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 #include "io/vrtc.h"
  62
  63 struct vmmdev_softc {
  64         struct vm       *vm;            /* vm instance cookie */
  65         struct cdev     *cdev;
  66         SLIST_ENTRY(vmmdev_softc) link;
  67         int             flags;
  68 };
  69 #define VSC_LINKED              0x01
  70
  71 static SLIST_HEAD(, vmmdev_softc) head;
  72
  73 static struct mtx vmmdev_mtx;
  74
  75 static MALLOC_DEFINE(M_VMMDEV, "vmmdev", "vmmdev");
  76
  77 SYSCTL_DECL(_hw_vmm);
  78
  79 static struct vmmdev_softc *
  80 vmmdev_lookup(const char *name)
  81 {
  82         struct vmmdev_softc *sc;
  83
  84 #ifdef notyet   /* XXX kernel is not compiled with invariants */
  85         mtx_assert(&vmmdev_mtx, MA_OWNED);
  86 #endif
  87
  88         SLIST_FOREACH(sc, &head, link) {
  89                 if (strcmp(name, vm_name(sc->vm)) == 0)
  90                         break;
  91         }
  92
  93         return (sc);
  94 }
  95
  96 static struct vmmdev_softc *
  97 vmmdev_lookup2(struct cdev *cdev)
  98 {
  99
 100         return (cdev->si_drv1);
 101 }
 102
 103 static int
 104 vmmdev_rw(struct cdev *cdev, struct uio *uio, int flags)
 105 {
 106         int error, off, c, prot;
 107         vm_paddr_t gpa;
 108         void *hpa, *cookie;
 109         struct vmmdev_softc *sc;
 110
 111         static char zerobuf[PAGE_SIZE];
 112
 113         error = 0;
 114         sc = vmmdev_lookup2(cdev);
 115         if (sc == NULL)
 116                 error = ENXIO;
 117
 118         prot = (uio->uio_rw == UIO_WRITE ? VM_PROT_WRITE : VM_PROT_READ);
 119         while (uio->uio_resid > 0 && error == 0) {
 120                 gpa = uio->uio_offset;
 121                 off = gpa & PAGE_MASK;
 122                 c = min(uio->uio_resid, PAGE_SIZE - off);
 123
 124                 /*
 125                  * The VM has a hole in its physical memory map. If we want to
 126                  * use 'dd' to inspect memory beyond the hole we need to
 127                  * provide bogus data for memory that lies in the hole.
 128                  *
 129                  * Since this device does not support lseek(2), dd(1) will
 130                  * read(2) blocks of data to simulate the lseek(2).
 131                  */
 132                 hpa = vm_gpa_hold(sc->vm, gpa, c, prot, &cookie);
 133                 if (hpa == NULL) {
 134                         if (uio->uio_rw == UIO_READ)
 135                                 error = uiomove(zerobuf, c, uio);
 136                         else
 137                                 error = EFAULT;
 138                 } else {
 139                         error = uiomove(hpa, c, uio);
 140                         vm_gpa_release(cookie);
 141                 }
 142         }
 143         return (error);
 144 }
 145
 146 static int
 147 vmmdev_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
 148              struct thread *td)
 149 {
 150         int error, vcpu, state_changed, size;
 151         cpuset_t *cpuset;
 152         struct vmmdev_softc *sc;
 153         struct vm_memory_segment *seg;
 154         struct vm_register *vmreg;
 155         struct vm_seg_desc *vmsegdesc;
 156         struct vm_run *vmrun;
 157         struct vm_exception *vmexc;
 158         struct vm_lapic_irq *vmirq;
 159         struct vm_lapic_msi *vmmsi;
 160         struct vm_ioapic_irq *ioapic_irq;
 161         struct vm_isa_irq *isa_irq;
 162         struct vm_isa_irq_trigger *isa_irq_trigger;
 163         struct vm_capability *vmcap;
 164         struct vm_pptdev *pptdev;
 165         struct vm_pptdev_mmio *pptmmio;
 166         struct vm_pptdev_msi *pptmsi;
 167         struct vm_pptdev_msix *pptmsix;
 168         struct vm_nmi *vmnmi;
 169         struct vm_stats *vmstats;
 170         struct vm_stat_desc *statdesc;
 171         struct vm_x2apic *x2apic;
 172         struct vm_gpa_pte *gpapte;
 173         struct vm_suspend *vmsuspend;
 174         struct vm_gla2gpa *gg;
 175         struct vm_activate_cpu *vac;
 176         struct vm_cpuset *vm_cpuset;
 177         struct vm_intinfo *vmii;
 178         struct vm_rtc_time *rtctime;
 179         struct vm_rtc_data *rtcdata;
 180
 181         sc = vmmdev_lookup2(cdev);
 182         if (sc == NULL)
 183                 return (ENXIO);
 184
 185         error = 0;
 186         vcpu = -1;
 187         state_changed = 0;
 188
 189         /*
 190          * Some VMM ioctls can operate only on vcpus that are not running.
