP_31_XOP_LHZX      279
45 #define OP_31_XOP_LHZUX     311
46 #define OP_31_XOP_MFSPR     339
47 #define OP_31_XOP_LHAX      343
48 #define OP_31_XOP_STHX      407
49 #define OP_31_XOP_STHUX     439
50 #define OP_31_XOP_MTSPR     467
51 #define OP_31_XOP_DCBI      470
52 #define OP_31_XOP_LWBRX     534
53 #define OP_31_XOP_TLBSYNC   566
54 #define OP_31_XOP_STWBRX    662
55 #define OP_31_XOP_LHBRX     790
56 #define OP_31_XOP_STHBRX    918
57 
58 #define OP_LWZ  32
59 #define OP_LWZU 33
60 #define OP_LBZ  34
61 #define OP_LBZU 35
62 #define OP_STW  36
63 #define OP_STWU 37
64 #define OP_STB  38
65 #define OP_STBU 39
66 #define OP_LHZ  40
67 #define OP_LHZU 41
68 #define OP_LHA  42
69 #define OP_LHAU 43
70 #define OP_STH  44
71 #define OP_STHU 45
72 
73 void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
74 {
75 	unsigned long dec_nsec;
76 	unsigned long long dec_time;
77 
78 	pr_debug("mtDEC: %x\n", vcpu->arch.dec);
79 	hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
80 
81 #ifdef CONFIG_PPC_BOOK3S
82 	/* mtdec lowers the interrupt line when positive. */
83 	kvmppc_core_dequeue_dec(vcpu);
84 
85 	/* POWER4+ triggers a dec interrupt if the value is < 0 */
86 	if (vcpu->arch.dec & 0x80000000) {
87 		kvmppc_core_queue_dec(vcpu);
88 		return;
89 	}
90 #endif
91 
92 #ifdef CONFIG_BOOKE
93 	/* On BOOKE, DEC = 0 is as good as decrementer not enabled */
94 	if (vcpu->arch.dec == 0)
95 		return;
96 #endif
97 
98 	/*
99 	 * The decrementer ticks at the same rate as the timebase, so
100 	 * that's how we convert the guest DEC value to the number of
101 	 * host ticks.
102 	 */
103 
104 	dec_time = vcpu->arch.dec;
105 	dec_time *= 1000;
106 	do_div(dec_time, tb_ticks_per_usec);
107 	dec_nsec = do_div(dec_time, NSEC_PER_SEC);
108 	hrtimer_start(&vcpu->arch.dec_timer,
109 		ktime_set(dec_time, dec_nsec), HRTIMER_MODE_REL);
110 	vcpu->arch.dec_jiffies = get_tb();
111 }
112 
113 u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb)
114 {
115 	u64 jd = tb - vcpu->arch.dec_jiffies;
116 
117 #ifdef CONFIG_BOOKE
118 	if (vcpu->arch.dec < jd)
119 		return 0;
120 #endif
121 
122 	return vcpu->arch.dec - jd;
123 }
124 
125 /* XXX to do:
126  * lhax
127  * lhaux
128  * lswx
129  * lswi
130  * stswx
131  * stswi
132  * lha
133  * lhau
134  * lmw
135  * stmw
136  *
137  * XXX is_bigendian should depend on MMU mapping or MSR[LE]
138  */
139 /* XXX Should probably auto-generate instruction decoding for a particular core
140  * from opcode tables in the future. */
141 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
142 {
143 	u32 inst = kvmppc_get_last_inst(vcpu);
144 	u32 ea;
145 	int ra;
146 	int rb;
147 	int rs;
148 	int rt;
149 	int sprn;
150 	enum emulation_result emulated = EMULATE_DONE;
151 	int advance = 1;
152 
153 	/* this default type might be overwritten by subcategories */
154 	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
155 
156 	pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
157 
158 	switch (get_op(inst)) {
