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[~andy/linux] / arch / powerpc / kvm / book3s_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 SUSE Linux Products GmbH 2009
16  *
17  * Authors: Alexander Graf <agraf@suse.de>
18  */
19
20 #include <asm/kvm_ppc.h>
21 #include <asm/disassemble.h>
22 #include <asm/kvm_book3s.h>
23 #include <asm/reg.h>
24 #include <asm/switch_to.h>
25 #include <asm/time.h>
26
27 #define OP_19_XOP_RFID          18
28 #define OP_19_XOP_RFI           50
29
30 #define OP_31_XOP_MFMSR         83
31 #define OP_31_XOP_MTMSR         146
32 #define OP_31_XOP_MTMSRD        178
33 #define OP_31_XOP_MTSR          210
34 #define OP_31_XOP_MTSRIN        242
35 #define OP_31_XOP_TLBIEL        274
36 #define OP_31_XOP_TLBIE         306
37 /* Opcode is officially reserved, reuse it as sc 1 when sc 1 doesn't trap */
38 #define OP_31_XOP_FAKE_SC1      308
39 #define OP_31_XOP_SLBMTE        402
40 #define OP_31_XOP_SLBIE         434
41 #define OP_31_XOP_SLBIA         498
42 #define OP_31_XOP_MFSR          595
43 #define OP_31_XOP_MFSRIN        659
44 #define OP_31_XOP_DCBA          758
45 #define OP_31_XOP_SLBMFEV       851
46 #define OP_31_XOP_EIOIO         854
47 #define OP_31_XOP_SLBMFEE       915
48
49 /* DCBZ is actually 1014, but we patch it to 1010 so we get a trap */
50 #define OP_31_XOP_DCBZ          1010
51
52 #define OP_LFS                  48
53 #define OP_LFD                  50
54 #define OP_STFS                 52
55 #define OP_STFD                 54
56
57 #define SPRN_GQR0               912
58 #define SPRN_GQR1               913
59 #define SPRN_GQR2               914
60 #define SPRN_GQR3               915
61 #define SPRN_GQR4               916
62 #define SPRN_GQR5               917
63 #define SPRN_GQR6               918
64 #define SPRN_GQR7               919
65
66 /* Book3S_32 defines mfsrin(v) - but that messes up our abstract
67  * function pointers, so let's just disable the define. */
68 #undef mfsrin
69
70 enum priv_level {
71         PRIV_PROBLEM = 0,
72         PRIV_SUPER = 1,
73         PRIV_HYPER = 2,
74 };
75
76 static bool spr_allowed(struct kvm_vcpu *vcpu, enum priv_level level)
77 {
78         /* PAPR VMs only access supervisor SPRs */
79         if (vcpu->arch.papr_enabled && (level > PRIV_SUPER))
80                 return false;
81
82         /* Limit user space to its own small SPR set */
83         if ((vcpu->arch.shared->msr & MSR_PR) && level > PRIV_PROBLEM)
84                 return false;
85
86         return true;
87 }
88
89 int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
90                            unsigned int inst, int *advance)
91 {
92         int emulated = EMULATE_DONE;
93         int rt = get_rt(inst);
94         int rs = get_rs(inst);
95         int ra = get_ra(inst);
96         int rb = get_rb(inst);
97
98         switch (get_op(inst)) {
99         case 19:
100                 switch (get_xop(inst)) {
101                 case OP_19_XOP_RFID:
102                 case OP_19_XOP_RFI:
103                         kvmppc_set_pc(vcpu, vcpu->arch.shared->srr0);
104                         kvmppc_set_msr(vcpu, vcpu->arch.shared->srr1);
105                         *advance = 0;
106                         break;
107
108                 default:
109                         emulated = EMULATE_FAIL;
110                         break;
111                 }
112                 break;
113         case 31:
114                 switch (get_xop(inst)) {
115                 case OP_31_XOP_MFMSR:
116                         kvmppc_set_gpr(vcpu, rt, vcpu->arch.shared->msr);
117                         break;
118                 case OP_31_XOP_MTMSRD:
119                 {
120                         ulong rs_val = kvmppc_get_gpr(vcpu, rs);
121                         if (inst & 0x10000) {
122                                 ulong new_msr = vcpu->arch.shared->msr;
123                                 new_msr &= ~(MSR_RI | MSR_EE);
124                                 new_msr |= rs_val & (MSR_RI | MSR_EE);
