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 #include "qemu/osdep.h"
  12 #include "qemu-common.h"
  13 #include "cpu.h"
  14 #include "exec/exec-all.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 = CPU(x86_env_get_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 = CPU(x86_env_get_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(VAPICROMState *s, X86CPU *cpu, target_ulong ip,
 387                        uint32_t target)
 388 {
 389     uint32_t offset;
 390
 391     offset = cpu_to_le32(target - ip - 5);
 392     patch_byte(cpu, ip, 0xe8); /* call near */
 393     cpu_memory_rw_debug(CPU(cpu), ip + 1, (void *)&offset, sizeof(offset), 1);
 394 }
 395
 396 static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip)
 397 {
 398     CPUState *cs = CPU(cpu);
 399     CPUX86State *env = &cpu->env;
 400     VAPICHandlers *handlers;
 401     uint8_t opcode[2];
 402     uint32_t imm32 = 0;
 403     target_ulong current_pc = 0;
 404     target_ulong current_cs_base = 0;
 405     uint32_t current_flags = 0;
 406
 407     if (smp_cpus == 1) {
 408         handlers = &s->rom_state.up;
 409     } else {
 410         handlers = &s->rom_state.mp;
 411     }
 412
 413     if (!kvm_enabled()) {
 414         cpu_get_tb_cpu_state(env, &current_pc, &current_cs_base,
 415                              &current_flags);
 416         /* Account this instruction, because we will exit the tb.
 417            This is the first instruction in the block. Therefore
 418            there is no need in restoring CPU state. */
 419         if (use_icount) {
 420             --cs->icount_decr.u16.low;
 421         }
 422     }
 423
 424     pause_all_vcpus();
 425
 426     cpu_memory_rw_debug(cs, ip, opcode, sizeof(opcode), 0);
 427
 428     switch (opcode[0]) {
 429     case 0x89: /* mov r32 to r/m32 */
 430         patch_byte(cpu, ip, 0x50 + modrm_reg(opcode[1]));  /* push reg */
 431         patch_call(s, cpu, ip + 1, handlers->set_tpr);
 432         break;
 433     case 0x8b: /* mov r/m32 to r32 */
 434         patch_byte(cpu, ip, 0x90);
 435         patch_call(s, cpu, ip + 1, handlers->get_tpr[modrm_reg(opcode[1])]);
 436         break;
 437     case 0xa1: /* mov abs to eax */
 438         patch_call(s, cpu, ip, handlers->get_tpr[0]);
 439         break;
 440     case 0xa3: /* mov eax to abs */
 441         patch_call(s, cpu, ip, handlers->set_tpr_eax);
 442         break;
 443     case 0xc7: /* mov imm32, r/m32 (c7/0) */
 444         patch_byte(cpu, ip, 0x68);  /* push imm32 */
 445         cpu_memory_rw_debug(cs, ip + 6, (void *)&imm32, sizeof(imm32), 0);
 446         cpu_memory_rw_debug(cs, ip + 1, (void *)&imm32, sizeof(imm32), 1);
 447         patch_call(s, cpu, ip + 5, handlers->set_tpr);
 448         break;
 449     case 0xff: /* push r/m32 */
 450         patch_byte(cpu, ip, 0x50); /* push eax */
 451         patch_call(s, cpu, ip + 1, handlers->get_tpr_stack);
 452         break;
 453     default:
 454         abort();
 455     }
 456
 457     resume_all_vcpus();
 458
 459     if (!kvm_enabled()) {
 460         /* tb_lock will be reset when cpu_loop_exit_noexc longjmps
 461          * back into the cpu_exec loop. */
 462         tb_lock();
 463         tb_gen_code(cs, current_pc, current_cs_base, current_flags, 1);
 464         cpu_loop_exit_noexc(cs);
 465     }
 466 }
 467
 468 void vapic_report_tpr_access(DeviceState *dev, CPUState *cs, target_ulong ip,
