arch/powerpc/kvm/emulate.c

   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 #include <linux/clockchips.h>
  27
  28 #include <asm/reg.h>
  29 #include <asm/time.h>
  30 #include <asm/byteorder.h>
  31 #include <asm/kvm_ppc.h>
  32 #include <asm/disassemble.h>
  33 #include <asm/ppc-opcode.h>
  34 #include "timing.h"
  35 #include "trace.h"
  36
  37 void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
  38 {
  39         unsigned long dec_nsec;
  40         unsigned long long dec_time;
  41
  42         pr_debug("mtDEC: %x\n", vcpu->arch.dec);
  43         hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
  44
  45 #ifdef CONFIG_PPC_BOOK3S
  46         /* mtdec lowers the interrupt line when positive. */
  47         kvmppc_core_dequeue_dec(vcpu);
  48
  49         /* POWER4+ triggers a dec interrupt if the value is < 0 */
  50         if (vcpu->arch.dec & 0x80000000) {
  51                 kvmppc_core_queue_dec(vcpu);
  52                 return;
  53         }
  54 #endif
  55
  56 #ifdef CONFIG_BOOKE
  57         /* On BOOKE, DEC = 0 is as good as decrementer not enabled */
  58         if (vcpu->arch.dec == 0)
  59                 return;
  60 #endif
  61
  62         /*
  63          * The decrementer ticks at the same rate as the timebase, so
  64          * that's how we convert the guest DEC value to the number of
  65          * host ticks.
  66          */
  67
  68         dec_time = vcpu->arch.dec;
  69         /*
  70          * Guest timebase ticks at the same frequency as host decrementer.
  71          * So use the host decrementer calculations for decrementer emulation.
  72          */
  73         dec_time = dec_time << decrementer_clockevent.shift;
  74         do_div(dec_time, decrementer_clockevent.mult);
  75         dec_nsec = do_div(dec_time, NSEC_PER_SEC);
  76         hrtimer_start(&vcpu->arch.dec_timer,
  77                 ktime_set(dec_time, dec_nsec), HRTIMER_MODE_REL);
  78         vcpu->arch.dec_jiffies = get_tb();
  79 }
  80
  81 u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb)
  82 {
  83         u64 jd = tb - vcpu->arch.dec_jiffies;
  84
  85 #ifdef CONFIG_BOOKE
  86         if (vcpu->arch.dec < jd)
  87                 return 0;
  88 #endif
  89
  90         return vcpu->arch.dec - jd;
  91 }
  92
  93 static int kvmppc_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
  94 {
  95         enum emulation_result emulated = EMULATE_DONE;
  96         ulong spr_val = kvmppc_get_gpr(vcpu, rs);
  97
  98         switch (sprn) {
  99         case SPRN_SRR0:
 100                 vcpu->arch.shared->srr0 = spr_val;
 101                 break;
 102         case SPRN_SRR1:
 103                 vcpu->arch.shared->srr1 = spr_val;
 104                 break;
 105
 106         /* XXX We need to context-switch the timebase for
 107          * watchdog and FIT. */
 108         case SPRN_TBWL: break;
 109         case SPRN_TBWU: break;
 110
 111         case SPRN_DEC:
 112                 vcpu->arch.dec = spr_val;
 113                 kvmppc_emulate_dec(vcpu);
 114                 break;
 115
 116         case SPRN_SPRG0:
 117                 vcpu->arch.shared->sprg0 = spr_val;
 118                 break;
 119         case SPRN_SPRG1:
 120                 vcpu->arch.shared->sprg1 = spr_val;
 121                 break;
 122         case SPRN_SPRG2:
 123                 vcpu->arch.shared->sprg2 = spr_val;
 124                 break;
 125         case SPRN_SPRG3:
 126                 vcpu->arch.shared->sprg3 = spr_val;
 127                 break;
 128
 129         /* PIR can legally be written, but we ignore it */
 130         case SPRN_PIR: break;
 131
 132         default:
 133                 emulated = kvmppc_core_emulate_mtspr(vcpu, sprn,
 134                                                      spr_val);
 135                 if (emulated == EMULATE_FAIL)
 136                         printk(KERN_INFO "mtspr: unknown spr "
 137                                 "0x%x\n", sprn);
 138                 break;
 139         }
 140
 141         kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
 142
 143         return emulated;
 144 }
 145
 146 static int kvmppc_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
 147 {
 148         enum emulation_result emulated = EMULATE_DONE;
 149         ulong spr_val = 0;
 150
 151         switch (sprn) {
 152         case SPRN_SRR0:
 153                 spr_val = vcpu->arch.shared->srr0;
 154                 break;
 155         case SPRN_SRR1:
 156                 spr_val = vcpu->arch.shared->srr1;
 157                 break;
 158         case SPRN_PVR:
 159                 spr_val = vcpu->arch.pvr;
 160                 break;
 161         case SPRN_PIR:
 162                 spr_val = vcpu->vcpu_id;
 163                 break;
 164
 165         /* Note: mftb and TBRL/TBWL are user-accessible, so
 166          * the guest can always access the real TB anyways.