125                                 vcpu->arch.shared->msr = new_msr;
126                         } else
127                                 kvmppc_set_msr(vcpu, rs_val);
128                         break;
129                 }
130                 case OP_31_XOP_MTMSR:
131                         kvmppc_set_msr(vcpu, kvmppc_get_gpr(vcpu, rs));
132                         break;
133                 case OP_31_XOP_MFSR:
134                 {
135                         int srnum;
136
137                         srnum = kvmppc_get_field(inst, 12 + 32, 15 + 32);
138                         if (vcpu->arch.mmu.mfsrin) {
139                                 u32 sr;
140                                 sr = vcpu->arch.mmu.mfsrin(vcpu, srnum);
141                                 kvmppc_set_gpr(vcpu, rt, sr);
142                         }
143                         break;
144                 }
145                 case OP_31_XOP_MFSRIN:
146                 {
147                         int srnum;
148
149                         srnum = (kvmppc_get_gpr(vcpu, rb) >> 28) & 0xf;
150                         if (vcpu->arch.mmu.mfsrin) {
151                                 u32 sr;
152                                 sr = vcpu->arch.mmu.mfsrin(vcpu, srnum);
153                                 kvmppc_set_gpr(vcpu, rt, sr);
154                         }
155                         break;
156                 }
157                 case OP_31_XOP_MTSR:
158                         vcpu->arch.mmu.mtsrin(vcpu,
159                                 (inst >> 16) & 0xf,
160                                 kvmppc_get_gpr(vcpu, rs));
161                         break;
162                 case OP_31_XOP_MTSRIN:
163                         vcpu->arch.mmu.mtsrin(vcpu,
164                                 (kvmppc_get_gpr(vcpu, rb) >> 28) & 0xf,
165                                 kvmppc_get_gpr(vcpu, rs));
166                         break;
167                 case OP_31_XOP_TLBIE:
168                 case OP_31_XOP_TLBIEL:
169                 {
170                         bool large = (inst & 0x00200000) ? true : false;
171                         ulong addr = kvmppc_get_gpr(vcpu, rb);
172                         vcpu->arch.mmu.tlbie(vcpu, addr, large);
173                         break;
174                 }
175 #ifdef CONFIG_KVM_BOOK3S_64_PR
176                 case OP_31_XOP_FAKE_SC1:
177                 {
178                         /* SC 1 papr hypercalls */
179                         ulong cmd = kvmppc_get_gpr(vcpu, 3);
180                         int i;
181
182                         if ((vcpu->arch.shared->msr & MSR_PR) ||
183                             !vcpu->arch.papr_enabled) {
184                                 emulated = EMULATE_FAIL;
185                                 break;
186                         }
187
188                         if (kvmppc_h_pr(vcpu, cmd) == EMULATE_DONE)
189                                 break;
190
191                         run->papr_hcall.nr = cmd;
192                         for (i = 0; i < 9; ++i) {
193                                 ulong gpr = kvmppc_get_gpr(vcpu, 4 + i);
194                                 run->papr_hcall.args[i] = gpr;
195                         }
196
197                         emulated = EMULATE_DO_PAPR;
198                         break;
199                 }
200 #endif
201                 case OP_31_XOP_EIOIO:
202                         break;
203                 case OP_31_XOP_SLBMTE:
204                         if (!vcpu->arch.mmu.slbmte)
205                                 return EMULATE_FAIL;
206
207                         vcpu->arch.mmu.slbmte(vcpu,
208                                         kvmppc_get_gpr(vcpu, rs),
209                                         kvmppc_get_gpr(vcpu, rb));
210                         break;
211                 case OP_31_XOP_SLBIE:
212                         if (!vcpu->arch.mmu.slbie)
213                                 return EMULATE_FAIL;
214
215                         vcpu->arch.mmu.slbie(vcpu,
