sys/x86/xen/hvm.c

   1 /*
   2  * Copyright (c) 2008, 2013 Citrix Systems, Inc.
   3  * Copyright (c) 2012 Spectra Logic Corporation
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/param.h>
  32 #include <sys/bus.h>
  33 #include <sys/kernel.h>
  34 #include <sys/malloc.h>
  35 #include <sys/proc.h>
  36 #include <sys/smp.h>
  37 #include <sys/systm.h>
  38
  39 #include <vm/vm.h>
  40 #include <vm/pmap.h>
  41
  42 #include <dev/pci/pcivar.h>
  43
  44 #include <machine/cpufunc.h>
  45 #include <machine/cpu.h>
  46 #include <machine/smp.h>
  47
  48 #include <x86/apicreg.h>
  49
  50 #include <xen/xen-os.h>
  51 #include <xen/features.h>
  52 #include <xen/gnttab.h>
  53 #include <xen/hypervisor.h>
  54 #include <xen/hvm.h>
  55 #include <xen/xen_intr.h>
  56
  57 #include <xen/interface/hvm/params.h>
  58 #include <xen/interface/vcpu.h>
  59
  60 /*--------------------------- Forward Declarations ---------------------------*/
  61 #ifdef SMP
  62 static driver_filter_t xen_smp_rendezvous_action;
  63 static driver_filter_t xen_invltlb;
  64 static driver_filter_t xen_invlpg;
  65 static driver_filter_t xen_invlrng;
  66 static driver_filter_t xen_invlcache;
  67 #ifdef __i386__
  68 static driver_filter_t xen_lazypmap;
  69 #endif
  70 static driver_filter_t xen_ipi_bitmap_handler;
  71 static driver_filter_t xen_cpustop_handler;
  72 static driver_filter_t xen_cpususpend_handler;
  73 static driver_filter_t xen_cpustophard_handler;
  74 #endif
  75 static void xen_ipi_vectored(u_int vector, int dest);
  76 static void xen_hvm_cpu_resume(void);
  77 static void xen_hvm_cpu_init(void);
  78
  79 /*---------------------------- Extern Declarations ---------------------------*/
  80 #ifdef __i386__
  81 extern void pmap_lazyfix_action(void);
  82 #endif
  83 #ifdef __amd64__
  84 extern int pmap_pcid_enabled;
  85 #endif
  86
  87 /* Variables used by mp_machdep to perform the bitmap IPI */
  88 extern volatile u_int cpu_ipi_pending[MAXCPU];
  89
  90 /*---------------------------------- Macros ----------------------------------*/
  91 #define IPI_TO_IDX(ipi) ((ipi) - APIC_IPI_INTS)
  92
  93 /*-------------------------------- Local Types -------------------------------*/
  94 enum xen_hvm_init_type {
  95         XEN_HVM_INIT_COLD,
  96         XEN_HVM_INIT_CANCELLED_SUSPEND,
  97         XEN_HVM_INIT_RESUME
  98 };
  99
 100 struct xen_ipi_handler
 101 {
 102         driver_filter_t *filter;
 103         const char      *description;
 104 };
 105
 106 /*-------------------------------- Global Data -------------------------------*/
 107 enum xen_domain_type xen_domain_type = XEN_NATIVE;
 108
 109 struct cpu_ops xen_hvm_cpu_ops = {
 110         .ipi_vectored   = lapic_ipi_vectored,
 111         .cpu_init       = xen_hvm_cpu_init,
 112         .cpu_resume     = xen_hvm_cpu_resume
 113 };
 114
 115 static MALLOC_DEFINE(M_XENHVM, "xen_hvm", "Xen HVM PV Support");