 191          */
 192         switch (cmd) {
 193         case VM_RUN:
 194         case VM_GET_REGISTER:
 195         case VM_SET_REGISTER:
 196         case VM_GET_SEGMENT_DESCRIPTOR:
 197         case VM_SET_SEGMENT_DESCRIPTOR:
 198         case VM_INJECT_EXCEPTION:
 199         case VM_GET_CAPABILITY:
 200         case VM_SET_CAPABILITY:
 201         case VM_PPTDEV_MSI:
 202         case VM_PPTDEV_MSIX:
 203         case VM_SET_X2APIC_STATE:
 204         case VM_GLA2GPA:
 205         case VM_ACTIVATE_CPU:
 206         case VM_SET_INTINFO:
 207         case VM_GET_INTINFO:
 208                 /*
 209                  * XXX fragile, handle with care
 210                  * Assumes that the first field of the ioctl data is the vcpu.
 211                  */
 212                 vcpu = *(int *)data;
 213                 if (vcpu < 0 || vcpu >= VM_MAXCPU) {
 214                         error = EINVAL;
 215                         goto done;
 216                 }
 217
 218                 error = vcpu_set_state(sc->vm, vcpu, VCPU_FROZEN, true);
 219                 if (error)
 220                         goto done;
 221
 222                 state_changed = 1;
 223                 break;
 224
 225         case VM_MAP_PPTDEV_MMIO:
 226         case VM_BIND_PPTDEV:
 227         case VM_UNBIND_PPTDEV:
 228         case VM_MAP_MEMORY:
 229         case VM_REINIT:
 230                 /*
 231                  * ioctls that operate on the entire virtual machine must
 232                  * prevent all vcpus from running.
