target/arm/kvm.c

   1 /*
   2  * ARM implementation of KVM hooks
   3  *
   4  * Copyright Christoffer Dall 2009-2010
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  *
   9  */
  10
  11 #include "qemu/osdep.h"
  12 #include <sys/ioctl.h>
  13
  14 #include <linux/kvm.h>
  15
  16 #include "qemu-common.h"
  17 #include "qemu/timer.h"
  18 #include "qemu/error-report.h"
  19 #include "sysemu/sysemu.h"
  20 #include "sysemu/kvm.h"
  21 #include "kvm_arm.h"
  22 #include "cpu.h"
  23 #include "trace.h"
  24 #include "internals.h"
  25 #include "hw/arm/arm.h"
  26 #include "hw/pci/pci.h"
  27 #include "exec/memattrs.h"
  28 #include "exec/address-spaces.h"
  29 #include "hw/boards.h"
  30 #include "qemu/log.h"
  31
  32 const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
  33     KVM_CAP_LAST_INFO
  34 };
  35
  36 static bool cap_has_mp_state;
  37
  38 static ARMHostCPUFeatures arm_host_cpu_features;
  39
  40 int kvm_arm_vcpu_init(CPUState *cs)
  41 {
  42     ARMCPU *cpu = ARM_CPU(cs);
  43     struct kvm_vcpu_init init;
  44
  45     init.target = cpu->kvm_target;
  46     memcpy(init.features, cpu->kvm_init_features, sizeof(init.features));
  47
  48     return kvm_vcpu_ioctl(cs, KVM_ARM_VCPU_INIT, &init);
  49 }
  50
  51 bool kvm_arm_create_scratch_host_vcpu(const uint32_t *cpus_to_try,
  52                                       int *fdarray,
  53                                       struct kvm_vcpu_init *init)
  54 {
  55     int ret, kvmfd = -1, vmfd = -1, cpufd = -1;
  56
  57     kvmfd = qemu_open("/dev/kvm", O_RDWR);
  58     if (kvmfd < 0) {
  59         goto err;
  60     }
  61     vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0);
  62     if (vmfd < 0) {
  63         goto err;
  64     }
  65     cpufd = ioctl(vmfd, KVM_CREATE_VCPU, 0);
  66     if (cpufd < 0) {
  67         goto err;
  68     }
  69
  70     if (!init) {
  71         /* Caller doesn't want the VCPU to be initialized, so skip it */
  72         goto finish;
  73     }
  74
  75     ret = ioctl(vmfd, KVM_ARM_PREFERRED_TARGET, init);
  76     if (ret >= 0) {
  77         ret = ioctl(cpufd, KVM_ARM_VCPU_INIT, init);
  78         if (ret < 0) {
  79             goto err;
  80         }
  81     } else if (cpus_to_try) {
  82         /* Old kernel which doesn't know about the
  83          * PREFERRED_TARGET ioctl: we know it will only support
  84          * creating one kind of guest CPU which is its preferred
  85          * CPU type.
  86          */
  87         while (*cpus_to_try != QEMU_KVM_ARM_TARGET_NONE) {
  88             init->target = *cpus_to_try++;
  89             memset(init->features, 0, sizeof(init->features));
  90             ret = ioctl(cpufd, KVM_ARM_VCPU_INIT, init);
  91             if (ret >= 0) {
  92                 break;
  93             }
  94         }
  95         if (ret < 0) {
  96             goto err;
  97         }
  98     } else {
  99         /* Treat a NULL cpus_to_try argument the same as an empty
 100          * list, which means we will fail the call since this must
 101          * be an old kernel which doesn't support PREFERRED_TARGET.
 102          */
 103         goto err;
 104     }
 105
 106 finish:
 107     fdarray[0] = kvmfd;
 108     fdarray[1] = vmfd;
 109     fdarray[2] = cpufd;
 110
 111     return true;
 112
 113 err:
 114     if (cpufd >= 0) {
 115         close(cpufd);
 116     }
 117     if (vmfd >= 0) {
 118         close(vmfd);
 119     }
 120     if (kvmfd >= 0) {
 121         close(kvmfd);
 122     }
 123
 124     return false;
 125 }
 126
 127 void kvm_arm_destroy_scratch_host_vcpu(int *fdarray)
 128 {
 129     int i;
 130
 131     for (i = 2; i >= 0; i--) {
 132         close(fdarray[i]);
 133     }
 134 }
 135
 136 void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
 137 {
 138     CPUARMState *env = &cpu->env;
 139
 140     if (!arm_host_cpu_features.dtb_compatible) {
 141         if (!kvm_enabled() ||
 142             !kvm_arm_get_host_cpu_features(&arm_host_cpu_features)) {
 143             /* We can't report this error yet, so flag that we need to
 144              * in arm_cpu_realizefn().
