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                 kvmppc_set_srr0(vcpu, spr_val);
 101                 break;
 102         case SPRN_SRR1:
 103                 kvmppc_set_srr1(vcpu, 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                 kvmppc_set_sprg0(vcpu, spr_val);
 118                 break;
 119         case SPRN_SPRG1:
 120                 kvmppc_set_sprg1(vcpu, spr_val);
 121                 break;
 122         case SPRN_SPRG2:
 123                 kvmppc_set_sprg2(vcpu, spr_val);
 124                 break;
 125         case SPRN_SPRG3:
 126                 kvmppc_set_sprg3(vcpu, 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 = kvmppc_get_srr0(vcpu);
 154                 break;
 155         case SPRN_SRR1:
 156                 spr_val = kvmppc_get_srr1(vcpu);
 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 = kvmppc_get_sprg0(vcpu);
 177                 break;
 178         case SPRN_SPRG1:
 179                 spr_val = kvmppc_get_sprg1(vcpu);
 180                 break;
 181         case SPRN_SPRG2:
 182                 spr_val = kvmppc_get_sprg2(vcpu);
 183                 break;
 184         case SPRN_SPRG3:
 185                 spr_val = kvmppc_get_sprg3(vcpu);
 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 Should probably auto-generate instruction decoding for a particular core
 211  * from opcode tables in the future. */
 212 int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
 213 {
 214         u32 inst;
 215         int rs, rt, sprn;
 216         enum emulation_result emulated;
 217         int advance = 1;
 218
 219         /* this default type might be overwritten by subcategories */
 220         kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
 221
 222         emulated = kvmppc_get_last_inst(vcpu, INST_GENERIC, &inst);
 223         if (emulated != EMULATE_DONE)
 224                 return emulated;
 225
 226         pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
 227
 228         rs = get_rs(inst);
 229         rt = get_rt(inst);
 230         sprn = get_sprn(inst);
 231
 232         switch (get_op(inst)) {
 233         case OP_TRAP:
 234 #ifdef CONFIG_PPC_BOOK3S
 235         case OP_TRAP_64:
 236                 kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
 237 #else
 238                 kvmppc_core_queue_program(vcpu,
 239                                           vcpu->arch.shared->esr | ESR_PTR);
 240 #endif
 241                 advance = 0;
 242                 break;
 243
 244         case 31:
 245                 switch (get_xop(inst)) {
 246
 247                 case OP_31_XOP_TRAP:
 248 #ifdef CONFIG_64BIT
 249                 case OP_31_XOP_TRAP_64:
 250 #endif
 251 #ifdef CONFIG_PPC_BOOK3S
 252                         kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
 253 #else
 254                         kvmppc_core_queue_program(vcpu,
 255                                         vcpu->arch.shared->esr | ESR_PTR);
 256 #endif
 257                         advance = 0;
 258                         break;
 259
 260                 case OP_31_XOP_MFSPR:
 261                         emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
 262                         break;
 263
 264                 case OP_31_XOP_MTSPR:
 265                         emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
 266                         break;
 267
 268                 case OP_31_XOP_TLBSYNC:
 269                         break;
 270
 271                 default:
 272                         /* Attempt core-specific emulation below. */
 273                         emulated = EMULATE_FAIL;
 274                 }
 275                 break;
 276
 277         case 0:
 278                 /*
 279                  * Instruction with primary opcode 0. Based on PowerISA
 280                  * these are illegal instructions.
 281                  */
 282                 if (inst == KVMPPC_INST_SW_BREAKPOINT) {
 283                         run->exit_reason = KVM_EXIT_DEBUG;
 284                         run->debug.arch.address = kvmppc_get_pc(vcpu);
 285                         emulated = EMULATE_EXIT_USER;
 286                         advance = 0;
 287                 } else
 288                         emulated = EMULATE_FAIL;
 289
 290                 break;
 291
 292         default:
 293                 emulated = EMULATE_FAIL;
 294         }
 295
 296         if (emulated == EMULATE_FAIL) {
 297                 emulated = vcpu->kvm->arch.kvm_ops->emulate_op(run, vcpu, inst,
 298                                                                &advance);
 299                 if (emulated == EMULATE_AGAIN) {
 300                         advance = 0;
 301                 } else if (emulated == EMULATE_FAIL) {
 302                         advance = 0;
 303                         printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
 304                                "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
 305                 }
 306         }
 307
 308         trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
 309
 310         /* Advance past emulated instruction. */
 311         if (advance)
 312                 kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
 313
 314         return emulated;
 315 }
 316 EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);