 116
 117 #ifdef SMP
 118 static struct xen_ipi_handler xen_ipis[] =
 119 {
 120         [IPI_TO_IDX(IPI_RENDEZVOUS)]    = { xen_smp_rendezvous_action,  "r"   },
 121         [IPI_TO_IDX(IPI_INVLTLB)]       = { xen_invltlb,                "itlb"},
 122         [IPI_TO_IDX(IPI_INVLPG)]        = { xen_invlpg,                 "ipg" },
 123         [IPI_TO_IDX(IPI_INVLRNG)]       = { xen_invlrng,                "irg" },
 124         [IPI_TO_IDX(IPI_INVLCACHE)]     = { xen_invlcache,              "ic"  },
 125 #ifdef __i386__
 126         [IPI_TO_IDX(IPI_LAZYPMAP)]      = { xen_lazypmap,               "lp"  },
 127 #endif
 128         [IPI_TO_IDX(IPI_BITMAP_VECTOR)] = { xen_ipi_bitmap_handler,     "b"   },
 129         [IPI_TO_IDX(IPI_STOP)]          = { xen_cpustop_handler,        "st"  },
 130         [IPI_TO_IDX(IPI_SUSPEND)]       = { xen_cpususpend_handler,     "sp"  },
 131         [IPI_TO_IDX(IPI_STOP_HARD)]     = { xen_cpustophard_handler,    "sth" },
 132 };
 133 #endif
 134
 135 /**
 136  * If non-zero, the hypervisor has been configured to use a direct
 137  * IDT event callback for interrupt injection.
 138  */
 139 int xen_vector_callback_enabled;
 140
 141 /*------------------------------- Per-CPU Data -------------------------------*/
 142 DPCPU_DEFINE(struct vcpu_info, vcpu_local_info);
 143 DPCPU_DEFINE(struct vcpu_info *, vcpu_info);
 144 #ifdef SMP
 145 DPCPU_DEFINE(xen_intr_handle_t, ipi_handle[nitems(xen_ipis)]);
 146 #endif
 147
 148 /*------------------ Hypervisor Access Shared Memory Regions -----------------*/
 149 /** Hypercall table accessed via HYPERVISOR_*_op() methods. */
 150 extern char *hypercall_page;
 151 shared_info_t *HYPERVISOR_shared_info;
 152 start_info_t *HYPERVISOR_start_info;
 153
 154 #ifdef SMP
 155 /*---------------------------- XEN PV IPI Handlers ---------------------------*/
 156 /*
 157  * This are C clones of the ASM functions found in apic_vector.s
 158  */
 159 static int
 160 xen_ipi_bitmap_handler(void *arg)
 161 {
 162         struct trapframe *frame;
 163
 164         frame = arg;
 165         ipi_bitmap_handler(*frame);
 166         return (FILTER_HANDLED);
 167 }
 168
 169 static int
 170 xen_smp_rendezvous_action(void *arg)
 171 {
 172 #ifdef COUNT_IPIS
 173         (*ipi_rendezvous_counts[PCPU_GET(cpuid)])++;
 174 #endif /* COUNT_IPIS */
 175
 176         smp_rendezvous_action();
 177         return (FILTER_HANDLED);
 178 }
 179
 180 static int
 181 xen_invltlb(void *arg)
 182 {
 183
 184         invltlb_handler();
 185         return (FILTER_HANDLED);
 186 }
 187
 188 #ifdef __amd64__
 189 static int
 190 xen_invltlb_pcid(void *arg)
 191 {
 192
 193         invltlb_pcid_handler();
 194         return (FILTER_HANDLED);
 195 }
 196 #endif
 197
 198 static int
 199 xen_invlpg(void *arg)
 200 {
 201
 202         invlpg_handler();