 145              */
 146             cpu->kvm_target = QEMU_KVM_ARM_TARGET_NONE;
 147             cpu->host_cpu_probe_failed = true;
 148             return;
 149         }
 150     }
 151
 152     cpu->kvm_target = arm_host_cpu_features.target;
 153     cpu->dtb_compatible = arm_host_cpu_features.dtb_compatible;
 154     env->features = arm_host_cpu_features.features;
 155 }
 156
 157 int kvm_arch_init(MachineState *ms, KVMState *s)
 158 {
 159     /* For ARM interrupt delivery is always asynchronous,
 160      * whether we are using an in-kernel VGIC or not.
 161      */
 162     kvm_async_interrupts_allowed = true;
 163
 164     /*
 165      * PSCI wakes up secondary cores, so we always need to
 166      * have vCPUs waiting in kernel space
 167      */
 168     kvm_halt_in_kernel_allowed = true;
 169
 170     cap_has_mp_state = kvm_check_extension(s, KVM_CAP_MP_STATE);
 171
 172     return 0;
 173 }
 174
 175 unsigned long kvm_arch_vcpu_id(CPUState *cpu)
 176 {
 177     return cpu->cpu_index;
 178 }
 179
 180 /* We track all the KVM devices which need their memory addresses
 181  * passing to the kernel in a list of these structures.
 182  * When board init is complete we run through the list and
 183  * tell the kernel the base addresses of the memory regions.
 184  * We use a MemoryListener to track mapping and unmapping of
 185  * the regions during board creation, so the board models don't
 186  * need to do anything special for the KVM case.
 187  */
 188 typedef struct KVMDevice {
 189     struct kvm_arm_device_addr kda;
 190     struct kvm_device_attr kdattr;
 191     MemoryRegion *mr;
 192     QSLIST_ENTRY(KVMDevice) entries;
 193     int dev_fd;
 194 } KVMDevice;
 195
 196 static QSLIST_HEAD(kvm_devices_head, KVMDevice) kvm_devices_head;
 197
 198 static void kvm_arm_devlistener_add(MemoryListener *listener,
 199                                     MemoryRegionSection *section)
 200 {
 201     KVMDevice *kd;
 202
 203     QSLIST_FOREACH(kd, &kvm_devices_head, entries) {
 204         if (section->mr == kd->mr) {
 205             kd->kda.addr = section->offset_within_address_space;
 206         }
 207     }
 208 }
 209
 210 static void kvm_arm_devlistener_del(MemoryListener *listener,
 211                                     MemoryRegionSection *section)
 212 {
 213     KVMDevice *kd;
 214
 215     QSLIST_FOREACH(kd, &kvm_devices_head, entries) {
 216         if (section->mr == kd->mr) {
 217             kd->kda.addr = -1;
 218         }
 219     }
 220 }
 221
 222 static MemoryListener devlistener = {
 223     .region_add = kvm_arm_devlistener_add,
 224     .region_del = kvm_arm_devlistener_del,
 225 };
 226
 227 static void kvm_arm_set_device_addr(KVMDevice *kd)
 228 {
 229     struct kvm_device_attr *attr = &kd->kdattr;
 230     int ret;
 231
 232     /* If the device control API is available and we have a device fd on the
 233      * KVMDevice struct, let's use the newer API