 469                              TPRAccess access)
 470 {
 471     VAPICROMState *s = VAPIC(dev);
 472     X86CPU *cpu = X86_CPU(cs);
 473     CPUX86State *env = &cpu->env;
 474
 475     cpu_synchronize_state(cs);
 476
 477     if (evaluate_tpr_instruction(s, cpu, &ip, access) < 0) {
 478         if (s->state == VAPIC_ACTIVE) {
 479             vapic_enable(s, cpu);
 480         }
 481         return;
 482     }
 483     if (update_rom_mapping(s, env, ip) < 0) {
 484         return;
 485     }
 486     if (vapic_enable(s, cpu) < 0) {
 487         return;
 488     }
 489     patch_instruction(s, cpu, ip);
 490 }
 491
 492 typedef struct VAPICEnableTPRReporting {
 493     DeviceState *apic;
 494     bool enable;
 495 } VAPICEnableTPRReporting;
 496
 497 static void vapic_do_enable_tpr_reporting(CPUState *cpu, run_on_cpu_data data)
 498 {
 499     VAPICEnableTPRReporting *info = data.host_ptr;
 500     apic_enable_tpr_access_reporting(info->apic, info->enable);
 501 }
 502
 503 static void vapic_enable_tpr_reporting(bool enable)
 504 {
 505     VAPICEnableTPRReporting info = {
 506         .enable = enable,
 507     };
 508     CPUState *cs;
 509     X86CPU *cpu;
 510
 511     CPU_FOREACH(cs) {
 512         cpu = X86_CPU(cs);
 513         info.apic = cpu->apic_state;
 514         run_on_cpu(cs, vapic_do_enable_tpr_reporting, RUN_ON_CPU_HOST_PTR(&info));
 515     }
 516 }
 517
 518 static void vapic_reset(DeviceState *dev)
 519 {
 520     VAPICROMState *s = VAPIC(dev);
 521
 522     s->state = VAPIC_INACTIVE;
 523     s->rom_state_paddr = 0;
 524     vapic_enable_tpr_reporting(false);
 525 }
 526
 527 /*
 528  * Set the IRQ polling hypercalls to the supported variant:
 529  *  - vmcall if using KVM in-kernel irqchip
 530  *  - 32-bit VAPIC port write otherwise
 531  */
 532 static int patch_hypercalls(VAPICROMState *s)
 533 {
 534     hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
 535     static const uint8_t vmcall_pattern[] = { /* vmcall */
 536         0xb8, 0x1, 0, 0, 0, 0xf, 0x1, 0xc1
 537     };
 538     static const uint8_t outl_pattern[] = { /* nop; outl %eax,0x7e */
 539         0xb8, 0x1, 0, 0, 0, 0x90, 0xe7, 0x7e
 540     };
 541     uint8_t alternates[2];
 542     const uint8_t *pattern;
 543     const uint8_t *patch;
 544     off_t pos;
 545     uint8_t *rom;
 546
 547     rom = g_malloc(s->rom_size);
 548     cpu_physical_memory_read(rom_paddr, rom, s->rom_size);
 549
 550     for (pos = 0; pos < s->rom_size - sizeof(vmcall_pattern); pos++) {
 551         if (kvm_irqchip_in_kernel()) {
 552             pattern = outl_pattern;
 553             alternates[0] = outl_pattern[7];
 554             alternates[1] = outl_pattern[7];
 555             patch = &vmcall_pattern[5];
 556         } else {
 557             pattern = vmcall_pattern;
 558             alternates[0] = vmcall_pattern[7];
 559             alternates[1] = 0xd9; /* AMD's VMMCALL */
 560             patch = &outl_pattern[5];
 561         }
 562         if (memcmp(rom + pos, pattern, 7) == 0 &&
 563             (rom[pos + 7] == alternates[0] || rom[pos + 7] == alternates[1])) {
 564             cpu_physical_memory_write(rom_paddr + pos + 5, patch, 3);
 565             /*
 566              * Don't flush the tb here. Under ordinary conditions, the patched
 567              * calls are miles away from the current IP. Under malicious
 568              * conditions, the guest could trick us to crash.