 203         return (FILTER_HANDLED);
 204 }
 205
 206 #ifdef __amd64__
 207 static int
 208 xen_invlpg_pcid(void *arg)
 209 {
 210
 211         invlpg_pcid_handler();
 212         return (FILTER_HANDLED);
 213 }
 214 #endif
 215
 216 static int
 217 xen_invlrng(void *arg)
 218 {
 219
 220         invlrng_handler();
 221         return (FILTER_HANDLED);
 222 }
 223
 224 static int
 225 xen_invlcache(void *arg)
 226 {
 227
 228         invlcache_handler();
 229         return (FILTER_HANDLED);
 230 }
 231
 232 #ifdef __i386__
 233 static int
 234 xen_lazypmap(void *arg)
 235 {
 236
 237         pmap_lazyfix_action();
 238         return (FILTER_HANDLED);
 239 }
 240 #endif
 241
 242 static int
 243 xen_cpustop_handler(void *arg)
 244 {
 245
 246         cpustop_handler();
 247         return (FILTER_HANDLED);
 248 }
 249
 250 static int
 251 xen_cpususpend_handler(void *arg)
 252 {
 253
 254         cpususpend_handler();
 255         return (FILTER_HANDLED);
 256 }
 257
 258 static int
 259 xen_cpustophard_handler(void *arg)
 260 {
 261
 262         ipi_nmi_handler();
 263         return (FILTER_HANDLED);
 264 }
 265
 266 /* Xen PV IPI sender */
 267 static void
 268 xen_ipi_vectored(u_int vector, int dest)
 269 {
 270         xen_intr_handle_t *ipi_handle;
 271         int ipi_idx, to_cpu, self;
 272
 273         ipi_idx = IPI_TO_IDX(vector);
 274         if (ipi_idx > nitems(xen_ipis))
 275                 panic("IPI out of range");
 276
 277         switch(dest) {
 278         case APIC_IPI_DEST_SELF:
 279                 ipi_handle = DPCPU_GET(ipi_handle);
 280                 xen_intr_signal(ipi_handle[ipi_idx]);
 281                 break;
 282         case APIC_IPI_DEST_ALL:
 283                 CPU_FOREACH(to_cpu) {
 284                         ipi_handle = DPCPU_ID_GET(to_cpu, ipi_handle);
 285                         xen_intr_signal(ipi_handle[ipi_idx]);
 286                 }
 287                 break;
 288         case APIC_IPI_DEST_OTHERS:
 289                 self = PCPU_GET(cpuid);
 290                 CPU_FOREACH(to_cpu) {
 291                         if (to_cpu != self) {
 292                                 ipi_handle = DPCPU_ID_GET(to_cpu, ipi_handle);
 293                                 xen_intr_signal(ipi_handle[ipi_idx]);
 294                         }
 295                 }
 296                 break;
 297         default:
 298                 to_cpu = apic_cpuid(dest);
 299                 ipi_handle = DPCPU_ID_GET(to_cpu, ipi_handle);
 300                 xen_intr_signal(ipi_handle[ipi_idx]);
 301                 break;
 302         }
 303 }
 304
 305 /* XEN diverged cpu operations */
 306 static void
 307 xen_hvm_cpu_resume(void)
 308 {
 309         u_int cpuid = PCPU_GET(cpuid);
 310
 311         /*
 312          * Reset pending bitmap IPIs, because Xen doesn't preserve pending
 313          * event channels on migration.
