sys/amd64/vmm/vmm_dev.c

   1 /*-
   2  * Copyright (c) 2011 NetApp, Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/kernel.h>
  34 #include <sys/queue.h>
  35 #include <sys/lock.h>
  36 #include <sys/mutex.h>
  37 #include <sys/malloc.h>
  38 #include <sys/conf.h>
  39 #include <sys/sysctl.h>
  40 #include <sys/libkern.h>
  41 #include <sys/ioccom.h>
  42 #include <sys/mman.h>
  43 #include <sys/uio.h>
  44
  45 #include <vm/vm.h>
  46 #include <vm/pmap.h>
  47 #include <vm/vm_map.h>
  48
  49 #include <machine/vmparam.h>
  50 #include <machine/vmm.h>
  51 #include <machine/vmm_instruction_emul.h>
  52 #include <machine/vmm_dev.h>
  53
  54 #include "vmm_lapic.h"
  55 #include "vmm_stat.h"
  56 #include "vmm_mem.h"
  57 #include "io/ppt.h"
  58 #include "io/vatpic.h"
  59 #include "io/vioapic.h"
  60 #include "io/vhpet.h"
  61
  62 struct vmmdev_softc {
  63         struct vm       *vm;            /* vm instance cookie */
  64         struct cdev     *cdev;
  65         SLIST_ENTRY(vmmdev_softc) link;
  66         int             flags;
  67 };
  68 #define VSC_LINKED              0x01
  69
  70 static SLIST_HEAD(, vmmdev_softc) head;
  71
  72 static struct mtx vmmdev_mtx;
  73
  74 static MALLOC_DEFINE(M_VMMDEV, "vmmdev", "vmmdev");
  75
  76 SYSCTL_DECL(_hw_vmm);
  77
  78 static struct vmmdev_softc *
  79 vmmdev_lookup(const char *name)
  80 {
  81         struct vmmdev_softc *sc;
  82
  83 #ifdef notyet   /* XXX kernel is not compiled with invariants */
  84         mtx_assert(&vmmdev_mtx, MA_OWNED);
  85 #endif
  86
  87         SLIST_FOREACH(sc, &head, link) {
  88                 if (strcmp(name, vm_name(sc->vm)) == 0)
  89                         break;
  90         }
  91
  92         return (sc);
  93 }
  94
  95 static struct vmmdev_softc *
  96 vmmdev_lookup2(struct cdev *cdev)
  97 {
  98
  99         return (cdev->si_drv1);
 100 }
 101
 102 static int
 103 vmmdev_rw(struct cdev *cdev, struct uio *uio, int flags)
 104 {
 105         int error, off, c, prot;
 106         vm_paddr_t gpa;
 107         void *hpa, *cookie;
 108         struct vmmdev_softc *sc;
 109
 110         static char zerobuf[PAGE_SIZE];
 111
 112         error = 0;
 113         sc = vmmdev_lookup2(cdev);
 114         if (sc == NULL)
 115                 error = ENXIO;
 116
 117         prot = (uio->uio_rw == UIO_WRITE ? VM_PROT_WRITE : VM_PROT_READ);
 118         while (uio->uio_resid > 0 && error == 0) {
 119                 gpa = uio->uio_offset;
 120                 off = gpa & PAGE_MASK;
 121                 c = min(uio->uio_resid, PAGE_SIZE - off);
 122
 123                 /*
 124                  * The VM has a hole in its physical memory map. If we want to
 125                  * use 'dd' to inspect memory beyond the hole we need to
 126                  * provide bogus data for memory that lies in the hole.
 127                  *
 128                  * Since this device does not support lseek(2), dd(1) will
 129                  * read(2) blocks of data to simulate the lseek(2).
