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 static void xen_ipi_vectored(u_int vector, int dest);
  75 static void xen_hvm_cpu_resume(void);
  76 #endif
  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 #ifdef SMP
 110 struct cpu_ops xen_hvm_cpu_ops = {
 111         .ipi_vectored   = lapic_ipi_vectored,
 112         .cpu_init       = xen_hvm_cpu_init,
 113         .cpu_resume     = xen_hvm_cpu_resume
 114 };
 115 #endif
 116
 117 static MALLOC_DEFINE(M_XENHVM, "xen_hvm", "Xen HVM PV Support");
 118
 119 #ifdef SMP
 120 static struct xen_ipi_handler xen_ipis[] =
 121 {
 122         [IPI_TO_IDX(IPI_RENDEZVOUS)]    = { xen_smp_rendezvous_action,  "r"   },
 123         [IPI_TO_IDX(IPI_INVLTLB)]       = { xen_invltlb,                "itlb"},
 124         [IPI_TO_IDX(IPI_INVLPG)]        = { xen_invlpg,                 "ipg" },
 125         [IPI_TO_IDX(IPI_INVLRNG)]       = { xen_invlrng,                "irg" },
 126         [IPI_TO_IDX(IPI_INVLCACHE)]     = { xen_invlcache,              "ic"  },
 127 #ifdef __i386__
 128         [IPI_TO_IDX(IPI_LAZYPMAP)]      = { xen_lazypmap,               "lp"  },
 129 #endif
 130         [IPI_TO_IDX(IPI_BITMAP_VECTOR)] = { xen_ipi_bitmap_handler,     "b"   },
 131         [IPI_TO_IDX(IPI_STOP)]          = { xen_cpustop_handler,        "st"  },
 132         [IPI_TO_IDX(IPI_SUSPEND)]       = { xen_cpususpend_handler,     "sp"  },
 133         [IPI_TO_IDX(IPI_STOP_HARD)]     = { xen_cpustophard_handler,    "sth" },
 134 };
 135 #endif
 136
 137 /**
 138  * If non-zero, the hypervisor has been configured to use a direct
 139  * IDT event callback for interrupt injection.
 140  */
 141 int xen_vector_callback_enabled;
 142
 143 /*------------------------------- Per-CPU Data -------------------------------*/
 144 DPCPU_DEFINE(struct vcpu_info, vcpu_local_info);
 145 DPCPU_DEFINE(struct vcpu_info *, vcpu_info);
 146 #ifdef SMP
 147 DPCPU_DEFINE(xen_intr_handle_t, ipi_handle[nitems(xen_ipis)]);
 148 #endif
 149
 150 /*------------------ Hypervisor Access Shared Memory Regions -----------------*/
 151 /** Hypercall table accessed via HYPERVISOR_*_op() methods. */
 152 char *hypercall_stubs;
 153 shared_info_t *HYPERVISOR_shared_info;
 154
 155
 156 /*------------------------------ Sysctl tunables -----------------------------*/
 157 int xen_disable_pv_disks = 0;
 158 int xen_disable_pv_nics = 0;
 159 TUNABLE_INT("hw.xen.disable_pv_disks", &xen_disable_pv_disks);
 160 TUNABLE_INT("hw.xen.disable_pv_nics", &xen_disable_pv_nics);
 161
 162 #ifdef SMP
 163 /*---------------------------- XEN PV IPI Handlers ---------------------------*/
 164 /*
 165  * This are C clones of the ASM functions found in apic_vector.s
 166  */
 167 static int
 168 xen_ipi_bitmap_handler(void *arg)
 169 {
 170         struct trapframe *frame;
 171
 172         frame = arg;
 173         ipi_bitmap_handler(*frame);
 174         return (FILTER_HANDLED);
 175 }
 176
 177 static int
 178 xen_smp_rendezvous_action(void *arg)
 179 {
 180 #ifdef COUNT_IPIS
 181         (*ipi_rendezvous_counts[PCPU_GET(cpuid)])++;
 182 #endif /* COUNT_IPIS */
 183
 184         smp_rendezvous_action();
 185         return (FILTER_HANDLED);
 186 }
 187
 188 static int
 189 xen_invltlb(void *arg)
 190 {
 191
 192         invltlb_handler();
