xref: /linux/arch/powerpc/kvm/emulate.c (revision dfc349402de8e95f6a42e8341e9ea193b718eee3)
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/timer.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 
36 #define OP_31_XOP_LWZX      23
37 #define OP_31_XOP_LBZX      87
38 #define OP_31_XOP_STWX      151
39 #define OP_31_XOP_STBX      215
40 #define OP_31_XOP_STBUX     247
41 #define OP_31_XOP_LHZX      279
42 #define OP_31_XOP_LHZUX     311
43 #define OP_31_XOP_MFSPR     339
44 #define OP_31_XOP_STHX      407
45 #define OP_31_XOP_STHUX     439
46 #define OP_31_XOP_MTSPR     467
47 #define OP_31_XOP_DCBI      470
48 #define OP_31_XOP_LWBRX     534
49 #define OP_31_XOP_TLBSYNC   566
50 #define OP_31_XOP_STWBRX    662
51 #define OP_31_XOP_LHBRX     790
52 #define OP_31_XOP_STHBRX    918
53 
54 #define OP_LWZ  32
55 #define OP_LWZU 33
56 #define OP_LBZ  34
57 #define OP_LBZU 35
58 #define OP_STW  36
59 #define OP_STWU 37
60 #define OP_STB  38
61 #define OP_STBU 39
62 #define OP_LHZ  40
63 #define OP_LHZU 41
64 #define OP_STH  44
65 #define OP_STHU 45
66 
67 void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
68 {
69 	if (vcpu->arch.tcr & TCR_DIE) {
70 		/* The decrementer ticks at the same rate as the timebase, so
71 		 * that's how we convert the guest DEC value to the number of
72 		 * host ticks. */
73 		unsigned long nr_jiffies;
74 
75 		nr_jiffies = vcpu->arch.dec / tb_ticks_per_jiffy;
76 		mod_timer(&vcpu->arch.dec_timer,
77 		          get_jiffies_64() + nr_jiffies);
78 	} else {
79 		del_timer(&vcpu->arch.dec_timer);
80 	}
81 }
82 
83 /* XXX to do:
84  * lhax
85  * lhaux
86  * lswx
87  * lswi
88  * stswx
89  * stswi
90  * lha
91  * lhau
92  * lmw
93  * stmw
94  *
95  * XXX is_bigendian should depend on MMU mapping or MSR[LE]
96  */
97 /* XXX Should probably auto-generate instruction decoding for a particular core
98  * from opcode tables in the future. */
99 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
100 {
101 	u32 inst = vcpu->arch.last_inst;
102 	u32 ea;
103 	int ra;
104 	int rb;
105 	int rs;
106 	int rt;
107 	int sprn;
108 	enum emulation_result emulated = EMULATE_DONE;
109 	int advance = 1;
110 
111 	/* this default type might be overwritten by subcategories */
112 	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
113 
114 	switch (get_op(inst)) {
115 	case OP_TRAP:
116 		vcpu->arch.esr |= ESR_PTR;
117 		kvmppc_core_queue_program(vcpu);
118 		advance = 0;
119 		break;
120 
121 	case 31:
122 		switch (get_xop(inst)) {
123 
124 		case OP_31_XOP_LWZX:
125 			rt = get_rt(inst);
126 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
127 			break;
128 
129 		case OP_31_XOP_LBZX:
130 			rt = get_rt(inst);
131 			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
132 			break;
133 
134 		case OP_31_XOP_STWX:
135 			rs = get_rs(inst);
136 			emulated = kvmppc_handle_store(run, vcpu,
137 			                               vcpu->arch.gpr[rs],
138 			                               4, 1);
139 			break;
140 
141 		case OP_31_XOP_STBX:
142 			rs = get_rs(inst);
143 			emulated = kvmppc_handle_store(run, vcpu,
144 			                               vcpu->arch.gpr[rs],
145 			                               1, 1);
146 			break;
147 
148 		case OP_31_XOP_STBUX:
149 			rs = get_rs(inst);
150 			ra = get_ra(inst);
151 			rb = get_rb(inst);
152 
153 			ea = vcpu->arch.gpr[rb];
154 			if (ra)
155 				ea += vcpu->arch.gpr[ra];
156 
157 			emulated = kvmppc_handle_store(run, vcpu,
158 			                               vcpu->arch.gpr[rs],
159 			                               1, 1);
160 			vcpu->arch.gpr[rs] = ea;
161 			break;
162 
163 		case OP_31_XOP_LHZX:
164 			rt = get_rt(inst);
165 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
166 			break;
167 