 130                  */
 131                 hpa = vm_gpa_hold(sc->vm, gpa, c, prot, &cookie);
 132                 if (hpa == NULL) {
 133                         if (uio->uio_rw == UIO_READ)
 134                                 error = uiomove(zerobuf, c, uio);
 135                         else
 136                                 error = EFAULT;
 137                 } else {
 138                         error = uiomove(hpa, c, uio);
 139                         vm_gpa_release(cookie);
 140                 }
 141         }
 142         return (error);
 143 }
 144
 145 static int
 146 vmmdev_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
 147              struct thread *td)
 148 {
 149         int error, vcpu, state_changed;
 150         struct vmmdev_softc *sc;
 151         struct vm_memory_segment *seg;
 152         struct vm_register *vmreg;
 153         struct vm_seg_desc *vmsegdesc;
 154         struct vm_run *vmrun;
 155         struct vm_exception *vmexc;
 156         struct vm_lapic_irq *vmirq;
 157         struct vm_lapic_msi *vmmsi;
 158         struct vm_ioapic_irq *ioapic_irq;
 159         struct vm_isa_irq *isa_irq;
 160         struct vm_isa_irq_trigger *isa_irq_trigger;
 161         struct vm_capability *vmcap;
 162         struct vm_pptdev *pptdev;
 163         struct vm_pptdev_mmio *pptmmio;
 164         struct vm_pptdev_msi *pptmsi;
 165         struct vm_pptdev_msix *pptmsix;
 166         struct vm_nmi *vmnmi;
 167         struct vm_stats *vmstats;
 168         struct vm_stat_desc *statdesc;
 169         struct vm_x2apic *x2apic;
 170         struct vm_gpa_pte *gpapte;
 171         struct vm_suspend *vmsuspend;
 172         struct vm_gla2gpa *gg;
 173
 174         sc = vmmdev_lookup2(cdev);
 175         if (sc == NULL)
 176                 return (ENXIO);
 177
 178         error = 0;
 179         vcpu = -1;
 180         state_changed = 0;
 181
 182         /*
 183          * Some VMM ioctls can operate only on vcpus that are not running.
 184          */
 185         switch (cmd) {
 186         case VM_RUN:
 187         case VM_GET_REGISTER:
 188         case VM_SET_REGISTER:
 189         case VM_GET_SEGMENT_DESCRIPTOR:
 190         case VM_SET_SEGMENT_DESCRIPTOR:
 191         case VM_INJECT_EXCEPTION:
 192         case VM_GET_CAPABILITY:
 193         case VM_SET_CAPABILITY:
 194         case VM_PPTDEV_MSI:
 195         case VM_PPTDEV_MSIX:
 196         case VM_SET_X2APIC_STATE:
 197         case VM_GLA2GPA:
 198                 /*
 199                  * XXX fragile, handle with care
 200                  * Assumes that the first field of the ioctl data is the vcpu.
 201                  */
 202                 vcpu = *(int *)data;
 203                 if (vcpu < 0 || vcpu >= VM_MAXCPU) {
 204                         error = EINVAL;
 205                         goto done;
 206                 }
 207
 208                 error = vcpu_set_state(sc->vm, vcpu, VCPU_FROZEN, true);
 209                 if (error)
 210                         goto done;
 211
 212                 state_changed = 1;
 213                 break;
 214
 215         case VM_MAP_PPTDEV_MMIO:
 216         case VM_BIND_PPTDEV:
 217         case VM_UNBIND_PPTDEV:
 218         case VM_MAP_MEMORY:
 219                 /*
 220                  * ioctls that operate on the entire virtual machine must
 221                  * prevent all vcpus from running.
