xref: /openbmc/linux/arch/powerpc/kvm/emulate.c (revision 82ced6fd)
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 
33 #define OP_TRAP 3
34 
35 #define OP_31_XOP_LWZX      23
36 #define OP_31_XOP_LBZX      87
37 #define OP_31_XOP_STWX      151
38 #define OP_31_XOP_STBX      215
39 #define OP_31_XOP_STBUX     247
40 #define OP_31_XOP_LHZX      279
41 #define OP_31_XOP_LHZUX     311
42 #define OP_31_XOP_MFSPR     339
43 #define OP_31_XOP_STHX      407
44 #define OP_31_XOP_STHUX     439
45 #define OP_31_XOP_MTSPR     467
46 #define OP_31_XOP_DCBI      470
47 #define OP_31_XOP_LWBRX     534
48 #define OP_31_XOP_TLBSYNC   566
49 #define OP_31_XOP_STWBRX    662
50 #define OP_31_XOP_LHBRX     790
51 #define OP_31_XOP_STHBRX    918
52 
53 #define OP_LWZ  32
54 #define OP_LWZU 33
55 #define OP_LBZ  34
56 #define OP_LBZU 35
57 #define OP_STW  36
58 #define OP_STWU 37
59 #define OP_STB  38
60 #define OP_STBU 39
61 #define OP_LHZ  40
62 #define OP_LHZU 41
63 #define OP_STH  44
64 #define OP_STHU 45
65 
66 void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
67 {
68 	if (vcpu->arch.tcr & TCR_DIE) {
69 		/* The decrementer ticks at the same rate as the timebase, so
70 		 * that's how we convert the guest DEC value to the number of
71 		 * host ticks. */
72 		unsigned long nr_jiffies;
73 
74 		nr_jiffies = vcpu->arch.dec / tb_ticks_per_jiffy;
75 		mod_timer(&vcpu->arch.dec_timer,
76 		          get_jiffies_64() + nr_jiffies);
77 	} else {
78 		del_timer(&vcpu->arch.dec_timer);
79 	}
80 }
81 
82 /* XXX to do:
83  * lhax
84  * lhaux
85  * lswx
86  * lswi
87  * stswx
88  * stswi
89  * lha
90  * lhau
91  * lmw
92  * stmw
93  *
94  * XXX is_bigendian should depend on MMU mapping or MSR[LE]
95  */
96 /* XXX Should probably auto-generate instruction decoding for a particular core
97  * from opcode tables in the future. */
98 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
99 {
100 	u32 inst = vcpu->arch.last_inst;
101 	u32 ea;
102 	int ra;
103 	int rb;
104 	int rs;
105 	int rt;
106 	int sprn;
107 	enum emulation_result emulated = EMULATE_DONE;
108 	int advance = 1;
109 
110 	/* this default type might be overwritten by subcategories */
111 	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
112 
113 	switch (get_op(inst)) {
114 	case OP_TRAP:
115 		vcpu->arch.esr |= ESR_PTR;
116 		kvmppc_core_queue_program(vcpu);
117 		advance = 0;
118 		break;
119 
120 	case 31:
121 		switch (get_xop(inst)) {
122 
123 		case OP_31_XOP_LWZX:
124 			rt = get_rt(inst);
125 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
126 			break;
127 
128 		case OP_31_XOP_LBZX:
129 			rt = get_rt(inst);
130 			emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
131 			break;
132 
133 		case OP_31_XOP_STWX:
134 			rs = get_rs(inst);
135 			emulated = kvmppc_handle_store(run, vcpu,
136 			                               vcpu->arch.gpr[rs],
137 			                               4, 1);
138 			break;
139 
140 		case OP_31_XOP_STBX:
141 			rs = get_rs(inst);
142 			emulated = kvmppc_handle_store(run, vcpu,
143 			                               vcpu->arch.gpr[rs],
144 			                               1, 1);
145 			break;
146 
147 		case OP_31_XOP_STBUX:
148 			rs = get_rs(inst);
149 			ra = get_ra(inst);
150 			rb = get_rb(inst);
151 
152 			ea = vcpu->arch.gpr[rb];
153 			if (ra)
154 				ea += vcpu->arch.gpr[ra];
155 
156 			emulated = kvmppc_handle_store(run, vcpu,
157 			                               vcpu->arch.gpr[rs],
158 			                               1, 1);
159 			vcpu->arch.gpr[rs] = ea;
160 			break;
161 
162 		case OP_31_XOP_LHZX:
163 			rt = get_rt(inst);
164 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
165 			break;
166 
167 		case OP_31_XOP_LHZUX:
168 			rt = get_rt(inst);
169 			ra = get_ra(inst);
170 			rb = get_rb(inst);
171 
172 			ea = vcpu->arch.gpr[rb];
173 			if (ra)
174 				ea += vcpu->arch.gpr[ra];
175 
176 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
177 			vcpu->arch.gpr[ra] = ea;
178 			break;
179 
180 		case OP_31_XOP_MFSPR:
181 			sprn = get_sprn(inst);
182 			rt = get_rt(inst);
183 
184 			switch (sprn) {
185 			case SPRN_SRR0:
186 				vcpu->arch.gpr[rt] = vcpu->arch.srr0; break;
187 			case SPRN_SRR1:
188 				vcpu->arch.gpr[rt] = vcpu->arch.srr1; break;
189 			case SPRN_PVR:
190 				vcpu->arch.gpr[rt] = vcpu->arch.pvr; break;
191 
192 			/* Note: mftb and TBRL/TBWL are user-accessible, so
193 			 * the guest can always access the real TB anyways.
