arch/powerpc/kernel/kvm.c

   1 /*
   2  * Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
   3  *
   4  * Authors:
   5  *     Alexander Graf <agraf@suse.de>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License, version 2, as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  */
  20
  21 #include <linux/kvm_host.h>
  22 #include <linux/init.h>
  23 #include <linux/export.h>
  24 #include <linux/kvm_para.h>
  25 #include <linux/slab.h>
  26 #include <linux/of.h>
  27
  28 #include <asm/reg.h>
  29 #include <asm/sections.h>
  30 #include <asm/cacheflush.h>
  31 #include <asm/disassemble.h>
  32
  33 #define KVM_MAGIC_PAGE          (-4096L)
  34 #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)
  35
  36 #define KVM_INST_LWZ            0x80000000
  37 #define KVM_INST_STW            0x90000000
  38 #define KVM_INST_LD             0xe8000000
  39 #define KVM_INST_STD            0xf8000000
  40 #define KVM_INST_NOP            0x60000000
  41 #define KVM_INST_B              0x48000000
  42 #define KVM_INST_B_MASK         0x03ffffff
  43 #define KVM_INST_B_MAX          0x01ffffff
  44
  45 #define KVM_MASK_RT             0x03e00000
  46 #define KVM_RT_30               0x03c00000
  47 #define KVM_MASK_RB             0x0000f800
  48 #define KVM_INST_MFMSR          0x7c0000a6
  49 #define KVM_INST_MFSPR_SPRG0    0x7c1042a6
  50 #define KVM_INST_MFSPR_SPRG1    0x7c1142a6
  51 #define KVM_INST_MFSPR_SPRG2    0x7c1242a6
  52 #define KVM_INST_MFSPR_SPRG3    0x7c1342a6
  53 #define KVM_INST_MFSPR_SRR0     0x7c1a02a6
  54 #define KVM_INST_MFSPR_SRR1     0x7c1b02a6
  55 #define KVM_INST_MFSPR_DAR      0x7c1302a6
  56 #define KVM_INST_MFSPR_DSISR    0x7c1202a6
  57
  58 #define KVM_INST_MTSPR_SPRG0    0x7c1043a6
  59 #define KVM_INST_MTSPR_SPRG1    0x7c1143a6
  60 #define KVM_INST_MTSPR_SPRG2    0x7c1243a6
  61 #define KVM_INST_MTSPR_SPRG3    0x7c1343a6
  62 #define KVM_INST_MTSPR_SRR0     0x7c1a03a6
  63 #define KVM_INST_MTSPR_SRR1     0x7c1b03a6
  64 #define KVM_INST_MTSPR_DAR      0x7c1303a6
  65 #define KVM_INST_MTSPR_DSISR    0x7c1203a6
  66
  67 #define KVM_INST_TLBSYNC        0x7c00046c
  68 #define KVM_INST_MTMSRD_L0      0x7c000164
  69 #define KVM_INST_MTMSRD_L1      0x7c010164
  70 #define KVM_INST_MTMSR          0x7c000124
  71
  72 #define KVM_INST_WRTEEI_0       0x7c000146
  73 #define KVM_INST_WRTEEI_1       0x7c008146
  74
  75 #define KVM_INST_MTSRIN         0x7c0001e4
  76
  77 static bool kvm_patching_worked = true;
  78 static char kvm_tmp[1024 * 1024];
  79 static int kvm_tmp_index;
  80
  81 static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
  82 {
  83         *inst = new_inst;
  84         flush_icache_range((ulong)inst, (ulong)inst + 4);
  85 }
  86
  87 static void kvm_patch_ins_ll(u32 *inst, long addr, u32 rt)
  88 {
  89 #ifdef CONFIG_64BIT
  90         kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
  91 #else
  92         kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000fffc));
  93 #endif
  94 }
  95
  96 static void kvm_patch_ins_ld(u32 *inst, long addr, u32 rt)
  97 {
  98 #ifdef CONFIG_64BIT
  99         kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
 100 #else
 101         kvm_patch_ins(inst, KVM_INST_LWZ | rt | ((addr + 4) & 0x0000fffc));
 102 #endif
 103 }
 104
 105 static void kvm_patch_ins_lwz(u32 *inst, long addr, u32 rt)
 106 {
 107         kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000ffff));
 108 }
 109
 110 static void kvm_patch_ins_std(u32 *inst, long addr, u32 rt)