 167          * In fact, we probably will never see these traps. */
 168         case SPRN_TBWL:
 169                 spr_val = get_tb() >> 32;
 170                 break;
 171         case SPRN_TBWU:
 172                 spr_val = get_tb();
 173                 break;
 174
 175         case SPRN_SPRG0:
 176                 spr_val = vcpu->arch.shared->sprg0;
 177                 break;
 178         case SPRN_SPRG1:
 179                 spr_val = vcpu->arch.shared->sprg1;
 180                 break;
 181         case SPRN_SPRG2:
 182                 spr_val = vcpu->arch.shared->sprg2;
 183                 break;
 184         case SPRN_SPRG3:
 185                 spr_val = vcpu->arch.shared->sprg3;
 186                 break;
 187         /* Note: SPRG4-7 are user-readable, so we don't get
 188          * a trap. */
 189
 190         case SPRN_DEC:
 191                 spr_val = kvmppc_get_dec(vcpu, get_tb());
 192                 break;
 193         default:
 194                 emulated = kvmppc_core_emulate_mfspr(vcpu, sprn,
 195                                                      &spr_val);
 196                 if (unlikely(emulated == EMULATE_FAIL)) {
 197                         printk(KERN_INFO "mfspr: unknown spr "
 198                                 "0x%x\n", sprn);
 199                 }
 200                 break;
 201         }
 202
 203         if (emulated == EMULATE_DONE)
 204                 kvmppc_set_gpr(vcpu, rt, spr_val);
 205         kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
 206
 207         return emulated;
 208 }
 209
 210 /* XXX to do:
 211  * lhax
 212  * lhaux
 213  * lswx
 214  * lswi
 215  * stswx
 216  * stswi
 217  * lha
 218  * lhau
 219  * lmw
 220  * stmw
 221  *
 222  * XXX is_bigendian should depend on MMU mapping or MSR[LE]
 223  */
 224 /* XXX Should probably auto-generate instruction decoding for a particular core
 225  * from opcode tables in the future. */
 226 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
 227 {
 228         u32 inst = kvmppc_get_last_inst(vcpu);
 229         int ra = get_ra(inst);
 230         int rs = get_rs(inst);
 231         int rt = get_rt(inst);
 232         int sprn = get_sprn(inst);
 233         enum emulation_result emulated = EMULATE_DONE;
 234         int advance = 1;
 235
 236         /* this default type might be overwritten by subcategories */
 237         kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
 238
 239         pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
 240
 241         switch (get_op(inst)) {
 242         case OP_TRAP:
 243 #ifdef CONFIG_PPC_BOOK3S
 244         case OP_TRAP_64:
 245                 kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
 246 #else
 247                 kvmppc_core_queue_program(vcpu,
 248                                           vcpu->arch.shared->esr | ESR_PTR);
 249 #endif
 250                 advance = 0;
 251                 break;
 252
 253         case 31:
 254                 switch (get_xop(inst)) {
 255
 256                 case OP_31_XOP_TRAP:
 257 #ifdef CONFIG_64BIT
 258                 case OP_31_XOP_TRAP_64:
 259 #endif
 260 #ifdef CONFIG_PPC_BOOK3S
 261                         kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
 262 #else
 263                         kvmppc_core_queue_program(vcpu,
 264                                         vcpu->arch.shared->esr | ESR_PTR);
 265 #endif
 266                         advance = 0;
 267                         break;
 268                 case OP_31_XOP_LWZX:
 269                         emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
 270                         break;
 271
 272                 case OP_31_XOP_LBZX:
 273                         emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 274                         break;
 275
 276                 case OP_31_XOP_LBZUX:
 277                         emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 278                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 279                         break;
 280
 281                 case OP_31_XOP_STWX:
 282                         emulated = kvmppc_handle_store(run, vcpu,
 283                                                        kvmppc_get_gpr(vcpu, rs),
 284                                                        4, 1);
 285                         break;
 286
 287                 case OP_31_XOP_STBX:
 288                         emulated = kvmppc_handle_store(run, vcpu,
 289                                                        kvmppc_get_gpr(vcpu, rs),
 290                                                        1, 1);
 291                         break;
 292
 293                 case OP_31_XOP_STBUX:
 294                         emulated = kvmppc_handle_store(run, vcpu,
 295                                                        kvmppc_get_gpr(vcpu, rs),
 296                                                        1, 1);
 297                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 298                         break;
 299
 300                 case OP_31_XOP_LHAX:
 301                         emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
 302                         break;
 303
 304                 case OP_31_XOP_LHZX:
 305                         emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 306                         break;
 307
 308                 case OP_31_XOP_LHZUX:
 309                         emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 310                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 311                         break;
 312
 313                 case OP_31_XOP_MFSPR:
 314                         emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
 315                         break;
 316
 317                 case OP_31_XOP_STHX:
 318                         emulated = kvmppc_handle_store(run, vcpu,
 319                                                        kvmppc_get_gpr(vcpu, rs),
 320                                                        2, 1);
 321                         break;
 322
 323                 case OP_31_XOP_STHUX:
 324                         emulated = kvmppc_handle_store(run, vcpu,
 325                                                        kvmppc_get_gpr(vcpu, rs),
 326                                                        2, 1);
 327                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 328                         break;
 329
 330                 case OP_31_XOP_MTSPR:
 331                         emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
