hw/i386/kvmvapic.c

   1 /*
   2  * TPR optimization for 32-bit Windows guests (XP and Server 2003)
   3  *
   4  * Copyright (C) 2007-2008 Qumranet Technologies
   5  * Copyright (C) 2012      Jan Kiszka, Siemens AG
   6  *
   7  * This work is licensed under the terms of the GNU GPL version 2, or
   8  * (at your option) any later version. See the COPYING file in the
   9  * top-level directory.
  10  */
  11
  12 #include "qemu/osdep.h"
  13 #include "qemu/module.h"
  14 #include "cpu.h"
  15 #include "sysemu/sysemu.h"
  16 #include "sysemu/cpus.h"
  17 #include "sysemu/hw_accel.h"
  18 #include "sysemu/kvm.h"
  19 #include "hw/i386/apic_internal.h"
  20 #include "hw/sysbus.h"
  21 #include "tcg/tcg.h"
  22
  23 #define VAPIC_IO_PORT           0x7e
  24
  25 #define VAPIC_CPU_SHIFT         7
  26
  27 #define ROM_BLOCK_SIZE          512
  28 #define ROM_BLOCK_MASK          (~(ROM_BLOCK_SIZE - 1))
  29
  30 typedef enum VAPICMode {
  31     VAPIC_INACTIVE = 0,
  32     VAPIC_ACTIVE   = 1,
  33     VAPIC_STANDBY  = 2,
  34 } VAPICMode;
  35
  36 typedef struct VAPICHandlers {
  37     uint32_t set_tpr;
  38     uint32_t set_tpr_eax;
  39     uint32_t get_tpr[8];
  40     uint32_t get_tpr_stack;
  41 } QEMU_PACKED VAPICHandlers;
  42
  43 typedef struct GuestROMState {
  44     char signature[8];
  45     uint32_t vaddr;
  46     uint32_t fixup_start;
  47     uint32_t fixup_end;
  48     uint32_t vapic_vaddr;
  49     uint32_t vapic_size;
  50     uint32_t vcpu_shift;
  51     uint32_t real_tpr_addr;
  52     VAPICHandlers up;
  53     VAPICHandlers mp;
  54 } QEMU_PACKED GuestROMState;
  55
  56 typedef struct VAPICROMState {
  57     SysBusDevice busdev;
  58     MemoryRegion io;
  59     MemoryRegion rom;
  60     uint32_t state;
  61     uint32_t rom_state_paddr;
  62     uint32_t rom_state_vaddr;
  63     uint32_t vapic_paddr;
  64     uint32_t real_tpr_addr;
  65     GuestROMState rom_state;
  66     size_t rom_size;
  67     bool rom_mapped_writable;
  68     VMChangeStateEntry *vmsentry;
  69 } VAPICROMState;
  70
  71 #define TYPE_VAPIC "kvmvapic"
  72 #define VAPIC(obj) OBJECT_CHECK(VAPICROMState, (obj), TYPE_VAPIC)
  73
  74 #define TPR_INSTR_ABS_MODRM             0x1
  75 #define TPR_INSTR_MATCH_MODRM_REG       0x2
  76
  77 typedef struct TPRInstruction {
  78     uint8_t opcode;
  79     uint8_t modrm_reg;
  80     unsigned int flags;
  81     TPRAccess access;
  82     size_t length;
  83     off_t addr_offset;
  84 } TPRInstruction;
  85
  86 /* must be sorted by length, shortest first */
  87 static const TPRInstruction tpr_instr[] = {
  88     { /* mov abs to eax */
  89         .opcode = 0xa1,
  90         .access = TPR_ACCESS_READ,
  91         .length = 5,
  92         .addr_offset = 1,
  93     },
  94     { /* mov eax to abs */
  95         .opcode = 0xa3,
  96         .access = TPR_ACCESS_WRITE,
  97         .length = 5,
  98         .addr_offset = 1,
  99     },
 100     { /* mov r32 to r/m32 */
 101         .opcode = 0x89,
 102         .flags = TPR_INSTR_ABS_MODRM,
 103         .access = TPR_ACCESS_WRITE,
 104         .length = 6,
 105         .addr_offset = 2,
 106     },
 107     { /* mov r/m32 to r32 */
 108         .opcode = 0x8b,
 109         .flags = TPR_INSTR_ABS_MODRM,
 110         .access = TPR_ACCESS_READ,
 111         .length = 6,
 112         .addr_offset = 2,
 113     },
 114     { /* push r/m32 */
 115         .opcode = 0xff,
