cpus.c 64.5 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408
/*
 * QEMU System Emulator
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qemu/osdep.h"
#include "qemu/config-file.h"
#include "cpu.h"
#include "monitor/monitor.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-misc.h"
#include "qapi/qapi-events-run-state.h"
#include "qapi/qmp/qerror.h"
#include "qemu/error-report.h"
#include "sysemu/sysemu.h"
#include "sysemu/block-backend.h"
#include "exec/gdbstub.h"
#include "sysemu/dma.h"
#include "sysemu/hw_accel.h"
#include "sysemu/kvm.h"
#include "sysemu/hax.h"
#include "sysemu/hvf.h"
#include "sysemu/whpx.h"
#include "exec/exec-all.h"

#include "qemu/thread.h"
#include "sysemu/cpus.h"
#include "sysemu/qtest.h"
#include "qemu/main-loop.h"
#include "qemu/option.h"
#include "qemu/bitmap.h"
#include "qemu/seqlock.h"
#include "tcg.h"
#include "hw/nmi.h"
#include "sysemu/replay.h"
#include "hw/boards.h"

#ifdef CONFIG_LINUX

#include <sys/prctl.h>

#ifndef PR_MCE_KILL
#define PR_MCE_KILL 33
#endif

#ifndef PR_MCE_KILL_SET
#define PR_MCE_KILL_SET 1
#endif

#ifndef PR_MCE_KILL_EARLY
#define PR_MCE_KILL_EARLY 1
#endif

#endif /* CONFIG_LINUX */

int64_t max_delay;
int64_t max_advance;

/* vcpu throttling controls */
static QEMUTimer *throttle_timer;
static unsigned int throttle_percentage;

#define CPU_THROTTLE_PCT_MIN 1
#define CPU_THROTTLE_PCT_MAX 99
#define CPU_THROTTLE_TIMESLICE_NS 10000000

bool cpu_is_stopped(CPUState *cpu)
{
    return cpu->stopped || !runstate_is_running();
}

static bool cpu_thread_is_idle(CPUState *cpu)
{
    if (cpu->stop || cpu->queued_work_first) {
        return false;
    }
    if (cpu_is_stopped(cpu)) {
        return true;
    }
    if (!cpu->halted || cpu_has_work(cpu) ||
        kvm_halt_in_kernel()) {
        return false;
    }
    return true;
}

static bool all_cpu_threads_idle(void)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        if (!cpu_thread_is_idle(cpu)) {
            return false;
        }
    }
    return true;
}

/***********************************************************/
/* guest cycle counter */

/* Protected by TimersState seqlock */

static bool icount_sleep = true;
/* Conversion factor from emulated instructions to virtual clock ticks.  */
static int icount_time_shift;
/* Arbitrarily pick 1MIPS as the minimum allowable speed.  */
#define MAX_ICOUNT_SHIFT 10

typedef struct TimersState {
    /* Protected by BQL.  */
    int64_t cpu_ticks_prev;
    int64_t cpu_ticks_offset;

    /* cpu_clock_offset can be read out of BQL, so protect it with
     * this lock.
     */
    QemuSeqLock vm_clock_seqlock;
    int64_t cpu_clock_offset;
    int32_t cpu_ticks_enabled;
    int64_t dummy;

    /* Compensate for varying guest execution speed.  */
    int64_t qemu_icount_bias;
    /* Only written by TCG thread */
    int64_t qemu_icount;
    /* for adjusting icount */
    int64_t vm_clock_warp_start;
    QEMUTimer *icount_rt_timer;
    QEMUTimer *icount_vm_timer;
    QEMUTimer *icount_warp_timer;
} TimersState;

static TimersState timers_state;
bool mttcg_enabled;

/*
 * We default to false if we know other options have been enabled
 * which are currently incompatible with MTTCG. Otherwise when each
 * guest (target) has been updated to support:
 *   - atomic instructions
 *   - memory ordering primitives (barriers)
 * they can set the appropriate CONFIG flags in ${target}-softmmu.mak
 *
 * Once a guest architecture has been converted to the new primitives
 * there are two remaining limitations to check.
 *
 * - The guest can't be oversized (e.g. 64 bit guest on 32 bit host)
 * - The host must have a stronger memory order than the guest
 *
 * It may be possible in future to support strong guests on weak hosts
 * but that will require tagging all load/stores in a guest with their
 * implicit memory order requirements which would likely slow things
 * down a lot.
 */

static bool check_tcg_memory_orders_compatible(void)
{
#if defined(TCG_GUEST_DEFAULT_MO) && defined(TCG_TARGET_DEFAULT_MO)
    return (TCG_GUEST_DEFAULT_MO & ~TCG_TARGET_DEFAULT_MO) == 0;
#else
    return false;
#endif
}

static bool default_mttcg_enabled(void)
{
    if (use_icount || TCG_OVERSIZED_GUEST) {
        return false;
    } else {
#ifdef TARGET_SUPPORTS_MTTCG
        return check_tcg_memory_orders_compatible();
#else
        return false;
#endif
    }
}

void qemu_tcg_configure(QemuOpts *opts, Error **errp)
{
    const char *t = qemu_opt_get(opts, "thread");
    if (t) {
        if (strcmp(t, "multi") == 0) {
            if (TCG_OVERSIZED_GUEST) {
                error_setg(errp, "No MTTCG when guest word size > hosts");
            } else if (use_icount) {
                error_setg(errp, "No MTTCG when icount is enabled");
            } else {
#ifndef TARGET_SUPPORTS_MTTCG
                error_report("Guest not yet converted to MTTCG - "
                             "you may get unexpected results");
#endif
                if (!check_tcg_memory_orders_compatible()) {
                    error_report("Guest expects a stronger memory ordering "
                                 "than the host provides");
                    error_printf("This may cause strange/hard to debug errors\n");
                }
                mttcg_enabled = true;
            }
        } else if (strcmp(t, "single") == 0) {
            mttcg_enabled = false;
        } else {
            error_setg(errp, "Invalid 'thread' setting %s", t);
        }
    } else {
        mttcg_enabled = default_mttcg_enabled();
    }
}

/* The current number of executed instructions is based on what we
 * originally budgeted minus the current state of the decrementing
 * icount counters in extra/u16.low.
 */
static int64_t cpu_get_icount_executed(CPUState *cpu)
{
    return cpu->icount_budget - (cpu->icount_decr.u16.low + cpu->icount_extra);
}

/*
 * Update the global shared timer_state.qemu_icount to take into
 * account executed instructions. This is done by the TCG vCPU
 * thread so the main-loop can see time has moved forward.
 */
void cpu_update_icount(CPUState *cpu)
{
    int64_t executed = cpu_get_icount_executed(cpu);
    cpu->icount_budget -= executed;

#ifdef CONFIG_ATOMIC64
    atomic_set__nocheck(&timers_state.qemu_icount,
                        atomic_read__nocheck(&timers_state.qemu_icount) +
                        executed);
#else /* FIXME: we need 64bit atomics to do this safely */
    timers_state.qemu_icount += executed;
#endif
}

int64_t cpu_get_icount_raw(void)
{
    CPUState *cpu = current_cpu;

    if (cpu && cpu->running) {
        if (!cpu->can_do_io) {
            error_report("Bad icount read");
            exit(1);
        }
        /* Take into account what has run */
        cpu_update_icount(cpu);
    }
#ifdef CONFIG_ATOMIC64
    return atomic_read__nocheck(&timers_state.qemu_icount);
#else /* FIXME: we need 64bit atomics to do this safely */
    return timers_state.qemu_icount;
#endif
}

/* Return the virtual CPU time, based on the instruction counter.  */
static int64_t cpu_get_icount_locked(void)
{
    int64_t icount = cpu_get_icount_raw();
    return timers_state.qemu_icount_bias + cpu_icount_to_ns(icount);
}

int64_t cpu_get_icount(void)
{
    int64_t icount;
    unsigned start;

    do {
        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
        icount = cpu_get_icount_locked();
    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));

    return icount;
}

int64_t cpu_icount_to_ns(int64_t icount)
{
    return icount << icount_time_shift;
}