 234      */
 235     if (kd->dev_fd >= 0) {
 236         uint64_t addr = kd->kda.addr;
 237         attr->addr = (uintptr_t)&addr;
 238         ret = kvm_device_ioctl(kd->dev_fd, KVM_SET_DEVICE_ATTR, attr);
 239     } else {
 240         ret = kvm_vm_ioctl(kvm_state, KVM_ARM_SET_DEVICE_ADDR, &kd->kda);
 241     }
 242
 243     if (ret < 0) {
 244         fprintf(stderr, "Failed to set device address: %s\n",
 245                 strerror(-ret));
 246         abort();
 247     }
 248 }
 249
 250 static void kvm_arm_machine_init_done(Notifier *notifier, void *data)
 251 {
 252     KVMDevice *kd, *tkd;
 253
 254     QSLIST_FOREACH_SAFE(kd, &kvm_devices_head, entries, tkd) {
 255         if (kd->kda.addr != -1) {
 256             kvm_arm_set_device_addr(kd);
 257         }
 258         memory_region_unref(kd->mr);
 259         g_free(kd);
 260     }
 261     memory_listener_unregister(&devlistener);
 262 }
 263
 264 static Notifier notify = {
 265     .notify = kvm_arm_machine_init_done,
 266 };
 267
 268 void kvm_arm_register_device(MemoryRegion *mr, uint64_t devid, uint64_t group,
 269                              uint64_t attr, int dev_fd)
 270 {
 271     KVMDevice *kd;
 272
 273     if (!kvm_irqchip_in_kernel()) {
 274         return;
 275     }
 276
 277     if (QSLIST_EMPTY(&kvm_devices_head)) {
 278         memory_listener_register(&devlistener, &address_space_memory);
 279         qemu_add_machine_init_done_notifier(&notify);
 280     }
 281     kd = g_new0(KVMDevice, 1);
 282     kd->mr = mr;
 283     kd->kda.id = devid;
 284     kd->kda.addr = -1;
 285     kd->kdattr.flags = 0;
 286     kd->kdattr.group = group;
 287     kd->kdattr.attr = attr;
 288     kd->dev_fd = dev_fd;
 289     QSLIST_INSERT_HEAD(&kvm_devices_head, kd, entries);
 290     memory_region_ref(kd->mr);
 291 }
 292
 293 static int compare_u64(const void *a, const void *b)
 294 {
 295     if (*(uint64_t *)a > *(uint64_t *)b) {
 296         return 1;
 297     }
 298     if (*(uint64_t *)a < *(uint64_t *)b) {
 299         return -1;
 300     }
 301     return 0;
 302 }
 303
 304 /* Initialize the CPUState's cpreg list according to the kernel's
 305  * definition of what CPU registers it knows about (and throw away
 306  * the previous TCG-created cpreg list).
 307  */
 308 int kvm_arm_init_cpreg_list(ARMCPU *cpu)
 309 {
 310     struct kvm_reg_list rl;
 311     struct kvm_reg_list *rlp;
 312     int i, ret, arraylen;
 313     CPUState *cs = CPU(cpu);
 314
 315     rl.n = 0;
 316     ret = kvm_vcpu_ioctl(cs, KVM_GET_REG_LIST, &rl);
 317     if (ret != -E2BIG) {
 318         return ret;
 319     }
 320     rlp = g_malloc(sizeof(struct kvm_reg_list) + rl.n * sizeof(uint64_t));
 321     rlp->n = rl.n;
 322     ret = kvm_vcpu_ioctl(cs, KVM_GET_REG_LIST, rlp);
 323     if (ret) {
 324         goto out;
 325     }
 326     /* Sort the list we get back from the kernel, since cpreg_tuples
 327      * must be in strictly ascending order.