 569              */
 570         }
 571     }
 572
 573     g_free(rom);
 574     return 0;
 575 }
 576
 577 /*
 578  * For TCG mode or the time KVM honors read-only memory regions, we need to
 579  * enable write access to the option ROM so that variables can be updated by
 580  * the guest.
 581  */
 582 static int vapic_map_rom_writable(VAPICROMState *s)
 583 {
 584     hwaddr rom_paddr = s->rom_state_paddr & ROM_BLOCK_MASK;
 585     MemoryRegionSection section;
 586     MemoryRegion *as;
 587     size_t rom_size;
 588     uint8_t *ram;
 589
 590     as = sysbus_address_space(&s->busdev);
 591
 592     if (s->rom_mapped_writable) {
 593         memory_region_del_subregion(as, &s->rom);
 594         object_unparent(OBJECT(&s->rom));
 595     }
 596
 597     /* grab RAM memory region (region @rom_paddr may still be pc.rom) */
 598     section = memory_region_find(as, 0, 1);
 599
 600     /* read ROM size from RAM region */
 601     if (rom_paddr + 2 >= memory_region_size(section.mr)) {
 602         return -1;
 603     }
 604     ram = memory_region_get_ram_ptr(section.mr);
 605     rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE;
 606     if (rom_size == 0) {
 607         return -1;
 608     }
 609     s->rom_size = rom_size;
 610
 611     /* We need to round to avoid creating subpages
 612      * from which we cannot run code. */
 613     rom_size += rom_paddr & ~TARGET_PAGE_MASK;
 614     rom_paddr &= TARGET_PAGE_MASK;
 615     rom_size = TARGET_PAGE_ALIGN(rom_size);
 616
 617     memory_region_init_alias(&s->rom, OBJECT(s), "kvmvapic-rom", section.mr,
 618                              rom_paddr, rom_size);
 619     memory_region_add_subregion_overlap(as, rom_paddr, &s->rom, 1000);
 620     s->rom_mapped_writable = true;
 621     memory_region_unref(section.mr);
 622
 623     return 0;
 624 }
 625
 626 static int vapic_prepare(VAPICROMState *s)
 627 {
 628     if (vapic_map_rom_writable(s) < 0) {
 629         return -1;
 630     }
 631
 632     if (patch_hypercalls(s) < 0) {
 633         return -1;
 634     }
 635
 636     vapic_enable_tpr_reporting(true);
 637
 638     return 0;
 639 }
 640
 641 static void vapic_write(void *opaque, hwaddr addr, uint64_t data,
 642                         unsigned int size)
 643 {
 644     VAPICROMState *s = opaque;
 645     X86CPU *cpu;
 646     CPUX86State *env;
 647     hwaddr rom_paddr;
 648
 649     if (!current_cpu) {
 650         return;
 651     }
 652
 653     cpu_synchronize_state(current_cpu);
 654     cpu = X86_CPU(current_cpu);
 655     env = &cpu->env;
 656
 657     /*
 658      * The VAPIC supports two PIO-based hypercalls, both via port 0x7E.
 659      *  o 16-bit write access:
 660      *    Reports the option ROM initialization to the hypervisor. Written
 661      *    value is the offset of the state structure in the ROM.
 662      *  o 8-bit write access:
 663      *    Reactivates the VAPIC after a guest hibernation, i.e. after the
 664      *    option ROM content has been re-initialized by a guest power cycle.
 665      *  o 32-bit write access:
 666      *    Poll for pending IRQs, considering the current VAPIC state.
 667      */
 668     switch (size) {
 669     case 2:
 670         if (s->state == VAPIC_INACTIVE) {
 671             rom_paddr = (env->segs[R_CS].base + env->eip) & ROM_BLOCK_MASK;
 672             s->rom_state_paddr = rom_paddr + data;
 673
 674             s->state = VAPIC_STANDBY;
 675         }
 676         if (vapic_prepare(s) < 0) {
 677             s->state = VAPIC_INACTIVE;
 678             s->rom_state_paddr = 0;
 679             break;
 680         }
 681         break;
 682     case 1:
 683         if (kvm_enabled()) {
 684             /*
 685              * Disable triggering instruction in ROM by writing a NOP.