 116         .modrm_reg = 6,
 117         .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG,
 118         .access = TPR_ACCESS_READ,
 119         .length = 6,
 120         .addr_offset = 2,
 121     },
 122     { /* mov imm32, r/m32 (c7/0) */
 123         .opcode = 0xc7,
 124         .modrm_reg = 0,
 125         .flags = TPR_INSTR_ABS_MODRM | TPR_INSTR_MATCH_MODRM_REG,
 126         .access = TPR_ACCESS_WRITE,
 127         .length = 10,
 128         .addr_offset = 2,
 129     },
 130 };
 131
 132 static void read_guest_rom_state(VAPICROMState *s)
 133 {
 134     cpu_physical_memory_read(s->rom_state_paddr, &s->rom_state,
 135                              sizeof(GuestROMState));
 136 }
 137
 138 static void write_guest_rom_state(VAPICROMState *s)
 139 {
 140     cpu_physical_memory_write(s->rom_state_paddr, &s->rom_state,
 141                               sizeof(GuestROMState));
 142 }
 143
 144 static void update_guest_rom_state(VAPICROMState *s)
 145 {
 146     read_guest_rom_state(s);
 147
 148     s->rom_state.real_tpr_addr = cpu_to_le32(s->real_tpr_addr);
 149     s->rom_state.vcpu_shift = cpu_to_le32(VAPIC_CPU_SHIFT);
 150
 151     write_guest_rom_state(s);
 152 }
 153
 154 static int find_real_tpr_addr(VAPICROMState *s, CPUX86State *env)
 155 {
 156     CPUState *cs = env_cpu(env);
 157     hwaddr paddr;
 158     target_ulong addr;
 159
 160     if (s->state == VAPIC_ACTIVE) {
 161         return 0;
 162     }
 163     /*
 164      * If there is no prior TPR access instruction we could analyze (which is
 165      * the case after resume from hibernation), we need to scan the possible
 166      * virtual address space for the APIC mapping.
 167      */
 168     for (addr = 0xfffff000; addr >= 0x80000000; addr -= TARGET_PAGE_SIZE) {
 169         paddr = cpu_get_phys_page_debug(cs, addr);
 170         if (paddr != APIC_DEFAULT_ADDRESS) {
 171             continue;
 172         }
 173         s->real_tpr_addr = addr + 0x80;
 174         update_guest_rom_state(s);
 175         return 0;
 176     }
 177     return -1;
 178 }
 179
 180 static uint8_t modrm_reg(uint8_t modrm)
 181 {
 182     return (modrm >> 3) & 7;
 183 }
 184
 185 static bool is_abs_modrm(uint8_t modrm)
 186 {
 187     return (modrm & 0xc7) == 0x05;
 188 }
 189
 190 static bool opcode_matches(uint8_t *opcode, const TPRInstruction *instr)
 191 {
 192     return opcode[0] == instr->opcode &&
 193         (!(instr->flags & TPR_INSTR_ABS_MODRM) || is_abs_modrm(opcode[1])) &&
 194         (!(instr->flags & TPR_INSTR_MATCH_MODRM_REG) ||
 195          modrm_reg(opcode[1]) == instr->modrm_reg);
 196 }
 197
 198 static int evaluate_tpr_instruction(VAPICROMState *s, X86CPU *cpu,
 199                                     target_ulong *pip, TPRAccess access)
 200 {
 201     CPUState *cs = CPU(cpu);
 202     const TPRInstruction *instr;
 203     target_ulong ip = *pip;
 204     uint8_t opcode[2];
 205     uint32_t real_tpr_addr;
 206     int i;
 207
 208     if ((ip & 0xf0000000ULL) != 0x80000000ULL &&
 209         (ip & 0xf0000000ULL) != 0xe0000000ULL) {
 210         return -1;
 211     }
 212
 213     /*
 214      * Early Windows 2003 SMP initialization contains a
 215      *
 216      *   mov imm32, r/m32
 217      *
 218      * instruction that is patched by TPR optimization. The problem is that
 219      * RSP, used by the patched instruction, is zero, so the guest gets a
 220      * double fault and dies.