 328      */
 329     qsort(&rlp->reg, rlp->n, sizeof(rlp->reg[0]), compare_u64);
 330
 331     for (i = 0, arraylen = 0; i < rlp->n; i++) {
 332         if (!kvm_arm_reg_syncs_via_cpreg_list(rlp->reg[i])) {
 333             continue;
 334         }
 335         switch (rlp->reg[i] & KVM_REG_SIZE_MASK) {
 336         case KVM_REG_SIZE_U32:
 337         case KVM_REG_SIZE_U64:
 338             break;
 339         default:
 340             fprintf(stderr, "Can't handle size of register in kernel list\n");
 341             ret = -EINVAL;
 342             goto out;
 343         }
 344
 345         arraylen++;
 346     }
 347
 348     cpu->cpreg_indexes = g_renew(uint64_t, cpu->cpreg_indexes, arraylen);
 349     cpu->cpreg_values = g_renew(uint64_t, cpu->cpreg_values, arraylen);
 350     cpu->cpreg_vmstate_indexes = g_renew(uint64_t, cpu->cpreg_vmstate_indexes,
 351                                          arraylen);
 352     cpu->cpreg_vmstate_values = g_renew(uint64_t, cpu->cpreg_vmstate_values,
 353                                         arraylen);
 354     cpu->cpreg_array_len = arraylen;
 355     cpu->cpreg_vmstate_array_len = arraylen;
 356
 357     for (i = 0, arraylen = 0; i < rlp->n; i++) {
 358         uint64_t regidx = rlp->reg[i];
 359         if (!kvm_arm_reg_syncs_via_cpreg_list(regidx)) {
 360             continue;
 361         }
 362         cpu->cpreg_indexes[arraylen] = regidx;
 363         arraylen++;
 364     }
 365     assert(cpu->cpreg_array_len == arraylen);
 366
 367     if (!write_kvmstate_to_list(cpu)) {
 368         /* Shouldn't happen unless kernel is inconsistent about
 369          * what registers exist.
 370          */
 371         fprintf(stderr, "Initial read of kernel register state failed\n");
 372         ret = -EINVAL;
 373         goto out;
 374     }
 375
 376 out:
 377     g_free(rlp);
 378     return ret;
 379 }
 380
 381 bool write_kvmstate_to_list(ARMCPU *cpu)
 382 {
 383     CPUState *cs = CPU(cpu);
 384     int i;
 385     bool ok = true;
 386
 387     for (i = 0; i < cpu->cpreg_array_len; i++) {
 388         struct kvm_one_reg r;
 389         uint64_t regidx = cpu->cpreg_indexes[i];
 390         uint32_t v32;
 391         int ret;
 392
 393         r.id = regidx;
 394
 395         switch (regidx & KVM_REG_SIZE_MASK) {
 396         case KVM_REG_SIZE_U32:
 397             r.addr = (uintptr_t)&v32;
 398             ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);
 399             if (!ret) {
 400                 cpu->cpreg_values[i] = v32;
 401             }
 402             break;
 403         case KVM_REG_SIZE_U64:
 404             r.addr = (uintptr_t)(cpu->cpreg_values + i);
 405             ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);
 406             break;
 407         default:
 408             abort();
 409         }
 410         if (ret) {
 411             ok = false;
 412         }
 413     }
 414     return ok;
 415 }
 416
 417 bool write_list_to_kvmstate(ARMCPU *cpu, int level)
 418 {
 419     CPUState *cs = CPU(cpu);
 420     int i;
 421     bool ok = true;
 422
 423     for (i = 0; i < cpu->cpreg_array_len; i++) {
 424         struct kvm_one_reg r;
 425         uint64_t regidx = cpu->cpreg_indexes[i];
 426         uint32_t v32;
 427         int ret;
 428
 429         if (kvm_arm_cpreg_level(regidx) > level) {
 430             continue;
 431         }
 432
 433         r.id = regidx;
 434         switch (regidx & KVM_REG_SIZE_MASK) {
 435         case KVM_REG_SIZE_U32:
 436             v32 = cpu->cpreg_values[i];
 437             r.addr = (uintptr_t)&v32;
 438             break;
 439         case KVM_REG_SIZE_U64:
 440             r.addr = (uintptr_t)(cpu->cpreg_values + i);
 441             break;
 442         default:
 443             abort();
 444         }
 445         ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);
 446         if (ret) {
 447             /* We might fail for "unknown register" and also for
 448              * "you tried to set a register which is constant with
 449              * a different value from what it actually contains".
 450              */
 451             ok = false;
 452         }
 453     }
 454     return ok;
 455 }
 456
 457 void kvm_arm_reset_vcpu(ARMCPU *cpu)
 458 {
 459     int ret;
 460
 461     /* Re-init VCPU so that all registers are set to
 462      * their respective reset values.
 463      */
 464     ret = kvm_arm_vcpu_init(CPU(cpu));
 465     if (ret < 0) {
 466         fprintf(stderr, "kvm_arm_vcpu_init failed: %s\n", strerror(-ret));
 467         abort();
 468     }
 469     if (!write_kvmstate_to_list(cpu)) {
 470         fprintf(stderr, "write_kvmstate_to_list failed\n");
 471         abort();
 472     }
 473 }
 474
 475 /*
 476  * Update KVM's MP_STATE based on what QEMU thinks it is
 477  */
 478 int kvm_arm_sync_mpstate_to_kvm(ARMCPU *cpu)
 479 {
 480     if (cap_has_mp_state) {
 481         struct kvm_mp_state mp_state = {
 482             .mp_state = (cpu->power_state == PSCI_OFF) ?