 233                  */
 234                 error = 0;
 235                 for (vcpu = 0; vcpu < VM_MAXCPU; vcpu++) {
 236                         error = vcpu_set_state(sc->vm, vcpu, VCPU_FROZEN, true);
 237                         if (error)
 238                                 break;
 239                 }
 240
 241                 if (error) {
 242                         while (--vcpu >= 0)
 243                                 vcpu_set_state(sc->vm, vcpu, VCPU_IDLE, false);
 244                         goto done;
 245                 }
 246
 247                 state_changed = 2;
 248                 break;
 249
 250         default:
 251                 break;
 252         }
 253
 254         switch(cmd) {
 255         case VM_RUN:
 256                 vmrun = (struct vm_run *)data;
 257                 error = vm_run(sc->vm, vmrun);
 258                 break;
 259         case VM_SUSPEND:
 260                 vmsuspend = (struct vm_suspend *)data;
 261                 error = vm_suspend(sc->vm, vmsuspend->how);
 262                 break;
 263         case VM_REINIT:
 264                 error = vm_reinit(sc->vm);
 265                 break;
 266         case VM_STAT_DESC: {
 267                 statdesc = (struct vm_stat_desc *)data;
 268                 error = vmm_stat_desc_copy(statdesc->index,
 269                                         statdesc->desc, sizeof(statdesc->desc));
 270                 break;
 271         }
 272         case VM_STATS: {
 273                 CTASSERT(MAX_VM_STATS >= MAX_VMM_STAT_ELEMS);
 274                 vmstats = (struct vm_stats *)data;
 275                 getmicrotime(&vmstats->tv);
 276                 error = vmm_stat_copy(sc->vm, vmstats->cpuid,
 277                                       &vmstats->num_entries, vmstats->statbuf);
 278                 break;
 279         }
 280         case VM_PPTDEV_MSI:
 281                 pptmsi = (struct vm_pptdev_msi *)data;
 282                 error = ppt_setup_msi(sc->vm, pptmsi->vcpu,
 283                                       pptmsi->bus, pptmsi->slot, pptmsi->func,
 284                                       pptmsi->addr, pptmsi->msg,
 285                                       pptmsi->numvec);
 286                 break;
 287         case VM_PPTDEV_MSIX:
 288                 pptmsix = (struct vm_pptdev_msix *)data;
 289                 error = ppt_setup_msix(sc->vm, pptmsix->vcpu,
 290                                        pptmsix->bus, pptmsix->slot,
 291                                        pptmsix->func, pptmsix->idx,
 292                                        pptmsix->addr, pptmsix->msg,
 293                                        pptmsix->vector_control);
 294                 break;
 295         case VM_MAP_PPTDEV_MMIO:
 296                 pptmmio = (struct vm_pptdev_mmio *)data;
 297                 error = ppt_map_mmio(sc->vm, pptmmio->bus, pptmmio->slot,
 298                                      pptmmio->func, pptmmio->gpa, pptmmio->len,
 299                                      pptmmio->hpa);
 300                 break;
 301         case VM_BIND_PPTDEV:
 302                 pptdev = (struct vm_pptdev *)data;
 303                 error = vm_assign_pptdev(sc->vm, pptdev->bus, pptdev->slot,
 304                                          pptdev->func);
 305                 break;
 306         case VM_UNBIND_PPTDEV:
 307                 pptdev = (struct vm_pptdev *)data;
 308                 error = vm_unassign_pptdev(sc->vm, pptdev->bus, pptdev->slot,
 309                                            pptdev->func);
 310                 break;
 311         case VM_INJECT_EXCEPTION:
 312                 vmexc = (struct vm_exception *)data;
 313                 error = vm_inject_exception(sc->vm, vmexc->cpuid, vmexc);
 314                 break;
 315         case VM_INJECT_NMI:
 316                 vmnmi = (struct vm_nmi *)data;
 317                 error = vm_inject_nmi(sc->vm, vmnmi->cpuid);
 318                 break;