/* return the time elapsed in VM between vm_start and vm_stop.  Unless
 * icount is active, cpu_get_ticks() uses units of the host CPU cycle
 * counter.
 *
 * Caller must hold the BQL
 */
int64_t cpu_get_ticks(void)
{
    int64_t ticks;

    if (use_icount) {
        return cpu_get_icount();
    }

    ticks = timers_state.cpu_ticks_offset;
    if (timers_state.cpu_ticks_enabled) {
        ticks += cpu_get_host_ticks();
    }

    if (timers_state.cpu_ticks_prev > ticks) {
        /* Note: non increasing ticks may happen if the host uses
           software suspend */
        timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks;
        ticks = timers_state.cpu_ticks_prev;
    }

    timers_state.cpu_ticks_prev = ticks;
    return ticks;
}

static int64_t cpu_get_clock_locked(void)
{
    int64_t time;

    time = timers_state.cpu_clock_offset;
    if (timers_state.cpu_ticks_enabled) {
        time += get_clock();
    }

    return time;
}

/* Return the monotonic time elapsed in VM, i.e.,
 * the time between vm_start and vm_stop
 */
int64_t cpu_get_clock(void)
{
    int64_t ti;
    unsigned start;

    do {
        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
        ti = cpu_get_clock_locked();
    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));

    return ti;
}

/* enable cpu_get_ticks()
 * Caller must hold BQL which serves as mutex for vm_clock_seqlock.
 */
void cpu_enable_ticks(void)
{
    /* Here, the really thing protected by seqlock is cpu_clock_offset. */
    seqlock_write_begin(&timers_state.vm_clock_seqlock);
    if (!timers_state.cpu_ticks_enabled) {
        timers_state.cpu_ticks_offset -= cpu_get_host_ticks();
        timers_state.cpu_clock_offset -= get_clock();
        timers_state.cpu_ticks_enabled = 1;
    }
    seqlock_write_end(&timers_state.vm_clock_seqlock);
}

/* disable cpu_get_ticks() : the clock is stopped. You must not call
 * cpu_get_ticks() after that.
 * Caller must hold BQL which serves as mutex for vm_clock_seqlock.
 */
void cpu_disable_ticks(void)
{
    /* Here, the really thing protected by seqlock is cpu_clock_offset. */
    seqlock_write_begin(&timers_state.vm_clock_seqlock);
    if (timers_state.cpu_ticks_enabled) {
        timers_state.cpu_ticks_offset += cpu_get_host_ticks();
        timers_state.cpu_clock_offset = cpu_get_clock_locked();
        timers_state.cpu_ticks_enabled = 0;
    }
    seqlock_write_end(&timers_state.vm_clock_seqlock);
}

/* Correlation between real and virtual time is always going to be
   fairly approximate, so ignore small variation.
   When the guest is idle real and virtual time will be aligned in
   the IO wait loop.  */
#define ICOUNT_WOBBLE (NANOSECONDS_PER_SECOND / 10)

static void icount_adjust(void)
{
    int64_t cur_time;
    int64_t cur_icount;
    int64_t delta;

    /* Protected by TimersState mutex.  */
    static int64_t last_delta;

    /* If the VM is not running, then do nothing.  */
    if (!runstate_is_running()) {
        return;
    }

    seqlock_write_begin(&timers_state.vm_clock_seqlock);
    cur_time = cpu_get_clock_locked();
    cur_icount = cpu_get_icount_locked();

    delta = cur_icount - cur_time;
    /* FIXME: This is a very crude algorithm, somewhat prone to oscillation.  */
    if (delta > 0
        && last_delta + ICOUNT_WOBBLE < delta * 2
        && icount_time_shift > 0) {
        /* The guest is getting too far ahead.  Slow time down.  */
        icount_time_shift--;
    }
    if (delta < 0
        && last_delta - ICOUNT_WOBBLE > delta * 2
        && icount_time_shift < MAX_ICOUNT_SHIFT) {
        /* The guest is getting too far behind.  Speed time up.  */
        icount_time_shift++;
    }
    last_delta = delta;
    timers_state.qemu_icount_bias = cur_icount
                              - (timers_state.qemu_icount << icount_time_shift);
    seqlock_write_end(&timers_state.vm_clock_seqlock);
}

static void icount_adjust_rt(void *opaque)
{
    timer_mod(timers_state.icount_rt_timer,
              qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000);
    icount_adjust();
}

static void icount_adjust_vm(void *opaque)
{
    timer_mod(timers_state.icount_vm_timer,
                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
                   NANOSECONDS_PER_SECOND / 10);
    icount_adjust();
}

static int64_t qemu_icount_round(int64_t count)
{
    return (count + (1 << icount_time_shift) - 1) >> icount_time_shift;
}

static void icount_warp_rt(void)
{
    unsigned seq;
    int64_t warp_start;

    /* The icount_warp_timer is rescheduled soon after vm_clock_warp_start
     * changes from -1 to another value, so the race here is okay.
     */
    do {
        seq = seqlock_read_begin(&timers_state.vm_clock_seqlock);
        warp_start = timers_state.vm_clock_warp_start;
    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, seq));

    if (warp_start == -1) {
        return;
    }

    seqlock_write_begin(&timers_state.vm_clock_seqlock);
    if (runstate_is_running()) {
        int64_t clock = REPLAY_CLOCK(REPLAY_CLOCK_VIRTUAL_RT,
                                     cpu_get_clock_locked());
        int64_t warp_delta;

        warp_delta = clock - timers_state.vm_clock_warp_start;
        if (use_icount == 2) {
            /*
             * In adaptive mode, do not let QEMU_CLOCK_VIRTUAL run too
             * far ahead of real time.
             */
            int64_t cur_icount = cpu_get_icount_locked();
            int64_t delta = clock - cur_icount;
            warp_delta = MIN(warp_delta, delta);
        }
        timers_state.qemu_icount_bias += warp_delta;
    }
    timers_state.vm_clock_warp_start = -1;
    seqlock_write_end(&timers_state.vm_clock_seqlock);

    if (qemu_clock_expired(QEMU_CLOCK_VIRTUAL)) {
        qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
    }
}

static void icount_timer_cb(void *opaque)
{
    /* No need for a checkpoint because the timer already synchronizes
     * with CHECKPOINT_CLOCK_VIRTUAL_RT.
     */
    icount_warp_rt();
}

void qtest_clock_warp(int64_t dest)
{
    int64_t clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
    AioContext *aio_context;
    assert(qtest_enabled());
    aio_context = qemu_get_aio_context();
    while (clock < dest) {
        int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
        int64_t warp = qemu_soonest_timeout(dest - clock, deadline);

        seqlock_write_begin(&timers_state.vm_clock_seqlock);
        timers_state.qemu_icount_bias += warp;
        seqlock_write_end(&timers_state.vm_clock_seqlock);

        qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
        timerlist_run_timers(aio_context->tlg.tl[QEMU_CLOCK_VIRTUAL]);
        clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
    }
    qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
}

void qemu_start_warp_timer(void)
{
    int64_t clock;
    int64_t deadline;

    if (!use_icount) {
        return;
    }

    /* Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers
     * do not fire, so computing the deadline does not make sense.
     */
    if (!runstate_is_running()) {
        return;
    }

    /* warp clock deterministically in record/replay mode */
    if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_START)) {
        return;
    }

    if (!all_cpu_threads_idle()) {
        return;
    }

    if (qtest_enabled()) {
        /* When testing, qtest commands advance icount.  */
        return;
    }

    /* We want to use the earliest deadline from ALL vm_clocks */
    clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
    deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
    if (deadline < 0) {
        static bool notified;
        if (!icount_sleep && !notified) {
            warn_report("icount sleep disabled and no active timers");
            notified = true;
        }
        return;
    }

    if (deadline > 0) {
        /*
         * Ensure QEMU_CLOCK_VIRTUAL proceeds even when the virtual CPU goes to
         * sleep.  Otherwise, the CPU might be waiting for a future timer
         * interrupt to wake it up, but the interrupt never comes because
         * the vCPU isn't running any insns and thus doesn't advance the
         * QEMU_CLOCK_VIRTUAL.
         */
        if (!icount_sleep) {
            /*
             * We never let VCPUs sleep in no sleep icount mode.
             * If there is a pending QEMU_CLOCK_VIRTUAL timer we just advance
             * to the next QEMU_CLOCK_VIRTUAL event and notify it.
             * It is useful when we want a deterministic execution time,
             * isolated from host latencies.
             */
            seqlock_write_begin(&timers_state.vm_clock_seqlock);
            timers_state.qemu_icount_bias += deadline;
            seqlock_write_end(&timers_state.vm_clock_seqlock);
            qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
        } else {
            /*
             * We do stop VCPUs and only advance QEMU_CLOCK_VIRTUAL after some
             * "real" time, (related to the time left until the next event) has
             * passed. The QEMU_CLOCK_VIRTUAL_RT clock will do this.
             * This avoids that the warps are visible externally; for example,
             * you will not be sending network packets continuously instead of
             * every 100ms.
             */
            seqlock_write_begin(&timers_state.vm_clock_seqlock);
            if (timers_state.vm_clock_warp_start == -1
                || timers_state.vm_clock_warp_start > clock) {
                timers_state.vm_clock_warp_start = clock;
            }
            seqlock_write_end(&timers_state.vm_clock_seqlock);
            timer_mod_anticipate(timers_state.icount_warp_timer,
                                 clock + deadline);
        }
    } else if (deadline == 0) {
        qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
    }
}

static void qemu_account_warp_timer(void)
{
    if (!use_icount || !icount_sleep) {
        return;
    }