194 			 * In fact, we probably will never see these traps. */
195 			case SPRN_TBWL:
196 				vcpu->arch.gpr[rt] = mftbl(); break;
197 			case SPRN_TBWU:
198 				vcpu->arch.gpr[rt] = mftbu(); break;
199 
200 			case SPRN_SPRG0:
201 				vcpu->arch.gpr[rt] = vcpu->arch.sprg0; break;
202 			case SPRN_SPRG1:
203 				vcpu->arch.gpr[rt] = vcpu->arch.sprg1; break;
204 			case SPRN_SPRG2:
205 				vcpu->arch.gpr[rt] = vcpu->arch.sprg2; break;
206 			case SPRN_SPRG3:
207 				vcpu->arch.gpr[rt] = vcpu->arch.sprg3; break;
208 			/* Note: SPRG4-7 are user-readable, so we don't get
209 			 * a trap. */
210 
211 			default:
212 				emulated = kvmppc_core_emulate_mfspr(vcpu, sprn, rt);
213 				if (emulated == EMULATE_FAIL) {
214 					printk("mfspr: unknown spr %x\n", sprn);
215 					vcpu->arch.gpr[rt] = 0;
216 				}
217 				break;
218 			}
219 			break;
220 
221 		case OP_31_XOP_STHX:
222 			rs = get_rs(inst);
223 			ra = get_ra(inst);
224 			rb = get_rb(inst);
225 
226 			emulated = kvmppc_handle_store(run, vcpu,
227 			                               vcpu->arch.gpr[rs],
228 			                               2, 1);
229 			break;
230 
231 		case OP_31_XOP_STHUX:
232 			rs = get_rs(inst);
233 			ra = get_ra(inst);
234 			rb = get_rb(inst);
235 
236 			ea = vcpu->arch.gpr[rb];
237 			if (ra)
238 				ea += vcpu->arch.gpr[ra];
239 
240 			emulated = kvmppc_handle_store(run, vcpu,
241 			                               vcpu->arch.gpr[rs],
242 			                               2, 1);
243 			vcpu->arch.gpr[ra] = ea;
244 			break;
245 
246 		case OP_31_XOP_MTSPR:
247 			sprn = get_sprn(inst);
248 			rs = get_rs(inst);
249 			switch (sprn) {
250 			case SPRN_SRR0:
251 				vcpu->arch.srr0 = vcpu->arch.gpr[rs]; break;
252 			case SPRN_SRR1:
253 				vcpu->arch.srr1 = vcpu->arch.gpr[rs]; break;
254 
255 			/* XXX We need to context-switch the timebase for
256 			 * watchdog and FIT. */
257 			case SPRN_TBWL: break;
258 			case SPRN_TBWU: break;
259 
260 			case SPRN_DEC:
261 				vcpu->arch.dec = vcpu->arch.gpr[rs];
262 				kvmppc_emulate_dec(vcpu);
263 				break;
264 
265 			case SPRN_SPRG0:
266 				vcpu->arch.sprg0 = vcpu->arch.gpr[rs]; break;
267 			case SPRN_SPRG1:
268 				vcpu->arch.sprg1 = vcpu->arch.gpr[rs]; break;
269 			case SPRN_SPRG2:
270 				vcpu->arch.sprg2 = vcpu->arch.gpr[rs]; break;
271 			case SPRN_SPRG3:
272 				vcpu->arch.sprg3 = vcpu->arch.gpr[rs]; break;
273 
274 			default:
275 				emulated = kvmppc_core_emulate_mtspr(vcpu, sprn, rs);
276 				if (emulated == EMULATE_FAIL)
277 					printk("mtspr: unknown spr %x\n", sprn);
278 				break;
279 			}
280 			break;
281 
282 		case OP_31_XOP_DCBI:
283 			/* Do nothing. The guest is performing dcbi because
284 			 * hardware DMA is not snooped by the dcache, but
285 			 * emulated DMA either goes through the dcache as
286 			 * normal writes, or the host kernel has handled dcache
287 			 * coherence. */
288 			break;
289 
290 		case OP_31_XOP_LWBRX:
291 			rt = get_rt(inst);
292 			emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
293 			break;
294 
295 		case OP_31_XOP_TLBSYNC:
296 			break;
297 
298 		case OP_31_XOP_STWBRX:
299 			rs = get_rs(inst);
300 			ra = get_ra(inst);
301 			rb = get_rb(inst);
302 
303 			emulated = kvmppc_handle_store(run, vcpu,
304 			                               vcpu->arch.gpr[rs],
305 			                               4, 0);