 686              *
 687              * We cannot do this in TCG mode as the reported IP is not
 688              * accurate.
 689              */
 690             pause_all_vcpus();
 691             patch_byte(cpu, env->eip - 2, 0x66);
 692             patch_byte(cpu, env->eip - 1, 0x90);
 693             resume_all_vcpus();
 694         }
 695
 696         if (s->state == VAPIC_ACTIVE) {
 697             break;
 698         }
 699         if (update_rom_mapping(s, env, env->eip) < 0) {
 700             break;
 701         }
 702         if (find_real_tpr_addr(s, env) < 0) {
 703             break;
 704         }
 705         vapic_enable(s, cpu);
 706         break;
 707     default:
 708     case 4:
 709         if (!kvm_irqchip_in_kernel()) {
 710             apic_poll_irq(cpu->apic_state);
 711         }
 712         break;
 713     }
 714 }
 715
 716 static uint64_t vapic_read(void *opaque, hwaddr addr, unsigned size)
 717 {
 718     return 0xffffffff;
 719 }
 720
 721 static const MemoryRegionOps vapic_ops = {
 722     .write = vapic_write,
 723     .read = vapic_read,
 724     .endianness = DEVICE_NATIVE_ENDIAN,
 725 };
 726
 727 static void vapic_realize(DeviceState *dev, Error **errp)
 728 {
 729     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 730     VAPICROMState *s = VAPIC(dev);
 731
 732     memory_region_init_io(&s->io, OBJECT(s), &vapic_ops, s, "kvmvapic", 2);
 733     sysbus_add_io(sbd, VAPIC_IO_PORT, &s->io);
 734     sysbus_init_ioports(sbd, VAPIC_IO_PORT, 2);
 735
 736     option_rom[nb_option_roms].name = "kvmvapic.bin";
 737     option_rom[nb_option_roms].bootindex = -1;
 738     nb_option_roms++;
 739 }
 740
 741 static void do_vapic_enable(CPUState *cs, run_on_cpu_data data)
 742 {
 743     VAPICROMState *s = data.host_ptr;
 744     X86CPU *cpu = X86_CPU(cs);
 745
 746     static const uint8_t enabled = 1;
 747     cpu_physical_memory_write(s->vapic_paddr + offsetof(VAPICState, enabled),
 748                               &enabled, sizeof(enabled));
 749     apic_enable_vapic(cpu->apic_state, s->vapic_paddr);
 750     s->state = VAPIC_ACTIVE;
 751 }
 752
 753 static void kvmvapic_vm_state_change(void *opaque, int running,
 754                                      RunState state)
 755 {
 756     VAPICROMState *s = opaque;
 757     uint8_t *zero;
 758
 759     if (!running) {
 760         return;
 761     }
 762
 763     if (s->state == VAPIC_ACTIVE) {
 764         if (smp_cpus == 1) {
 765             run_on_cpu(first_cpu, do_vapic_enable, RUN_ON_CPU_HOST_PTR(s));
 766         } else {
 767             zero = g_malloc0(s->rom_state.vapic_size);
 768             cpu_physical_memory_write(s->vapic_paddr, zero,
 769                                       s->rom_state.vapic_size);
 770             g_free(zero);
 771         }
 772     }
 773
 774     qemu_del_vm_change_state_handler(s->vmsentry);
 775     s->vmsentry = NULL;
 776 }
 777
 778 static int vapic_post_load(void *opaque, int version_id)
 779 {
 780     VAPICROMState *s = opaque;
 781
 782     /*
 783      * The old implementation of qemu-kvm did not provide the state
 784      * VAPIC_STANDBY. Reconstruct it.
