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 = vcpu->kvm->arch.kvm_ops->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 = vcpu->kvm->arch.kvm_ops->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  */
 223 /* XXX Should probably auto-generate instruction decoding for a particular core
 224  * from opcode tables in the future. */
 225 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
 226 {
 227         u32 inst = kvmppc_get_last_inst(vcpu);
 228         int ra = get_ra(inst);
 229         int rs = get_rs(inst);
 230         int rt = get_rt(inst);
 231         int sprn = get_sprn(inst);
 232         enum emulation_result emulated = EMULATE_DONE;
 233         int advance = 1;
 234
 235         /* this default type might be overwritten by subcategories */
 236         kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
 237
 238         pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
 239
 240         switch (get_op(inst)) {
 241         case OP_TRAP:
 242 #ifdef CONFIG_PPC_BOOK3S
 243         case OP_TRAP_64:
 244                 kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
 245 #else
 246                 kvmppc_core_queue_program(vcpu,
 247                                           vcpu->arch.shared->esr | ESR_PTR);
 248 #endif
 249                 advance = 0;
 250                 break;
 251
 252         case 31:
 253                 switch (get_xop(inst)) {
 254
 255                 case OP_31_XOP_TRAP:
 256 #ifdef CONFIG_64BIT
 257                 case OP_31_XOP_TRAP_64:
 258 #endif
 259 #ifdef CONFIG_PPC_BOOK3S
 260                         kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
 261 #else
 262                         kvmppc_core_queue_program(vcpu,
 263                                         vcpu->arch.shared->esr | ESR_PTR);
 264 #endif
 265                         advance = 0;
 266                         break;
 267                 case OP_31_XOP_LWZX:
 268                         emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
 269                         break;
 270
 271                 case OP_31_XOP_LBZX:
 272                         emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 273                         break;
 274
 275                 case OP_31_XOP_LBZUX:
 276                         emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 277                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 278                         break;
 279
 280                 case OP_31_XOP_STWX:
 281                         emulated = kvmppc_handle_store(run, vcpu,
 282                                                        kvmppc_get_gpr(vcpu, rs),
 283                                                        4, 1);
 284                         break;
 285
 286                 case OP_31_XOP_STBX:
 287                         emulated = kvmppc_handle_store(run, vcpu,
 288                                                        kvmppc_get_gpr(vcpu, rs),
 289                                                        1, 1);
 290                         break;
 291
 292                 case OP_31_XOP_STBUX:
 293                         emulated = kvmppc_handle_store(run, vcpu,
 294                                                        kvmppc_get_gpr(vcpu, rs),
 295                                                        1, 1);
 296                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 297                         break;
 298
 299                 case OP_31_XOP_LHAX:
 300                         emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
 301                         break;
 302
 303                 case OP_31_XOP_LHZX:
 304                         emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 305                         break;
 306
 307                 case OP_31_XOP_LHZUX:
 308                         emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 309                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 310                         break;
 311
 312                 case OP_31_XOP_MFSPR:
 313                         emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
 314                         break;
 315
 316                 case OP_31_XOP_STHX:
 317                         emulated = kvmppc_handle_store(run, vcpu,
 318                                                        kvmppc_get_gpr(vcpu, rs),
 319                                                        2, 1);
 320                         break;
 321
 322                 case OP_31_XOP_STHUX:
 323                         emulated = kvmppc_handle_store(run, vcpu,
 324                                                        kvmppc_get_gpr(vcpu, rs),
 325                                                        2, 1);
 326                         kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 327                         break;
 328
 329                 case OP_31_XOP_MTSPR:
 330                         emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
 331                         break;
 332
 333                 case OP_31_XOP_DCBST:
 334                 case OP_31_XOP_DCBF:
 335                 case OP_31_XOP_DCBI:
 336                         /* Do nothing. The guest is performing dcbi because
 337                          * hardware DMA is not snooped by the dcache, but
 338                          * emulated DMA either goes through the dcache as
 339                          * normal writes, or the host kernel has handled dcache