 221      */
 222     if (cpu->env.regs[R_ESP] == 0) {
 223         return -1;
 224     }
 225
 226     if (kvm_enabled() && !kvm_irqchip_in_kernel()) {
 227         /*
 228          * KVM without kernel-based TPR access reporting will pass an IP that
 229          * points after the accessing instruction. So we need to look backward
 230          * to find the reason.
 231          */
 232         for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) {
 233             instr = &tpr_instr[i];
 234             if (instr->access != access) {
 235                 continue;
 236             }
 237             if (cpu_memory_rw_debug(cs, ip - instr->length, opcode,
 238                                     sizeof(opcode), 0) < 0) {
 239                 return -1;
 240             }
 241             if (opcode_matches(opcode, instr)) {
 242                 ip -= instr->length;
 243                 goto instruction_ok;
 244             }
 245         }
 246         return -1;
 247     } else {
 248         if (cpu_memory_rw_debug(cs, ip, opcode, sizeof(opcode), 0) < 0) {
 249             return -1;
 250         }
 251         for (i = 0; i < ARRAY_SIZE(tpr_instr); i++) {
 252             instr = &tpr_instr[i];
 253             if (opcode_matches(opcode, instr)) {
 254                 goto instruction_ok;
 255             }
 256         }
 257         return -1;
 258     }
 259
 260 instruction_ok:
 261     /*
 262      * Grab the virtual TPR address from the instruction
 263      * and update the cached values.
 264      */
 265     if (cpu_memory_rw_debug(cs, ip + instr->addr_offset,
 266                             (void *)&real_tpr_addr,
 267                             sizeof(real_tpr_addr), 0) < 0) {
 268         return -1;
 269     }
 270     real_tpr_addr = le32_to_cpu(real_tpr_addr);
 271     if ((real_tpr_addr & 0xfff) != 0x80) {
 272         return -1;
 273     }
 274     s->real_tpr_addr = real_tpr_addr;
 275     update_guest_rom_state(s);
 276
 277     *pip = ip;
 278     return 0;
 279 }
 280
 281 static int update_rom_mapping(VAPICROMState *s, CPUX86State *env, target_ulong ip)
 282 {
 283     CPUState *cs = env_cpu(env);
 284     hwaddr paddr;
 285     uint32_t rom_state_vaddr;
 286     uint32_t pos, patch, offset;
 287
 288     /* nothing to do if already activated */
 289     if (s->state == VAPIC_ACTIVE) {
 290         return 0;
 291     }
 292
 293     /* bail out if ROM init code was not executed (missing ROM?) */
 294     if (s->state == VAPIC_INACTIVE) {
 295         return -1;
 296     }
 297
 298     /* find out virtual address of the ROM */
 299     rom_state_vaddr = s->rom_state_paddr + (ip & 0xf0000000);
 300     paddr = cpu_get_phys_page_debug(cs, rom_state_vaddr);
 301     if (paddr == -1) {
 302         return -1;
 303     }
 304     paddr += rom_state_vaddr & ~TARGET_PAGE_MASK;
 305     if (paddr != s->rom_state_paddr) {
 306         return -1;
 307     }
 308     read_guest_rom_state(s);
 309     if (memcmp(s->rom_state.signature, "kvm aPiC", 8) != 0) {
 310         return -1;
 311     }
 312     s->rom_state_vaddr = rom_state_vaddr;
 313
 314     /* fixup addresses in ROM if needed */
 315     if (rom_state_vaddr == le32_to_cpu(s->rom_state.vaddr)) {
 316         return 0;
 317     }
 318     for (pos = le32_to_cpu(s->rom_state.fixup_start);
 319          pos < le32_to_cpu(s->rom_state.fixup_end);
 320          pos += 4) {
 321         cpu_physical_memory_read(paddr + pos - s->rom_state.vaddr,
 322                                  &offset, sizeof(offset));
 323         offset = le32_to_cpu(offset);
 324         cpu_physical_memory_read(paddr + offset, &patch, sizeof(patch));
 325         patch = le32_to_cpu(patch);
 326         patch += rom_state_vaddr - le32_to_cpu(s->rom_state.vaddr);
 327         patch = cpu_to_le32(patch);
 328         cpu_physical_memory_write(paddr + offset, &patch, sizeof(patch));
 329     }
 330     read_guest_rom_state(s);
 331     s->vapic_paddr = paddr + le32_to_cpu(s->rom_state.vapic_vaddr) -
 332         le32_to_cpu(s->rom_state.vaddr);
 333
 334     return 0;
 335 }
 336
 337 /*
 338  * Tries to read the unique processor number from the Kernel Processor Control
 339  * Region (KPCR) of 32-bit Windows XP and Server 2003. Returns -1 if the KPCR
 340  * cannot be accessed or is considered invalid. This also ensures that we are
 341  * not patching the wrong guest.