159 	case OP_TRAP:
160 #ifdef CONFIG_PPC_BOOK3S
161 	case OP_TRAP_64:
162 		kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
163 #else
164 		kvmppc_core_queue_program(vcpu,
165 					  vcpu->arch.shared->esr | ESR_PTR);
166 #endif
167 		advance = 0;
168 		break;
169 
170 	case 31:
171 		switch (get_xop(inst)) {
172 
173 		case OP_31_XOP_LWZX:
174 			rt = get_rt(inst);
175 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
176 			break;
177 
178 		case OP_31_XOP_LBZX:
179 			rt = get_rt(inst);
180 			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
181 			break;
182 
183 		case OP_31_XOP_LBZUX:
184 			rt = get_rt(inst);
185 			ra = get_ra(inst);
186 			rb = get_rb(inst);
187 
188 			ea = kvmppc_get_gpr(vcpu, rb);
189 			if (ra)
190 				ea += kvmppc_get_gpr(vcpu, ra);
191 
192 			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
193 			kvmppc_set_gpr(vcpu, ra, ea);
194 			break;
195 
196 		case OP_31_XOP_STWX:
197 			rs = get_rs(inst);
198 			emulated = kvmppc_handle_store(run, vcpu,
199 						       kvmppc_get_gpr(vcpu, rs),
200 			                               4, 1);
201 			break;
202 
203 		case OP_31_XOP_STBX:
204 			rs = get_rs(inst);
205 			emulated = kvmppc_handle_store(run, vcpu,
206 						       kvmppc_get_gpr(vcpu, rs),
207 			                               1, 1);
208 			break;
209 
210 		case OP_31_XOP_STBUX:
211 			rs = get_rs(inst);
212 			ra = get_ra(inst);
213 			rb = get_rb(inst);
214 
215 			ea = kvmppc_get_gpr(vcpu, rb);
216 			if (ra)
217 				ea += kvmppc_get_gpr(vcpu, ra);
218 
219 			emulated = kvmppc_handle_store(run, vcpu,
220 						       kvmppc_get_gpr(vcpu, rs),
221 			                               1, 1);
222 			kvmppc_set_gpr(vcpu, rs, ea);
223 			break;
224 
225 		case OP_31_XOP_LHAX:
226 			rt = get_rt(inst);
227 			emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
228 			break;
229 
230 		case OP_31_XOP_LHZX:
231 			rt = get_rt(inst);
232 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
233 			break;
234 
235 		case OP_31_XOP_LHZUX:
236 			rt = get_rt(inst);
237 			ra = get_ra(inst);
238 			rb = get_rb(inst);
239 
240 			ea = kvmppc_get_gpr(vcpu, rb);
241 			if (ra)
242 				ea += kvmppc_get_gpr(vcpu, ra);
243 
244 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
245 			kvmppc_set_gpr(vcpu, ra, ea);
246 			break;
247 
248 		case OP_31_XOP_MFSPR:
249 			sprn = get_sprn(inst);
250 			rt = get_rt(inst);
251 
252 			switch (sprn) {
253 			case SPRN_SRR0:
254 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->srr0);
255 				break;
256 			case SPRN_SRR1:
257 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->srr1);
258 				break;
259 			case SPRN_PVR:
260 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.pvr); break;
261 			case SPRN_PIR:
262 				kvmppc_set_gpr(vcpu, rt, vcpu->vcpu_id); break;
263 			case SPRN_MSSSR0:
264 				kvmppc_set_gpr(vcpu, rt, 0); break;
265 
266 			/* Note: mftb and TBRL/TBWL are user-accessible, so
267 			 * the guest can always access the real TB anyways.