 314          */
 315         cpu_ipi_pending[cpuid] = 0;
 316
 317         /* register vcpu_info area */
 318         xen_hvm_cpu_init();
 319 }
 320
 321 static void
 322 xen_cpu_ipi_init(int cpu)
 323 {
 324         xen_intr_handle_t *ipi_handle;
 325         const struct xen_ipi_handler *ipi;
 326         device_t dev;
 327         int idx, rc;
 328
 329         ipi_handle = DPCPU_ID_GET(cpu, ipi_handle);
 330         dev = pcpu_find(cpu)->pc_device;
 331         KASSERT((dev != NULL), ("NULL pcpu device_t"));
 332
 333         for (ipi = xen_ipis, idx = 0; idx < nitems(xen_ipis); ipi++, idx++) {
 334
 335                 if (ipi->filter == NULL) {
 336                         ipi_handle[idx] = NULL;
 337                         continue;
 338                 }
 339
 340                 rc = xen_intr_alloc_and_bind_ipi(dev, cpu, ipi->filter,
 341                     INTR_TYPE_TTY, &ipi_handle[idx]);
 342                 if (rc != 0)
 343                         panic("Unable to allocate a XEN IPI port");
 344                 xen_intr_describe(ipi_handle[idx], "%s", ipi->description);
 345         }
 346 }
 347
 348 static void
 349 xen_setup_cpus(void)
 350 {
 351         int i;
 352
 353         if (!xen_vector_callback_enabled)
 354                 return;
 355
 356 #ifdef __amd64__
 357         if (pmap_pcid_enabled) {
 358                 xen_ipis[IPI_TO_IDX(IPI_INVLTLB)].filter = xen_invltlb_pcid;
 359                 xen_ipis[IPI_TO_IDX(IPI_INVLPG)].filter = xen_invlpg_pcid;
 360         }
 361 #endif
 362         CPU_FOREACH(i)
 363                 xen_cpu_ipi_init(i);
 364
 365         /* Set the xen pv ipi ops to replace the native ones */
 366         cpu_ops.ipi_vectored = xen_ipi_vectored;
 367 }
 368 #endif
 369
 370 /*---------------------- XEN Hypervisor Probe and Setup ----------------------*/
 371 static uint32_t
 372 xen_hvm_cpuid_base(void)
 373 {
 374         uint32_t base, regs[4];
 375
 376         for (base = 0x40000000; base < 0x40010000; base += 0x100) {
 377                 do_cpuid(base, regs);
 378                 if (!memcmp("XenVMMXenVMM", &regs[1], 12)
 379                     && (regs[0] - base) >= 2)
 380                         return (base);
 381         }
 382         return (0);
 383 }
 384
 385 /*
 386  * Allocate and fill in the hypcall page.
 387  */
 388 static int
 389 xen_hvm_init_hypercall_stubs(enum xen_hvm_init_type init_type)
 390 {
 391         uint32_t base, regs[4];
 392         int i;
 393
 394         if (xen_pv_domain()) {
 395                 /* hypercall page is already set in the PV case */
 396                 return (0);
 397         }
 398
 399         base = xen_hvm_cpuid_base();
 400         if (base == 0)
 401                 return (ENXIO);
 402
 403         if (init_type == XEN_HVM_INIT_COLD) {
 404                 do_cpuid(base + 1, regs);
 405                 printf("XEN: Hypervisor version %d.%d detected.\n",
 406                     regs[0] >> 16, regs[0] & 0xffff);
 407         }
 408
 409         /*
 410          * Find the hypercall pages.
 411          */
 412         do_cpuid(base + 2, regs);
 413
 414         for (i = 0; i < regs[0]; i++)
 415                 wrmsr(regs[1], vtophys(&hypercall_page + i * PAGE_SIZE) + i);
 416
 417         return (0);
 418 }
 419
 420 static void
 421 xen_hvm_init_shared_info_page(void)
 422 {
 423         struct xen_add_to_physmap xatp;
 424
 425         if (xen_pv_domain()) {
 426                 /*
 427                  * Already setup in the PV case, shared_info is passed inside
 428                  * of the start_info struct at start of day.
 429                  */
 430                 return;
 431         }
 432
 433         if (HYPERVISOR_shared_info == NULL) {
 434                 HYPERVISOR_shared_info = malloc(PAGE_SIZE, M_XENHVM, M_NOWAIT);
 435                 if (HYPERVISOR_shared_info == NULL)
 436                         panic("Unable to allocate Xen shared info page");
 437         }
 438
 439         xatp.domid = DOMID_SELF;
 440         xatp.idx = 0;
 441         xatp.space = XENMAPSPACE_shared_info;
 442         xatp.gpfn = vtophys(HYPERVISOR_shared_info) >> PAGE_SHIFT;
 443         if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
 444                 panic("HYPERVISOR_memory_op failed");
 445 }
 446
 447 /*
 448  * Tell the hypervisor how to contact us for event channel callbacks.