 193         return (FILTER_HANDLED);
 194 }
 195
 196 #ifdef __amd64__
 197 static int
 198 xen_invltlb_pcid(void *arg)
 199 {
 200
 201         invltlb_pcid_handler();
 202         return (FILTER_HANDLED);
 203 }
 204 #endif
 205
 206 static int
 207 xen_invlpg(void *arg)
 208 {
 209
 210         invlpg_handler();
 211         return (FILTER_HANDLED);
 212 }
 213
 214 #ifdef __amd64__
 215 static int
 216 xen_invlpg_pcid(void *arg)
 217 {
 218
 219         invlpg_pcid_handler();
 220         return (FILTER_HANDLED);
 221 }
 222 #endif
 223
 224 static int
 225 xen_invlrng(void *arg)
 226 {
 227
 228         invlrng_handler();
 229         return (FILTER_HANDLED);
 230 }
 231
 232 static int
 233 xen_invlcache(void *arg)
 234 {
 235
 236         invlcache_handler();
 237         return (FILTER_HANDLED);
 238 }
 239
 240 #ifdef __i386__
 241 static int
 242 xen_lazypmap(void *arg)
 243 {
 244
 245         pmap_lazyfix_action();
 246         return (FILTER_HANDLED);
 247 }
 248 #endif
 249
 250 static int
 251 xen_cpustop_handler(void *arg)
 252 {
 253
 254         cpustop_handler();
 255         return (FILTER_HANDLED);
 256 }
 257
 258 static int
 259 xen_cpususpend_handler(void *arg)
 260 {
 261
 262         cpususpend_handler();
 263         return (FILTER_HANDLED);
 264 }
 265
 266 static int
 267 xen_cpustophard_handler(void *arg)
 268 {
 269
 270         ipi_nmi_handler();
 271         return (FILTER_HANDLED);
 272 }
 273
 274 /* Xen PV IPI sender */
 275 static void
 276 xen_ipi_vectored(u_int vector, int dest)
 277 {
 278         xen_intr_handle_t *ipi_handle;
 279         int ipi_idx, to_cpu, self;
 280
 281         ipi_idx = IPI_TO_IDX(vector);
 282         if (ipi_idx > nitems(xen_ipis))
 283                 panic("IPI out of range");
 284
 285         switch(dest) {
 286         case APIC_IPI_DEST_SELF:
 287                 ipi_handle = DPCPU_GET(ipi_handle);
 288                 xen_intr_signal(ipi_handle[ipi_idx]);
 289                 break;
 290         case APIC_IPI_DEST_ALL:
 291                 CPU_FOREACH(to_cpu) {
 292                         ipi_handle = DPCPU_ID_GET(to_cpu, ipi_handle);
 293                         xen_intr_signal(ipi_handle[ipi_idx]);
 294                 }
 295                 break;
 296         case APIC_IPI_DEST_OTHERS:
 297                 self = PCPU_GET(cpuid);
 298                 CPU_FOREACH(to_cpu) {
 299                         if (to_cpu != self) {
 300                                 ipi_handle = DPCPU_ID_GET(to_cpu, ipi_handle);
 301                                 xen_intr_signal(ipi_handle[ipi_idx]);
 302                         }
 303                 }
 304                 break;
 305         default:
 306                 to_cpu = apic_cpuid(dest);
 307                 ipi_handle = DPCPU_ID_GET(to_cpu, ipi_handle);
 308                 xen_intr_signal(ipi_handle[ipi_idx]);
 309                 break;
 310         }
 311 }
 312
 313 /*---------------------- XEN diverged cpu operations -------------------------*/
 314 static void
 315 xen_hvm_cpu_resume(void)
 316 {
 317         u_int cpuid = PCPU_GET(cpuid);
 318
 319         /*
 320          * Reset pending bitmap IPIs, because Xen doesn't preserve pending
 321          * event channels on migration.