    /* Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers
     * do not fire, so computing the deadline does not make sense.
     */
    if (!runstate_is_running()) {
        return;
    }

    /* warp clock deterministically in record/replay mode */
    if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_ACCOUNT)) {
        return;
    }

    timer_del(timers_state.icount_warp_timer);
    icount_warp_rt();
}

static bool icount_state_needed(void *opaque)
{
    return use_icount;
}

static bool warp_timer_state_needed(void *opaque)
{
    TimersState *s = opaque;
    return s->icount_warp_timer != NULL;
}

static bool adjust_timers_state_needed(void *opaque)
{
    TimersState *s = opaque;
    return s->icount_rt_timer != NULL;
}

/*
 * Subsection for warp timer migration is optional, because may not be created
 */
static const VMStateDescription icount_vmstate_warp_timer = {
    .name = "timer/icount/warp_timer",
    .version_id = 1,
    .minimum_version_id = 1,
    .needed = warp_timer_state_needed,
    .fields = (VMStateField[]) {
        VMSTATE_INT64(vm_clock_warp_start, TimersState),
        VMSTATE_TIMER_PTR(icount_warp_timer, TimersState),
        VMSTATE_END_OF_LIST()
    }
};

static const VMStateDescription icount_vmstate_adjust_timers = {
    .name = "timer/icount/timers",
    .version_id = 1,
    .minimum_version_id = 1,
    .needed = adjust_timers_state_needed,
    .fields = (VMStateField[]) {
        VMSTATE_TIMER_PTR(icount_rt_timer, TimersState),
        VMSTATE_TIMER_PTR(icount_vm_timer, TimersState),
        VMSTATE_END_OF_LIST()
    }
};

/*
 * This is a subsection for icount migration.
 */
static const VMStateDescription icount_vmstate_timers = {
    .name = "timer/icount",
    .version_id = 1,
    .minimum_version_id = 1,
    .needed = icount_state_needed,
    .fields = (VMStateField[]) {
        VMSTATE_INT64(qemu_icount_bias, TimersState),
        VMSTATE_INT64(qemu_icount, TimersState),
        VMSTATE_END_OF_LIST()
    },
    .subsections = (const VMStateDescription*[]) {
        &icount_vmstate_warp_timer,
        &icount_vmstate_adjust_timers,
        NULL
    }
};

static const VMStateDescription vmstate_timers = {
    .name = "timer",
    .version_id = 2,
    .minimum_version_id = 1,
    .fields = (VMStateField[]) {
        VMSTATE_INT64(cpu_ticks_offset, TimersState),
        VMSTATE_INT64(dummy, TimersState),
        VMSTATE_INT64_V(cpu_clock_offset, TimersState, 2),
        VMSTATE_END_OF_LIST()
    },
    .subsections = (const VMStateDescription*[]) {
        &icount_vmstate_timers,
        NULL
    }
};

static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque)
{
    double pct;
    double throttle_ratio;
    long sleeptime_ns;

    if (!cpu_throttle_get_percentage()) {
        return;
    }

    pct = (double)cpu_throttle_get_percentage()/100;
    throttle_ratio = pct / (1 - pct);
    sleeptime_ns = (long)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS);

    qemu_mutex_unlock_iothread();
    g_usleep(sleeptime_ns / 1000); /* Convert ns to us for usleep call */
    qemu_mutex_lock_iothread();
    atomic_set(&cpu->throttle_thread_scheduled, 0);
}

static void cpu_throttle_timer_tick(void *opaque)
{
    CPUState *cpu;
    double pct;

    /* Stop the timer if needed */
    if (!cpu_throttle_get_percentage()) {
        return;
    }
    CPU_FOREACH(cpu) {
        if (!atomic_xchg(&cpu->throttle_thread_scheduled, 1)) {
            async_run_on_cpu(cpu, cpu_throttle_thread,
                             RUN_ON_CPU_NULL);
        }
    }

    pct = (double)cpu_throttle_get_percentage()/100;
    timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) +
                                   CPU_THROTTLE_TIMESLICE_NS / (1-pct));
}

void cpu_throttle_set(int new_throttle_pct)
{
    /* Ensure throttle percentage is within valid range */
    new_throttle_pct = MIN(new_throttle_pct, CPU_THROTTLE_PCT_MAX);
    new_throttle_pct = MAX(new_throttle_pct, CPU_THROTTLE_PCT_MIN);

    atomic_set(&throttle_percentage, new_throttle_pct);

    timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) +
                                       CPU_THROTTLE_TIMESLICE_NS);
}

void cpu_throttle_stop(void)
{
    atomic_set(&throttle_percentage, 0);
}

bool cpu_throttle_active(void)
{
    return (cpu_throttle_get_percentage() != 0);
}

int cpu_throttle_get_percentage(void)
{
    return atomic_read(&throttle_percentage);
}

void cpu_ticks_init(void)
{
    seqlock_init(&timers_state.vm_clock_seqlock);
    vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
    throttle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT,
                                           cpu_throttle_timer_tick, NULL);
}

void configure_icount(QemuOpts *opts, Error **errp)
{
    const char *option;
    char *rem_str = NULL;

    option = qemu_opt_get(opts, "shift");
    if (!option) {
        if (qemu_opt_get(opts, "align") != NULL) {
            error_setg(errp, "Please specify shift option when using align");
        }
        return;
    }

    icount_sleep = qemu_opt_get_bool(opts, "sleep", true);
    if (icount_sleep) {
        timers_state.icount_warp_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT,
                                         icount_timer_cb, NULL);
    }

    icount_align_option = qemu_opt_get_bool(opts, "align", false);

    if (icount_align_option && !icount_sleep) {
        error_setg(errp, "align=on and sleep=off are incompatible");
    }
    if (strcmp(option, "auto") != 0) {
        errno = 0;
        icount_time_shift = strtol(option, &rem_str, 0);
        if (errno != 0 || *rem_str != '\0' || !strlen(option)) {
            error_setg(errp, "icount: Invalid shift value");
        }
        use_icount = 1;
        return;
    } else if (icount_align_option) {
        error_setg(errp, "shift=auto and align=on are incompatible");
    } else if (!icount_sleep) {
        error_setg(errp, "shift=auto and sleep=off are incompatible");
    }

    use_icount = 2;

    /* 125MIPS seems a reasonable initial guess at the guest speed.
       It will be corrected fairly quickly anyway.  */
    icount_time_shift = 3;

    /* Have both realtime and virtual time triggers for speed adjustment.
       The realtime trigger catches emulated time passing too slowly,
       the virtual time trigger catches emulated time passing too fast.
       Realtime triggers occur even when idle, so use them less frequently
       than VM triggers.  */
    timers_state.vm_clock_warp_start = -1;
    timers_state.icount_rt_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL_RT,
                                   icount_adjust_rt, NULL);
    timer_mod(timers_state.icount_rt_timer,
                   qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000);
    timers_state.icount_vm_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                        icount_adjust_vm, NULL);
    timer_mod(timers_state.icount_vm_timer,
                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
                   NANOSECONDS_PER_SECOND / 10);
}

/***********************************************************/
/* TCG vCPU kick timer
 *
 * The kick timer is responsible for moving single threaded vCPU
 * emulation on to the next vCPU. If more than one vCPU is running a
 * timer event with force a cpu->exit so the next vCPU can get
 * scheduled.
 *
 * The timer is removed if all vCPUs are idle and restarted again once
 * idleness is complete.
 */

static QEMUTimer *tcg_kick_vcpu_timer;
static CPUState *tcg_current_rr_cpu;

#define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10)

static inline int64_t qemu_tcg_next_kick(void)
{
    return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + TCG_KICK_PERIOD;
}

/* Kick the currently round-robin scheduled vCPU */
static void qemu_cpu_kick_rr_cpu(void)
{
    CPUState *cpu;
    do {
        cpu = atomic_mb_read(&tcg_current_rr_cpu);
        if (cpu) {
            cpu_exit(cpu);
        }
    } while (cpu != atomic_mb_read(&tcg_current_rr_cpu));
}

static void do_nothing(CPUState *cpu, run_on_cpu_data unused)
{
}

void qemu_timer_notify_cb(void *opaque, QEMUClockType type)
{
    if (!use_icount || type != QEMU_CLOCK_VIRTUAL) {
        qemu_notify_event();
        return;
    }

    if (qemu_in_vcpu_thread()) {
        /* A CPU is currently running; kick it back out to the
         * tcg_cpu_exec() loop so it will recalculate its
         * icount deadline immediately.
         */
        qemu_cpu_kick(current_cpu);
    } else if (first_cpu) {
        /* qemu_cpu_kick is not enough to kick a halted CPU out of
         * qemu_tcg_wait_io_event.  async_run_on_cpu, instead,
         * causes cpu_thread_is_idle to return false.  This way,
         * handle_icount_deadline can run.
         * If we have no CPUs at all for some reason, we don't
         * need to do anything.
         */
        async_run_on_cpu(first_cpu, do_nothing, RUN_ON_CPU_NULL);
    }
}

static void kick_tcg_thread(void *opaque)
{
    timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick());
    qemu_cpu_kick_rr_cpu();
}

static void start_tcg_kick_timer(void)
{
    assert(!mttcg_enabled);
    if (!tcg_kick_vcpu_timer && CPU_NEXT(first_cpu)) {
        tcg_kick_vcpu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                           kick_tcg_thread, NULL);
        timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick());
    }
}

static void stop_tcg_kick_timer(void)
{
    assert(!mttcg_enabled);
    if (tcg_kick_vcpu_timer) {
        timer_del(tcg_kick_vcpu_timer);
        tcg_kick_vcpu_timer = NULL;
    }
}