216                                         kvmppc_get_gpr(vcpu, rb));
217                         break;
218                 case OP_31_XOP_SLBIA:
219                         if (!vcpu->arch.mmu.slbia)
220                                 return EMULATE_FAIL;
221
222                         vcpu->arch.mmu.slbia(vcpu);
223                         break;
224                 case OP_31_XOP_SLBMFEE:
225                         if (!vcpu->arch.mmu.slbmfee) {
226                                 emulated = EMULATE_FAIL;
227                         } else {
228                                 ulong t, rb_val;
229
230                                 rb_val = kvmppc_get_gpr(vcpu, rb);
231                                 t = vcpu->arch.mmu.slbmfee(vcpu, rb_val);
232                                 kvmppc_set_gpr(vcpu, rt, t);
233                         }
234                         break;
235                 case OP_31_XOP_SLBMFEV:
236                         if (!vcpu->arch.mmu.slbmfev) {
237                                 emulated = EMULATE_FAIL;
238                         } else {
239                                 ulong t, rb_val;
240
241                                 rb_val = kvmppc_get_gpr(vcpu, rb);
242                                 t = vcpu->arch.mmu.slbmfev(vcpu, rb_val);
243                                 kvmppc_set_gpr(vcpu, rt, t);
244                         }
245                         break;
246                 case OP_31_XOP_DCBA:
247                         /* Gets treated as NOP */
248                         break;
249                 case OP_31_XOP_DCBZ:
250                 {
251                         ulong rb_val = kvmppc_get_gpr(vcpu, rb);
252                         ulong ra_val = 0;
253                         ulong addr, vaddr;
254                         u32 zeros[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
255                         u32 dsisr;
256                         int r;
257
258                         if (ra)
259                                 ra_val = kvmppc_get_gpr(vcpu, ra);
260
261                         addr = (ra_val + rb_val) & ~31ULL;
262                         if (!(vcpu->arch.shared->msr & MSR_SF))
263                                 addr &= 0xffffffff;
264                         vaddr = addr;
265
266                         r = kvmppc_st(vcpu, &addr, 32, zeros, true);
267                         if ((r == -ENOENT) || (r == -EPERM)) {
268                                 struct kvmppc_book3s_shadow_vcpu *svcpu;
269
270                                 svcpu = svcpu_get(vcpu);
271                                 *advance = 0;
272                                 vcpu->arch.shared->dar = vaddr;
273                                 svcpu->fault_dar = vaddr;
274
275                                 dsisr = DSISR_ISSTORE;
276                                 if (r == -ENOENT)
277                                         dsisr |= DSISR_NOHPTE;
278                                 else if (r == -EPERM)
279                                         dsisr |= DSISR_PROTFAULT;
280
281                                 vcpu->arch.shared->dsisr = dsisr;
282                                 svcpu->fault_dsisr = dsisr;
283                                 svcpu_put(svcpu);
284
285                                 kvmppc_book3s_queue_irqprio(vcpu,
286                                         BOOK3S_INTERRUPT_DATA_STORAGE);
287                         }
288
289                         break;
290                 }
291                 default:
292                         emulated = EMULATE_FAIL;
293                 }
294                 break;
295         default:
296                 emulated = EMULATE_FAIL;
297         }
298
299         if (emulated == EMULATE_FAIL)
300                 emulated = kvmppc_emulate_paired_single(run, vcpu);
301
302         return emulated;
303 }
304
305 void kvmppc_set_bat(struct kvm_vcpu *vcpu, struct kvmppc_bat *bat, bool upper,
306                     u32 val)
307 {
308         if (upper) {
309                 /* Upper BAT */