 342  */
 343 static int get_kpcr_number(X86CPU *cpu)
 344 {
 345     CPUX86State *env = &cpu->env;
 346     struct kpcr {
 347         uint8_t  fill1[0x1c];
 348         uint32_t self;
 349         uint8_t  fill2[0x31];
 350         uint8_t  number;
 351     } QEMU_PACKED kpcr;
 352
 353     if (cpu_memory_rw_debug(CPU(cpu), env->segs[R_FS].base,
 354                             (void *)&kpcr, sizeof(kpcr), 0) < 0 ||
 355         kpcr.self != env->segs[R_FS].base) {
 356         return -1;
 357     }
 358     return kpcr.number;
 359 }
 360
 361 static int vapic_enable(VAPICROMState *s, X86CPU *cpu)
 362 {
 363     int cpu_number = get_kpcr_number(cpu);
 364     hwaddr vapic_paddr;
 365     static const uint8_t enabled = 1;
 366
 367     if (cpu_number < 0) {
 368         return -1;
 369     }
 370     vapic_paddr = s->vapic_paddr +
 371         (((hwaddr)cpu_number) << VAPIC_CPU_SHIFT);
 372     cpu_physical_memory_write(vapic_paddr + offsetof(VAPICState, enabled),
 373                               &enabled, sizeof(enabled));
 374     apic_enable_vapic(cpu->apic_state, vapic_paddr);
 375
 376     s->state = VAPIC_ACTIVE;
 377
 378     return 0;
 379 }
 380
 381 static void patch_byte(X86CPU *cpu, target_ulong addr, uint8_t byte)
 382 {
 383     cpu_memory_rw_debug(CPU(cpu), addr, &byte, 1, 1);
 384 }
 385
 386 static void patch_call(X86CPU *cpu, target_ulong ip, uint32_t target)
 387 {
 388     uint32_t offset;
 389
 390     offset = cpu_to_le32(target - ip - 5);
 391     patch_byte(cpu, ip, 0xe8); /* call near */
 392     cpu_memory_rw_debug(CPU(cpu), ip + 1, (void *)&offset, sizeof(offset), 1);
 393 }
 394
 395 typedef struct PatchInfo {
 396     VAPICHandlers *handler;
 397     target_ulong ip;
 398 } PatchInfo;
 399
 400 static void do_patch_instruction(CPUState *cs, run_on_cpu_data data)
 401 {
 402     X86CPU *x86_cpu = X86_CPU(cs);
 403     PatchInfo *info = (PatchInfo *) data.host_ptr;
 404     VAPICHandlers *handlers = info->handler;
 405     target_ulong ip = info->ip;
 406     uint8_t opcode[2];
 407     uint32_t imm32 = 0;
 408
 409     cpu_memory_rw_debug(cs, ip, opcode, sizeof(opcode), 0);
 410
 411     switch (opcode[0]) {
 412     case 0x89: /* mov r32 to r/m32 */
 413         patch_byte(x86_cpu, ip, 0x50 + modrm_reg(opcode[1]));  /* push reg */
 414         patch_call(x86_cpu, ip + 1, handlers->set_tpr);
 415         break;
 416     case 0x8b: /* mov r/m32 to r32 */
 417         patch_byte(x86_cpu, ip, 0x90);
 418         patch_call(x86_cpu, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]);
 419         break;
 420     case 0xa1: /* mov abs to eax */
 421         patch_call(x86_cpu, ip, handlers->get_tpr[0]);
 422         break;
 423     case 0xa3: /* mov eax to abs */
 424         patch_call(x86_cpu, ip, handlers->set_tpr_eax);
 425         break;
 426     case 0xc7: /* mov imm32, r/m32 (c7/0) */
 427         patch_byte(x86_cpu, ip, 0x68);  /* push imm32 */
 428         cpu_memory_rw_debug(cs, ip + 6, (void *)&imm32, sizeof(imm32), 0);
 429         cpu_memory_rw_debug(cs, ip + 1, (void *)&imm32, sizeof(imm32), 1);
 430         patch_call(x86_cpu, ip + 5, handlers->set_tpr);
 431         break;
 432     case 0xff: /* push r/m32 */
 433         patch_byte(x86_cpu, ip, 0x50); /* push eax */
 434         patch_call(x86_cpu, ip + 1, handlers->get_tpr_stack);
 435         break;
 436     default:
 437         abort();
 438     }
 439
 440     g_free(info);
 441 }
 442
 443 static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip)
 444 {
 445     CPUState *cs = CPU(cpu);
 446     VAPICHandlers *handlers;
 447     PatchInfo *info;
 448
 449     if (smp_cpus == 1) {
 450         handlers = &s->rom_state.up;
 451     } else {
 452         handlers = &s->rom_state.mp;