 449  */
 450 void
 451 xen_hvm_set_callback(device_t dev)
 452 {
 453         struct xen_hvm_param xhp;
 454         int irq;
 455
 456         if (xen_vector_callback_enabled)
 457                 return;
 458
 459         xhp.domid = DOMID_SELF;
 460         xhp.index = HVM_PARAM_CALLBACK_IRQ;
 461         if (xen_feature(XENFEAT_hvm_callback_vector) != 0) {
 462                 int error;
 463
 464                 xhp.value = HVM_CALLBACK_VECTOR(IDT_EVTCHN);
 465                 error = HYPERVISOR_hvm_op(HVMOP_set_param, &xhp);
 466                 if (error == 0) {
 467                         xen_vector_callback_enabled = 1;
 468                         return;
 469                 }
 470                 printf("Xen HVM callback vector registration failed (%d). "
 471                     "Falling back to emulated device interrupt\n", error);
 472         }
 473         xen_vector_callback_enabled = 0;
 474         if (dev == NULL) {
 475                 /*
 476                  * Called from early boot or resume.
 477                  * xenpci will invoke us again later.
 478                  */
 479                 return;
 480         }
 481
 482         irq = pci_get_irq(dev);
 483         if (irq < 16) {
 484                 xhp.value = HVM_CALLBACK_GSI(irq);
 485         } else {
 486                 u_int slot;
 487                 u_int pin;
 488
 489                 slot = pci_get_slot(dev);
 490                 pin = pci_get_intpin(dev) - 1;
 491                 xhp.value = HVM_CALLBACK_PCI_INTX(slot, pin);
 492         }
 493
 494         if (HYPERVISOR_hvm_op(HVMOP_set_param, &xhp) != 0)
 495                 panic("Can't set evtchn callback");
 496 }
 497
 498 #define XEN_MAGIC_IOPORT 0x10
 499 enum {
 500         XMI_MAGIC                        = 0x49d2,
 501         XMI_UNPLUG_IDE_DISKS             = 0x01,
 502         XMI_UNPLUG_NICS                  = 0x02,
 503         XMI_UNPLUG_IDE_EXCEPT_PRI_MASTER = 0x04
 504 };
 505
 506 static void
 507 xen_hvm_disable_emulated_devices(void)
 508 {
 509
 510         if (xen_pv_domain()) {
 511                 /*
 512                  * No emulated devices in the PV case, so no need to unplug
 513                  * anything.
 514                  */
 515                 return;
 516         }
 517
 518         if (inw(XEN_MAGIC_IOPORT) != XMI_MAGIC)
 519                 return;
 520
 521         if (bootverbose)
 522                 printf("XEN: Disabling emulated block and network devices\n");
 523         outw(XEN_MAGIC_IOPORT, XMI_UNPLUG_IDE_DISKS|XMI_UNPLUG_NICS);
 524 }
 525
 526 static void
 527 xen_hvm_init(enum xen_hvm_init_type init_type)
 528 {
 529         int error;
 530         int i;
 531
 532         if (init_type == XEN_HVM_INIT_CANCELLED_SUSPEND)
 533                 return;
 534
 535         error = xen_hvm_init_hypercall_stubs(init_type);
 536
 537         switch (init_type) {
 538         case XEN_HVM_INIT_COLD:
 539                 if (error != 0)
 540                         return;
 541
 542                 /*
 543                  * If xen_domain_type is not set at this point
 544                  * it means we are inside a (PV)HVM guest, because
 545                  * for PVH the guest type is set much earlier
 546                  * (see hammer_time_xen).