 319         case VM_LAPIC_IRQ:
 320                 vmirq = (struct vm_lapic_irq *)data;
 321                 error = lapic_intr_edge(sc->vm, vmirq->cpuid, vmirq->vector);
 322                 break;
 323         case VM_LAPIC_LOCAL_IRQ:
 324                 vmirq = (struct vm_lapic_irq *)data;
 325                 error = lapic_set_local_intr(sc->vm, vmirq->cpuid,
 326                     vmirq->vector);
 327                 break;
 328         case VM_LAPIC_MSI:
 329                 vmmsi = (struct vm_lapic_msi *)data;
 330                 error = lapic_intr_msi(sc->vm, vmmsi->addr, vmmsi->msg);
 331                 break;
 332         case VM_IOAPIC_ASSERT_IRQ:
 333                 ioapic_irq = (struct vm_ioapic_irq *)data;
 334                 error = vioapic_assert_irq(sc->vm, ioapic_irq->irq);
 335                 break;
 336         case VM_IOAPIC_DEASSERT_IRQ:
 337                 ioapic_irq = (struct vm_ioapic_irq *)data;
 338                 error = vioapic_deassert_irq(sc->vm, ioapic_irq->irq);
 339                 break;
 340         case VM_IOAPIC_PULSE_IRQ:
 341                 ioapic_irq = (struct vm_ioapic_irq *)data;
 342                 error = vioapic_pulse_irq(sc->vm, ioapic_irq->irq);
 343                 break;
 344         case VM_IOAPIC_PINCOUNT:
 345                 *(int *)data = vioapic_pincount(sc->vm);
 346                 break;
 347         case VM_ISA_ASSERT_IRQ:
 348                 isa_irq = (struct vm_isa_irq *)data;
 349                 error = vatpic_assert_irq(sc->vm, isa_irq->atpic_irq);
 350                 if (error == 0 && isa_irq->ioapic_irq != -1)
 351                         error = vioapic_assert_irq(sc->vm,
 352                             isa_irq->ioapic_irq);
 353                 break;
 354         case VM_ISA_DEASSERT_IRQ:
 355                 isa_irq = (struct vm_isa_irq *)data;
 356                 error = vatpic_deassert_irq(sc->vm, isa_irq->atpic_irq);
 357                 if (error == 0 && isa_irq->ioapic_irq != -1)
 358                         error = vioapic_deassert_irq(sc->vm,
 359                             isa_irq->ioapic_irq);
 360                 break;
 361         case VM_ISA_PULSE_IRQ:
 362                 isa_irq = (struct vm_isa_irq *)data;
 363                 error = vatpic_pulse_irq(sc->vm, isa_irq->atpic_irq);
 364                 if (error == 0 && isa_irq->ioapic_irq != -1)
 365                         error = vioapic_pulse_irq(sc->vm, isa_irq->ioapic_irq);
 366                 break;
 367         case VM_ISA_SET_IRQ_TRIGGER:
 368                 isa_irq_trigger = (struct vm_isa_irq_trigger *)data;
 369                 error = vatpic_set_irq_trigger(sc->vm,
 370                     isa_irq_trigger->atpic_irq, isa_irq_trigger->trigger);
 371                 break;
 372         case VM_MAP_MEMORY:
 373                 seg = (struct vm_memory_segment *)data;
 374                 error = vm_malloc(sc->vm, seg->gpa, seg->len);
 375                 break;
 376         case VM_GET_MEMORY_SEG:
 377                 seg = (struct vm_memory_segment *)data;
 378                 seg->len = 0;
 379                 (void)vm_gpabase2memseg(sc->vm, seg->gpa, seg);
 380                 error = 0;
 381                 break;
 382         case VM_GET_REGISTER:
 383                 vmreg = (struct vm_register *)data;
 384                 error = vm_get_register(sc->vm, vmreg->cpuid, vmreg->regnum,
 385                                         &vmreg->regval);
 386                 break;
 387         case VM_SET_REGISTER:
 388                 vmreg = (struct vm_register *)data;
 389                 error = vm_set_register(sc->vm, vmreg->cpuid, vmreg->regnum,
 390                                         vmreg->regval);
 391                 break;
 392         case VM_SET_SEGMENT_DESCRIPTOR:
 393                 vmsegdesc = (struct vm_seg_desc *)data;
 394                 error = vm_set_seg_desc(sc->vm, vmsegdesc->cpuid,
 395                                         vmsegdesc->regnum,