 453     }
 454
 455     info  = g_new(PatchInfo, 1);
 456     info->handler = handlers;
 457     info->ip = ip;
 458
 459     async_safe_run_on_cpu(cs, do_patch_instruction, RUN_ON_CPU_HOST_PTR(info));
 460 }
 461
 462 void vapic_report_tpr_access(DeviceState *dev, CPUState *cs, target_ulong ip,
 463                              TPRAccess access)
 464 {
 465     VAPICROMState *s = VAPIC(dev);
 466     X86CPU *cpu = X86_CPU(cs);
 467     CPUX86State *env = &cpu->env;
 468
 469     cpu_synchronize_state(cs);
 470
 471     if (evaluate_tpr_instruction(s, cpu, &ip, access) < 0) {
 472         if (s->state == VAPIC_ACTIVE) {
 473             vapic_enable(s, cpu);
 474         }
 475         return;
 476     }
 477     if (update_rom_mapping(s, env, ip) < 0) {
 478         return;
 479     }
 480     if (vapic_enable(s, cpu) < 0) {
 481         return;
 482     }
 483     patch_instruction(s, cpu, ip);
 484 }
 485
 486 typedef struct VAPICEnableTPRReporting {
 487     DeviceState *apic;
 488     bool enable;
 489 } VAPICEnableTPRReporting;
 490
 491 static void vapic_do_enable_tpr_reporting(CPUState *cpu, run_on_cpu_data data)
 492 {
 493     VAPICEnableTPRReporting *info = data.host_ptr;
 494     apic_enable_tpr_access_reporting(info->apic, info->enable);
 495 }
 496
 497 static void vapic_enable_tpr_reporting(bool enable)
 498 {
 499     VAPICEnableTPRReporting info = {
 500         .enable = enable,
 501     };
 502     CPUState *cs;
 503     X86CPU *cpu;
 504
 505     CPU_FOREACH(cs) {
 506         cpu = X86_CPU(cs);
 507         info.apic = cpu->apic_state;
 508         run_on_cpu(cs, vapic_do_enable_tpr_reporting, RUN_ON_CPU_HOST_PTR(&info));
 509     }
 510 }
 511
 512 static void vapic_reset(DeviceState *dev)
 513 {
 514     VAPICROMState *s = VAPIC(dev);
 515
 516     s->state = VAPIC_INACTIVE;
 517     s->rom_state_paddr = 0;
 518     vapic_enable_tpr_reporting(false);
 519 }
 520
 521 /*
 522  * Set the IRQ polling hypercalls to the supported variant:
 523  *  - vmcall if using KVM in-kernel irqchip
 524  *  - 32-bit VAPIC port write otherwise
 525  */
 526 static int patch_hypercalls(VAPICROMState *s)
 527 {
 528     hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
 529     static const uint8_t vmcall_pattern[] = { /* vmcall */
 530         0xb8, 0x1, 0, 0, 0, 0xf, 0x1, 0xc1
 531     };
 532     static const uint8_t outl_pattern[] = { /* nop; outl %eax,0x7e */
 533         0xb8, 0x1, 0, 0, 0, 0x90, 0xe7, 0x7e
 534     };
 535     uint8_t alternates[2];
 536     const uint8_t *pattern;
 537     const uint8_t *patch;
 538     off_t pos;
 539     uint8_t *rom;
 540
 541     rom = g_malloc(s->rom_size);
 542     cpu_physical_memory_read(rom_paddr, rom, s->rom_size);
 543
 544     for (pos = 0; pos < s->rom_size - sizeof(vmcall_pattern); pos++) {
 545         if (kvm_irqchip_in_kernel()) {
 546             pattern = outl_pattern;
 547             alternates[0] = outl_pattern[7];
 548             alternates[1] = outl_pattern[7];
 549             patch = &vmcall_pattern[5];
 550         } else {
 551             pattern = vmcall_pattern;
 552             alternates[0] = vmcall_pattern[7];
 553             alternates[1] = 0xd9; /* AMD's VMMCALL */
 554             patch = &outl_pattern[5];
 555         }
 556         if (memcmp(rom + pos, pattern, 7) == 0 &&
 557             (rom[pos + 7] == alternates[0] || rom[pos + 7] == alternates[1])) {
 558             cpu_physical_memory_write(rom_paddr + pos + 5, patch, 3);
 559             /*
 560              * Don't flush the tb here. Under ordinary conditions, the patched
 561              * calls are miles away from the current IP. Under malicious
 562              * conditions, the guest could trick us to crash.