168 		case OP_31_XOP_LHZUX:
169 			rt = get_rt(inst);
170 			ra = get_ra(inst);
171 			rb = get_rb(inst);
172 
173 			ea = vcpu->arch.gpr[rb];
174 			if (ra)
175 				ea += vcpu->arch.gpr[ra];
176 
177 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
178 			vcpu->arch.gpr[ra] = ea;
179 			break;
180 
181 		case OP_31_XOP_MFSPR:
182 			sprn = get_sprn(inst);
183 			rt = get_rt(inst);
184 
185 			switch (sprn) {
186 			case SPRN_SRR0:
187 				vcpu->arch.gpr[rt] = vcpu->arch.srr0; break;
188 			case SPRN_SRR1:
189 				vcpu->arch.gpr[rt] = vcpu->arch.srr1; break;
190 			case SPRN_PVR:
191 				vcpu->arch.gpr[rt] = mfspr(SPRN_PVR); break;
192 			case SPRN_PIR:
193 				vcpu->arch.gpr[rt] = mfspr(SPRN_PIR); break;
194 
195 			/* Note: mftb and TBRL/TBWL are user-accessible, so
196 			 * the guest can always access the real TB anyways.
197 			 * In fact, we probably will never see these traps. */
198 			case SPRN_TBWL:
199 				vcpu->arch.gpr[rt] = mftbl(); break;
200 			case SPRN_TBWU:
201 				vcpu->arch.gpr[rt] = mftbu(); break;
202 
203 			case SPRN_SPRG0:
204 				vcpu->arch.gpr[rt] = vcpu->arch.sprg0; break;
205 			case SPRN_SPRG1:
206 				vcpu->arch.gpr[rt] = vcpu->arch.sprg1; break;
207 			case SPRN_SPRG2:
208 				vcpu->arch.gpr[rt] = vcpu->arch.sprg2; break;
209 			case SPRN_SPRG3:
210 				vcpu->arch.gpr[rt] = vcpu->arch.sprg3; break;
211 			/* Note: SPRG4-7 are user-readable, so we don't get
212 			 * a trap. */
213 
214 			default:
215 				emulated = kvmppc_core_emulate_mfspr(vcpu, sprn, rt);
216 				if (emulated == EMULATE_FAIL) {
217 					printk("mfspr: unknown spr %x\n", sprn);
218 					vcpu->arch.gpr[rt] = 0;
219 				}
220 				break;
221 			}
222 			break;
223 
224 		case OP_31_XOP_STHX:
225 			rs = get_rs(inst);
226 			ra = get_ra(inst);
227 			rb = get_rb(inst);
228 
229 			emulated = kvmppc_handle_store(run, vcpu,
230 			                               vcpu->arch.gpr[rs],
231 			                               2, 1);
232 			break;
233 
234 		case OP_31_XOP_STHUX:
235 			rs = get_rs(inst);
236 			ra = get_ra(inst);
237 			rb = get_rb(inst);
238 
239 			ea = vcpu->arch.gpr[rb];
240 			if (ra)
241 				ea += vcpu->arch.gpr[ra];
242 
243 			emulated = kvmppc_handle_store(run, vcpu,
244 			                               vcpu->arch.gpr[rs],
245 			                               2, 1);
246 			vcpu->arch.gpr[ra] = ea;
247 			break;
248 
249 		case OP_31_XOP_MTSPR:
250 			sprn = get_sprn(inst);
251 			rs = get_rs(inst);
252 			switch (sprn) {
253 			case SPRN_SRR0:
254 				vcpu->arch.srr0 = vcpu->arch.gpr[rs]; break;
255 			case SPRN_SRR1:
256 				vcpu->arch.srr1 = vcpu->arch.gpr[rs]; break;
257 
258 			/* XXX We need to context-switch the timebase for
259 			 * watchdog and FIT. */
260 			case SPRN_TBWL: break;
261 			case SPRN_TBWU: break;
262 
263 			case SPRN_DEC:
264 				vcpu->arch.dec = vcpu->arch.gpr[rs];
265 				kvmppc_emulate_dec(vcpu);
266 				break;
267 
268 			case SPRN_SPRG0:
269 				vcpu->arch.sprg0 = vcpu->arch.gpr[rs]; break;
270 			case SPRN_SPRG1:
271 				vcpu->arch.sprg1 = vcpu->arch.gpr[rs]; break;
272 			case SPRN_SPRG2:
273 				vcpu->arch.sprg2 = vcpu->arch.gpr[rs]; break;
274 			case SPRN_SPRG3:
275 				vcpu->arch.sprg3 = vcpu->arch.gpr[rs]; break;
276 
277 			default:
278 				emulated = kvmppc_core_emulate_mtspr(vcpu, sprn, rs);
279 				if (emulated == EMULATE_FAIL)
280 					printk("mtspr: unknown spr %x\n", sprn);
281 				break;
282 			}
283 			break;
284 
285 		case OP_31_XOP_DCBI:
286 			/* Do nothing. The guest is performing dcbi because
287 			 * hardware DMA is not snooped by the dcache, but
288 			 * emulated DMA either goes through the dcache as
289 			 * normal writes, or the host kernel has handled dcache
290 			 * coherence. */
291 			break;
292 
