Archipelago » qemu

/*

 * QEMU KVM support

 *

 * Copyright IBM, Corp. 2008

 *           Red Hat, Inc. 2008

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *  Glauber Costa     <gcosta@redhat.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 *

 */

#include <sys/types.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include <stdarg.h>

#include <linux/kvm.h>

#include "qemu-common.h"

#include "qemu-barrier.h"

#include "sysemu.h"

#include "hw/hw.h"

#include "gdbstub.h"

#include "kvm.h"

#include "bswap.h"

#include "memory.h"

/* This check must be after config-host.h is included */

#ifdef CONFIG_EVENTFD

#include <sys/eventfd.h>

#endif

/* KVM uses PAGE_SIZE in it's definition of COALESCED_MMIO_MAX */

#define PAGE_SIZE TARGET_PAGE_SIZE

//#define DEBUG_KVM

#ifdef DEBUG_KVM

#define DPRINTF(fmt, ...) \

    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)

#else

#define DPRINTF(fmt, ...) \

    do { } while (0)

#endif

typedef struct KVMSlot

{

    target_phys_addr_t start_addr;

    ram_addr_t memory_size;

    void *ram;

    int slot;

    int flags;

} KVMSlot;

typedef struct kvm_dirty_log KVMDirtyLog;

struct KVMState

{

    KVMSlot slots[32];

    int fd;

    int vmfd;

    int coalesced_mmio;

    struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;

    bool coalesced_flush_in_progress;

    int broken_set_mem_region;

    int migration_log;

    int vcpu_events;

    int robust_singlestep;

    int debugregs;

#ifdef KVM_CAP_SET_GUEST_DEBUG

    struct kvm_sw_breakpoint_head kvm_sw_breakpoints;

#endif

    int irqchip_in_kernel;

    int pit_in_kernel;

    int xsave, xcrs;

    int many_ioeventfds;

};

KVMState *kvm_state;

static const KVMCapabilityInfo kvm_required_capabilites[] = {

    KVM_CAP_INFO(USER_MEMORY),

    KVM_CAP_INFO(DESTROY_MEMORY_REGION_WORKS),

    KVM_CAP_LAST_INFO

};

static KVMSlot *kvm_alloc_slot(KVMState *s)

{

    int i;

    for (i = 0; i < ARRAY_SIZE(s->slots); i++) {

        if (s->slots[i].memory_size == 0) {

            return &s->slots[i];

        }

    }

    fprintf(stderr, "%s: no free slot available\n", __func__);

    abort();

}

static KVMSlot *kvm_lookup_matching_slot(KVMState *s,

                                         target_phys_addr_t start_addr,

                                         target_phys_addr_t end_addr)

{

    int i;

    for (i = 0; i < ARRAY_SIZE(s->slots); i++) {

        KVMSlot *mem = &s->slots[i];

        if (start_addr == mem->start_addr &&

            end_addr == mem->start_addr + mem->memory_size) {

            return mem;

        }

    }

    return NULL;

}

/*

 * Find overlapping slot with lowest start address

 */

static KVMSlot *kvm_lookup_overlapping_slot(KVMState *s,

                                            target_phys_addr_t start_addr,

                                            target_phys_addr_t end_addr)

{

    KVMSlot *found = NULL;

    int i;

    for (i = 0; i < ARRAY_SIZE(s->slots); i++) {

        KVMSlot *mem = &s->slots[i];

        if (mem->memory_size == 0 ||

            (found && found->start_addr < mem->start_addr)) {

            continue;

        }

        if (end_addr > mem->start_addr &&

            start_addr < mem->start_addr + mem->memory_size) {

            found = mem;

        }

    }

    return found;

}

int kvm_physical_memory_addr_from_host(KVMState *s, void *ram,

                                       target_phys_addr_t *phys_addr)

{

    int i;

    for (i = 0; i < ARRAY_SIZE(s->slots); i++) {

        KVMSlot *mem = &s->slots[i];

        if (ram >= mem->ram && ram < mem->ram + mem->memory_size) {

            *phys_addr = mem->start_addr + (ram - mem->ram);

            return 1;

        }

    }

    return 0;

}

static int kvm_set_user_memory_region(KVMState *s, KVMSlot *slot)

{

    struct kvm_userspace_memory_region mem;

    mem.slot = slot->slot;

    mem.guest_phys_addr = slot->start_addr;

    mem.memory_size = slot->memory_size;

    mem.userspace_addr = (unsigned long)slot->ram;

    mem.flags = slot->flags;

    if (s->migration_log) {

        mem.flags |= KVM_MEM_LOG_DIRTY_PAGES;

    }

    return kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);

}

static void kvm_reset_vcpu(void *opaque)

{

    CPUState *env = opaque;

    kvm_arch_reset_vcpu(env);

}

int kvm_irqchip_in_kernel(void)

{

    return kvm_state->irqchip_in_kernel;

}

int kvm_pit_in_kernel(void)

{

    return kvm_state->pit_in_kernel;

}

int kvm_init_vcpu(CPUState *env)

{

    KVMState *s = kvm_state;

    long mmap_size;

    int ret;

    DPRINTF("kvm_init_vcpu\n");

    ret = kvm_vm_ioctl(s, KVM_CREATE_VCPU, env->cpu_index);

    if (ret < 0) {

        DPRINTF("kvm_create_vcpu failed\n");

        goto err;