 563              */
 564         }
 565     }
 566
 567     g_free(rom);
 568     return 0;
 569 }
 570
 571 /*
 572  * For TCG mode or the time KVM honors read-only memory regions, we need to
 573  * enable write access to the option ROM so that variables can be updated by
 574  * the guest.
 575  */
 576 static int vapic_map_rom_writable(VAPICROMState *s)
 577 {
 578     hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
 579     MemoryRegionSection section;
 580     MemoryRegion *as;
 581     size_t rom_size;
 582     uint8_t *ram;
 583
 584     as = sysbus_address_space(&s->busdev);
 585
 586     if (s->rom_mapped_writable) {
 587         memory_region_del_subregion(as, &s->rom);
 588         object_unparent(OBJECT(&s->rom));
 589     }
 590
 591     /* grab RAM memory region (region @rom_paddr may still be pc.rom) */
 592     section = memory_region_find(as, 0, 1);
 593
 594     /* read ROM size from RAM region */
 595     if (rom_paddr + 2 >= memory_region_size(section.mr)) {
 596         return -1;
 597     }
 598     ram = memory_region_get_ram_ptr(section.mr);
 599     rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE;
 600     if (rom_size == 0) {
 601         return -1;
 602     }
 603     s->rom_size = rom_size;
 604
 605     /* We need to round to avoid creating subpages
 606      * from which we cannot run code. */
 607     rom_size += rom_paddr & ~TARGET_PAGE_MASK;
 608     rom_paddr &= TARGET_PAGE_MASK;
 609     rom_size = TARGET_PAGE_ALIGN(rom_size);
 610
 611     memory_region_init_alias(&s->rom, OBJECT(s), "kvmvapic-rom", section.mr,
 612                              rom_paddr, rom_size);
 613     memory_region_add_subregion_overlap(as, rom_paddr, &s->rom, 1000);
 614     s->rom_mapped_writable = true;
 615     memory_region_unref(section.mr);
 616
 617     return 0;
 618 }
 619
 620 static int vapic_prepare(VAPICROMState *s)
 621 {
 622     if (vapic_map_rom_writable(s) < 0) {
 623         return -1;
 624     }
 625
 626     if (patch_hypercalls(s) < 0) {
 627         return -1;
 628     }
 629
 630     vapic_enable_tpr_reporting(true);
 631
 632     return 0;
 633 }
 634
 635 static void vapic_write(void *opaque, hwaddr addr, uint64_t data,
 636                         unsigned int size)
 637 {
 638     VAPICROMState *s = opaque;
 639     X86CPU *cpu;
 640     CPUX86State *env;
 641     hwaddr rom_paddr;
 642
 643     if (!current_cpu) {
 644         return;
 645     }
 646
 647     cpu_synchronize_state(current_cpu);
 648     cpu = X86_CPU(current_cpu);
 649     env = &cpu->env;
 650
 651     /*
 652      * The VAPIC supports two PIO-based hypercalls, both via port 0x7E.
 653      *  o 16-bit write access:
 654      *    Reports the option ROM initialization to the hypervisor. Written
 655      *    value is the offset of the state structure in the ROM.