/***********************************************************/
void hw_error(const char *fmt, ...)
{
    va_list ap;
    CPUState *cpu;

    va_start(ap, fmt);
    fprintf(stderr, "qemu: hardware error: ");
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
    CPU_FOREACH(cpu) {
        fprintf(stderr, "CPU #%d:\n", cpu->cpu_index);
        cpu_dump_state(cpu, stderr, fprintf, CPU_DUMP_FPU);
    }
    va_end(ap);
    abort();
}

void cpu_synchronize_all_states(void)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        cpu_synchronize_state(cpu);
        /* TODO: move to cpu_synchronize_state() */
        if (hvf_enabled()) {
            hvf_cpu_synchronize_state(cpu);
        }
    }
}

void cpu_synchronize_all_post_reset(void)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        cpu_synchronize_post_reset(cpu);
        /* TODO: move to cpu_synchronize_post_reset() */
        if (hvf_enabled()) {
            hvf_cpu_synchronize_post_reset(cpu);
        }
    }
}

void cpu_synchronize_all_post_init(void)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        cpu_synchronize_post_init(cpu);
        /* TODO: move to cpu_synchronize_post_init() */
        if (hvf_enabled()) {
            hvf_cpu_synchronize_post_init(cpu);
        }
    }
}

void cpu_synchronize_all_pre_loadvm(void)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        cpu_synchronize_pre_loadvm(cpu);
    }
}

static int do_vm_stop(RunState state, bool send_stop)
{
    int ret = 0;

    if (runstate_is_running()) {
        cpu_disable_ticks();
        pause_all_vcpus();
        runstate_set(state);
        vm_state_notify(0, state);
        if (send_stop) {
            qapi_event_send_stop(&error_abort);
        }
    }

    bdrv_drain_all();
    replay_disable_events();
    ret = bdrv_flush_all();

    return ret;
}

/* Special vm_stop() variant for terminating the process.  Historically clients
 * did not expect a QMP STOP event and so we need to retain compatibility.
 */
int vm_shutdown(void)
{
    return do_vm_stop(RUN_STATE_SHUTDOWN, false);
}

static bool cpu_can_run(CPUState *cpu)
{
    if (cpu->stop) {
        return false;
    }
    if (cpu_is_stopped(cpu)) {
        return false;
    }
    return true;
}

static void cpu_handle_guest_debug(CPUState *cpu)
{
    gdb_set_stop_cpu(cpu);
    qemu_system_debug_request();
    cpu->stopped = true;
}

#ifdef CONFIG_LINUX
static void sigbus_reraise(void)
{
    sigset_t set;
    struct sigaction action;

    memset(&action, 0, sizeof(action));
    action.sa_handler = SIG_DFL;
    if (!sigaction(SIGBUS, &action, NULL)) {
        raise(SIGBUS);
        sigemptyset(&set);
        sigaddset(&set, SIGBUS);
        pthread_sigmask(SIG_UNBLOCK, &set, NULL);
    }
    perror("Failed to re-raise SIGBUS!\n");
    abort();
}

static void sigbus_handler(int n, siginfo_t *siginfo, void *ctx)
{
    if (siginfo->si_code != BUS_MCEERR_AO && siginfo->si_code != BUS_MCEERR_AR) {
        sigbus_reraise();
    }

    if (current_cpu) {
        /* Called asynchronously in VCPU thread.  */
        if (kvm_on_sigbus_vcpu(current_cpu, siginfo->si_code, siginfo->si_addr)) {
            sigbus_reraise();
        }
    } else {
        /* Called synchronously (via signalfd) in main thread.  */
        if (kvm_on_sigbus(siginfo->si_code, siginfo->si_addr)) {
            sigbus_reraise();
        }
    }
}

static void qemu_init_sigbus(void)
{
    struct sigaction action;

    memset(&action, 0, sizeof(action));
    action.sa_flags = SA_SIGINFO;
    action.sa_sigaction = sigbus_handler;
    sigaction(SIGBUS, &action, NULL);

    prctl(PR_MCE_KILL, PR_MCE_KILL_SET, PR_MCE_KILL_EARLY, 0, 0);
}
#else /* !CONFIG_LINUX */
static void qemu_init_sigbus(void)
{
}
#endif /* !CONFIG_LINUX */

static QemuMutex qemu_global_mutex;

static QemuThread io_thread;

/* cpu creation */
static QemuCond qemu_cpu_cond;
/* system init */
static QemuCond qemu_pause_cond;

void qemu_init_cpu_loop(void)
{
    qemu_init_sigbus();
    qemu_cond_init(&qemu_cpu_cond);
    qemu_cond_init(&qemu_pause_cond);
    qemu_mutex_init(&qemu_global_mutex);

    qemu_thread_get_self(&io_thread);
}

void run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data)
{
    do_run_on_cpu(cpu, func, data, &qemu_global_mutex);
}

static void qemu_kvm_destroy_vcpu(CPUState *cpu)
{
    if (kvm_destroy_vcpu(cpu) < 0) {
        error_report("kvm_destroy_vcpu failed");
        exit(EXIT_FAILURE);
    }
}

static void qemu_tcg_destroy_vcpu(CPUState *cpu)
{
}

static void qemu_cpu_stop(CPUState *cpu, bool exit)
{
    g_assert(qemu_cpu_is_self(cpu));
    cpu->stop = false;
    cpu->stopped = true;
    if (exit) {
        cpu_exit(cpu);
    }
    qemu_cond_broadcast(&qemu_pause_cond);
}

static void qemu_wait_io_event_common(CPUState *cpu)
{
    atomic_mb_set(&cpu->thread_kicked, false);
    if (cpu->stop) {
        qemu_cpu_stop(cpu, false);
    }
    process_queued_cpu_work(cpu);
}

static void qemu_tcg_rr_wait_io_event(CPUState *cpu)
{
    while (all_cpu_threads_idle()) {
        stop_tcg_kick_timer();
        qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
    }

    start_tcg_kick_timer();

    qemu_wait_io_event_common(cpu);
}

static void qemu_wait_io_event(CPUState *cpu)
{
    while (cpu_thread_is_idle(cpu)) {
        qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
    }

#ifdef _WIN32
    /* Eat dummy APC queued by qemu_cpu_kick_thread.  */
    if (!tcg_enabled()) {
        SleepEx(0, TRUE);
    }
#endif
    qemu_wait_io_event_common(cpu);
}

static void *qemu_kvm_cpu_thread_fn(void *arg)
{
    CPUState *cpu = arg;
    int r;

    rcu_register_thread();

    qemu_mutex_lock_iothread();
    qemu_thread_get_self(cpu->thread);
    cpu->thread_id = qemu_get_thread_id();
    cpu->can_do_io = 1;
    current_cpu = cpu;

    r = kvm_init_vcpu(cpu);
    if (r < 0) {
        error_report("kvm_init_vcpu failed: %s", strerror(-r));
        exit(1);
    }

    kvm_init_cpu_signals(cpu);

    /* signal CPU creation */
    cpu->created = true;
    qemu_cond_signal(&qemu_cpu_cond);

    do {
        if (cpu_can_run(cpu)) {
            r = kvm_cpu_exec(cpu);
            if (r == EXCP_DEBUG) {
                cpu_handle_guest_debug(cpu);
            }
        }
        qemu_wait_io_event(cpu);
    } while (!cpu->unplug || cpu_can_run(cpu));

    qemu_kvm_destroy_vcpu(cpu);
    cpu->created = false;
    qemu_cond_signal(&qemu_cpu_cond);
    qemu_mutex_unlock_iothread();
    rcu_unregister_thread();
    return NULL;
}

static void *qemu_dummy_cpu_thread_fn(void *arg)
{
#ifdef _WIN32
    error_report("qtest is not supported under Windows");
    exit(1);
#else
    CPUState *cpu = arg;
    sigset_t waitset;
    int r;

    rcu_register_thread();

    qemu_mutex_lock_iothread();
    qemu_thread_get_self(cpu->thread);
    cpu->thread_id = qemu_get_thread_id();
    cpu->can_do_io = 1;
    current_cpu = cpu;

    sigemptyset(&waitset);
    sigaddset(&waitset, SIG_IPI);

