xref: /openbmc/linux/arch/powerpc/kvm/emulate.c (revision 81d67439)
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  *
17  * Authors: Hollis Blanchard <hollisb@us.ibm.com>
18  */
19 
20 #include <linux/jiffies.h>
21 #include <linux/hrtimer.h>
22 #include <linux/types.h>
23 #include <linux/string.h>
24 #include <linux/kvm_host.h>
25 
26 #include <asm/reg.h>
27 #include <asm/time.h>
28 #include <asm/byteorder.h>
29 #include <asm/kvm_ppc.h>
30 #include <asm/disassemble.h>
31 #include "timing.h"
32 #include "trace.h"
33 
34 #define OP_TRAP 3
35 #define OP_TRAP_64 2
36 
37 #define OP_31_XOP_LWZX      23
38 #define OP_31_XOP_LBZX      87
39 #define OP_31_XOP_STWX      151
40 #define OP_31_XOP_STBX      215
41 #define OP_31_XOP_LBZUX     119
42 #define OP_31_XOP_STBUX     247
43 #define OP_31_XOP_LHZX      279
44 #define OP_31_XOP_LHZUX     311
45 #define OP_31_XOP_MFSPR     339
46 #define OP_31_XOP_LHAX      343
47 #define OP_31_XOP_STHX      407
48 #define OP_31_XOP_STHUX     439
49 #define OP_31_XOP_MTSPR     467
50 #define OP_31_XOP_DCBI      470
51 #define OP_31_XOP_LWBRX     534
52 #define OP_31_XOP_TLBSYNC   566
53 #define OP_31_XOP_STWBRX    662
54 #define OP_31_XOP_LHBRX     790
55 #define OP_31_XOP_STHBRX    918
56 
57 #define OP_LWZ  32
58 #define OP_LWZU 33
59 #define OP_LBZ  34
60 #define OP_LBZU 35
61 #define OP_STW  36
62 #define OP_STWU 37
63 #define OP_STB  38
64 #define OP_STBU 39
65 #define OP_LHZ  40
66 #define OP_LHZU 41
67 #define OP_LHA  42
68 #define OP_LHAU 43
69 #define OP_STH  44
70 #define OP_STHU 45
71 
72 #ifdef CONFIG_PPC_BOOK3S
73 static int kvmppc_dec_enabled(struct kvm_vcpu *vcpu)
74 {
75 	return 1;
76 }
77 #else
78 static int kvmppc_dec_enabled(struct kvm_vcpu *vcpu)
79 {
80 	return vcpu->arch.tcr & TCR_DIE;
81 }
82 #endif
83 
84 void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
85 {
86 	unsigned long dec_nsec;
87 
88 	pr_debug("mtDEC: %x\n", vcpu->arch.dec);
89 #ifdef CONFIG_PPC_BOOK3S
90 	/* mtdec lowers the interrupt line when positive. */
91 	kvmppc_core_dequeue_dec(vcpu);
92 
93 	/* POWER4+ triggers a dec interrupt if the value is < 0 */
94 	if (vcpu->arch.dec & 0x80000000) {
95 		hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
96 		kvmppc_core_queue_dec(vcpu);
97 		return;
98 	}
99 #endif
100 	if (kvmppc_dec_enabled(vcpu)) {
101 		/* The decrementer ticks at the same rate as the timebase, so
102 		 * that's how we convert the guest DEC value to the number of
103 		 * host ticks. */
104 
105 		hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
106 		dec_nsec = vcpu->arch.dec;
107 		dec_nsec *= 1000;
108 		dec_nsec /= tb_ticks_per_usec;
109 		hrtimer_start(&vcpu->arch.dec_timer, ktime_set(0, dec_nsec),
110 			      HRTIMER_MODE_REL);
111 		vcpu->arch.dec_jiffies = get_tb();
112 	} else {
113 		hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
114 	}
115 }
116 
117 u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb)
118 {
119 	u64 jd = tb - vcpu->arch.dec_jiffies;
120 	return vcpu->arch.dec - jd;
121 }
122 
123 /* XXX to do:
124  * lhax
125  * lhaux
126  * lswx
127  * lswi
128  * stswx
129  * stswi
130  * lha
131  * lhau
132  * lmw
133  * stmw
134  *
135  * XXX is_bigendian should depend on MMU mapping or MSR[LE]
136  */
137 /* XXX Should probably auto-generate instruction decoding for a particular core
138  * from opcode tables in the future. */
139 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