 322          */
 323         cpu_ipi_pending[cpuid] = 0;
 324
 325         /* register vcpu_info area */
 326         xen_hvm_cpu_init();
 327 }
 328
 329 static void
 330 xen_cpu_ipi_init(int cpu)
 331 {
 332         xen_intr_handle_t *ipi_handle;
 333         const struct xen_ipi_handler *ipi;
 334         device_t dev;
 335         int idx, rc;
 336
 337         ipi_handle = DPCPU_ID_GET(cpu, ipi_handle);
 338         dev = pcpu_find(cpu)->pc_device;
 339         KASSERT((dev != NULL), ("NULL pcpu device_t"));
 340
 341         for (ipi = xen_ipis, idx = 0; idx < nitems(xen_ipis); ipi++, idx++) {
 342
 343                 if (ipi->filter == NULL) {
 344                         ipi_handle[idx] = NULL;
 345                         continue;
 346                 }
 347
 348                 rc = xen_intr_alloc_and_bind_ipi(dev, cpu, ipi->filter,
 349                     INTR_TYPE_TTY, &ipi_handle[idx]);
 350                 if (rc != 0)
 351                         panic("Unable to allocate a XEN IPI port");
 352                 xen_intr_describe(ipi_handle[idx], "%s", ipi->description);
 353         }
 354 }
 355
 356 static void
 357 xen_setup_cpus(void)
 358 {
 359         int i;
 360
 361         if (!xen_hvm_domain() || !xen_vector_callback_enabled)
 362                 return;
 363
 364 #ifdef __amd64__
 365         if (pmap_pcid_enabled) {
 366                 xen_ipis[IPI_TO_IDX(IPI_INVLTLB)].filter = xen_invltlb_pcid;
 367                 xen_ipis[IPI_TO_IDX(IPI_INVLPG)].filter = xen_invlpg_pcid;
 368         }
 369 #endif
 370         CPU_FOREACH(i)
 371                 xen_cpu_ipi_init(i);
 372
 373         /* Set the xen pv ipi ops to replace the native ones */
 374         cpu_ops.ipi_vectored = xen_ipi_vectored;
 375 }
 376 #endif
 377
 378 /*---------------------- XEN Hypervisor Probe and Setup ----------------------*/
 379 static uint32_t
 380 xen_hvm_cpuid_base(void)
 381 {
 382         uint32_t base, regs[4];
 383
 384         for (base = 0x40000000; base < 0x40010000; base += 0x100) {
 385                 do_cpuid(base, regs);
 386                 if (!memcmp("XenVMMXenVMM", &regs[1], 12)
 387                     && (regs[0] - base) >= 2)
 388                         return (base);
 389         }
 390         return (0);
 391 }
 392
 393 /*
 394  * Allocate and fill in the hypcall page.
 395  */
 396 static int
 397 xen_hvm_init_hypercall_stubs(void)
 398 {
 399         uint32_t base, regs[4];
 400         int i;
 401
 402         base = xen_hvm_cpuid_base();
 403         if (base == 0)
 404                 return (ENXIO);
 405
 406         if (hypercall_stubs == NULL) {
 407                 do_cpuid(base + 1, regs);
 408                 printf("XEN: Hypervisor version %d.%d detected.\n",
 409                     regs[0] >> 16, regs[0] & 0xffff);
 410         }
 411
 412         /*
 413          * Find the hypercall pages.
 414          */
 415         do_cpuid(base + 2, regs);
 416
 417         if (hypercall_stubs == NULL) {
 418                 size_t call_region_size;
 419
 420                 call_region_size = regs[0] * PAGE_SIZE;
 421                 hypercall_stubs = malloc(call_region_size, M_XENHVM, M_NOWAIT);
 422                 if (hypercall_stubs == NULL)
 423                         panic("Unable to allocate Xen hypercall region");
 424         }
 425
 426         for (i = 0; i < regs[0]; i++)
 427                 wrmsr(regs[1], vtophys(hypercall_stubs + i * PAGE_SIZE) + i);
 428
 429         return (0);
 430 }
 431
 432 static void
 433 xen_hvm_init_shared_info_page(void)
 434 {
 435         struct xen_add_to_physmap xatp;
 436
 437         if (HYPERVISOR_shared_info == NULL) {
 438                 HYPERVISOR_shared_info = malloc(PAGE_SIZE, M_XENHVM, M_NOWAIT);
 439                 if (HYPERVISOR_shared_info == NULL)
 440                         panic("Unable to allocate Xen shared info page");
 441         }
 442
 443         xatp.domid = DOMID_SELF;
 444         xatp.idx = 0;
 445         xatp.space = XENMAPSPACE_shared_info;
 446         xatp.gpfn = vtophys(HYPERVISOR_shared_info) >> PAGE_SHIFT;
 447         if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
 448                 panic("HYPERVISOR_memory_op failed");
 449 }
 450
 451 /*
 452  * Tell the hypervisor how to contact us for event channel callbacks.