    /* signal CPU creation */
    cpu->created = true;
    qemu_cond_signal(&qemu_cpu_cond);

    do {
        qemu_mutex_unlock_iothread();
        do {
            int sig;
            r = sigwait(&waitset, &sig);
        } while (r == -1 && (errno == EAGAIN || errno == EINTR));
        if (r == -1) {
            perror("sigwait");
            exit(1);
        }
        qemu_mutex_lock_iothread();
        qemu_wait_io_event(cpu);
    } while (!cpu->unplug);

    rcu_unregister_thread();
    return NULL;
#endif
}

static int64_t tcg_get_icount_limit(void)
{
    int64_t deadline;

    if (replay_mode != REPLAY_MODE_PLAY) {
        deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);

        /* Maintain prior (possibly buggy) behaviour where if no deadline
         * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
         * INT32_MAX nanoseconds ahead, we still use INT32_MAX
         * nanoseconds.
         */
        if ((deadline < 0) || (deadline > INT32_MAX)) {
            deadline = INT32_MAX;
        }

        return qemu_icount_round(deadline);
    } else {
        return replay_get_instructions();
    }
}

static void handle_icount_deadline(void)
{
    assert(qemu_in_vcpu_thread());
    if (use_icount) {
        int64_t deadline =
            qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);

        if (deadline == 0) {
            /* Wake up other AioContexts.  */
            qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
            qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
        }
    }
}

static void prepare_icount_for_run(CPUState *cpu)
{
    if (use_icount) {
        int insns_left;

        /* These should always be cleared by process_icount_data after
         * each vCPU execution. However u16.high can be raised
         * asynchronously by cpu_exit/cpu_interrupt/tcg_handle_interrupt
         */
        g_assert(cpu->icount_decr.u16.low == 0);
        g_assert(cpu->icount_extra == 0);

        cpu->icount_budget = tcg_get_icount_limit();
        insns_left = MIN(0xffff, cpu->icount_budget);
        cpu->icount_decr.u16.low = insns_left;
        cpu->icount_extra = cpu->icount_budget - insns_left;

        replay_mutex_lock();
    }
}

static void process_icount_data(CPUState *cpu)
{
    if (use_icount) {
        /* Account for executed instructions */
        cpu_update_icount(cpu);

        /* Reset the counters */
        cpu->icount_decr.u16.low = 0;
        cpu->icount_extra = 0;
        cpu->icount_budget = 0;

        replay_account_executed_instructions();

        replay_mutex_unlock();
    }
}


static int tcg_cpu_exec(CPUState *cpu)
{
    int ret;
#ifdef CONFIG_PROFILER
    int64_t ti;
#endif

    assert(tcg_enabled());
#ifdef CONFIG_PROFILER
    ti = profile_getclock();
#endif
    cpu_exec_start(cpu);
    ret = cpu_exec(cpu);
    cpu_exec_end(cpu);
#ifdef CONFIG_PROFILER
    tcg_time += profile_getclock() - ti;
#endif
    return ret;
}

/* Destroy any remaining vCPUs which have been unplugged and have
 * finished running
 */
static void deal_with_unplugged_cpus(void)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        if (cpu->unplug && !cpu_can_run(cpu)) {
            qemu_tcg_destroy_vcpu(cpu);
            cpu->created = false;
            qemu_cond_signal(&qemu_cpu_cond);
            break;
        }
    }
}

/* Single-threaded TCG
 *
 * In the single-threaded case each vCPU is simulated in turn. If
 * there is more than a single vCPU we create a simple timer to kick
 * the vCPU and ensure we don't get stuck in a tight loop in one vCPU.
 * This is done explicitly rather than relying on side-effects
 * elsewhere.
 */

static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
{
    CPUState *cpu = arg;

    assert(tcg_enabled());
    rcu_register_thread();
    tcg_register_thread();

    qemu_mutex_lock_iothread();
    qemu_thread_get_self(cpu->thread);

    cpu->thread_id = qemu_get_thread_id();
    cpu->created = true;
    cpu->can_do_io = 1;
    qemu_cond_signal(&qemu_cpu_cond);

    /* wait for initial kick-off after machine start */
    while (first_cpu->stopped) {
        qemu_cond_wait(first_cpu->halt_cond, &qemu_global_mutex);

        /* process any pending work */
        CPU_FOREACH(cpu) {
            current_cpu = cpu;
            qemu_wait_io_event_common(cpu);
        }
    }

    start_tcg_kick_timer();

    cpu = first_cpu;

    /* process any pending work */
    cpu->exit_request = 1;

    while (1) {
        qemu_mutex_unlock_iothread();
        replay_mutex_lock();
        qemu_mutex_lock_iothread();
        /* Account partial waits to QEMU_CLOCK_VIRTUAL.  */
        qemu_account_warp_timer();

        /* Run the timers here.  This is much more efficient than
         * waking up the I/O thread and waiting for completion.
         */
        handle_icount_deadline();

        replay_mutex_unlock();

        if (!cpu) {
            cpu = first_cpu;
        }

        while (cpu && !cpu->queued_work_first && !cpu->exit_request) {

            atomic_mb_set(&tcg_current_rr_cpu, cpu);
            current_cpu = cpu;

            qemu_clock_enable(QEMU_CLOCK_VIRTUAL,
                              (cpu->singlestep_enabled & SSTEP_NOTIMER) == 0);

            if (cpu_can_run(cpu)) {
                int r;

                qemu_mutex_unlock_iothread();
                prepare_icount_for_run(cpu);

                /* If the icount budget is already exhausted, break now so this
                 * CPU has a chance to execute during the next turn. */
                if (!cpu->icount_budget) {
                    qemu_mutex_lock_iothread();
                    break;
                }

                r = tcg_cpu_exec(cpu);

                process_icount_data(cpu);
                qemu_mutex_lock_iothread();

                if (r == EXCP_DEBUG) {
                    cpu_handle_guest_debug(cpu);
                    break;
                } else if (r == EXCP_ATOMIC) {
                    qemu_mutex_unlock_iothread();
                    cpu_exec_step_atomic(cpu);
                    qemu_mutex_lock_iothread();
                    break;
                }
            } else if (cpu->stop) {
                if (cpu->unplug) {
                    cpu = CPU_NEXT(cpu);
                }
                break;
            }

            cpu = CPU_NEXT(cpu);
        } /* while (cpu && !cpu->exit_request).. */

        /* Does not need atomic_mb_set because a spurious wakeup is okay.  */
        atomic_set(&tcg_current_rr_cpu, NULL);

        if (cpu && cpu->exit_request) {
            atomic_mb_set(&cpu->exit_request, 0);
        }

        /*
         * When all cpus are sleeping (e.g just entered WFE)
         * and SystemC is waiting because it is ahead of qemu,
         * it can lead to a deadlock where the main_loop is waiting.
         * The solution is to wake up the main_loop, so it then warp timers,
         * which makes qemu jump to the end of quantum and unlock SystemC.
        */
        if (all_cpu_threads_idle()) {
            qemu_notify_event();
        }

        qemu_tcg_rr_wait_io_event(cpu ? cpu : QTAILQ_FIRST(&cpus));
        deal_with_unplugged_cpus();
    }

    rcu_unregister_thread();
    return NULL;
}

static void *qemu_hax_cpu_thread_fn(void *arg)
{
    CPUState *cpu = arg;
    int r;

    rcu_register_thread();
    qemu_mutex_lock_iothread();
    qemu_thread_get_self(cpu->thread);

    cpu->thread_id = qemu_get_thread_id();
    cpu->created = true;
    cpu->halted = 0;
    current_cpu = cpu;

    hax_init_vcpu(cpu);
    qemu_cond_signal(&qemu_cpu_cond);

    do {
        if (cpu_can_run(cpu)) {
            r = hax_smp_cpu_exec(cpu);
            if (r == EXCP_DEBUG) {
                cpu_handle_guest_debug(cpu);
            }
        }

        qemu_wait_io_event(cpu);
    } while (!cpu->unplug || cpu_can_run(cpu));
    rcu_unregister_thread();
    return NULL;
}

/* The HVF-specific vCPU thread function. This one should only run when the host
 * CPU supports the VMX "unrestricted guest" feature. */
static void *qemu_hvf_cpu_thread_fn(void *arg)
{
    CPUState *cpu = arg;

    int r;

    assert(hvf_enabled());

    rcu_register_thread();

    qemu_mutex_lock_iothread();
    qemu_thread_get_self(cpu->thread);

    cpu->thread_id = qemu_get_thread_id();
    cpu->can_do_io = 1;
    current_cpu = cpu;

    hvf_init_vcpu(cpu);