310                 u32 bl = (val >> 2) & 0x7ff;
311                 bat->bepi_mask = (~bl << 17);
312                 bat->bepi = val & 0xfffe0000;
313                 bat->vs = (val & 2) ? 1 : 0;
314                 bat->vp = (val & 1) ? 1 : 0;
315                 bat->raw = (bat->raw & 0xffffffff00000000ULL) | val;
316         } else {
317                 /* Lower BAT */
318                 bat->brpn = val & 0xfffe0000;
319                 bat->wimg = (val >> 3) & 0xf;
320                 bat->pp = val & 3;
321                 bat->raw = (bat->raw & 0x00000000ffffffffULL) | ((u64)val << 32);
322         }
323 }
324
325 static struct kvmppc_bat *kvmppc_find_bat(struct kvm_vcpu *vcpu, int sprn)
326 {
327         struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
328         struct kvmppc_bat *bat;
329
330         switch (sprn) {
331         case SPRN_IBAT0U ... SPRN_IBAT3L:
332                 bat = &vcpu_book3s->ibat[(sprn - SPRN_IBAT0U) / 2];
333                 break;
334         case SPRN_IBAT4U ... SPRN_IBAT7L:
335                 bat = &vcpu_book3s->ibat[4 + ((sprn - SPRN_IBAT4U) / 2)];
336                 break;
337         case SPRN_DBAT0U ... SPRN_DBAT3L:
338                 bat = &vcpu_book3s->dbat[(sprn - SPRN_DBAT0U) / 2];
339                 break;
340         case SPRN_DBAT4U ... SPRN_DBAT7L:
341                 bat = &vcpu_book3s->dbat[4 + ((sprn - SPRN_DBAT4U) / 2)];
342                 break;
343         default:
344                 BUG();
345         }
346
347         return bat;
348 }
349
350 int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
351 {
352         int emulated = EMULATE_DONE;
353
354         switch (sprn) {
355         case SPRN_SDR1:
356                 if (!spr_allowed(vcpu, PRIV_HYPER))
357                         goto unprivileged;
358                 to_book3s(vcpu)->sdr1 = spr_val;
359                 break;
360         case SPRN_DSISR:
361                 vcpu->arch.shared->dsisr = spr_val;
362                 break;
363         case SPRN_DAR:
364                 vcpu->arch.shared->dar = spr_val;
365                 break;
366         case SPRN_HIOR:
367                 to_book3s(vcpu)->hior = spr_val;
368                 break;
369         case SPRN_IBAT0U ... SPRN_IBAT3L:
370         case SPRN_IBAT4U ... SPRN_IBAT7L:
371         case SPRN_DBAT0U ... SPRN_DBAT3L:
372         case SPRN_DBAT4U ... SPRN_DBAT7L:
373         {
374                 struct kvmppc_bat *bat = kvmppc_find_bat(vcpu, sprn);
375
376                 kvmppc_set_bat(vcpu, bat, !(sprn % 2), (u32)spr_val);
377                 /* BAT writes happen so rarely that we're ok to flush
378                  * everything here */
379                 kvmppc_mmu_pte_flush(vcpu, 0, 0);
380                 kvmppc_mmu_flush_segments(vcpu);
381                 break;
382         }
383         case SPRN_HID0:
384                 to_book3s(vcpu)->hid[0] = spr_val;
385                 break;
386         case SPRN_HID1:
387                 to_book3s(vcpu)->hid[1] = spr_val;
388                 break;
389         case SPRN_HID2:
390                 to_book3s(vcpu)->hid[2] = spr_val;
391                 break;
392         case SPRN_HID2_GEKKO:
393                 to_book3s(vcpu)->hid[2] = spr_val;
394                 /* HID2.PSE controls paired single on gekko */
395                 switch (vcpu->arch.pvr) {
396                 case 0x00080200:        /* lonestar 2.0 */
397                 case 0x00088202:        /* lonestar 2.2 */
398                 case 0x70000100:        /* gekko 1.0 */
399                 case 0x00080100:        /* gekko 2.0 */
400                 case 0x00083203:        /* gekko 2.3a */
401                 case 0x00083213:        /* gekko 2.3b */
402                 case 0x00083204:        /* gekko 2.4 */
403                 case 0x00083214:        /* gekko 2.4e (8SE) - retail HW2 */
404                 case 0x00087200:        /* broadway */
405                         if (vcpu->arch.hflags & BOOK3S_HFLAG_NATIVE_PS) {