 111 {
 112 #ifdef CONFIG_64BIT
 113         kvm_patch_ins(inst, KVM_INST_STD | rt | (addr & 0x0000fffc));
 114 #else
 115         kvm_patch_ins(inst, KVM_INST_STW | rt | ((addr + 4) & 0x0000fffc));
 116 #endif
 117 }
 118
 119 static void kvm_patch_ins_stw(u32 *inst, long addr, u32 rt)
 120 {
 121         kvm_patch_ins(inst, KVM_INST_STW | rt | (addr & 0x0000fffc));
 122 }
 123
 124 static void kvm_patch_ins_nop(u32 *inst)
 125 {
 126         kvm_patch_ins(inst, KVM_INST_NOP);
 127 }
 128
 129 static void kvm_patch_ins_b(u32 *inst, int addr)
 130 {
 131 #if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC_BOOK3S)
 132         /* On relocatable kernels interrupts handlers and our code
 133            can be in different regions, so we don't patch them */
 134
 135         if ((ulong)inst < (ulong)&__end_interrupts)
 136                 return;
 137 #endif
 138
 139         kvm_patch_ins(inst, KVM_INST_B | (addr & KVM_INST_B_MASK));
 140 }
 141
 142 static u32 *kvm_alloc(int len)
 143 {
 144         u32 *p;
 145
 146         if ((kvm_tmp_index + len) > ARRAY_SIZE(kvm_tmp)) {
 147                 printk(KERN_ERR "KVM: No more space (%d + %d)\n",
 148                                 kvm_tmp_index, len);
 149                 kvm_patching_worked = false;
 150                 return NULL;
 151         }
 152
 153         p = (void*)&kvm_tmp[kvm_tmp_index];
 154         kvm_tmp_index += len;
 155
 156         return p;
 157 }
 158
 159 extern u32 kvm_emulate_mtmsrd_branch_offs;
 160 extern u32 kvm_emulate_mtmsrd_reg_offs;
 161 extern u32 kvm_emulate_mtmsrd_orig_ins_offs;
 162 extern u32 kvm_emulate_mtmsrd_len;
 163 extern u32 kvm_emulate_mtmsrd[];
 164
 165 static void kvm_patch_ins_mtmsrd(u32 *inst, u32 rt)
 166 {
 167         u32 *p;
 168         int distance_start;
 169         int distance_end;
 170         ulong next_inst;
 171
 172         p = kvm_alloc(kvm_emulate_mtmsrd_len * 4);
 173         if (!p)
 174                 return;
 175
 176         /* Find out where we are and put everything there */
 177         distance_start = (ulong)p - (ulong)inst;
 178         next_inst = ((ulong)inst + 4);
 179         distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsrd_branch_offs];
 180
 181         /* Make sure we only write valid b instructions */
 182         if (distance_start > KVM_INST_B_MAX) {
 183                 kvm_patching_worked = false;
 184                 return;
 185         }
 186
 187         /* Modify the chunk to fit the invocation */
 188         memcpy(p, kvm_emulate_mtmsrd, kvm_emulate_mtmsrd_len * 4);
 189         p[kvm_emulate_mtmsrd_branch_offs] |= distance_end & KVM_INST_B_MASK;
 190         switch (get_rt(rt)) {
 191         case 30:
 192                 kvm_patch_ins_ll(&p[kvm_emulate_mtmsrd_reg_offs],
 193                                  magic_var(scratch2), KVM_RT_30);
 194                 break;
 195         case 31:
 196                 kvm_patch_ins_ll(&p[kvm_emulate_mtmsrd_reg_offs],
 197                                  magic_var(scratch1), KVM_RT_30);
 198                 break;
 199         default:
 200                 p[kvm_emulate_mtmsrd_reg_offs] |= rt;
 201                 break;
 202         }
 203
 204         p[kvm_emulate_mtmsrd_orig_ins_offs] = *inst;
 205         flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsrd_len * 4);
 206
 207         /* Patch the invocation */
 208         kvm_patch_ins_b(inst, distance_start);
 209 }
 210
 211 extern u32 kvm_emulate_mtmsr_branch_offs;