268 			 * In fact, we probably will never see these traps. */
269 			case SPRN_TBWL:
270 				kvmppc_set_gpr(vcpu, rt, get_tb() >> 32); break;
271 			case SPRN_TBWU:
272 				kvmppc_set_gpr(vcpu, rt, get_tb()); break;
273 
274 			case SPRN_SPRG0:
275 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg0);
276 				break;
277 			case SPRN_SPRG1:
278 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg1);
279 				break;
280 			case SPRN_SPRG2:
281 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg2);
282 				break;
283 			case SPRN_SPRG3:
284 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg3);
285 				break;
286 			/* Note: SPRG4-7 are user-readable, so we don't get
287 			 * a trap. */
288 
289 			case SPRN_DEC:
290 			{
291 				kvmppc_set_gpr(vcpu, rt,
292 					       kvmppc_get_dec(vcpu, get_tb()));
293 				break;
294 			}
295 			default:
296 				emulated = kvmppc_core_emulate_mfspr(vcpu, sprn, rt);
297 				if (emulated == EMULATE_FAIL) {
298 					printk("mfspr: unknown spr %x\n", sprn);
299 					kvmppc_set_gpr(vcpu, rt, 0);
300 				}
301 				break;
302 			}
303 			kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
304 			break;
305 
306 		case OP_31_XOP_STHX:
307 			rs = get_rs(inst);
308 			ra = get_ra(inst);
309 			rb = get_rb(inst);
310 
311 			emulated = kvmppc_handle_store(run, vcpu,
312 						       kvmppc_get_gpr(vcpu, rs),
313 			                               2, 1);
314 			break;
315 
316 		case OP_31_XOP_STHUX:
317 			rs = get_rs(inst);
318 			ra = get_ra(inst);
319 			rb = get_rb(inst);
320 
321 			ea = kvmppc_get_gpr(vcpu, rb);
322 			if (ra)
323 				ea += kvmppc_get_gpr(vcpu, ra);
324 
325 			emulated = kvmppc_handle_store(run, vcpu,
326 						       kvmppc_get_gpr(vcpu, rs),
327 			                               2, 1);
328 			kvmppc_set_gpr(vcpu, ra, ea);
329 			break;
330 
331 		case OP_31_XOP_MTSPR:
332 			sprn = get_sprn(inst);
333 			rs = get_rs(inst);
334 			switch (sprn) {
335 			case SPRN_SRR0:
336 				vcpu->arch.shared->srr0 = kvmppc_get_gpr(vcpu, rs);
337 				break;
338 			case SPRN_SRR1:
339 				vcpu->arch.shared->srr1 = kvmppc_get_gpr(vcpu, rs);
340 				break;
341 
342 			/* XXX We need to context-switch the timebase for
343 			 * watchdog and FIT. */
344 			case SPRN_TBWL: break;
345 			case SPRN_TBWU: break;
346 
347 			case SPRN_MSSSR0: break;
348 
349 			case SPRN_DEC:
350 				vcpu->arch.dec = kvmppc_get_gpr(vcpu, rs);
351 				kvmppc_emulate_dec(vcpu);
352 				break;
353 
354 			case SPRN_SPRG0:
355 				vcpu->arch.shared->sprg0 = kvmppc_get_gpr(vcpu, rs);
356 				break;
357 			case SPRN_SPRG1:
358 				vcpu->arch.shared->sprg1 = kvmppc_get_gpr(vcpu, rs);
359 				break;
360 			case SPRN_SPRG2:
361 				vcpu->arch.shared->sprg2 = kvmppc_get_gpr(vcpu, rs);
362 				break;
363 			case SPRN_SPRG3:
364 				vcpu->arch.shared->sprg3 = kvmppc_get_gpr(vcpu, rs);
365 				break;
366 
367 			default:
368 				emulated = kvmppc_core_emulate_mtspr(vcpu, sprn, rs);
369 				if (emulated == EMULATE_FAIL)
370 					printk("mtspr: unknown spr %x\n", sprn);
371 				break;
372 			}
373 			kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
374 			break;
375 
376 		case OP_31_XOP_DCBI:
377 			/* Do nothing. The guest is performing dcbi because
378 			 * hardware DMA is not snooped by the dcache, but
379 			 * emulated DMA either goes through the dcache as
380 			 * normal writes, or the host kernel has handled dcache
381 			 * coherence. */
382 			break;
383 
384 		case OP_31_XOP_LWBRX:
385 			rt = get_rt(inst);
386 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
387 			break;
388 
389 		case OP_31_XOP_TLBSYNC:
390 			break;
391 
392 		case OP_31_XOP_STWBRX:
393 			rs = get_rs(inst);
394 			ra = get_ra(inst);
395 			rb = get_rb(inst);
396 
397 			emulated = kvmppc_handle_store(run, vcpu,
398 						       kvmppc_get_gpr(vcpu, rs),
399 			                               4, 0);
400 			break;
401 
402 		case OP_31_XOP_LHBRX:
403 			rt = get_rt(inst);
404 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
405 			break;
406 
407 		case OP_31_XOP_STHBRX:
408 			rs = get_rs(inst);
409 			ra = get_ra(inst);
410 			rb = get_rb(inst);
411 
412 			emulated = kvmppc_handle_store(run, vcpu,
413 						       kvmppc_get_gpr(vcpu, rs),
414 			                               2, 0);
415 			break;
416 
417 		default:
418 			/* Attempt core-specific emulation below. */
419 			emulated = EMULATE_FAIL;
420 		}
421 		break;
422 
423 	case OP_LWZ:
424 		rt = get_rt(inst);
425 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
426 		break;
427 
428 	case OP_LWZU:
429 		ra = get_ra(inst);
430 		rt = get_rt(inst);
431 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
432 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
433 		break;
434 
435 	case OP_LBZ:
436 		rt = get_rt(inst);
437 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
438 		break;
439 
440 	case OP_LBZU:
441 		ra = get_ra(inst);
442 		rt = get_rt(inst);
443 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
444 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
445 		break;
446 
447 	case OP_STW:
448 		rs = get_rs(inst);
449 		emulated = kvmppc_handle_store(run, vcpu,
450 					       kvmppc_get_gpr(vcpu, rs),
451 		                               4, 1);
452 		break;
453 
454 	case OP_STWU:
455 		ra = get_ra(inst);
456 		rs = get_rs(inst);
457 		emulated = kvmppc_handle_store(run, vcpu,
458 					       kvmppc_get_gpr(vcpu, rs),
459 		                               4, 1);
460 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
461 		break;
462 
463 	case OP_STB:
464 		rs = get_rs(inst);
465 		emulated = kvmppc_handle_store(run, vcpu,
466 					       kvmppc_get_gpr(vcpu, rs),
467 		                               1, 1);
468 		break;
469 
470 	case OP_STBU:
471 		ra = get_ra(inst);
472 		rs = get_rs(inst);
473 		emulated = kvmppc_handle_store(run, vcpu,
474 					       kvmppc_get_gpr(vcpu, rs),
475 		                               1, 1);
476 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
477 		break;
478 
479 	case OP_LHZ:
480 		rt = get_rt(inst);
481 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
482 		break;
483 
484 	case OP_LHZU:
485 		ra = get_ra(inst);
486 		rt = get_rt(inst);
487 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
488 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
489 		break;
490 
491 	case OP_LHA:
492 		rt = get_rt(inst);
493 		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
494 		break;
495 
496 	case OP_LHAU:
497 		ra = get_ra(inst);
498 		rt = get_rt(inst);
499 		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
500 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
501 		break;
502 
503 	case OP_STH:
504 		rs = get_rs(inst);
505 		emulated = kvmppc_handle_store(run, vcpu,
506 					       kvmppc_get_gpr(vcpu, rs),
507 		                               2, 1);
508 		break;
509 
510 	case OP_STHU:
511 		ra = get_ra(inst);
512 		rs = get_rs(inst);
513 		emulated = kvmppc_handle_store(run, vcpu,
514 					       kvmppc_get_gpr(vcpu, rs),
515 		                               2, 1);
516 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
517 		break;
518 
519 	default:
520 		emulated = EMULATE_FAIL;
521 	}
522 
523 	if (emulated == EMULATE_FAIL) {
524 		emulated = kvmppc_core_emulate_op(run, vcpu, inst, &advance);
525 		if (emulated == EMULATE_AGAIN) {
526 			advance = 0;
527 		} else if (emulated == EMULATE_FAIL) {
528 			advance = 0;
529 			printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
530 			       "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
531 			kvmppc_core_queue_program(vcpu, 0);
532 		}
533 	}
534 
535 	trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
536 
537 	/* Advance past emulated instruction. */
538 	if (advance)
539 		kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
540 
541 	return emulated;
542 }
543