 483             KVM_MP_STATE_STOPPED : KVM_MP_STATE_RUNNABLE
 484         };
 485         int ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MP_STATE, &mp_state);
 486         if (ret) {
 487             fprintf(stderr, "%s: failed to set MP_STATE %d/%s\n",
 488                     __func__, ret, strerror(-ret));
 489             return -1;
 490         }
 491     }
 492
 493     return 0;
 494 }
 495
 496 /*
 497  * Sync the KVM MP_STATE into QEMU
 498  */
 499 int kvm_arm_sync_mpstate_to_qemu(ARMCPU *cpu)
 500 {
 501     if (cap_has_mp_state) {
 502         struct kvm_mp_state mp_state;
 503         int ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MP_STATE, &mp_state);
 504         if (ret) {
 505             fprintf(stderr, "%s: failed to get MP_STATE %d/%s\n",
 506                     __func__, ret, strerror(-ret));
 507             abort();
 508         }
 509         cpu->power_state = (mp_state.mp_state == KVM_MP_STATE_STOPPED) ?
 510             PSCI_OFF : PSCI_ON;
 511     }
 512
 513     return 0;
 514 }
 515
 516 void kvm_arch_pre_run(CPUState *cs, struct kvm_run *run)
 517 {
 518 }
 519
 520 MemTxAttrs kvm_arch_post_run(CPUState *cs, struct kvm_run *run)
 521 {
 522     ARMCPU *cpu;
 523     uint32_t switched_level;
 524
 525     if (kvm_irqchip_in_kernel()) {
 526         /*
 527          * We only need to sync timer states with user-space interrupt
 528          * controllers, so return early and save cycles if we don't.
 529          */
 530         return MEMTXATTRS_UNSPECIFIED;
 531     }
 532
 533     cpu = ARM_CPU(cs);
 534
 535     /* Synchronize our shadowed in-kernel device irq lines with the kvm ones */
 536     if (run->s.regs.device_irq_level != cpu->device_irq_level) {
 537         switched_level = cpu->device_irq_level ^ run->s.regs.device_irq_level;
 538
 539         qemu_mutex_lock_iothread();
 540
 541         if (switched_level & KVM_ARM_DEV_EL1_VTIMER) {
 542             qemu_set_irq(cpu->gt_timer_outputs[GTIMER_VIRT],
 543                          !!(run->s.regs.device_irq_level &
 544                             KVM_ARM_DEV_EL1_VTIMER));
 545             switched_level &= ~KVM_ARM_DEV_EL1_VTIMER;
 546         }
 547
 548         if (switched_level & KVM_ARM_DEV_EL1_PTIMER) {
 549             qemu_set_irq(cpu->gt_timer_outputs[GTIMER_PHYS],
 550                          !!(run->s.regs.device_irq_level &
 551                             KVM_ARM_DEV_EL1_PTIMER));
 552             switched_level &= ~KVM_ARM_DEV_EL1_PTIMER;
 553         }
 554
 555         if (switched_level & KVM_ARM_DEV_PMU) {
 556             qemu_set_irq(cpu->pmu_interrupt,
 557                          !!(run->s.regs.device_irq_level & KVM_ARM_DEV_PMU));
 558             switched_level &= ~KVM_ARM_DEV_PMU;
 559         }
 560
 561         if (switched_level) {
 562             qemu_log_mask(LOG_UNIMP, "%s: unhandled in-kernel device IRQ %x\n",
 563                           __func__, switched_level);
 564         }
 565
 566         /* We also mark unknown levels as processed to not waste cycles */
 567         cpu->device_irq_level = run->s.regs.device_irq_level;
 568         qemu_mutex_unlock_iothread();
 569     }
 570
 571     return MEMTXATTRS_UNSPECIFIED;
 572 }
 573
 574
 575 int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
 576 {
 577     int ret = 0;
 578
 579     switch (run->exit_reason) {
 580     case KVM_EXIT_DEBUG:
 581         if (kvm_arm_handle_debug(cs, &run->debug.arch)) {
 582             ret = EXCP_DEBUG;
 583         } /* otherwise return to guest */
 584         break;
 585     default:
 586         qemu_log_mask(LOG_UNIMP, "%s: un-handled exit reason %d\n",
 587                       __func__, run->exit_reason);
 588         break;
 589     }
 590     return ret;
 591 }
 592
 593 bool kvm_arch_stop_on_emulation_error(CPUState *cs)
 594 {
 595     return true;
 596 }
 597
 598 int kvm_arch_process_async_events(CPUState *cs)
 599 {
 600     return 0;
 601 }
 602
 603 /* The #ifdef protections are until 32bit headers are imported and can
 604  * be removed once both 32 and 64 bit reach feature parity.