 212 extern u32 kvm_emulate_mtmsr_reg1_offs;
 213 extern u32 kvm_emulate_mtmsr_reg2_offs;
 214 extern u32 kvm_emulate_mtmsr_orig_ins_offs;
 215 extern u32 kvm_emulate_mtmsr_len;
 216 extern u32 kvm_emulate_mtmsr[];
 217
 218 static void kvm_patch_ins_mtmsr(u32 *inst, u32 rt)
 219 {
 220         u32 *p;
 221         int distance_start;
 222         int distance_end;
 223         ulong next_inst;
 224
 225         p = kvm_alloc(kvm_emulate_mtmsr_len * 4);
 226         if (!p)
 227                 return;
 228
 229         /* Find out where we are and put everything there */
 230         distance_start = (ulong)p - (ulong)inst;
 231         next_inst = ((ulong)inst + 4);
 232         distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsr_branch_offs];
 233
 234         /* Make sure we only write valid b instructions */
 235         if (distance_start > KVM_INST_B_MAX) {
 236                 kvm_patching_worked = false;
 237                 return;
 238         }
 239
 240         /* Modify the chunk to fit the invocation */
 241         memcpy(p, kvm_emulate_mtmsr, kvm_emulate_mtmsr_len * 4);
 242         p[kvm_emulate_mtmsr_branch_offs] |= distance_end & KVM_INST_B_MASK;
 243
 244         /* Make clobbered registers work too */
 245         switch (get_rt(rt)) {
 246         case 30:
 247                 kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
 248                                  magic_var(scratch2), KVM_RT_30);
 249                 kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
 250                                  magic_var(scratch2), KVM_RT_30);
 251                 break;
 252         case 31:
 253                 kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg1_offs],
 254                                  magic_var(scratch1), KVM_RT_30);
 255                 kvm_patch_ins_ll(&p[kvm_emulate_mtmsr_reg2_offs],
 256                                  magic_var(scratch1), KVM_RT_30);
 257                 break;
 258         default:
 259                 p[kvm_emulate_mtmsr_reg1_offs] |= rt;
 260                 p[kvm_emulate_mtmsr_reg2_offs] |= rt;
 261                 break;
 262         }
 263
 264         p[kvm_emulate_mtmsr_orig_ins_offs] = *inst;
 265         flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsr_len * 4);
 266
 267         /* Patch the invocation */
 268         kvm_patch_ins_b(inst, distance_start);
 269 }
 270
 271 #ifdef CONFIG_BOOKE
 272
 273 extern u32 kvm_emulate_wrteei_branch_offs;
 274 extern u32 kvm_emulate_wrteei_ee_offs;
 275 extern u32 kvm_emulate_wrteei_len;
 276 extern u32 kvm_emulate_wrteei[];
 277
 278 static void kvm_patch_ins_wrteei(u32 *inst)
 279 {
 280         u32 *p;
 281         int distance_start;
 282         int distance_end;
 283         ulong next_inst;
 284
 285         p = kvm_alloc(kvm_emulate_wrteei_len * 4);
 286         if (!p)
 287                 return;
 288
 289         /* Find out where we are and put everything there */
 290         distance_start = (ulong)p - (ulong)inst;
 291         next_inst = ((ulong)inst + 4);
 292         distance_end = next_inst - (ulong)&p[kvm_emulate_wrteei_branch_offs];
 293
 294         /* Make sure we only write valid b instructions */
 295         if (distance_start > KVM_INST_B_MAX) {
 296                 kvm_patching_worked = false;
 297                 return;
 298         }
 299
 300         /* Modify the chunk to fit the invocation */
 301         memcpy(p, kvm_emulate_wrteei, kvm_emulate_wrteei_len * 4);