140 {
141 	u32 inst = kvmppc_get_last_inst(vcpu);
142 	u32 ea;
143 	int ra;
144 	int rb;
145 	int rs;
146 	int rt;
147 	int sprn;
148 	enum emulation_result emulated = EMULATE_DONE;
149 	int advance = 1;
150 
151 	/* this default type might be overwritten by subcategories */
152 	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
153 
154 	pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
155 
156 	switch (get_op(inst)) {
157 	case OP_TRAP:
158 #ifdef CONFIG_PPC_BOOK3S
159 	case OP_TRAP_64:
160 		kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
161 #else
162 		kvmppc_core_queue_program(vcpu, vcpu->arch.esr | ESR_PTR);
163 #endif
164 		advance = 0;
165 		break;
166 
167 	case 31:
168 		switch (get_xop(inst)) {
169 
170 		case OP_31_XOP_LWZX:
171 			rt = get_rt(inst);
172 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
173 			break;
174 
175 		case OP_31_XOP_LBZX:
176 			rt = get_rt(inst);
177 			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
178 			break;
179 
180 		case OP_31_XOP_LBZUX:
181 			rt = get_rt(inst);
182 			ra = get_ra(inst);
183 			rb = get_rb(inst);
184 
185 			ea = kvmppc_get_gpr(vcpu, rb);
186 			if (ra)
187 				ea += kvmppc_get_gpr(vcpu, ra);
188 
189 			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
190 			kvmppc_set_gpr(vcpu, ra, ea);
191 			break;
192 
193 		case OP_31_XOP_STWX:
194 			rs = get_rs(inst);
195 			emulated = kvmppc_handle_store(run, vcpu,
196 						       kvmppc_get_gpr(vcpu, rs),
197 			                               4, 1);
198 			break;
199 
200 		case OP_31_XOP_STBX:
201 			rs = get_rs(inst);
202 			emulated = kvmppc_handle_store(run, vcpu,
203 						       kvmppc_get_gpr(vcpu, rs),
204 			                               1, 1);
205 			break;
206 
207 		case OP_31_XOP_STBUX:
208 			rs = get_rs(inst);
209 			ra = get_ra(inst);
210 			rb = get_rb(inst);
211 
212 			ea = kvmppc_get_gpr(vcpu, rb);
213 			if (ra)
214 				ea += kvmppc_get_gpr(vcpu, ra);
215 
216 			emulated = kvmppc_handle_store(run, vcpu,
217 						       kvmppc_get_gpr(vcpu, rs),
218 			                               1, 1);
219 			kvmppc_set_gpr(vcpu, rs, ea);
220 			break;
221 
222 		case OP_31_XOP_LHAX:
223 			rt = get_rt(inst);
224 			emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
225 			break;
226 
227 		case OP_31_XOP_LHZX:
228 			rt = get_rt(inst);
229 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
230 			break;
231 
232 		case OP_31_XOP_LHZUX:
233 			rt = get_rt(inst);
234 			ra = get_ra(inst);
235 			rb = get_rb(inst);
236 
237 			ea = kvmppc_get_gpr(vcpu, rb);
238 			if (ra)
239 				ea += kvmppc_get_gpr(vcpu, ra);
240 
241 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
242 			kvmppc_set_gpr(vcpu, ra, ea);
243 			break;
244 
245 		case OP_31_XOP_MFSPR:
246 			sprn = get_sprn(inst);
247 			rt = get_rt(inst);
248 
249 			switch (sprn) {
250 			case SPRN_SRR0:
251 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->srr0);
252 				break;
253 			case SPRN_SRR1:
254 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->srr1);
255 				break;
256 			case SPRN_PVR:
257 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.pvr); break;
258 			case SPRN_PIR:
259 				kvmppc_set_gpr(vcpu, rt, vcpu->vcpu_id); break;
260 			case SPRN_MSSSR0:
261 				kvmppc_set_gpr(vcpu, rt, 0); break;
262 
263 			/* Note: mftb and TBRL/TBWL are user-accessible, so
264 			 * the guest can always access the real TB anyways.