 547                  */
 548                 if (!xen_domain()) {
 549                         xen_domain_type = XEN_HVM_DOMAIN;
 550                         vm_guest = VM_GUEST_XEN;
 551                 }
 552
 553                 setup_xen_features();
 554                 cpu_ops = xen_hvm_cpu_ops;
 555                 break;
 556         case XEN_HVM_INIT_RESUME:
 557                 if (error != 0)
 558                         panic("Unable to init Xen hypercall stubs on resume");
 559
 560                 /* Clear stale vcpu_info. */
 561                 CPU_FOREACH(i)
 562                         DPCPU_ID_SET(i, vcpu_info, NULL);
 563                 break;
 564         default:
 565                 panic("Unsupported HVM initialization type");
 566         }
 567
 568         xen_vector_callback_enabled = 0;
 569         xen_hvm_set_callback(NULL);
 570
 571         /*
 572          * On (PV)HVM domains we need to request the hypervisor to
 573          * fill the shared info page, for PVH guest the shared_info page
 574          * is passed inside the start_info struct and is already set, so this
 575          * functions are no-ops.
 576          */
 577         xen_hvm_init_shared_info_page();
 578         xen_hvm_disable_emulated_devices();
 579 }
 580
 581 void
 582 xen_hvm_suspend(void)
 583 {
 584 }
 585
 586 void
 587 xen_hvm_resume(bool suspend_cancelled)
 588 {
 589
 590         xen_hvm_init(suspend_cancelled ?
 591             XEN_HVM_INIT_CANCELLED_SUSPEND : XEN_HVM_INIT_RESUME);
 592
 593         /* Register vcpu_info area for CPU#0. */
 594         xen_hvm_cpu_init();
 595 }
 596
 597 static void
 598 xen_hvm_sysinit(void *arg __unused)
 599 {
 600         xen_hvm_init(XEN_HVM_INIT_COLD);
 601 }
 602
 603 static void
 604 xen_set_vcpu_id(void)
 605 {
 606         struct pcpu *pc;
 607         int i;
 608
 609         if (!xen_hvm_domain())
 610                 return;
 611
 612         /* Set vcpu_id to acpi_id */
 613         CPU_FOREACH(i) {
 614                 pc = pcpu_find(i);
 615                 pc->pc_vcpu_id = pc->pc_acpi_id;
 616                 if (bootverbose)
 617                         printf("XEN: CPU %u has VCPU ID %u\n",
 618                                i, pc->pc_vcpu_id);
 619         }
 620 }
 621
 622 static void
 623 xen_hvm_cpu_init(void)
 624 {
 625         struct vcpu_register_vcpu_info info;
 626         struct vcpu_info *vcpu_info;
 627         int cpu, rc;
 628
 629         if (!xen_domain())
 630                 return;
 631
 632         if (DPCPU_GET(vcpu_info) != NULL) {
 633                 /*
 634                  * vcpu_info is already set.  We're resuming
 635                  * from a failed migration and our pre-suspend
 636                  * configuration is still valid.
 637                  */
 638                 return;
 639         }
 640
 641         vcpu_info = DPCPU_PTR(vcpu_local_info);
 642         cpu = PCPU_GET(vcpu_id);
 643         info.mfn = vtophys(vcpu_info) >> PAGE_SHIFT;
 644         info.offset = vtophys(vcpu_info) - trunc_page(vtophys(vcpu_info));
 645
 646         rc = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
 647         if (rc != 0)
 648                 DPCPU_SET(vcpu_info, &HYPERVISOR_shared_info->vcpu_info[cpu]);
 649         else
 650                 DPCPU_SET(vcpu_info, vcpu_info);
 651 }
 652
 653 SYSINIT(xen_hvm_init, SI_SUB_HYPERVISOR, SI_ORDER_FIRST, xen_hvm_sysinit, NULL);
 654 #ifdef SMP
 655 /* We need to setup IPIs before APs are started */
 656 SYSINIT(xen_setup_cpus, SI_SUB_SMP-1, SI_ORDER_FIRST, xen_setup_cpus, NULL);
 657 #endif
 658 SYSINIT(xen_hvm_cpu_init, SI_SUB_INTR, SI_ORDER_FIRST, xen_hvm_cpu_init, NULL);
 659 SYSINIT(xen_set_vcpu_id, SI_SUB_CPU, SI_ORDER_ANY, xen_set_vcpu_id, NULL);