 396                                         &vmsegdesc->desc);
 397                 break;
 398         case VM_GET_SEGMENT_DESCRIPTOR:
 399                 vmsegdesc = (struct vm_seg_desc *)data;
 400                 error = vm_get_seg_desc(sc->vm, vmsegdesc->cpuid,
 401                                         vmsegdesc->regnum,
 402                                         &vmsegdesc->desc);
 403                 break;
 404         case VM_GET_CAPABILITY:
 405                 vmcap = (struct vm_capability *)data;
 406                 error = vm_get_capability(sc->vm, vmcap->cpuid,
 407                                           vmcap->captype,
 408                                           &vmcap->capval);
 409                 break;
 410         case VM_SET_CAPABILITY:
 411                 vmcap = (struct vm_capability *)data;
 412                 error = vm_set_capability(sc->vm, vmcap->cpuid,
 413                                           vmcap->captype,
 414                                           vmcap->capval);
 415                 break;
 416         case VM_SET_X2APIC_STATE:
 417                 x2apic = (struct vm_x2apic *)data;
 418                 error = vm_set_x2apic_state(sc->vm,
 419                                             x2apic->cpuid, x2apic->state);
 420                 break;
 421         case VM_GET_X2APIC_STATE:
 422                 x2apic = (struct vm_x2apic *)data;
 423                 error = vm_get_x2apic_state(sc->vm,
 424                                             x2apic->cpuid, &x2apic->state);
 425                 break;
 426         case VM_GET_GPA_PMAP:
 427                 gpapte = (struct vm_gpa_pte *)data;
 428                 pmap_get_mapping(vmspace_pmap(vm_get_vmspace(sc->vm)),
 429                                  gpapte->gpa, gpapte->pte, &gpapte->ptenum);
 430                 error = 0;
 431                 break;
 432         case VM_GET_HPET_CAPABILITIES:
 433                 error = vhpet_getcap((struct vm_hpet_cap *)data);
 434                 break;
 435         case VM_GLA2GPA: {
 436                 CTASSERT(PROT_READ == VM_PROT_READ);
 437                 CTASSERT(PROT_WRITE == VM_PROT_WRITE);
 438                 CTASSERT(PROT_EXEC == VM_PROT_EXECUTE);
 439                 gg = (struct vm_gla2gpa *)data;
 440                 error = vmm_gla2gpa(sc->vm, gg->vcpuid, &gg->paging, gg->gla,
 441                     gg->prot, &gg->gpa);
 442                 KASSERT(error == 0 || error == 1 || error == -1,
 443                     ("%s: vmm_gla2gpa unknown error %d", __func__, error));
 444                 if (error >= 0) {
 445                         /*
 446                          * error = 0: the translation was successful
 447                          * error = 1: a fault was injected into the guest
 448                          */
 449                         gg->fault = error;
 450                         error = 0;
 451                 } else {
 452                         error = EFAULT;
 453                 }
 454                 break;
 455         }
 456         case VM_ACTIVATE_CPU:
 457                 vac = (struct vm_activate_cpu *)data;
 458                 error = vm_activate_cpu(sc->vm, vac->vcpuid);
 459                 break;
 460         case VM_GET_CPUS:
 461                 error = 0;
 462                 vm_cpuset = (struct vm_cpuset *)data;
 463                 size = vm_cpuset->cpusetsize;
 464                 if (size < sizeof(cpuset_t) || size > CPU_MAXSIZE / NBBY) {
 465                         error = ERANGE;
 466                         break;
 467                 }
 468                 cpuset = malloc(size, M_TEMP, M_WAITOK | M_ZERO);
 469                 if (vm_cpuset->which == VM_ACTIVE_CPUS)
 470                         *cpuset = vm_active_cpus(sc->vm);
 471                 else if (vm_cpuset->which == VM_SUSPENDED_CPUS)
 472                         *cpuset = vm_suspended_cpus(sc->vm);
 473                 else
 474                         error = EINVAL;