293 		case OP_31_XOP_LWBRX:
294 			rt = get_rt(inst);
295 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
296 			break;
297 
298 		case OP_31_XOP_TLBSYNC:
299 			break;
300 
301 		case OP_31_XOP_STWBRX:
302 			rs = get_rs(inst);
303 			ra = get_ra(inst);
304 			rb = get_rb(inst);
305 
306 			emulated = kvmppc_handle_store(run, vcpu,
307 			                               vcpu->arch.gpr[rs],
308 			                               4, 0);
309 			break;
310 
311 		case OP_31_XOP_LHBRX:
312 			rt = get_rt(inst);
313 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
314 			break;
315 
316 		case OP_31_XOP_STHBRX:
317 			rs = get_rs(inst);
318 			ra = get_ra(inst);
319 			rb = get_rb(inst);
320 
321 			emulated = kvmppc_handle_store(run, vcpu,
322 			                               vcpu->arch.gpr[rs],
323 			                               2, 0);
324 			break;
325 
326 		default:
327 			/* Attempt core-specific emulation below. */
328 			emulated = EMULATE_FAIL;
329 		}
330 		break;
331 
332 	case OP_LWZ:
333 		rt = get_rt(inst);
334 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
335 		break;
336 
337 	case OP_LWZU:
338 		ra = get_ra(inst);
339 		rt = get_rt(inst);
340 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
341 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
342 		break;
343 
344 	case OP_LBZ:
345 		rt = get_rt(inst);
346 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
347 		break;
348 
349 	case OP_LBZU:
350 		ra = get_ra(inst);
351 		rt = get_rt(inst);
352 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
353 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
354 		break;
355 
356 	case OP_STW:
357 		rs = get_rs(inst);
358 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
359 		                               4, 1);
360 		break;
361 
362 	case OP_STWU:
363 		ra = get_ra(inst);
364 		rs = get_rs(inst);
365 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
366 		                               4, 1);
367 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
368 		break;
369 
370 	case OP_STB:
371 		rs = get_rs(inst);
372 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
373 		                               1, 1);
374 		break;
375 
376 	case OP_STBU:
377 		ra = get_ra(inst);
378 		rs = get_rs(inst);
379 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
380 		                               1, 1);
381 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
382 		break;
383 
384 	case OP_LHZ:
385 		rt = get_rt(inst);
386 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
387 		break;
388 
389 	case OP_LHZU:
390 		ra = get_ra(inst);
391 		rt = get_rt(inst);
392 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
393 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
394 		break;
395 
396 	case OP_STH:
397 		rs = get_rs(inst);
398 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
399 		                               2, 1);
400 		break;
401 
402 	case OP_STHU:
403 		ra = get_ra(inst);
404 		rs = get_rs(inst);
405 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
406 		                               2, 1);
407 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
408 		break;
409 
410 	default:
411 		emulated = EMULATE_FAIL;
412 	}
413 
414 	if (emulated == EMULATE_FAIL) {
415 		emulated = kvmppc_core_emulate_op(run, vcpu, inst, &advance);
416 		if (emulated == EMULATE_FAIL) {
417 			advance = 0;
418 			printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
419 			       "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
420 		}
421 	}
422 
423 	trace_kvm_ppc_instr(inst, vcpu->arch.pc, emulated);
424 
425 	if (advance)
426 		vcpu->arch.pc += 4; /* Advance past emulated instruction. */
427 
428 	return emulated;
429 }
430