 453  */
 454 void
 455 xen_hvm_set_callback(device_t dev)
 456 {
 457         struct xen_hvm_param xhp;
 458         int irq;
 459
 460         if (xen_vector_callback_enabled)
 461                 return;
 462
 463         xhp.domid = DOMID_SELF;
 464         xhp.index = HVM_PARAM_CALLBACK_IRQ;
 465         if (xen_feature(XENFEAT_hvm_callback_vector) != 0) {
 466                 int error;
 467
 468                 xhp.value = HVM_CALLBACK_VECTOR(IDT_EVTCHN);
 469                 error = HYPERVISOR_hvm_op(HVMOP_set_param, &xhp);
 470                 if (error == 0) {
 471                         xen_vector_callback_enabled = 1;
 472                         return;
 473                 }
 474                 printf("Xen HVM callback vector registration failed (%d). "
 475                     "Falling back to emulated device interrupt\n", error);
 476         }
 477         xen_vector_callback_enabled = 0;
 478         if (dev == NULL) {
 479                 /*
 480                  * Called from early boot or resume.
 481                  * xenpci will invoke us again later.
 482                  */
 483                 return;
 484         }
 485
 486         irq = pci_get_irq(dev);
 487         if (irq < 16) {
 488                 xhp.value = HVM_CALLBACK_GSI(irq);
 489         } else {
 490                 u_int slot;
 491                 u_int pin;
 492
 493                 slot = pci_get_slot(dev);
 494                 pin = pci_get_intpin(dev) - 1;
 495                 xhp.value = HVM_CALLBACK_PCI_INTX(slot, pin);
 496         }
 497
 498         if (HYPERVISOR_hvm_op(HVMOP_set_param, &xhp) != 0)
 499                 panic("Can't set evtchn callback");
 500 }
 501
 502 #define XEN_MAGIC_IOPORT 0x10
 503 enum {
 504         XMI_MAGIC                        = 0x49d2,
 505         XMI_UNPLUG_IDE_DISKS             = 0x01,
 506         XMI_UNPLUG_NICS                  = 0x02,
 507         XMI_UNPLUG_IDE_EXCEPT_PRI_MASTER = 0x04
 508 };
 509
 510 static void
 511 xen_hvm_disable_emulated_devices(void)
 512 {
 513         u_short disable_devs = 0;
 514
 515         if (inw(XEN_MAGIC_IOPORT) != XMI_MAGIC)
 516                 return;
 517
 518         if (xen_disable_pv_disks == 0) {
 519                 if (bootverbose)
 520                         printf("XEN: disabling emulated disks\n");
 521                 disable_devs |= XMI_UNPLUG_IDE_DISKS;
 522         }
 523         if (xen_disable_pv_nics == 0) {
 524                 if (bootverbose)
 525                         printf("XEN: disabling emulated nics\n");
 526                 disable_devs |= XMI_UNPLUG_NICS;
 527         }
 528
 529         if (disable_devs != 0)
 530                 outw(XEN_MAGIC_IOPORT, disable_devs);
 531 }
 532
 533 static void
 534 xen_hvm_init(enum xen_hvm_init_type init_type)
 535 {
 536         int error;
 537         int i;
 538
 539         if (init_type == XEN_HVM_INIT_CANCELLED_SUSPEND)
 540                 return;
 541
 542         error = xen_hvm_init_hypercall_stubs();
 543
 544         switch (init_type) {
 545         case XEN_HVM_INIT_COLD:
 546                 if (error != 0)
 547                         return;
 548
 549                 setup_xen_features();
