LXR linux/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
  37void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
  38{
  39        unsigned long dec_nsec;
  40        unsigned long long dec_time;
  41
  42        pr_debug("mtDEC: %lx\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
  81u32 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
  93static 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 = (u32) 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
 146static 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. */
 212int 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                        if (emulated == EMULATE_AGAIN) {
 263                                emulated = EMULATE_DONE;
 264                                advance = 0;
 265                        }
 266                        break;
 267
 268                case OP_31_XOP_MTSPR:
 269                        emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
 270                        if (emulated == EMULATE_AGAIN) {
 271                                emulated = EMULATE_DONE;
 272                                advance = 0;
 273                        }
 274                        break;
 275
 276                case OP_31_XOP_TLBSYNC:
 277                        break;
 278
 279                default:
 280                        /* Attempt core-specific emulation below. */
 281                        emulated = EMULATE_FAIL;
 282                }
 283                break;
 284
 285        case 0:
 286                /*
 287                 * Instruction with primary opcode 0. Based on PowerISA
 288                 * these are illegal instructions.
 289                 */
 290                if (inst == KVMPPC_INST_SW_BREAKPOINT) {
 291                        run->exit_reason = KVM_EXIT_DEBUG;
 292                        run->debug.arch.address = kvmppc_get_pc(vcpu);
 293                        emulated = EMULATE_EXIT_USER;
 294                        advance = 0;
 295                } else
 296                        emulated = EMULATE_FAIL;
 297
 298                break;
 299
 300        default:
 301                emulated = EMULATE_FAIL;
 302        }
 303
 304        if (emulated == EMULATE_FAIL) {
 305                emulated = vcpu->kvm->arch.kvm_ops->emulate_op(run, vcpu, inst,
 306                                                               &advance);
 307                if (emulated == EMULATE_AGAIN) {
 308                        advance = 0;
 309                } else if (emulated == EMULATE_FAIL) {
 310                        advance = 0;
 311                        printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
 312                               "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
 313                }
 314        }
 315
 316        trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
 317
 318        /* Advance past emulated instruction. */
 319        if (advance)
 320                kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
 321
 322        return emulated;
 323}
 324EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);
 325