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