 222                  */
 223                 error = 0;
 224                 for (vcpu = 0; vcpu < VM_MAXCPU; vcpu++) {
 225                         error = vcpu_set_state(sc->vm, vcpu, VCPU_FROZEN, true);
 226                         if (error)
 227                                 break;
 228                 }
 229
 230                 if (error) {
 231                         while (--vcpu >= 0)
 232                                 vcpu_set_state(sc->vm, vcpu, VCPU_IDLE, false);
 233                         goto done;
 234                 }
 235
 236                 state_changed = 2;
 237                 break;
 238
 239         default:
 240                 break;
 241         }
 242
 243         switch(cmd) {
 244         case VM_RUN:
 245                 vmrun = (struct vm_run *)data;
 246                 error = vm_run(sc->vm, vmrun);
 247                 break;
 248         case VM_SUSPEND:
 249                 vmsuspend = (struct vm_suspend *)data;
 250                 error = vm_suspend(sc->vm, vmsuspend->how);
 251                 break;
 252         case VM_STAT_DESC: {
 253                 statdesc = (struct vm_stat_desc *)data;
 254                 error = vmm_stat_desc_copy(statdesc->index,
 255                                         statdesc->desc, sizeof(statdesc->desc));
 256                 break;
 257         }
 258         case VM_STATS: {
 259                 CTASSERT(MAX_VM_STATS >= MAX_VMM_STAT_ELEMS);
 260                 vmstats = (struct vm_stats *)data;
 261                 getmicrotime(&vmstats->tv);
 262                 error = vmm_stat_copy(sc->vm, vmstats->cpuid,
 263                                       &vmstats->num_entries, vmstats->statbuf);
 264                 break;
 265         }
 266         case VM_PPTDEV_MSI:
 267                 pptmsi = (struct vm_pptdev_msi *)data;
 268                 error = ppt_setup_msi(sc->vm, pptmsi->vcpu,
 269                                       pptmsi->bus, pptmsi->slot, pptmsi->func,
 270                                       pptmsi->addr, pptmsi->msg,
 271                                       pptmsi->numvec);
 272                 break;
 273         case VM_PPTDEV_MSIX:
 274                 pptmsix = (struct vm_pptdev_msix *)data;
 275                 error = ppt_setup_msix(sc->vm, pptmsix->vcpu,
 276                                        pptmsix->bus, pptmsix->slot,
 277                                        pptmsix->func, pptmsix->idx,
 278                                        pptmsix->addr, pptmsix->msg,
 279                                        pptmsix->vector_control);
 280                 break;
 281         case VM_MAP_PPTDEV_MMIO:
 282                 pptmmio = (struct vm_pptdev_mmio *)data;
 283                 error = ppt_map_mmio(sc->vm, pptmmio->bus, pptmmio->slot,
 284                                      pptmmio->func, pptmmio->gpa, pptmmio->len,
 285                                      pptmmio->hpa);
 286                 break;
 287         case VM_BIND_PPTDEV:
 288                 pptdev = (struct vm_pptdev *)data;
 289                 error = vm_assign_pptdev(sc->vm, pptdev->bus, pptdev->slot,
 290                                          pptdev->func);
 291                 break;
 292         case VM_UNBIND_PPTDEV:
 293                 pptdev = (struct vm_pptdev *)data;
 294                 error = vm_unassign_pptdev(sc->vm, pptdev->bus, pptdev->slot,
 295                                            pptdev->func);
 296                 break;
 297         case VM_INJECT_EXCEPTION:
 298                 vmexc = (struct vm_exception *)data;
 299                 error = vm_inject_exception(sc->vm, vmexc->cpuid, vmexc);
 300                 break;
 301         case VM_INJECT_NMI:
 302                 vmnmi = (struct vm_nmi *)data;
 303                 error = vm_inject_nmi(sc->vm, vmnmi->cpuid);
 304                 break;
 305         case VM_LAPIC_IRQ:
 306                 vmirq = (struct vm_lapic_irq *)data;
 307                 error = lapic_intr_edge(sc->vm, vmirq->cpuid, vmirq->vector);
 308                 break;
 309         case VM_LAPIC_LOCAL_IRQ:
 310                 vmirq = (struct vm_lapic_irq *)data;
 311                 error = lapic_set_local_intr(sc->vm, vmirq->cpuid,
 312                     vmirq->vector);
 313                 break;
 314         case VM_LAPIC_MSI:
 315                 vmmsi = (struct vm_lapic_msi *)data;
 316                 error = lapic_intr_msi(sc->vm, vmmsi->addr, vmmsi->msg);