306 			break;
307 
308 		case OP_31_XOP_LHBRX:
309 			rt = get_rt(inst);
310 			emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
311 			break;
312 
313 		case OP_31_XOP_STHBRX:
314 			rs = get_rs(inst);
315 			ra = get_ra(inst);
316 			rb = get_rb(inst);
317 
318 			emulated = kvmppc_handle_store(run, vcpu,
319 			                               vcpu->arch.gpr[rs],
320 			                               2, 0);
321 			break;
322 
323 		default:
324 			/* Attempt core-specific emulation below. */
325 			emulated = EMULATE_FAIL;
326 		}
327 		break;
328 
329 	case OP_LWZ:
330 		rt = get_rt(inst);
331 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
332 		break;
333 
334 	case OP_LWZU:
335 		ra = get_ra(inst);
336 		rt = get_rt(inst);
337 		emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
338 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
339 		break;
340 
341 	case OP_LBZ:
342 		rt = get_rt(inst);
343 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
344 		break;
345 
346 	case OP_LBZU:
347 		ra = get_ra(inst);
348 		rt = get_rt(inst);
349 		emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
350 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
351 		break;
352 
353 	case OP_STW:
354 		rs = get_rs(inst);
355 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
356 		                               4, 1);
357 		break;
358 
359 	case OP_STWU:
360 		ra = get_ra(inst);
361 		rs = get_rs(inst);
362 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
363 		                               4, 1);
364 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
365 		break;
366 
367 	case OP_STB:
368 		rs = get_rs(inst);
369 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
370 		                               1, 1);
371 		break;
372 
373 	case OP_STBU:
374 		ra = get_ra(inst);
375 		rs = get_rs(inst);
376 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
377 		                               1, 1);
378 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
379 		break;
380 
381 	case OP_LHZ:
382 		rt = get_rt(inst);
383 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
384 		break;
385 
386 	case OP_LHZU:
387 		ra = get_ra(inst);
388 		rt = get_rt(inst);
389 		emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
390 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
391 		break;
392 
393 	case OP_STH:
394 		rs = get_rs(inst);
395 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
396 		                               2, 1);
397 		break;
398 
399 	case OP_STHU:
400 		ra = get_ra(inst);
401 		rs = get_rs(inst);
402 		emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
403 		                               2, 1);
404 		vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
405 		break;
406 
407 	default:
408 		emulated = EMULATE_FAIL;
409 	}
410 
411 	if (emulated == EMULATE_FAIL) {
412 		emulated = kvmppc_core_emulate_op(run, vcpu, inst, &advance);
413 		if (emulated == EMULATE_FAIL) {
414 			advance = 0;
415 			printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
416 			       "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
417 		}
418 	}
419 
420 	KVMTRACE_3D(PPC_INSTR, vcpu, inst, (int)vcpu->arch.pc, emulated, entryexit);
421 
422 	if (advance)
423 		vcpu->arch.pc += 4; /* Advance past emulated instruction. */
424 
425 	return emulated;
426 }
427