 605  */
 606 void kvm_arch_update_guest_debug(CPUState *cs, struct kvm_guest_debug *dbg)
 607 {
 608 #ifdef KVM_GUESTDBG_USE_SW_BP
 609     if (kvm_sw_breakpoints_active(cs)) {
 610         dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
 611     }
 612 #endif
 613 #ifdef KVM_GUESTDBG_USE_HW
 614     if (kvm_arm_hw_debug_active(cs)) {
 615         dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW;
 616         kvm_arm_copy_hw_debug_data(&dbg->arch);
 617     }
 618 #endif
 619 }
 620
 621 void kvm_arch_init_irq_routing(KVMState *s)
 622 {
 623 }
 624
 625 int kvm_arch_irqchip_create(MachineState *ms, KVMState *s)
 626 {
 627      if (machine_kernel_irqchip_split(ms)) {
 628          perror("-machine kernel_irqchip=split is not supported on ARM.");
 629          exit(1);
 630     }
 631
 632     /* If we can create the VGIC using the newer device control API, we
 633      * let the device do this when it initializes itself, otherwise we
 634      * fall back to the old API */
 635     return kvm_check_extension(s, KVM_CAP_DEVICE_CTRL);
 636 }
 637
 638 int kvm_arm_vgic_probe(void)
 639 {
 640     if (kvm_create_device(kvm_state,
 641                           KVM_DEV_TYPE_ARM_VGIC_V3, true) == 0) {
 642         return 3;
 643     } else if (kvm_create_device(kvm_state,
 644                                  KVM_DEV_TYPE_ARM_VGIC_V2, true) == 0) {
 645         return 2;
 646     } else {
 647         return 0;
 648     }
 649 }
 650
 651 int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
 652                              uint64_t address, uint32_t data, PCIDevice *dev)
 653 {
 654     AddressSpace *as = pci_device_iommu_address_space(dev);
 655     hwaddr xlat, len, doorbell_gpa;
 656     MemoryRegionSection mrs;
 657     MemoryRegion *mr;
 658     int ret = 1;
 659
 660     if (as == &address_space_memory) {
 661         return 0;
 662     }
 663
 664     /* MSI doorbell address is translated by an IOMMU */
 665
 666     rcu_read_lock();
 667     mr = address_space_translate(as, address, &xlat, &len, true);
 668     if (!mr) {
 669         goto unlock;
 670     }
 671     mrs = memory_region_find(mr, xlat, 1);
 672     if (!mrs.mr) {
 673         goto unlock;
 674     }
 675
 676     doorbell_gpa = mrs.offset_within_address_space;
 677     memory_region_unref(mrs.mr);
 678
 679     route->u.msi.address_lo = doorbell_gpa;
 680     route->u.msi.address_hi = doorbell_gpa >> 32;
 681
 682     trace_kvm_arm_fixup_msi_route(address, doorbell_gpa);
 683
 684     ret = 0;
 685
 686 unlock:
 687     rcu_read_unlock();
 688     return ret;
 689 }
 690
 691 int kvm_arch_add_msi_route_post(struct kvm_irq_routing_entry *route,
 692                                 int vector, PCIDevice *dev)
 693 {
 694     return 0;
 695 }
 696
 697 int kvm_arch_release_virq_post(int virq)
 698 {
 699     return 0;
 700 }
 701
 702 int kvm_arch_msi_data_to_gsi(uint32_t data)
 703 {
 704     return (data - 32) & 0xffff;
 705 }