 317                 break;
 318         case VM_IOAPIC_ASSERT_IRQ:
 319                 ioapic_irq = (struct vm_ioapic_irq *)data;
 320                 error = vioapic_assert_irq(sc->vm, ioapic_irq->irq);
 321                 break;
 322         case VM_IOAPIC_DEASSERT_IRQ:
 323                 ioapic_irq = (struct vm_ioapic_irq *)data;
 324                 error = vioapic_deassert_irq(sc->vm, ioapic_irq->irq);
 325                 break;
 326         case VM_IOAPIC_PULSE_IRQ:
 327                 ioapic_irq = (struct vm_ioapic_irq *)data;
 328                 error = vioapic_pulse_irq(sc->vm, ioapic_irq->irq);
 329                 break;
 330         case VM_IOAPIC_PINCOUNT:
 331                 *(int *)data = vioapic_pincount(sc->vm);
 332                 break;
 333         case VM_ISA_ASSERT_IRQ:
 334                 isa_irq = (struct vm_isa_irq *)data;
 335                 error = vatpic_assert_irq(sc->vm, isa_irq->atpic_irq);
 336                 if (error == 0 && isa_irq->ioapic_irq != -1)
 337                         error = vioapic_assert_irq(sc->vm,
 338                             isa_irq->ioapic_irq);
 339                 break;
 340         case VM_ISA_DEASSERT_IRQ:
 341                 isa_irq = (struct vm_isa_irq *)data;
 342                 error = vatpic_deassert_irq(sc->vm, isa_irq->atpic_irq);
 343                 if (error == 0 && isa_irq->ioapic_irq != -1)
 344                         error = vioapic_deassert_irq(sc->vm,
 345                             isa_irq->ioapic_irq);
 346                 break;
 347         case VM_ISA_PULSE_IRQ:
 348                 isa_irq = (struct vm_isa_irq *)data;
 349                 error = vatpic_pulse_irq(sc->vm, isa_irq->atpic_irq);
 350                 if (error == 0 && isa_irq->ioapic_irq != -1)
 351                         error = vioapic_pulse_irq(sc->vm, isa_irq->ioapic_irq);
 352                 break;
 353         case VM_ISA_SET_IRQ_TRIGGER:
 354                 isa_irq_trigger = (struct vm_isa_irq_trigger *)data;
 355                 error = vatpic_set_irq_trigger(sc->vm,
 356                     isa_irq_trigger->atpic_irq, isa_irq_trigger->trigger);
 357                 break;
 358         case VM_MAP_MEMORY:
 359                 seg = (struct vm_memory_segment *)data;
 360                 error = vm_malloc(sc->vm, seg->gpa, seg->len);
 361                 break;
 362         case VM_GET_MEMORY_SEG:
 363                 seg = (struct vm_memory_segment *)data;
 364                 seg->len = 0;
 365                 (void)vm_gpabase2memseg(sc->vm, seg->gpa, seg);
 366                 error = 0;
 367                 break;
 368         case VM_GET_REGISTER:
 369                 vmreg = (struct vm_register *)data;
 370                 error = vm_get_register(sc->vm, vmreg->cpuid, vmreg->regnum,
 371                                         &vmreg->regval);
 372                 break;
 373         case VM_SET_REGISTER:
 374                 vmreg = (struct vm_register *)data;
 375                 error = vm_set_register(sc->vm, vmreg->cpuid, vmreg->regnum,
 376                                         vmreg->regval);
 377                 break;
 378         case VM_SET_SEGMENT_DESCRIPTOR:
 379                 vmsegdesc = (struct vm_seg_desc *)data;
 380                 error = vm_set_seg_desc(sc->vm, vmsegdesc->cpuid,
 381                                         vmsegdesc->regnum,
 382                                         &vmsegdesc->desc);
 383                 break;
 384         case VM_GET_SEGMENT_DESCRIPTOR:
 385                 vmsegdesc = (struct vm_seg_desc *)data;
 386                 error = vm_get_seg_desc(sc->vm, vmsegdesc->cpuid,
 387                                         vmsegdesc->regnum,
 388                                         &vmsegdesc->desc);
 389                 break;
 390         case VM_GET_CAPABILITY:
 391                 vmcap = (struct vm_capability *)data;
 392                 error = vm_get_capability(sc->vm, vmcap->cpuid,
 393                                           vmcap->captype,
 394                                           &vmcap->capval);
 395                 break;
 396         case VM_SET_CAPABILITY:
 397                 vmcap = (struct vm_capability *)data;
 398                 error = vm_set_capability(sc->vm, vmcap->cpuid,
 399                                           vmcap->captype,
 400                                           vmcap->capval);
 401                 break;
 402         case VM_SET_X2APIC_STATE:
 403                 x2apic = (struct vm_x2apic *)data;
 404                 error = vm_set_x2apic_state(sc->vm,
 405                                             x2apic->cpuid, x2apic->state);
 406                 break;
 407         case VM_GET_X2APIC_STATE:
 408                 x2apic = (struct vm_x2apic *)data;
 409                 error = vm_get_x2apic_state(sc->vm,
 410                                             x2apic->cpuid, &x2apic->state);
 411                 break;
 412         case VM_GET_GPA_PMAP:
 413                 gpapte = (struct vm_gpa_pte *)data;
 414                 pmap_get_mapping(vmspace_pmap(vm_get_vmspace(sc->vm)),
 415                                  gpapte->gpa, gpapte->pte, &gpapte->ptenum);
 416                 error = 0;
 417                 break;
 418         case VM_GET_HPET_CAPABILITIES:
 419                 error = vhpet_getcap((struct vm_hpet_cap *)data);
 420                 break;
 421         case VM_GLA2GPA: {
 422                 CTASSERT(PROT_READ == VM_PROT_READ);
 423                 CTASSERT(PROT_WRITE == VM_PROT_WRITE);
 424                 CTASSERT(PROT_EXEC == VM_PROT_EXECUTE);
 425                 gg = (struct vm_gla2gpa *)data;
 426                 error = vmm_gla2gpa(sc->vm, gg->vcpuid, &gg->paging, gg->gla,
 427                     gg->prot, &gg->gpa);
 428                 KASSERT(error == 0 || error == 1 || error == -1,
 429                     ("%s: vmm_gla2gpa unknown error %d", __func__, error));
 430                 if (error >= 0) {
 431                         /*
 432                          * error = 0: the translation was successful
 433                          * error = 1: a fault was injected into the guest
 434                          */
 435                         gg->fault = error;
 436                         error = 0;
 437                 } else {
 438                         error = EFAULT;
 439                 }
 440                 break;
 441         }
 442         default:
 443                 error = ENOTTY;
 444                 break;
 445         }
 446
 447         if (state_changed == 1) {
 448                 vcpu_set_state(sc->vm, vcpu, VCPU_IDLE, false);
 449         } else if (state_changed == 2) {
 450                 for (vcpu = 0; vcpu < VM_MAXCPU; vcpu++)
 451                         vcpu_set_state(sc->vm, vcpu, VCPU_IDLE, false);
 452         }
 453
 454 done:
 455         /* Make sure that no handler returns a bogus value like ERESTART */
 456         KASSERT(error >= 0, ("vmmdev_ioctl: invalid error return %d", error));
 457         return (error);
 458 }
 459
 460 static int
 461 vmmdev_mmap_single(struct cdev *cdev, vm_ooffset_t *offset,
 462                    vm_size_t size, struct vm_object **object, int nprot)
 463 {
 464         int error;
 465         struct vmmdev_softc *sc;
 466
 467         sc = vmmdev_lookup2(cdev);
 468         if (sc != NULL && (nprot & PROT_EXEC) == 0)
 469                 error = vm_get_memobj(sc->vm, *offset, size, offset, object);
 470         else
 471                 error = EINVAL;
 472
 473         return (error);
 474 }
 475
 476 static void
 477 vmmdev_destroy(void *arg)
 478 {
 479
 480         struct vmmdev_softc *sc = arg;
 481
 482         if (sc->cdev != NULL)
 483                 destroy_dev(sc->cdev);
 484
 485         if (sc->vm != NULL)
 486                 vm_destroy(sc->vm);
 487
 488         if ((sc->flags & VSC_LINKED) != 0) {
 489                 mtx_lock(&vmmdev_mtx);
 490                 SLIST_REMOVE(&head, sc, vmmdev_softc, link);
 491                 mtx_unlock(&vmmdev_mtx);
 492         }
 493
 494         free(sc, M_VMMDEV);
 495 }
 496
 497 static int
 498 sysctl_vmm_destroy(SYSCTL_HANDLER_ARGS)
 499 {
 500         int error;
 501         char buf[VM_MAX_NAMELEN];
 502         struct vmmdev_softc *sc;
 503         struct cdev *cdev;
 504
 505         strlcpy(buf, "beavis", sizeof(buf));
 506         error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
 507         if (error != 0 || req->newptr == NULL)
 508                 return (error);
 509
 510         mtx_lock(&vmmdev_mtx);
 511         sc = vmmdev_lookup(buf);
 512         if (sc == NULL || sc->cdev == NULL) {
 513                 mtx_unlock(&vmmdev_mtx);
 514                 return (EINVAL);
 515         }
 516
 517         /*
 518          * The 'cdev' will be destroyed asynchronously when 'si_threadcount'
 519          * goes down to 0 so we should not do it again in the callback.