 656      *  o 8-bit write access:
 657      *    Reactivates the VAPIC after a guest hibernation, i.e. after the
 658      *    option ROM content has been re-initialized by a guest power cycle.
 659      *  o 32-bit write access:
 660      *    Poll for pending IRQs, considering the current VAPIC state.
 661      */
 662     switch (size) {
 663     case 2:
 664         if (s->state == VAPIC_INACTIVE) {
 665             rom_paddr = (env->segs[R_CS].base + env->eip) & ROM_BLOCK_MASK;
 666             s->rom_state_paddr = rom_paddr + data;
 667
 668             s->state = VAPIC_STANDBY;
 669         }
 670         if (vapic_prepare(s) < 0) {
 671             s->state = VAPIC_INACTIVE;
 672             s->rom_state_paddr = 0;
 673             break;
 674         }
 675         break;
 676     case 1:
 677         if (kvm_enabled()) {
 678             /*
 679              * Disable triggering instruction in ROM by writing a NOP.
 680              *
 681              * We cannot do this in TCG mode as the reported IP is not
 682              * accurate.
 683              */
 684             pause_all_vcpus();
 685             patch_byte(cpu, env->eip - 2, 0x66);
 686             patch_byte(cpu, env->eip - 1, 0x90);
 687             resume_all_vcpus();
 688         }
 689
 690         if (s->state == VAPIC_ACTIVE) {
 691             break;
 692         }
 693         if (update_rom_mapping(s, env, env->eip) < 0) {
 694             break;
 695         }
 696         if (find_real_tpr_addr(s, env) < 0) {
 697             break;
 698         }
 699         vapic_enable(s, cpu);
 700         break;
 701     default:
 702     case 4:
 703         if (!kvm_irqchip_in_kernel()) {
 704             apic_poll_irq(cpu->apic_state);
 705         }
 706         break;
 707     }
 708 }
 709
 710 static uint64_t vapic_read(void *opaque, hwaddr addr, unsigned size)
 711 {
 712     return 0xffffffff;
 713 }
 714
 715 static const MemoryRegionOps vapic_ops = {
 716     .write = vapic_write,
 717     .read = vapic_read,
 718     .endianness = DEVICE_NATIVE_ENDIAN,
 719 };
 720
 721 static void vapic_realize(DeviceState *dev, Error **errp)
 722 {
 723     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 724     VAPICROMState *s = VAPIC(dev);
 725
 726     memory_region_init_io(&s->io, OBJECT(s), &vapic_ops, s, "kvmvapic", 2);
 727     sysbus_add_io(sbd, VAPIC_IO_PORT, &s->io);
 728     sysbus_init_ioports(sbd, VAPIC_IO_PORT, 2);
 729
 730     option_rom[nb_option_roms].name = "kvmvapic.bin";
 731     option_rom[nb_option_roms].bootindex = -1;
 732     nb_option_roms++;
 733 }
 734
 735 static void do_vapic_enable(CPUState *cs, run_on_cpu_data data)
 736 {
 737     VAPICROMState *s = data.host_ptr;
 738     X86CPU *cpu = X86_CPU(cs);
 739
 740     static const uint8_t enabled = 1;
 741     cpu_physical_memory_write(s->vapic_paddr + offsetof(VAPICState, enabled),
 742                               &enabled, sizeof(enabled));
 743     apic_enable_vapic(cpu->apic_state, s->vapic_paddr);
 744     s->state = VAPIC_ACTIVE;
 745 }
 746
 747 static void kvmvapic_vm_state_change(void *opaque, int running,
 748                                      RunState state)
 749 {
 750     VAPICROMState *s = opaque;
 751     uint8_t *zero;
 752
 753     if (!running) {
 754         return;
 755     }
 756
 757     if (s->state == VAPIC_ACTIVE) {
 758         if (smp_cpus == 1) {
 759             run_on_cpu(first_cpu, do_vapic_enable, RUN_ON_CPU_HOST_PTR(s));
 760         } else {
 761             zero = g_malloc0(s->rom_state.vapic_size);
 762             cpu_physical_memory_write(s->vapic_paddr, zero,
 763                                       s->rom_state.vapic_size);
 764             g_free(zero);
 765         }
 766     }
 767
 768     qemu_del_vm_change_state_handler(s->vmsentry);
 769     s->vmsentry = NULL;
 770 }
 771
 772 static int vapic_post_load(void *opaque, int version_id)
 773 {
 774     VAPICROMState *s = opaque;
 775
 776     /*
 777      * The old implementation of qemu-kvm did not provide the state
 778      * VAPIC_STANDBY. Reconstruct it.