 302         p[kvm_emulate_wrteei_branch_offs] |= distance_end & KVM_INST_B_MASK;
 303         p[kvm_emulate_wrteei_ee_offs] |= (*inst & MSR_EE);
 304         flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrteei_len * 4);
 305
 306         /* Patch the invocation */
 307         kvm_patch_ins_b(inst, distance_start);
 308 }
 309
 310 #endif
 311
 312 #ifdef CONFIG_PPC_BOOK3S_32
 313
 314 extern u32 kvm_emulate_mtsrin_branch_offs;
 315 extern u32 kvm_emulate_mtsrin_reg1_offs;
 316 extern u32 kvm_emulate_mtsrin_reg2_offs;
 317 extern u32 kvm_emulate_mtsrin_orig_ins_offs;
 318 extern u32 kvm_emulate_mtsrin_len;
 319 extern u32 kvm_emulate_mtsrin[];
 320
 321 static void kvm_patch_ins_mtsrin(u32 *inst, u32 rt, u32 rb)
 322 {
 323         u32 *p;
 324         int distance_start;
 325         int distance_end;
 326         ulong next_inst;
 327
 328         p = kvm_alloc(kvm_emulate_mtsrin_len * 4);
 329         if (!p)
 330                 return;
 331
 332         /* Find out where we are and put everything there */
 333         distance_start = (ulong)p - (ulong)inst;
 334         next_inst = ((ulong)inst + 4);
 335         distance_end = next_inst - (ulong)&p[kvm_emulate_mtsrin_branch_offs];
 336
 337         /* Make sure we only write valid b instructions */
 338         if (distance_start > KVM_INST_B_MAX) {
 339                 kvm_patching_worked = false;
 340                 return;
 341         }
 342
 343         /* Modify the chunk to fit the invocation */
 344         memcpy(p, kvm_emulate_mtsrin, kvm_emulate_mtsrin_len * 4);
 345         p[kvm_emulate_mtsrin_branch_offs] |= distance_end & KVM_INST_B_MASK;
 346         p[kvm_emulate_mtsrin_reg1_offs] |= (rb << 10);
 347         p[kvm_emulate_mtsrin_reg2_offs] |= rt;
 348         p[kvm_emulate_mtsrin_orig_ins_offs] = *inst;
 349         flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtsrin_len * 4);
 350
 351         /* Patch the invocation */
 352         kvm_patch_ins_b(inst, distance_start);
 353 }
 354
 355 #endif
 356
 357 static void kvm_map_magic_page(void *data)
 358 {
 359         u32 *features = data;
 360
 361         ulong in[8];
 362         ulong out[8];
 363
 364         in[0] = KVM_MAGIC_PAGE;
 365         in[1] = KVM_MAGIC_PAGE;
 366
 367         kvm_hypercall(in, out, HC_VENDOR_KVM | KVM_HC_PPC_MAP_MAGIC_PAGE);
 368
 369         *features = out[0];
 370 }
 371
 372 static void kvm_check_ins(u32 *inst, u32 features)
 373 {
 374         u32 _inst = *inst;
 375         u32 inst_no_rt = _inst & ~KVM_MASK_RT;
 376         u32 inst_rt = _inst & KVM_MASK_RT;
 377
 378         switch (inst_no_rt) {
 379         /* Loads */
 380         case KVM_INST_MFMSR:
 381                 kvm_patch_ins_ld(inst, magic_var(msr), inst_rt);
 382                 break;
 383         case KVM_INST_MFSPR_SPRG0:
 384                 kvm_patch_ins_ld(inst, magic_var(sprg0), inst_rt);
 385                 break;
 386         case KVM_INST_MFSPR_SPRG1:
 387                 kvm_patch_ins_ld(inst, magic_var(sprg1), inst_rt);
 388                 break;
 389         case KVM_INST_MFSPR_SPRG2:
 390                 kvm_patch_ins_ld(inst, magic_var(sprg2), inst_rt);
 391                 break;
 392         case KVM_INST_MFSPR_SPRG3:
 393                 kvm_patch_ins_ld(inst, magic_var(sprg3), inst_rt);
 394                 break;
 395         case KVM_INST_MFSPR_SRR0:
 396                 kvm_patch_ins_ld(inst, magic_var(srr0), inst_rt);
 397                 break;