406                                 /* Native paired singles */
407                         } else if (spr_val & (1 << 29)) { /* HID2.PSE */
408                                 vcpu->arch.hflags |= BOOK3S_HFLAG_PAIRED_SINGLE;
409                                 kvmppc_giveup_ext(vcpu, MSR_FP);
410                         } else {
411                                 vcpu->arch.hflags &= ~BOOK3S_HFLAG_PAIRED_SINGLE;
412                         }
413                         break;
414                 }
415                 break;
416         case SPRN_HID4:
417         case SPRN_HID4_GEKKO:
418                 to_book3s(vcpu)->hid[4] = spr_val;
419                 break;
420         case SPRN_HID5:
421                 to_book3s(vcpu)->hid[5] = spr_val;
422                 /* guest HID5 set can change is_dcbz32 */
423                 if (vcpu->arch.mmu.is_dcbz32(vcpu) &&
424                     (mfmsr() & MSR_HV))
425                         vcpu->arch.hflags |= BOOK3S_HFLAG_DCBZ32;
426                 break;
427         case SPRN_PURR:
428                 to_book3s(vcpu)->purr_offset = spr_val - get_tb();
429                 break;
430         case SPRN_SPURR:
431                 to_book3s(vcpu)->spurr_offset = spr_val - get_tb();
432                 break;
433         case SPRN_GQR0:
434         case SPRN_GQR1:
435         case SPRN_GQR2:
436         case SPRN_GQR3:
437         case SPRN_GQR4:
438         case SPRN_GQR5:
439         case SPRN_GQR6:
440         case SPRN_GQR7:
441                 to_book3s(vcpu)->gqr[sprn - SPRN_GQR0] = spr_val;
442                 break;
443         case SPRN_ICTC:
444         case SPRN_THRM1:
445         case SPRN_THRM2:
446         case SPRN_THRM3:
447         case SPRN_CTRLF:
448         case SPRN_CTRLT:
449         case SPRN_L2CR:
450         case SPRN_DSCR:
451         case SPRN_MMCR0_GEKKO:
452         case SPRN_MMCR1_GEKKO:
453         case SPRN_PMC1_GEKKO:
454         case SPRN_PMC2_GEKKO:
455         case SPRN_PMC3_GEKKO:
456         case SPRN_PMC4_GEKKO:
457         case SPRN_WPAR_GEKKO:
458         case SPRN_MSSSR0:
459                 break;
460 unprivileged:
461         default:
462                 printk(KERN_INFO "KVM: invalid SPR write: %d\n", sprn);
463 #ifndef DEBUG_SPR
464                 emulated = EMULATE_FAIL;
465 #endif
466                 break;
467         }
468
469         return emulated;
470 }
471
472 int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val)
473 {
474         int emulated = EMULATE_DONE;
475
476         switch (sprn) {
477         case SPRN_IBAT0U ... SPRN_IBAT3L:
478         case SPRN_IBAT4U ... SPRN_IBAT7L:
479         case SPRN_DBAT0U ... SPRN_DBAT3L:
480         case SPRN_DBAT4U ... SPRN_DBAT7L:
481         {
482                 struct kvmppc_bat *bat = kvmppc_find_bat(vcpu, sprn);
483
484                 if (sprn % 2)
485                         *spr_val = bat->raw >> 32;
486                 else
487                         *spr_val = bat->raw;
488
489                 break;
490         }
491         case SPRN_SDR1:
492                 if (!spr_allowed(vcpu, PRIV_HYPER))
493                         goto unprivileged;
494                 *spr_val = to_book3s(vcpu)->sdr1;
495                 break;
496         case SPRN_DSISR:
497                 *spr_val = vcpu->arch.shared->dsisr;
498                 break;
499         case SPRN_DAR:
500                 *spr_val = vcpu->arch.shared->dar;
501                 break;
502         case SPRN_HIOR:
503                 *spr_val = to_book3s(vcpu)->hior;
504                 break;
505         case SPRN_HID0:
506                 *spr_val = to_book3s(vcpu)->hid[0];
507                 break;
508         case SPRN_HID1:
509                 *spr_val = to_book3s(vcpu)->hid[1];
510                 break;
511         case SPRN_HID2:
512         case SPRN_HID2_GEKKO:
513                 *spr_val = to_book3s(vcpu)->hid[2];
514                 break;
515         case SPRN_HID4:
516         case SPRN_HID4_GEKKO:
517                 *spr_val = to_book3s(vcpu)->hid[4];