 475                 if (error == 0)
 476                         error = copyout(cpuset, vm_cpuset->cpus, size);
 477                 free(cpuset, M_TEMP);
 478                 break;
 479         case VM_SET_INTINFO:
 480                 vmii = (struct vm_intinfo *)data;
 481                 error = vm_exit_intinfo(sc->vm, vmii->vcpuid, vmii->info1);
 482                 break;
 483         case VM_GET_INTINFO:
 484                 vmii = (struct vm_intinfo *)data;
 485                 error = vm_get_intinfo(sc->vm, vmii->vcpuid, &vmii->info1,
 486                     &vmii->info2);
 487                 break;
 488         case VM_RTC_WRITE:
 489                 rtcdata = (struct vm_rtc_data *)data;
 490                 error = vrtc_nvram_write(sc->vm, rtcdata->offset,
 491                     rtcdata->value);
 492                 break;
 493         case VM_RTC_READ:
 494                 rtcdata = (struct vm_rtc_data *)data;
 495                 error = vrtc_nvram_read(sc->vm, rtcdata->offset,
 496                     &rtcdata->value);
 497                 break;
 498         case VM_RTC_SETTIME:
 499                 rtctime = (struct vm_rtc_time *)data;
 500                 error = vrtc_set_time(sc->vm, rtctime->secs);
 501                 break;
 502         case VM_RTC_GETTIME:
 503                 error = 0;
 504                 rtctime = (struct vm_rtc_time *)data;
 505                 rtctime->secs = vrtc_get_time(sc->vm);
 506                 break;
 507         default:
 508                 error = ENOTTY;
 509                 break;
 510         }
 511
 512         if (state_changed == 1) {
 513                 vcpu_set_state(sc->vm, vcpu, VCPU_IDLE, false);
 514         } else if (state_changed == 2) {
 515                 for (vcpu = 0; vcpu < VM_MAXCPU; vcpu++)
 516                         vcpu_set_state(sc->vm, vcpu, VCPU_IDLE, false);
 517         }
 518
 519 done:
 520         /* Make sure that no handler returns a bogus value like ERESTART */
 521         KASSERT(error >= 0, ("vmmdev_ioctl: invalid error return %d", error));
 522         return (error);
 523 }
 524
 525 static int
 526 vmmdev_mmap_single(struct cdev *cdev, vm_ooffset_t *offset,
 527                    vm_size_t size, struct vm_object **object, int nprot)
 528 {
 529         int error;
 530         struct vmmdev_softc *sc;
 531
 532         sc = vmmdev_lookup2(cdev);
 533         if (sc != NULL && (nprot & PROT_EXEC) == 0)
 534                 error = vm_get_memobj(sc->vm, *offset, size, offset, object);
 535         else
 536                 error = EINVAL;
 537
 538         return (error);
 539 }
 540
 541 static void
 542 vmmdev_destroy(void *arg)
 543 {
 544
 545         struct vmmdev_softc *sc = arg;
 546
 547         if (sc->cdev != NULL)
 548                 destroy_dev(sc->cdev);
 549
 550         if (sc->vm != NULL)
 551                 vm_destroy(sc->vm);
 552
 553         if ((sc->flags & VSC_LINKED) != 0) {
 554                 mtx_lock(&vmmdev_mtx);
 555                 SLIST_REMOVE(&head, sc, vmmdev_softc, link);
 556                 mtx_unlock(&vmmdev_mtx);
 557         }
 558
 559         free(sc, M_VMMDEV);
 560 }
 561
 562 static int
 563 sysctl_vmm_destroy(SYSCTL_HANDLER_ARGS)
 564 {
 565         int error;
 566         char buf[VM_MAX_NAMELEN];
 567         struct vmmdev_softc *sc;
 568         struct cdev *cdev;
 569
 570         strlcpy(buf, "beavis", sizeof(buf));
 571         error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
 572         if (error != 0 || req->newptr == NULL)
 573                 return (error);
 574
 575         mtx_lock(&vmmdev_mtx);
 576         sc = vmmdev_lookup(buf);
 577         if (sc == NULL || sc->cdev == NULL) {
 578                 mtx_unlock(&vmmdev_mtx);
 579                 return (EINVAL);
 580         }
 581
 582         /*
 583          * The 'cdev' will be destroyed asynchronously when 'si_threadcount'
 584          * goes down to 0 so we should not do it again in the callback.