265 			 * In fact, we probably will never see these traps. */
266 			case SPRN_TBWL:
267 				kvmppc_set_gpr(vcpu, rt, get_tb() >> 32); break;
268 			case SPRN_TBWU:
269 				kvmppc_set_gpr(vcpu, rt, get_tb()); break;
270 
271 			case SPRN_SPRG0:
272 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg0);
273 				break;
274 			case SPRN_SPRG1:
275 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg1);
276 				break;
277 			case SPRN_SPRG2:
278 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg2);
279 				break;
280 			case SPRN_SPRG3:
281 				kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->sprg3);
282 				break;
283 			/* Note: SPRG4-7 are user-readable, so we don't get
284 			 * a trap. */
285 
286 			case SPRN_DEC:
287 			{
288 				kvmppc_set_gpr(vcpu, rt,
289 					       kvmppc_get_dec(vcpu, get_tb()));
290 				break;
291 			}
292 			default:
293 				emulated = kvmppc_core_emulate_mfspr(vcpu, sprn, rt);
294 				if (emulated == EMULATE_FAIL) {
295 					printk("mfspr: unknown spr %x\n", sprn);
296 					kvmppc_set_gpr(vcpu, rt, 0);
297 				}
298 				break;
299 			}
300 			kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
301 			break;
302 
303 		case OP_31_XOP_STHX:
304 			rs = get_rs(inst);
305 			ra = get_ra(inst);
306 			rb = get_rb(inst);
307 
308 			emulated = kvmppc_handle_store(run, vcpu,
309 						       kvmppc_get_gpr(vcpu, rs),
310 			                               2, 1);
311 			break;
312 
313 		case OP_31_XOP_STHUX:
314 			rs = get_rs(inst);
315 			ra = get_ra(inst);
316 			rb = get_rb(inst);
317 
318 			ea = kvmppc_get_gpr(vcpu, rb);
319 			if (ra)
320 				ea += kvmppc_get_gpr(vcpu, ra);
321 
322 			emulated = kvmppc_handle_store(run, vcpu,
323 						       kvmppc_get_gpr(vcpu, rs),
324 			                               2, 1);
325 			kvmppc_set_gpr(vcpu, ra, ea);
326 			break;
327 
328 		case OP_31_XOP_MTSPR:
329 			sprn = get_sprn(inst);
330 			rs = get_rs(inst);
331 			switch (sprn) {
332 			case SPRN_SRR0:
333 				vcpu->arch.shared->srr0 = kvmppc_get_gpr(vcpu, rs);
334 				break;
335 			case SPRN_SRR1:
336 				vcpu->arch.shared->srr1 = kvmppc_get_gpr(vcpu, rs);
337 				break;
338 
339 			/* XXX We need to context-switch the timebase for
340 			 * watchdog and FIT. */
341 			case SPRN_TBWL: break;
342 			case SPRN_TBWU: break;
343 
344 			case SPRN_MSSSR0: break;
345 
346 			case SPRN_DEC:
347 				vcpu->arch.dec = kvmppc_get_gpr(vcpu, rs);
348 				kvmppc_emulate_dec(vcpu);
349 				break;
350 
351 			case SPRN_SPRG0:
352 				vcpu->arch.shared->sprg0 = kvmppc_get_gpr(vcpu, rs);
353 				break;
354 			case SPRN_SPRG1:
355 				vcpu->arch.shared->sprg1 = kvmppc_get_gpr(vcpu, rs);
356 				break;
357 			case SPRN_SPRG2:
358 				vcpu->arch.shared->sprg2 = kvmppc_get_gpr(vcpu, rs);
359 				break;
360 			case SPRN_SPRG3:
361 				vcpu->arch.shared->sprg3 = kvmppc_get_gpr(vcpu, rs);
362 				break;
363 
364 			default:
365 				emulated = kvmppc_core_emulate_mtspr(vcpu, sprn, rs);
366 				if (emulated == EMULATE_FAIL)
367 					printk("mtspr: unknown spr %x\n", sprn);
368 				break;
369 			}
370 			kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
371 			break;
372 
373 		case OP_31_XOP_DCBI:
374 			/* Do nothing. The guest is performing dcbi because
375 			 * hardware DMA is not snooped by the dcache, but
376 			 * emulated DMA either goes through the dcache as
377 			 * normal writes, or the host kernel has handled dcache
378 			 * coherence. */
379 			break;
380 
381 		case OP_31_XOP_LWBRX:
382 			rt = get_rt(inst);
383 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
384 			break;
385 
386 		case OP_31_XOP_TLBSYNC:
387 			break;
388 
389 		case OP_31_XOP_STWBRX:
390 			rs = get_rs(inst);
391 			ra = get_ra(inst);
392 			rb = get_rb(inst);
393 
394 			emulated = kvmppc_handle_store(run, vcpu,
395 						       kvmppc_get_gpr(vcpu, rs),
396 			                               4, 0);
397 			break;
398 
399 		case OP_31_XOP_LHBRX:
400 			rt = get_rt(inst);
401 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
402 			break;
403 
404 		case OP_31_XOP_STHBRX:
405 			rs = get_rs(inst);
406 			ra = get_ra(inst);
407 			rb = get_rb(inst);
408 
409 			emulated = kvmppc_handle_store(run, vcpu,
410 						       kvmppc_get_gpr(vcpu, rs),
411 			                               2, 0);
412 			break;
413 
414 		default:
415 			/* Attempt core-specific emulation below. */
416 			emulated = EMULATE_FAIL;
417 		}
418 		break;
419 
420 	case OP_LWZ:
421 		rt = get_rt(inst);
422 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
423 		break;
424 
425 	case OP_LWZU:
426 		ra = get_ra(inst);
427 		rt = get_rt(inst);
428 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
429 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
430 		break;
431 
432 	case OP_LBZ:
433 		rt = get_rt(inst);
434 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
435 		break;
436 
437 	case OP_LBZU:
438 		ra = get_ra(inst);
439 		rt = get_rt(inst);
440 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
441 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
442 		break;
443 
444 	case OP_STW:
445 		rs = get_rs(inst);
446 		emulated = kvmppc_handle_store(run, vcpu,
447 					       kvmppc_get_gpr(vcpu, rs),
448 		                               4, 1);
449 		break;
450 
451 	case OP_STWU:
452 		ra = get_ra(inst);
453 		rs = get_rs(inst);
454 		emulated = kvmppc_handle_store(run, vcpu,
455 					       kvmppc_get_gpr(vcpu, rs),
456 		                               4, 1);
457 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
458 		break;
459 
460 	case OP_STB:
461 		rs = get_rs(inst);
462 		emulated = kvmppc_handle_store(run, vcpu,
463 					       kvmppc_get_gpr(vcpu, rs),
464 		                               1, 1);
465 		break;
466 
467 	case OP_STBU:
468 		ra = get_ra(inst);
469 		rs = get_rs(inst);
470 		emulated = kvmppc_handle_store(run, vcpu,
471 					       kvmppc_get_gpr(vcpu, rs),
472 		                               1, 1);
473 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
474 		break;
475 
476 	case OP_LHZ:
477 		rt = get_rt(inst);
478 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
479 		break;
480 
481 	case OP_LHZU:
482 		ra = get_ra(inst);
483 		rt = get_rt(inst);
484 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
485 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
486 		break;
487 
488 	case OP_LHA:
489 		rt = get_rt(inst);
490 		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
491 		break;
492 
493 	case OP_LHAU:
494 		ra = get_ra(inst);
495 		rt = get_rt(inst);
496 		emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
497 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
498 		break;
499 
500 	case OP_STH:
501 		rs = get_rs(inst);
502 		emulated = kvmppc_handle_store(run, vcpu,
503 					       kvmppc_get_gpr(vcpu, rs),
504 		                               2, 1);
505 		break;
506 
507 	case OP_STHU:
508 		ra = get_ra(inst);
509 		rs = get_rs(inst);
510 		emulated = kvmppc_handle_store(run, vcpu,
511 					       kvmppc_get_gpr(vcpu, rs),
512 		                               2, 1);
513 		kvmppc_set_gpr(vcpu, ra, vcpu->arch.paddr_accessed);
514 		break;
515 
516 	default:
517 		emulated = EMULATE_FAIL;
518 	}
519 
520 	if (emulated == EMULATE_FAIL) {
521 		emulated = kvmppc_core_emulate_op(run, vcpu, inst, &advance);
522 		if (emulated == EMULATE_AGAIN) {
523 			advance = 0;
524 		} else if (emulated == EMULATE_FAIL) {
525 			advance = 0;
526 			printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
527 			       "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
528 			kvmppc_core_queue_program(vcpu, 0);
529 		}
530 	}
531 
532 	trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
533 
534 	/* Advance past emulated instruction. */
535 	if (advance)
536 		kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
537 
538 	return emulated;
539 }
540