 785      */
 786     if (s->state == VAPIC_INACTIVE && s->rom_state_paddr != 0) {
 787         s->state = VAPIC_STANDBY;
 788     }
 789
 790     if (s->state != VAPIC_INACTIVE) {
 791         if (vapic_prepare(s) < 0) {
 792             return -1;
 793         }
 794     }
 795
 796     if (!s->vmsentry) {
 797         s->vmsentry =
 798             qemu_add_vm_change_state_handler(kvmvapic_vm_state_change, s);
 799     }
 800     return 0;
 801 }
 802
 803 static const VMStateDescription vmstate_handlers = {
 804     .name = "kvmvapic-handlers",
 805     .version_id = 1,
 806     .minimum_version_id = 1,
 807     .fields = (VMStateField[]) {
 808         VMSTATE_UINT32(set_tpr, VAPICHandlers),
 809         VMSTATE_UINT32(set_tpr_eax, VAPICHandlers),
 810         VMSTATE_UINT32_ARRAY(get_tpr, VAPICHandlers, 8),
 811         VMSTATE_UINT32(get_tpr_stack, VAPICHandlers),
 812         VMSTATE_END_OF_LIST()
 813     }
 814 };
 815
 816 static const VMStateDescription vmstate_guest_rom = {
 817     .name = "kvmvapic-guest-rom",
 818     .version_id = 1,
 819     .minimum_version_id = 1,
 820     .fields = (VMStateField[]) {
 821         VMSTATE_UNUSED(8),     /* signature */
 822         VMSTATE_UINT32(vaddr, GuestROMState),
 823         VMSTATE_UINT32(fixup_start, GuestROMState),
 824         VMSTATE_UINT32(fixup_end, GuestROMState),
 825         VMSTATE_UINT32(vapic_vaddr, GuestROMState),
 826         VMSTATE_UINT32(vapic_size, GuestROMState),
 827         VMSTATE_UINT32(vcpu_shift, GuestROMState),
 828         VMSTATE_UINT32(real_tpr_addr, GuestROMState),
 829         VMSTATE_STRUCT(up, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
 830         VMSTATE_STRUCT(mp, GuestROMState, 0, vmstate_handlers, VAPICHandlers),
 831         VMSTATE_END_OF_LIST()
 832     }
 833 };
 834
 835 static const VMStateDescription vmstate_vapic = {
 836     .name = "kvm-tpr-opt",      /* compatible with qemu-kvm VAPIC */
 837     .version_id = 1,
 838     .minimum_version_id = 1,
 839     .post_load = vapic_post_load,
 840     .fields = (VMStateField[]) {
 841         VMSTATE_STRUCT(rom_state, VAPICROMState, 0, vmstate_guest_rom,
 842                        GuestROMState),
 843         VMSTATE_UINT32(state, VAPICROMState),
 844         VMSTATE_UINT32(real_tpr_addr, VAPICROMState),
 845         VMSTATE_UINT32(rom_state_vaddr, VAPICROMState),
 846         VMSTATE_UINT32(vapic_paddr, VAPICROMState),
 847         VMSTATE_UINT32(rom_state_paddr, VAPICROMState),
 848         VMSTATE_END_OF_LIST()
 849     }
 850 };
 851
 852 static void vapic_class_init(ObjectClass *klass, void *data)
 853 {
 854     DeviceClass *dc = DEVICE_CLASS(klass);
 855
 856     dc->reset   = vapic_reset;
 857     dc->vmsd    = &vmstate_vapic;
 858     dc->realize = vapic_realize;
 859 }
 860
 861 static const TypeInfo vapic_type = {
 862     .name          = TYPE_VAPIC,
 863     .parent        = TYPE_SYS_BUS_DEVICE,
 864     .instance_size = sizeof(VAPICROMState),
 865     .class_init    = vapic_class_init,
 866 };
 867
 868 static void vapic_register(void)
 869 {
 870     type_register_static(&vapic_type);
 871 }
 872
 873 type_init(vapic_register);