    /* signal CPU creation */
    cpu->created = true;
    qemu_cond_signal(&qemu_cpu_cond);

    do {
        if (cpu_can_run(cpu)) {
            r = hvf_vcpu_exec(cpu);
            if (r == EXCP_DEBUG) {
                cpu_handle_guest_debug(cpu);
            }
        }
        qemu_wait_io_event(cpu);
    } while (!cpu->unplug || cpu_can_run(cpu));

    hvf_vcpu_destroy(cpu);
    cpu->created = false;
    qemu_cond_signal(&qemu_cpu_cond);
    qemu_mutex_unlock_iothread();
    rcu_unregister_thread();
    return NULL;
}

static void *qemu_whpx_cpu_thread_fn(void *arg)
{
    CPUState *cpu = arg;
    int r;

    rcu_register_thread();

    qemu_mutex_lock_iothread();
    qemu_thread_get_self(cpu->thread);
    cpu->thread_id = qemu_get_thread_id();
    current_cpu = cpu;

    r = whpx_init_vcpu(cpu);
    if (r < 0) {
        fprintf(stderr, "whpx_init_vcpu failed: %s\n", strerror(-r));
        exit(1);
    }

    /* signal CPU creation */
    cpu->created = true;
    qemu_cond_signal(&qemu_cpu_cond);

    do {
        if (cpu_can_run(cpu)) {
            r = whpx_vcpu_exec(cpu);
            if (r == EXCP_DEBUG) {
                cpu_handle_guest_debug(cpu);
            }
        }
        while (cpu_thread_is_idle(cpu)) {
            qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
        }
        qemu_wait_io_event_common(cpu);
    } while (!cpu->unplug || cpu_can_run(cpu));

    whpx_destroy_vcpu(cpu);
    cpu->created = false;
    qemu_cond_signal(&qemu_cpu_cond);
    qemu_mutex_unlock_iothread();
    rcu_unregister_thread();
    return NULL;
}

#ifdef _WIN32
static void CALLBACK dummy_apc_func(ULONG_PTR unused)
{
}
#endif

/* Multi-threaded TCG
 *
 * In the multi-threaded case each vCPU has its own thread. The TLS
 * variable current_cpu can be used deep in the code to find the
 * current CPUState for a given thread.
 */

static void *qemu_tcg_cpu_thread_fn(void *arg)
{
    CPUState *cpu = arg;

    assert(tcg_enabled());
    g_assert(!use_icount);

    rcu_register_thread();
    tcg_register_thread();

    qemu_mutex_lock_iothread();
    qemu_thread_get_self(cpu->thread);

    cpu->thread_id = qemu_get_thread_id();
    cpu->created = true;
    cpu->can_do_io = 1;
    current_cpu = cpu;
    qemu_cond_signal(&qemu_cpu_cond);

    /* process any pending work */
    cpu->exit_request = 1;

    do {
        if (cpu_can_run(cpu)) {
            int r;
            qemu_mutex_unlock_iothread();
            r = tcg_cpu_exec(cpu);
            qemu_mutex_lock_iothread();
            switch (r) {
            case EXCP_DEBUG:
                cpu_handle_guest_debug(cpu);
                break;
            case EXCP_HALTED:
                /* during start-up the vCPU is reset and the thread is
                 * kicked several times. If we don't ensure we go back
                 * to sleep in the halted state we won't cleanly
                 * start-up when the vCPU is enabled.
                 *
                 * cpu->halted should ensure we sleep in wait_io_event
                 */
                g_assert(cpu->halted);
                break;
            case EXCP_ATOMIC:
                qemu_mutex_unlock_iothread();
                cpu_exec_step_atomic(cpu);
                qemu_mutex_lock_iothread();
            default:
                /* Ignore everything else? */
                break;
            }
        }

        atomic_mb_set(&cpu->exit_request, 0);
        qemu_wait_io_event(cpu);
    } while (!cpu->unplug || cpu_can_run(cpu));

    qemu_tcg_destroy_vcpu(cpu);
    cpu->created = false;
    qemu_cond_signal(&qemu_cpu_cond);
    qemu_mutex_unlock_iothread();
    rcu_unregister_thread();
    return NULL;
}

static void qemu_cpu_kick_thread(CPUState *cpu)
{
#ifndef _WIN32
    int err;

    if (cpu->thread_kicked) {
        return;
    }
    cpu->thread_kicked = true;
    err = pthread_kill(cpu->thread->thread, SIG_IPI);
    if (err) {
        fprintf(stderr, "qemu:%s: %s", __func__, strerror(err));
        exit(1);
    }
#else /* _WIN32 */
    if (!qemu_cpu_is_self(cpu)) {
        if (whpx_enabled()) {
            whpx_vcpu_kick(cpu);
        } else if (!QueueUserAPC(dummy_apc_func, cpu->hThread, 0)) {
            fprintf(stderr, "%s: QueueUserAPC failed with error %lu\n",
                    __func__, GetLastError());
            exit(1);
        }
    }
#endif
}

void qemu_cpu_kick(CPUState *cpu)
{
    qemu_cond_broadcast(cpu->halt_cond);
    if (tcg_enabled()) {
        cpu_exit(cpu);
        /* NOP unless doing single-thread RR */
        qemu_cpu_kick_rr_cpu();
    } else {
        if (hax_enabled()) {
            /*
             * FIXME: race condition with the exit_request check in
             * hax_vcpu_hax_exec
             */
            cpu->exit_request = 1;
        }
        qemu_cpu_kick_thread(cpu);
    }
}

void qemu_cpu_kick_self(void)
{
    assert(current_cpu);
    qemu_cpu_kick_thread(current_cpu);
}

bool qemu_cpu_is_self(CPUState *cpu)
{
    return qemu_thread_is_self(cpu->thread);
}

bool qemu_in_vcpu_thread(void)
{
    return current_cpu && qemu_cpu_is_self(current_cpu);
}

static __thread bool iothread_locked = false;

bool qemu_mutex_iothread_locked(void)
{
    return iothread_locked;
}

void qemu_mutex_lock_iothread(void)
{
    g_assert(!qemu_mutex_iothread_locked());
    qemu_mutex_lock(&qemu_global_mutex);
    iothread_locked = true;
}

void qemu_mutex_unlock_iothread(void)
{
    g_assert(qemu_mutex_iothread_locked());
    iothread_locked = false;
    qemu_mutex_unlock(&qemu_global_mutex);
}

static bool all_vcpus_paused(void)
{
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        if (!cpu->stopped) {
            return false;
        }
    }

    return true;
}

void pause_all_vcpus(void)
{
    CPUState *cpu;

    qemu_clock_enable(QEMU_CLOCK_VIRTUAL, false);
    CPU_FOREACH(cpu) {
        if (qemu_cpu_is_self(cpu)) {
            qemu_cpu_stop(cpu, true);
        } else {
            cpu->stop = true;
            qemu_cpu_kick(cpu);
        }
    }

    /* We need to drop the replay_lock so any vCPU threads woken up
     * can finish their replay tasks
     */
    replay_mutex_unlock();

    while (!all_vcpus_paused()) {
        qemu_cond_wait(&qemu_pause_cond, &qemu_global_mutex);
        CPU_FOREACH(cpu) {
            qemu_cpu_kick(cpu);
        }
    }

    qemu_mutex_unlock_iothread();
    replay_mutex_lock();
    qemu_mutex_lock_iothread();
}

void cpu_resume(CPUState *cpu)
{
    cpu->stop = false;
    cpu->stopped = false;
    qemu_cpu_kick(cpu);
}

void resume_all_vcpus(void)
{
    CPUState *cpu;

    qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
    CPU_FOREACH(cpu) {
        cpu_resume(cpu);
    }
}

void cpu_remove_sync(CPUState *cpu)
{
    cpu->stop = true;
    cpu->unplug = true;
    qemu_cpu_kick(cpu);
    qemu_mutex_unlock_iothread();
    qemu_thread_join(cpu->thread);
    qemu_mutex_lock_iothread();
}

/* For temporary buffers for forming a name */
#define VCPU_THREAD_NAME_SIZE 16

static void qemu_tcg_init_vcpu(CPUState *cpu)
{
    char thread_name[VCPU_THREAD_NAME_SIZE];
    static QemuCond *single_tcg_halt_cond;
    static QemuThread *single_tcg_cpu_thread;
    static int tcg_region_inited;

    assert(tcg_enabled());
    /*
     * Initialize TCG regions--once. Now is a good time, because:
     * (1) TCG's init context, prologue and target globals have been set up.
     * (2) qemu_tcg_mttcg_enabled() works now (TCG init code runs before the
     *     -accel flag is processed, so the check doesn't work then).
     */
    if (!tcg_region_inited) {
        tcg_region_inited = 1;
        tcg_region_init();
    }

    if (qemu_tcg_mttcg_enabled() || !single_tcg_cpu_thread) {
        cpu->thread = g_malloc0(sizeof(QemuThread));
        cpu->halt_cond = g_malloc0(sizeof(QemuCond));
        qemu_cond_init(cpu->halt_cond);

        if (qemu_tcg_mttcg_enabled()) {
            /* create a thread per vCPU with TCG (MTTCG) */
            parallel_cpus = true;
            snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG",
                 cpu->cpu_index);

            qemu_thread_create(cpu->thread, thread_name, qemu_tcg_cpu_thread_fn,
                               cpu, QEMU_THREAD_JOINABLE);