 779      */
 780     if (s->state == VAPIC_INACTIVE && s->rom_state_paddr != 0) {
 781         s->state = VAPIC_STANDBY;
 782     }
 783
 784     if (s->state != VAPIC_INACTIVE) {
 785         if (vapic_prepare(s) < 0) {
 786             return -1;
 787         }
 788     }
 789
 790     if (!s->vmsentry) {
 791         s->vmsentry =
 792             qemu_add_vm_change_state_handler(kvmvapic_vm_state_change, s);
 793     }
 794     return 0;
 795 }
 796
 797 static const VMStateDescription vmstate_handlers = {
 798     .name = "kvmvapic-handlers",
 799     .version_id = 1,
 800     .minimum_version_id = 1,
 801     .fields = (VMStateField[]) {
 802         VMSTATE_UINT32(set_tpr, VAPICHandlers),
 803         VMSTATE_UINT32(set_tpr_eax, VAPICHandlers),
 804         VMSTATE_UINT32_ARRAY(get_tpr, VAPICHandlers, 8),
 805         VMSTATE_UINT32(get_tpr_stack, VAPICHandlers),
 806         VMSTATE_END_OF_LIST()
 807     }
 808 };
 809
 810 static const VMStateDescription vmstate_guest_rom = {
 811     .name = "kvmvapic-guest-rom",
 812     .version_id = 1,
 813     .minimum_version_id = 1,
 814     .fields = (VMStateField[]) {
 815         VMSTATE_UNUSED(8),     /* signature */
 816         VMSTATE_UINT32(vaddr, GuestROMState),
 817         VMSTATE_UINT32(fixup_start, GuestROMState),
 818         VMSTATE_UINT32(fixup_end, GuestROMState),
 819         VMSTATE_UINT32(vapic_vaddr, GuestROMState),
 820         VMSTATE_UINT32(vapic_size, GuestROMState),
 821         VMSTATE_UINT32(vcpu_shift, GuestROMState),
 822         VMSTATE_UINT32(real_tpr_addr, GuestROMState),
 823         VMSTATE_STRUCT(up, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
 824         VMSTATE_STRUCT(mp, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
 825         VMSTATE_END_OF_LIST()
 826     }
 827 };
 828
 829 static const VMStateDescription vmstate_vapic = {
 830     .name = "kvm-tpr-opt",      /* compatible with qemu-kvm VAPIC */
 831     .version_id = 1,
 832     .minimum_version_id = 1,
 833     .post_load = vapic_post_load,
 834     .fields = (VMStateField[]) {
 835         VMSTATE_STRUCT(rom_state, VAPICROMState, 0, vmstate_guest_rom,
 836                        GuestROMState),
 837         VMSTATE_UINT32(state, VAPICROMState),
 838         VMSTATE_UINT32(real_tpr_addr, VAPICROMState),
 839         VMSTATE_UINT32(rom_state_vaddr, VAPICROMState),
 840         VMSTATE_UINT32(vapic_paddr, VAPICROMState),
 841         VMSTATE_UINT32(rom_state_paddr, VAPICROMState),
 842         VMSTATE_END_OF_LIST()
 843     }
 844 };
 845
 846 static void vapic_class_init(ObjectClass *klass, void *data)
 847 {
 848     DeviceClass *dc = DEVICE_CLASS(klass);
 849
 850     dc->reset   = vapic_reset;
 851     dc->vmsd    = &vmstate_vapic;
 852     dc->realize = vapic_realize;
 853 }
 854
 855 static const TypeInfo vapic_type = {
 856     .name          = TYPE_VAPIC,
 857     .parent        = TYPE_SYS_BUS_DEVICE,
 858     .instance_size = sizeof(VAPICROMState),
 859     .class_init    = vapic_class_init,
 860 };
 861
 862 static void vapic_register(void)
 863 {
 864     type_register_static(&vapic_type);
 865 }
 866
 867 type_init(vapic_register);