 398         case KVM_INST_MFSPR_SRR1:
 399                 kvm_patch_ins_ld(inst, magic_var(srr1), inst_rt);
 400                 break;
 401         case KVM_INST_MFSPR_DAR:
 402                 kvm_patch_ins_ld(inst, magic_var(dar), inst_rt);
 403                 break;
 404         case KVM_INST_MFSPR_DSISR:
 405                 kvm_patch_ins_lwz(inst, magic_var(dsisr), inst_rt);
 406                 break;
 407
 408         /* Stores */
 409         case KVM_INST_MTSPR_SPRG0:
 410                 kvm_patch_ins_std(inst, magic_var(sprg0), inst_rt);
 411                 break;
 412         case KVM_INST_MTSPR_SPRG1:
 413                 kvm_patch_ins_std(inst, magic_var(sprg1), inst_rt);
 414                 break;
 415         case KVM_INST_MTSPR_SPRG2:
 416                 kvm_patch_ins_std(inst, magic_var(sprg2), inst_rt);
 417                 break;
 418         case KVM_INST_MTSPR_SPRG3:
 419                 kvm_patch_ins_std(inst, magic_var(sprg3), inst_rt);
 420                 break;
 421         case KVM_INST_MTSPR_SRR0:
 422                 kvm_patch_ins_std(inst, magic_var(srr0), inst_rt);
 423                 break;
 424         case KVM_INST_MTSPR_SRR1:
 425                 kvm_patch_ins_std(inst, magic_var(srr1), inst_rt);
 426                 break;
 427         case KVM_INST_MTSPR_DAR:
 428                 kvm_patch_ins_std(inst, magic_var(dar), inst_rt);
 429                 break;
 430         case KVM_INST_MTSPR_DSISR:
 431                 kvm_patch_ins_stw(inst, magic_var(dsisr), inst_rt);
 432                 break;
 433
 434         /* Nops */
 435         case KVM_INST_TLBSYNC:
 436                 kvm_patch_ins_nop(inst);
 437                 break;
 438
 439         /* Rewrites */
 440         case KVM_INST_MTMSRD_L1:
 441                 kvm_patch_ins_mtmsrd(inst, inst_rt);
 442                 break;
 443         case KVM_INST_MTMSR:
 444         case KVM_INST_MTMSRD_L0:
 445                 kvm_patch_ins_mtmsr(inst, inst_rt);
 446                 break;
 447         }
 448
 449         switch (inst_no_rt & ~KVM_MASK_RB) {
 450 #ifdef CONFIG_PPC_BOOK3S_32
 451         case KVM_INST_MTSRIN:
 452                 if (features & KVM_MAGIC_FEAT_SR) {
 453                         u32 inst_rb = _inst & KVM_MASK_RB;
 454                         kvm_patch_ins_mtsrin(inst, inst_rt, inst_rb);
 455                 }
 456                 break;
 457                 break;
 458 #endif
 459         }
 460
 461         switch (_inst) {
 462 #ifdef CONFIG_BOOKE
 463         case KVM_INST_WRTEEI_0:
 464         case KVM_INST_WRTEEI_1:
 465                 kvm_patch_ins_wrteei(inst);
 466                 break;
 467 #endif
 468         }
 469 }
 470
 471 static void kvm_use_magic_page(void)
 472 {
 473         u32 *p;
 474         u32 *start, *end;
 475         u32 tmp;
 476         u32 features;
 477
 478         /* Tell the host to map the magic page to -4096 on all CPUs */
 479         on_each_cpu(kvm_map_magic_page, &features, 1);
 480
 481         /* Quick self-test to see if the mapping works */
 482         if (__get_user(tmp, (u32*)KVM_MAGIC_PAGE)) {
 483                 kvm_patching_worked = false;
 484                 return;
 485         }
 486
 487         /* Now loop through all code and find instructions */
 488         start = (void*)_stext;
 489         end = (void*)_etext;
 490
 491         for (p = start; p < end; p++)
 492                 kvm_check_ins(p, features);
 493
 494         printk(KERN_INFO "KVM: Live patching for a fast VM %s\n",