        } else {
            /* share a single thread for all cpus with TCG */
            snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "ALL CPUs/TCG");
            qemu_thread_create(cpu->thread, thread_name,
                               qemu_tcg_rr_cpu_thread_fn,
                               cpu, QEMU_THREAD_JOINABLE);

            single_tcg_halt_cond = cpu->halt_cond;
            single_tcg_cpu_thread = cpu->thread;
        }
#ifdef _WIN32
        cpu->hThread = qemu_thread_get_handle(cpu->thread);
#endif
    } else {
        /* For non-MTTCG cases we share the thread */
        cpu->thread = single_tcg_cpu_thread;
        cpu->halt_cond = single_tcg_halt_cond;
        cpu->thread_id = first_cpu->thread_id;
        cpu->can_do_io = 1;
        cpu->created = true;
    }
}

static void qemu_hax_start_vcpu(CPUState *cpu)
{
    char thread_name[VCPU_THREAD_NAME_SIZE];

    cpu->thread = g_malloc0(sizeof(QemuThread));
    cpu->halt_cond = g_malloc0(sizeof(QemuCond));
    qemu_cond_init(cpu->halt_cond);

    snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/HAX",
             cpu->cpu_index);
    qemu_thread_create(cpu->thread, thread_name, qemu_hax_cpu_thread_fn,
                       cpu, QEMU_THREAD_JOINABLE);
#ifdef _WIN32
    cpu->hThread = qemu_thread_get_handle(cpu->thread);
#endif
}

static void qemu_kvm_start_vcpu(CPUState *cpu)
{
    char thread_name[VCPU_THREAD_NAME_SIZE];

    cpu->thread = g_malloc0(sizeof(QemuThread));
    cpu->halt_cond = g_malloc0(sizeof(QemuCond));
    qemu_cond_init(cpu->halt_cond);
    snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/KVM",
             cpu->cpu_index);
    qemu_thread_create(cpu->thread, thread_name, qemu_kvm_cpu_thread_fn,
                       cpu, QEMU_THREAD_JOINABLE);
}

static void qemu_hvf_start_vcpu(CPUState *cpu)
{
    char thread_name[VCPU_THREAD_NAME_SIZE];

    /* HVF currently does not support TCG, and only runs in
     * unrestricted-guest mode. */
    assert(hvf_enabled());

    cpu->thread = g_malloc0(sizeof(QemuThread));
    cpu->halt_cond = g_malloc0(sizeof(QemuCond));
    qemu_cond_init(cpu->halt_cond);

    snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/HVF",
             cpu->cpu_index);
    qemu_thread_create(cpu->thread, thread_name, qemu_hvf_cpu_thread_fn,
                       cpu, QEMU_THREAD_JOINABLE);
}

static void qemu_whpx_start_vcpu(CPUState *cpu)
{
    char thread_name[VCPU_THREAD_NAME_SIZE];

    cpu->thread = g_malloc0(sizeof(QemuThread));
    cpu->halt_cond = g_malloc0(sizeof(QemuCond));
    qemu_cond_init(cpu->halt_cond);
    snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/WHPX",
             cpu->cpu_index);
    qemu_thread_create(cpu->thread, thread_name, qemu_whpx_cpu_thread_fn,
                       cpu, QEMU_THREAD_JOINABLE);
#ifdef _WIN32
    cpu->hThread = qemu_thread_get_handle(cpu->thread);
#endif
}

static void qemu_dummy_start_vcpu(CPUState *cpu)
{
    char thread_name[VCPU_THREAD_NAME_SIZE];

    cpu->thread = g_malloc0(sizeof(QemuThread));
    cpu->halt_cond = g_malloc0(sizeof(QemuCond));
    qemu_cond_init(cpu->halt_cond);
    snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/DUMMY",
             cpu->cpu_index);
    qemu_thread_create(cpu->thread, thread_name, qemu_dummy_cpu_thread_fn, cpu,
                       QEMU_THREAD_JOINABLE);
}

void qemu_init_vcpu(CPUState *cpu)
{
    cpu->nr_cores = smp_cores;
    cpu->nr_threads = smp_threads;
    cpu->stopped = true;

    if (!cpu->as) {
        /* If the target cpu hasn't set up any address spaces itself,
         * give it the default one.
         */
        cpu->num_ases = 1;
        cpu_address_space_init(cpu, 0, "cpu-memory", cpu->memory);
    }

    if (kvm_enabled()) {
        qemu_kvm_start_vcpu(cpu);
    } else if (hax_enabled()) {
        qemu_hax_start_vcpu(cpu);
    } else if (hvf_enabled()) {
        qemu_hvf_start_vcpu(cpu);
    } else if (tcg_enabled()) {
        qemu_tcg_init_vcpu(cpu);
    } else if (whpx_enabled()) {
        qemu_whpx_start_vcpu(cpu);
    } else {
        qemu_dummy_start_vcpu(cpu);
    }

    while (!cpu->created) {
        qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex);
    }
}

void cpu_stop_current(void)
{
    if (current_cpu) {
        qemu_cpu_stop(current_cpu, true);
    }
}

int vm_stop(RunState state)
{
    if (qemu_in_vcpu_thread()) {
        qemu_system_vmstop_request_prepare();
        qemu_system_vmstop_request(state);
        /*
         * FIXME: should not return to device code in case
         * vm_stop() has been requested.
         */
        cpu_stop_current();
        return 0;
    }

    return do_vm_stop(state, true);
}

/**
 * Prepare for (re)starting the VM.
 * Returns -1 if the vCPUs are not to be restarted (e.g. if they are already
 * running or in case of an error condition), 0 otherwise.
 */
int vm_prepare_start(void)
{
    RunState requested;

    qemu_vmstop_requested(&requested);
    if (runstate_is_running() && requested == RUN_STATE__MAX) {
        return -1;
    }

    /* Ensure that a STOP/RESUME pair of events is emitted if a
     * vmstop request was pending.  The BLOCK_IO_ERROR event, for
     * example, according to documentation is always followed by
     * the STOP event.
     */
    if (runstate_is_running()) {
        qapi_event_send_stop(&error_abort);
        qapi_event_send_resume(&error_abort);
        return -1;
    }

    /* We are sending this now, but the CPUs will be resumed shortly later */
    qapi_event_send_resume(&error_abort);

    replay_enable_events();
    cpu_enable_ticks();
    runstate_set(RUN_STATE_RUNNING);
    vm_state_notify(1, RUN_STATE_RUNNING);
    return 0;
}

void vm_start(void)
{
    if (!vm_prepare_start()) {
        resume_all_vcpus();
    }
}

/* does a state transition even if the VM is already stopped,
   current state is forgotten forever */
int vm_stop_force_state(RunState state)
{
    if (runstate_is_running()) {
        return vm_stop(state);
    } else {
        runstate_set(state);

        bdrv_drain_all();
        /* Make sure to return an error if the flush in a previous vm_stop()
         * failed. */
        return bdrv_flush_all();
    }
}

void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg)
{
    /* XXX: implement xxx_cpu_list for targets that still miss it */
#if defined(cpu_list)
    cpu_list(f, cpu_fprintf);
#endif
}