 340                          * coherence. */
 341                         break;
 342
 343                 case OP_31_XOP_LWBRX:
 344                         emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
 345                         break;
 346
 347                 case OP_31_XOP_TLBSYNC:
 348                         break;
 349
 350                 case OP_31_XOP_STWBRX:
 351                         emulated = kvmppc_handle_store(run, vcpu,
 352                                                        kvmppc_get_gpr(vcpu, rs),
 353                                                        4, 0);
 354                         break;
 355
 356                 case OP_31_XOP_LHBRX:
 357                         emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
 358                         break;
 359
 360                 case OP_31_XOP_STHBRX:
 361                         emulated = kvmppc_handle_store(run, vcpu,
 362                                                        kvmppc_get_gpr(vcpu, rs),
 363                                                        2, 0);
 364                         break;
 365
 366                 default:
 367                         /* Attempt core-specific emulation below. */
 368                         emulated = EMULATE_FAIL;
 369                 }
 370                 break;
 371
 372         case OP_LWZ:
 373                 emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
 374                 break;
 375
 376         /* TBD: Add support for other 64 bit load variants like ldu, ldux, ldx etc. */
 377         case OP_LD:
 378                 rt = get_rt(inst);
 379                 emulated = kvmppc_handle_load(run, vcpu, rt, 8, 1);
 380                 break;
 381
 382         case OP_LWZU:
 383                 emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
 384                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 385                 break;
 386
 387         case OP_LBZ:
 388                 emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 389                 break;
 390
 391         case OP_LBZU:
 392                 emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
 393                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 394                 break;
 395
 396         case OP_STW:
 397                 emulated = kvmppc_handle_store(run, vcpu,
 398                                                kvmppc_get_gpr(vcpu, rs),
 399                                                4, 1);
 400                 break;
 401
 402         /* TBD: Add support for other 64 bit store variants like stdu, stdux, stdx etc. */
 403         case OP_STD:
 404                 rs = get_rs(inst);
 405                 emulated = kvmppc_handle_store(run, vcpu,
 406                                                kvmppc_get_gpr(vcpu, rs),
 407                                                8, 1);
 408                 break;
 409
 410         case OP_STWU:
 411                 emulated = kvmppc_handle_store(run, vcpu,
 412                                                kvmppc_get_gpr(vcpu, rs),
 413                                                4, 1);
 414                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 415                 break;
 416
 417         case OP_STB:
 418                 emulated = kvmppc_handle_store(run, vcpu,
 419                                                kvmppc_get_gpr(vcpu, rs),
 420                                                1, 1);
 421                 break;
 422
 423         case OP_STBU:
 424                 emulated = kvmppc_handle_store(run, vcpu,
 425                                                kvmppc_get_gpr(vcpu, rs),
 426                                                1, 1);
 427                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 428                 break;
 429
 430         case OP_LHZ:
 431                 emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 432                 break;
 433
 434         case OP_LHZU:
 435                 emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
 436                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 437                 break;
 438
 439         case OP_LHA:
 440                 emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
 441                 break;
 442
 443         case OP_LHAU:
 444                 emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
 445                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 446                 break;
 447
 448         case OP_STH:
 449                 emulated = kvmppc_handle_store(run, vcpu,
 450                                                kvmppc_get_gpr(vcpu, rs),
 451                                                2, 1);
 452                 break;
 453
 454         case OP_STHU:
 455                 emulated = kvmppc_handle_store(run, vcpu,
 456                                                kvmppc_get_gpr(vcpu, rs),
 457                                                2, 1);
 458                 kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 459                 break;
 460
 461         default:
 462                 emulated = EMULATE_FAIL;
 463         }
 464
 465         if (emulated == EMULATE_FAIL) {
 466                 emulated = vcpu->kvm->arch.kvm_ops->emulate_op(run, vcpu, inst,
 467                                                                &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 }
 486 EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);