 495                          kvm_patching_worked ? "worked" : "failed");
 496 }
 497
 498 unsigned long kvm_hypercall(unsigned long *in,
 499                             unsigned long *out,
 500                             unsigned long nr)
 501 {
 502         unsigned long register r0 asm("r0");
 503         unsigned long register r3 asm("r3") = in[0];
 504         unsigned long register r4 asm("r4") = in[1];
 505         unsigned long register r5 asm("r5") = in[2];
 506         unsigned long register r6 asm("r6") = in[3];
 507         unsigned long register r7 asm("r7") = in[4];
 508         unsigned long register r8 asm("r8") = in[5];
 509         unsigned long register r9 asm("r9") = in[6];
 510         unsigned long register r10 asm("r10") = in[7];
 511         unsigned long register r11 asm("r11") = nr;
 512         unsigned long register r12 asm("r12");
 513
 514         asm volatile("bl        kvm_hypercall_start"
 515                      : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6),
 516                        "=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11),
 517                        "=r"(r12)
 518                      : "r"(r3), "r"(r4), "r"(r5), "r"(r6), "r"(r7), "r"(r8),
 519                        "r"(r9), "r"(r10), "r"(r11)
 520                      : "memory", "cc", "xer", "ctr", "lr");
 521
 522         out[0] = r4;
 523         out[1] = r5;
 524         out[2] = r6;
 525         out[3] = r7;
 526         out[4] = r8;
 527         out[5] = r9;
 528         out[6] = r10;
 529         out[7] = r11;
 530
 531         return r3;
 532 }
 533 EXPORT_SYMBOL_GPL(kvm_hypercall);
 534
 535 static int kvm_para_setup(void)
 536 {
 537         extern u32 kvm_hypercall_start;
 538         struct device_node *hyper_node;
 539         u32 *insts;
 540         int len, i;
 541
 542         hyper_node = of_find_node_by_path("/hypervisor");
 543         if (!hyper_node)
 544                 return -1;
 545
 546         insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len);
 547         if (len % 4)
 548                 return -1;
 549         if (len > (4 * 4))
 550                 return -1;
 551
 552         for (i = 0; i < (len / 4); i++)
 553                 kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]);
 554
 555         return 0;
 556 }
 557
 558 static __init void kvm_free_tmp(void)
 559 {
 560         unsigned long start, end;
 561
 562         start = (ulong)&kvm_tmp[kvm_tmp_index + (PAGE_SIZE - 1)] & PAGE_MASK;
 563         end = (ulong)&kvm_tmp[ARRAY_SIZE(kvm_tmp)] & PAGE_MASK;
 564
 565         /* Free the tmp space we don't need */
 566         for (; start < end; start += PAGE_SIZE) {
 567                 ClearPageReserved(virt_to_page(start));
 568                 init_page_count(virt_to_page(start));
 569                 free_page(start);
 570                 totalram_pages++;
 571         }
 572 }
 573
 574 static int __init kvm_guest_init(void)
 575 {
 576         if (!kvm_para_available())
 577                 goto free_tmp;
 578
 579         if (kvm_para_setup())
 580                 goto free_tmp;
 581
 582         if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
 583                 kvm_use_magic_page();
 584
 585 #ifdef CONFIG_PPC_BOOK3S_64
 586         /* Enable napping */
 587         powersave_nap = 1;
 588 #endif
 589
 590 free_tmp:
 591         kvm_free_tmp();
 592
 593         return 0;
 594 }
 595
 596 postcore_initcall(kvm_guest_init);