 332                         break;
 333
 334                 case OP_31_XOP_DCBST:
 335                 case OP_31_XOP_DCBF:
 336                 case OP_31_XOP_DCBI:
 337                         /* Do nothing. The guest is performing dcbi because
 338                          * hardware DMA is not snooped by the dcache, but
 339                          * emulated DMA either goes through the dcache as
 340                          * normal writes, or the host kernel has handled dcache
 341                          * coherence. */
 342                         break;
 343
 344                 case OP_31_XOP_LWBRX:
 345                         emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
 346                         break;
 347
 348                 case OP_31_XOP_TLBSYNC:
 349                         break;
 350
 351                 case OP_31_XOP_STWBRX:
 352                         emulated = kvmppc_handle_store(run, vcpu,
 353                                                        kvmppc_get_gpr(vcpu, rs),
 354                                                        4, 0);
 355                         break;
 356
 357                 case OP_31_XOP_LHBRX:
 358                         emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
 359                         break;
 360
 361                 case OP_31_XOP_STHBRX:
 362                         emulated = kvmppc_handle_store(run, vcpu,
 363                                                        kvmppc_get_gpr(vcpu, rs),
 364                                                        2, 0);
 365                         break;
 366
 367                 default:
 368                         /* Attempt core-specific emulation below. */
 369                         emulated = EMULATE_FAIL;
 370                 }
 371                 break;
 372
 373         case OP_LWZ:
 374                 emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
 375                 break;
 376
 377         /* TBD: Add support for other 64 bit load variants like ldu, ldux, ldx etc. */
 378         case OP_LD:
 379                 rt = get_rt(inst);
 380                 emulated = kvmppc_handle_load(run, vcpu, rt, 8, 1);
 381                 break;
 382
 383         case OP_LWZU:
 384                 emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
 385                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 386                 break;
 387
 388         case OP_LBZ:
 389                 emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 390                 break;
 391
 392         case OP_LBZU:
 393                 emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 394                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 395                 break;
 396
 397         case OP_STW:
 398                 emulated = kvmppc_handle_store(run, vcpu,
 399                                                kvmppc_get_gpr(vcpu, rs),
 400                                                4, 1);
 401                 break;
 402
 403         /* TBD: Add support for other 64 bit store variants like stdu, stdux, stdx etc. */
 404         case OP_STD:
 405                 rs = get_rs(inst);
 406                 emulated = kvmppc_handle_store(run, vcpu,
 407                                                kvmppc_get_gpr(vcpu, rs),
 408                                                8, 1);
 409                 break;
 410
 411         case OP_STWU:
 412                 emulated = kvmppc_handle_store(run, vcpu,
 413                                                kvmppc_get_gpr(vcpu, rs),
 414                                                4, 1);
 415                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 416                 break;
 417
 418         case OP_STB:
 419                 emulated = kvmppc_handle_store(run, vcpu,
 420                                                kvmppc_get_gpr(vcpu, rs),
 421                                                1, 1);
 422                 break;
 423
 424         case OP_STBU:
 425                 emulated = kvmppc_handle_store(run, vcpu,
 426                                                kvmppc_get_gpr(vcpu, rs),
 427                                                1, 1);
 428                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 429                 break;
 430
 431         case OP_LHZ:
 432                 emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 433                 break;
 434
 435         case OP_LHZU:
 436                 emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 437                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 438                 break;
 439
 440         case OP_LHA:
 441                 emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
 442                 break;
 443
 444         case OP_LHAU:
 445                 emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
 446                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 447                 break;
 448
 449         case OP_STH:
 450                 emulated = kvmppc_handle_store(run, vcpu,
 451                                                kvmppc_get_gpr(vcpu, rs),
 452                                                2, 1);
 453                 break;
 454
 455         case OP_STHU:
 456                 emulated = kvmppc_handle_store(run, vcpu,
 457                                                kvmppc_get_gpr(vcpu, rs),
 458                                                2, 1);
 459                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 460                 break;
 461
 462         default:
 463                 emulated = EMULATE_FAIL;
 464         }
 465
 466         if (emulated == EMULATE_FAIL) {
 467                 emulated = kvmppc_core_emulate_op(run, vcpu, inst, &advance);
 468                 if (emulated == EMULATE_AGAIN) {
 469                         advance = 0;
 470                 } else if (emulated == EMULATE_FAIL) {
 471                         advance = 0;
 472                         printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
 473                                "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
 474                         kvmppc_core_queue_program(vcpu, 0);
 475                 }
 476         }
 477
 478         trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
 479
 480         /* Advance past emulated instruction. */
 481         if (advance)
 482                 kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
 483
 484         return emulated;
 485 }