 550 #ifdef SMP
 551                 cpu_ops = xen_hvm_cpu_ops;
 552 #endif
 553                 vm_guest = VM_GUEST_XEN;
 554                 break;
 555         case XEN_HVM_INIT_RESUME:
 556                 if (error != 0)
 557                         panic("Unable to init Xen hypercall stubs on resume");
 558
 559                 /* Clear stale vcpu_info. */
 560                 CPU_FOREACH(i)
 561                         DPCPU_ID_SET(i, vcpu_info, NULL);
 562                 break;
 563         default:
 564                 panic("Unsupported HVM initialization type");
 565         }
 566
 567         xen_vector_callback_enabled = 0;
 568         xen_domain_type = XEN_HVM_DOMAIN;
 569         xen_hvm_init_shared_info_page();
 570         xen_hvm_set_callback(NULL);
 571         xen_hvm_disable_emulated_devices();
 572 }
 573
 574 void
 575 xen_hvm_suspend(void)
 576 {
 577 }
 578
 579 void
 580 xen_hvm_resume(bool suspend_cancelled)
 581 {
 582
 583         xen_hvm_init(suspend_cancelled ?
 584             XEN_HVM_INIT_CANCELLED_SUSPEND : XEN_HVM_INIT_RESUME);
 585
 586         /* Register vcpu_info area for CPU#0. */
 587         xen_hvm_cpu_init();
 588 }
 589
 590 static void
 591 xen_hvm_sysinit(void *arg __unused)
 592 {
 593         xen_hvm_init(XEN_HVM_INIT_COLD);
 594 }
 595
 596 static void
 597 xen_set_vcpu_id(void)
 598 {
 599         struct pcpu *pc;
 600         int i;
 601
 602         /* Set vcpu_id to acpi_id */
 603         CPU_FOREACH(i) {
 604                 pc = pcpu_find(i);
 605                 pc->pc_vcpu_id = pc->pc_acpi_id;
 606                 if (bootverbose)
 607                         printf("XEN: CPU %u has VCPU ID %u\n",
 608                                i, pc->pc_vcpu_id);
 609         }
 610 }
 611
 612 static void
 613 xen_hvm_cpu_init(void)
 614 {
 615         struct vcpu_register_vcpu_info info;
 616         struct vcpu_info *vcpu_info;
 617         int cpu, rc;
 618
 619         if (!xen_domain())
 620                 return;
 621
 622         if (DPCPU_GET(vcpu_info) != NULL) {
 623                 /*
 624                  * vcpu_info is already set.  We're resuming
 625                  * from a failed migration and our pre-suspend
 626                  * configuration is still valid.
 627                  */
 628                 return;
 629         }
 630
 631         vcpu_info = DPCPU_PTR(vcpu_local_info);
 632         cpu = PCPU_GET(vcpu_id);
 633         info.mfn = vtophys(vcpu_info) >> PAGE_SHIFT;
 634         info.offset = vtophys(vcpu_info) - trunc_page(vtophys(vcpu_info));
 635
 636         rc = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
 637         if (rc != 0)
 638                 DPCPU_SET(vcpu_info, &HYPERVISOR_shared_info->vcpu_info[cpu]);
 639         else
 640                 DPCPU_SET(vcpu_info, vcpu_info);
 641 }
 642
 643 SYSINIT(xen_hvm_init, SI_SUB_HYPERVISOR, SI_ORDER_FIRST, xen_hvm_sysinit, NULL);
 644 #ifdef SMP
 645 SYSINIT(xen_setup_cpus, SI_SUB_SMP, SI_ORDER_FIRST, xen_setup_cpus, NULL);
 646 #endif
 647 SYSINIT(xen_hvm_cpu_init, SI_SUB_INTR, SI_ORDER_FIRST, xen_hvm_cpu_init, NULL);
 648 SYSINIT(xen_set_vcpu_id, SI_SUB_CPU, SI_ORDER_ANY, xen_set_vcpu_id, NULL);