 520          */
 521         cdev = sc->cdev;
 522         sc->cdev = NULL;
 523         mtx_unlock(&vmmdev_mtx);
 524
 525         /*
 526          * Schedule the 'cdev' to be destroyed:
 527          *
 528          * - any new operations on this 'cdev' will return an error (ENXIO).
 529          *
 530          * - when the 'si_threadcount' dwindles down to zero the 'cdev' will
 531          *   be destroyed and the callback will be invoked in a taskqueue
 532          *   context.
 533          */
 534         destroy_dev_sched_cb(cdev, vmmdev_destroy, sc);
 535
 536         return (0);
 537 }
 538 SYSCTL_PROC(_hw_vmm, OID_AUTO, destroy, CTLTYPE_STRING | CTLFLAG_RW,
 539             NULL, 0, sysctl_vmm_destroy, "A", NULL);
 540
 541 static struct cdevsw vmmdevsw = {
 542         .d_name         = "vmmdev",
 543         .d_version      = D_VERSION,
 544         .d_ioctl        = vmmdev_ioctl,
 545         .d_mmap_single  = vmmdev_mmap_single,
 546         .d_read         = vmmdev_rw,
 547         .d_write        = vmmdev_rw,
 548 };
 549
 550 static int
 551 sysctl_vmm_create(SYSCTL_HANDLER_ARGS)
 552 {
 553         int error;
 554         struct vm *vm;
 555         struct cdev *cdev;
 556         struct vmmdev_softc *sc, *sc2;
 557         char buf[VM_MAX_NAMELEN];
 558
 559         strlcpy(buf, "beavis", sizeof(buf));
 560         error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
 561         if (error != 0 || req->newptr == NULL)
 562                 return (error);
 563
 564         mtx_lock(&vmmdev_mtx);
 565         sc = vmmdev_lookup(buf);
 566         mtx_unlock(&vmmdev_mtx);
 567         if (sc != NULL)
 568                 return (EEXIST);
 569
 570         error = vm_create(buf, &vm);
 571         if (error != 0)
 572                 return (error);
 573
 574         sc = malloc(sizeof(struct vmmdev_softc), M_VMMDEV, M_WAITOK | M_ZERO);
 575         sc->vm = vm;
 576
 577         /*
 578          * Lookup the name again just in case somebody sneaked in when we
 579          * dropped the lock.
 580          */
 581         mtx_lock(&vmmdev_mtx);
 582         sc2 = vmmdev_lookup(buf);
 583         if (sc2 == NULL) {
 584                 SLIST_INSERT_HEAD(&head, sc, link);
 585                 sc->flags |= VSC_LINKED;
 586         }
 587         mtx_unlock(&vmmdev_mtx);
 588
 589         if (sc2 != NULL) {
 590                 vmmdev_destroy(sc);
 591                 return (EEXIST);
 592         }
 593
 594         error = make_dev_p(MAKEDEV_CHECKNAME, &cdev, &vmmdevsw, NULL,
 595                            UID_ROOT, GID_WHEEL, 0600, "vmm/%s", buf);
 596         if (error != 0) {
 597                 vmmdev_destroy(sc);
 598                 return (error);
 599         }
 600
 601         mtx_lock(&vmmdev_mtx);
 602         sc->cdev = cdev;
 603         sc->cdev->si_drv1 = sc;
 604         mtx_unlock(&vmmdev_mtx);
 605
 606         return (0);
 607 }
 608 SYSCTL_PROC(_hw_vmm, OID_AUTO, create, CTLTYPE_STRING | CTLFLAG_RW,
 609             NULL, 0, sysctl_vmm_create, "A", NULL);
 610
 611 void
 612 vmmdev_init(void)
 613 {
 614         mtx_init(&vmmdev_mtx, "vmm device mutex", NULL, MTX_DEF);
 615 }
 616
 617 int
 618 vmmdev_cleanup(void)
 619 {
 620         int error;
 621
 622         if (SLIST_EMPTY(&head))
 623                 error = 0;
 624         else
 625                 error = EBUSY;
 626
 627         return (error);
 628 }