 585          */
 586         cdev = sc->cdev;
 587         sc->cdev = NULL;
 588         mtx_unlock(&vmmdev_mtx);
 589
 590         /*
 591          * Schedule the 'cdev' to be destroyed:
 592          *
 593          * - any new operations on this 'cdev' will return an error (ENXIO).
 594          *
 595          * - when the 'si_threadcount' dwindles down to zero the 'cdev' will
 596          *   be destroyed and the callback will be invoked in a taskqueue
 597          *   context.
 598          */
 599         destroy_dev_sched_cb(cdev, vmmdev_destroy, sc);
 600
 601         return (0);
 602 }
 603 SYSCTL_PROC(_hw_vmm, OID_AUTO, destroy, CTLTYPE_STRING | CTLFLAG_RW,
 604             NULL, 0, sysctl_vmm_destroy, "A", NULL);
 605
 606 static struct cdevsw vmmdevsw = {
 607         .d_name         = "vmmdev",
 608         .d_version      = D_VERSION,
 609         .d_ioctl        = vmmdev_ioctl,
 610         .d_mmap_single  = vmmdev_mmap_single,
 611         .d_read         = vmmdev_rw,
 612         .d_write        = vmmdev_rw,
 613 };
 614
 615 static int
 616 sysctl_vmm_create(SYSCTL_HANDLER_ARGS)
 617 {
 618         int error;
 619         struct vm *vm;
 620         struct cdev *cdev;
 621         struct vmmdev_softc *sc, *sc2;
 622         char buf[VM_MAX_NAMELEN];
 623
 624         strlcpy(buf, "beavis", sizeof(buf));
 625         error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
 626         if (error != 0 || req->newptr == NULL)
 627                 return (error);
 628
 629         mtx_lock(&vmmdev_mtx);
 630         sc = vmmdev_lookup(buf);
 631         mtx_unlock(&vmmdev_mtx);
 632         if (sc != NULL)
 633                 return (EEXIST);
 634
 635         error = vm_create(buf, &vm);
 636         if (error != 0)
 637                 return (error);
 638
 639         sc = malloc(sizeof(struct vmmdev_softc), M_VMMDEV, M_WAITOK | M_ZERO);
 640         sc->vm = vm;
 641
 642         /*
 643          * Lookup the name again just in case somebody sneaked in when we
 644          * dropped the lock.
 645          */
 646         mtx_lock(&vmmdev_mtx);
 647         sc2 = vmmdev_lookup(buf);
 648         if (sc2 == NULL) {
 649                 SLIST_INSERT_HEAD(&head, sc, link);
 650                 sc->flags |= VSC_LINKED;
 651         }
 652         mtx_unlock(&vmmdev_mtx);
 653
 654         if (sc2 != NULL) {
 655                 vmmdev_destroy(sc);
 656                 return (EEXIST);
 657         }
 658
 659         error = make_dev_p(MAKEDEV_CHECKNAME, &cdev, &vmmdevsw, NULL,
 660                            UID_ROOT, GID_WHEEL, 0600, "vmm/%s", buf);
 661         if (error != 0) {
 662                 vmmdev_destroy(sc);
 663                 return (error);
 664         }
 665
 666         mtx_lock(&vmmdev_mtx);
 667         sc->cdev = cdev;
 668         sc->cdev->si_drv1 = sc;
 669         mtx_unlock(&vmmdev_mtx);
 670
 671         return (0);
 672 }
 673 SYSCTL_PROC(_hw_vmm, OID_AUTO, create, CTLTYPE_STRING | CTLFLAG_RW,
 674             NULL, 0, sysctl_vmm_create, "A", NULL);
 675
 676 void
 677 vmmdev_init(void)
 678 {
 679         mtx_init(&vmmdev_mtx, "vmm device mutex", NULL, MTX_DEF);
 680 }
 681
 682 int
 683 vmmdev_cleanup(void)
 684 {
 685         int error;
 686
 687         if (SLIST_EMPTY(&head))
 688                 error = 0;
 689         else
 690                 error = EBUSY;
 691
 692         return (error);
 693 }