CpuInfoList *qmp_query_cpus(Error **errp)
{
    MachineState *ms = MACHINE(qdev_get_machine());
    MachineClass *mc = MACHINE_GET_CLASS(ms);
    CpuInfoList *head = NULL, *cur_item = NULL;
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        CpuInfoList *info;
#if defined(TARGET_I386)
        X86CPU *x86_cpu = X86_CPU(cpu);
        CPUX86State *env = &x86_cpu->env;
#elif defined(TARGET_PPC)
        PowerPCCPU *ppc_cpu = POWERPC_CPU(cpu);
        CPUPPCState *env = &ppc_cpu->env;
#elif defined(TARGET_SPARC)
        SPARCCPU *sparc_cpu = SPARC_CPU(cpu);
        CPUSPARCState *env = &sparc_cpu->env;
#elif defined(TARGET_RISCV)
        RISCVCPU *riscv_cpu = RISCV_CPU(cpu);
        CPURISCVState *env = &riscv_cpu->env;
#elif defined(TARGET_MIPS)
        MIPSCPU *mips_cpu = MIPS_CPU(cpu);
        CPUMIPSState *env = &mips_cpu->env;
#elif defined(TARGET_TRICORE)
        TriCoreCPU *tricore_cpu = TRICORE_CPU(cpu);
        CPUTriCoreState *env = &tricore_cpu->env;
#elif defined(TARGET_S390X)
        S390CPU *s390_cpu = S390_CPU(cpu);
        CPUS390XState *env = &s390_cpu->env;
#endif

        cpu_synchronize_state(cpu);

        info = g_malloc0(sizeof(*info));
        info->value = g_malloc0(sizeof(*info->value));
        info->value->CPU = cpu->cpu_index;
        info->value->current = (cpu == first_cpu);
        info->value->halted = cpu->halted;
        info->value->qom_path = object_get_canonical_path(OBJECT(cpu));
        info->value->thread_id = cpu->thread_id;
#if defined(TARGET_I386)
        info->value->arch = CPU_INFO_ARCH_X86;
        info->value->u.x86.pc = env->eip + env->segs[R_CS].base;
#elif defined(TARGET_PPC)
        info->value->arch = CPU_INFO_ARCH_PPC;
        info->value->u.ppc.nip = env->nip;
#elif defined(TARGET_SPARC)
        info->value->arch = CPU_INFO_ARCH_SPARC;
        info->value->u.q_sparc.pc = env->pc;
        info->value->u.q_sparc.npc = env->npc;
#elif defined(TARGET_MIPS)
        info->value->arch = CPU_INFO_ARCH_MIPS;
        info->value->u.q_mips.PC = env->active_tc.PC;
#elif defined(TARGET_TRICORE)
        info->value->arch = CPU_INFO_ARCH_TRICORE;
        info->value->u.tricore.PC = env->PC;
#elif defined(TARGET_S390X)
        info->value->arch = CPU_INFO_ARCH_S390;
        info->value->u.s390.cpu_state = env->cpu_state;
#elif defined(TARGET_RISCV)
        info->value->arch = CPU_INFO_ARCH_RISCV;
        info->value->u.riscv.pc = env->pc;
#else
        info->value->arch = CPU_INFO_ARCH_OTHER;
#endif
        info->value->has_props = !!mc->cpu_index_to_instance_props;
        if (info->value->has_props) {
            CpuInstanceProperties *props;
            props = g_malloc0(sizeof(*props));
            *props = mc->cpu_index_to_instance_props(ms, cpu->cpu_index);
            info->value->props = props;
        }

        /* XXX: waiting for the qapi to support GSList */
        if (!cur_item) {
            head = cur_item = info;
        } else {
            cur_item->next = info;
            cur_item = info;
        }
    }

    return head;
}

static CpuInfoArch sysemu_target_to_cpuinfo_arch(SysEmuTarget target)
{
    /*
     * The @SysEmuTarget -> @CpuInfoArch mapping below is based on the
     * TARGET_ARCH -> TARGET_BASE_ARCH mapping in the "configure" script.
     */
    switch (target) {
    case SYS_EMU_TARGET_I386:
    case SYS_EMU_TARGET_X86_64:
        return CPU_INFO_ARCH_X86;

    case SYS_EMU_TARGET_PPC:
    case SYS_EMU_TARGET_PPCEMB:
    case SYS_EMU_TARGET_PPC64:
        return CPU_INFO_ARCH_PPC;

    case SYS_EMU_TARGET_SPARC:
    case SYS_EMU_TARGET_SPARC64:
        return CPU_INFO_ARCH_SPARC;

    case SYS_EMU_TARGET_MIPS:
    case SYS_EMU_TARGET_MIPSEL:
    case SYS_EMU_TARGET_MIPS64:
    case SYS_EMU_TARGET_MIPS64EL:
        return CPU_INFO_ARCH_MIPS;

    case SYS_EMU_TARGET_TRICORE:
        return CPU_INFO_ARCH_TRICORE;

    case SYS_EMU_TARGET_S390X:
        return CPU_INFO_ARCH_S390;

    case SYS_EMU_TARGET_RISCV32:
    case SYS_EMU_TARGET_RISCV64:
        return CPU_INFO_ARCH_RISCV;

    default:
        return CPU_INFO_ARCH_OTHER;
    }
}

static void cpustate_to_cpuinfo_s390(CpuInfoS390 *info, const CPUState *cpu)
{
#ifdef TARGET_S390X
    S390CPU *s390_cpu = S390_CPU(cpu);
    CPUS390XState *env = &s390_cpu->env;

    info->cpu_state = env->cpu_state;
#else
    abort();
#endif
}

/*
 * fast means: we NEVER interrupt vCPU threads to retrieve
 * information from KVM.
 */
CpuInfoFastList *qmp_query_cpus_fast(Error **errp)
{
    MachineState *ms = MACHINE(qdev_get_machine());
    MachineClass *mc = MACHINE_GET_CLASS(ms);
    CpuInfoFastList *head = NULL, *cur_item = NULL;
    SysEmuTarget target = qapi_enum_parse(&SysEmuTarget_lookup, TARGET_NAME,
                                          -1, &error_abort);
    CPUState *cpu;

    CPU_FOREACH(cpu) {
        CpuInfoFastList *info = g_malloc0(sizeof(*info));
        info->value = g_malloc0(sizeof(*info->value));

        info->value->cpu_index = cpu->cpu_index;
        info->value->qom_path = object_get_canonical_path(OBJECT(cpu));
        info->value->thread_id = cpu->thread_id;

        info->value->has_props = !!mc->cpu_index_to_instance_props;
        if (info->value->has_props) {
            CpuInstanceProperties *props;
            props = g_malloc0(sizeof(*props));
            *props = mc->cpu_index_to_instance_props(ms, cpu->cpu_index);
            info->value->props = props;
        }

        info->value->arch = sysemu_target_to_cpuinfo_arch(target);
        info->value->target = target;
        if (target == SYS_EMU_TARGET_S390X) {
            cpustate_to_cpuinfo_s390(&info->value->u.s390x, cpu);
        }

        if (!cur_item) {
            head = cur_item = info;
        } else {
            cur_item->next = info;
            cur_item = info;
        }
    }

    return head;
}

void qmp_memsave(int64_t addr, int64_t size, const char *filename,
                 bool has_cpu, int64_t cpu_index, Error **errp)
{
    FILE *f;
    uint32_t l;
    CPUState *cpu;
    uint8_t buf[1024];
    int64_t orig_addr = addr, orig_size = size;

    if (!has_cpu) {
        cpu_index = 0;
    }

    cpu = qemu_get_cpu(cpu_index);
    if (cpu == NULL) {
        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu-index",
                   "a CPU number");
        return;
    }

    f = fopen(filename, "wb");
    if (!f) {
        error_setg_file_open(errp, errno, filename);
        return;
    }

    while (size != 0) {
        l = sizeof(buf);
        if (l > size)
            l = size;
        if (cpu_memory_rw_debug(cpu, addr, buf, l, 0) != 0) {
            error_setg(errp, "Invalid addr 0x%016" PRIx64 "/size %" PRId64
                             " specified", orig_addr, orig_size);
            goto exit;
        }
        if (fwrite(buf, 1, l, f) != l) {
            error_setg(errp, QERR_IO_ERROR);
            goto exit;
        }
        addr += l;
        size -= l;
    }

exit:
    fclose(f);
}

void qmp_pmemsave(int64_t addr, int64_t size, const char *filename,
                  Error **errp)
{
    FILE *f;
    uint32_t l;
    uint8_t buf[1024];

    f = fopen(filename, "wb");
    if (!f) {
        error_setg_file_open(errp, errno, filename);
        return;
    }

    while (size != 0) {
        l = sizeof(buf);
        if (l > size)
            l = size;
        cpu_physical_memory_read(addr, buf, l);
        if (fwrite(buf, 1, l, f) != l) {
            error_setg(errp, QERR_IO_ERROR);
            goto exit;
        }
        addr += l;
        size -= l;
    }

exit:
    fclose(f);
}

void qmp_inject_nmi(Error **errp)
{
    nmi_monitor_handle(monitor_get_cpu_index(), errp);
}

void dump_drift_info(FILE *f, fprintf_function cpu_fprintf)
{
    if (!use_icount) {
        return;
    }

    cpu_fprintf(f, "Host - Guest clock  %"PRIi64" ms\n",
                (cpu_get_clock() - cpu_get_icount())/SCALE_MS);
    if (icount_align_option) {
        cpu_fprintf(f, "Max guest delay     %"PRIi64" ms\n", -max_delay/SCALE_MS);
        cpu_fprintf(f, "Max guest advance   %"PRIi64" ms\n", max_advance/SCALE_MS);
    } else {
        cpu_fprintf(f, "Max guest delay     NA\n");
        cpu_fprintf(f, "Max guest advance   NA\n");
    }
}