518                 break;
519         case SPRN_HID5:
520                 *spr_val = to_book3s(vcpu)->hid[5];
521                 break;
522         case SPRN_CFAR:
523         case SPRN_DSCR:
524                 *spr_val = 0;
525                 break;
526         case SPRN_PURR:
527                 *spr_val = get_tb() + to_book3s(vcpu)->purr_offset;
528                 break;
529         case SPRN_SPURR:
530                 *spr_val = get_tb() + to_book3s(vcpu)->purr_offset;
531                 break;
532         case SPRN_GQR0:
533         case SPRN_GQR1:
534         case SPRN_GQR2:
535         case SPRN_GQR3:
536         case SPRN_GQR4:
537         case SPRN_GQR5:
538         case SPRN_GQR6:
539         case SPRN_GQR7:
540                 *spr_val = to_book3s(vcpu)->gqr[sprn - SPRN_GQR0];
541                 break;
542         case SPRN_THRM1:
543         case SPRN_THRM2:
544         case SPRN_THRM3:
545         case SPRN_CTRLF:
546         case SPRN_CTRLT:
547         case SPRN_L2CR:
548         case SPRN_MMCR0_GEKKO:
549         case SPRN_MMCR1_GEKKO:
550         case SPRN_PMC1_GEKKO:
551         case SPRN_PMC2_GEKKO:
552         case SPRN_PMC3_GEKKO:
553         case SPRN_PMC4_GEKKO:
554         case SPRN_WPAR_GEKKO:
555         case SPRN_MSSSR0:
556                 *spr_val = 0;
557                 break;
558         default:
559 unprivileged:
560                 printk(KERN_INFO "KVM: invalid SPR read: %d\n", sprn);
561 #ifndef DEBUG_SPR
562                 emulated = EMULATE_FAIL;
563 #endif
564                 break;
565         }
566
567         return emulated;
568 }
569
570 u32 kvmppc_alignment_dsisr(struct kvm_vcpu *vcpu, unsigned int inst)
571 {
572         u32 dsisr = 0;
573
574         /*
575          * This is what the spec says about DSISR bits (not mentioned = 0):
576          *
577          * 12:13                [DS]    Set to bits 30:31
578          * 15:16                [X]     Set to bits 29:30
579          * 17                   [X]     Set to bit 25
580          *                      [D/DS]  Set to bit 5
581          * 18:21                [X]     Set to bits 21:24
582          *                      [D/DS]  Set to bits 1:4
583          * 22:26                        Set to bits 6:10 (RT/RS/FRT/FRS)
584          * 27:31                        Set to bits 11:15 (RA)
585          */
586
587         switch (get_op(inst)) {
588         /* D-form */
589         case OP_LFS:
590         case OP_LFD:
591         case OP_STFD:
592         case OP_STFS:
593                 dsisr |= (inst >> 12) & 0x4000; /* bit 17 */
594                 dsisr |= (inst >> 17) & 0x3c00; /* bits 18:21 */
595                 break;
596         /* X-form */
597         case 31:
598                 dsisr |= (inst << 14) & 0x18000; /* bits 15:16 */
599                 dsisr |= (inst << 8)  & 0x04000; /* bit 17 */
600                 dsisr |= (inst << 3)  & 0x03c00; /* bits 18:21 */
601                 break;
602         default:
603                 printk(KERN_INFO "KVM: Unaligned instruction 0x%x\n", inst);
604                 break;
605         }
606
607         dsisr |= (inst >> 16) & 0x03ff; /* bits 22:31 */
608
609         return dsisr;
610 }
611
612 ulong kvmppc_alignment_dar(struct kvm_vcpu *vcpu, unsigned int inst)
613 {
614         ulong dar = 0;
615         ulong ra = get_ra(inst);
616         ulong rb = get_rb(inst);
617
618         switch (get_op(inst)) {
619         case OP_LFS:
620         case OP_LFD:
621         case OP_STFD:
622         case OP_STFS:
623                 if (ra)
624                         dar = kvmppc_get_gpr(vcpu, ra);
625                 dar += (s32)((s16)inst);
626                 break;
627         case 31:
628                 if (ra)
629                         dar = kvmppc_get_gpr(vcpu, ra);
630                 dar += kvmppc_get_gpr(vcpu, rb);
631                 break;
632         default:
633                 printk(KERN_INFO "KVM: Unaligned instruction 0x%x\n", inst);
634                 break;
635         }
636
637         return dar;
638 }