    }

    env->kvm_fd = ret;

    env->kvm_state = s;

    env->kvm_vcpu_dirty = 1;

    mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0);

    if (mmap_size < 0) {

        ret = mmap_size;

        DPRINTF("KVM_GET_VCPU_MMAP_SIZE failed\n");

        goto err;

    }

    env->kvm_run = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED,

                        env->kvm_fd, 0);

    if (env->kvm_run == MAP_FAILED) {

        ret = -errno;

        DPRINTF("mmap'ing vcpu state failed\n");

        goto err;

    }

    if (s->coalesced_mmio && !s->coalesced_mmio_ring) {

        s->coalesced_mmio_ring =

            (void *)env->kvm_run + s->coalesced_mmio * PAGE_SIZE;

    }

    ret = kvm_arch_init_vcpu(env);

    if (ret == 0) {

        qemu_register_reset(kvm_reset_vcpu, env);

        kvm_arch_reset_vcpu(env);

    }

err:

    return ret;

}

/*

 * dirty pages logging control

 */

static int kvm_mem_flags(KVMState *s, bool log_dirty)

{

    return log_dirty ? KVM_MEM_LOG_DIRTY_PAGES : 0;

}

static int kvm_slot_dirty_pages_log_change(KVMSlot *mem, bool log_dirty)

{

    KVMState *s = kvm_state;

    int flags, mask = KVM_MEM_LOG_DIRTY_PAGES;

    int old_flags;

    old_flags = mem->flags;

    flags = (mem->flags & ~mask) | kvm_mem_flags(s, log_dirty);

    mem->flags = flags;

    /* If nothing changed effectively, no need to issue ioctl */

    if (s->migration_log) {

        flags |= KVM_MEM_LOG_DIRTY_PAGES;

    }

    if (flags == old_flags) {

        return 0;

    }

    return kvm_set_user_memory_region(s, mem);

}

static int kvm_dirty_pages_log_change(target_phys_addr_t phys_addr,

                                      ram_addr_t size, bool log_dirty)

{

    KVMState *s = kvm_state;

    KVMSlot *mem = kvm_lookup_matching_slot(s, phys_addr, phys_addr + size);

    if (mem == NULL)  {

        fprintf(stderr, "BUG: %s: invalid parameters " TARGET_FMT_plx "-"

                TARGET_FMT_plx "\n", __func__, phys_addr,

                (target_phys_addr_t)(phys_addr + size - 1));

        return -EINVAL;

    }

    return kvm_slot_dirty_pages_log_change(mem, log_dirty);

}

static void kvm_log_start(MemoryListener *listener,

                          MemoryRegionSection *section)

{

    int r;

    r = kvm_dirty_pages_log_change(section->offset_within_address_space,

                                   section->size, true);

    if (r < 0) {

        abort();

    }

}

static void kvm_log_stop(MemoryListener *listener,

                          MemoryRegionSection *section)

{

    int r;

    r = kvm_dirty_pages_log_change(section->offset_within_address_space,

                                   section->size, false);

    if (r < 0) {

        abort();

    }

}

static int kvm_set_migration_log(int enable)

{

    KVMState *s = kvm_state;

    KVMSlot *mem;

    int i, err;

    s->migration_log = enable;

    for (i = 0; i < ARRAY_SIZE(s->slots); i++) {

        mem = &s->slots[i];

        if (!mem->memory_size) {

            continue;

        }

        if (!!(mem->flags & KVM_MEM_LOG_DIRTY_PAGES) == enable) {

            continue;

        }

        err = kvm_set_user_memory_region(s, mem);

        if (err) {

            return err;

        }

    }

    return 0;

}

/* get kvm's dirty pages bitmap and update qemu's */

static int kvm_get_dirty_pages_log_range(MemoryRegionSection *section,

                                         unsigned long *bitmap)

{

    unsigned int i, j;

    unsigned long page_number, addr, addr1, c;

    unsigned int len = ((section->size / TARGET_PAGE_SIZE) + HOST_LONG_BITS - 1) / HOST_LONG_BITS;

    /*

     * bitmap-traveling is faster than memory-traveling (for addr...)

     * especially when most of the memory is not dirty.

     */

    for (i = 0; i < len; i++) {

        if (bitmap[i] != 0) {

            c = leul_to_cpu(bitmap[i]);

            do {

                j = ffsl(c) - 1;

                c &= ~(1ul << j);

                page_number = i * HOST_LONG_BITS + j;

                addr1 = page_number * TARGET_PAGE_SIZE;

                addr = section->offset_within_region + addr1;

                memory_region_set_dirty(section->mr, addr);

            } while (c != 0);

        }

    }

    return 0;

}

#define ALIGN(x, y)  (((x)+(y)-1) & ~((y)-1))

/**

 * kvm_physical_sync_dirty_bitmap - Grab dirty bitmap from kernel space

 * This function updates qemu's dirty bitmap using cpu_physical_memory_set_dirty().

 * This means all bits are set to dirty.

 *

 * @start_add: start of logged region.

 * @end_addr: end of logged region.

 */

static int kvm_physical_sync_dirty_bitmap(MemoryRegionSection *section)

{

    KVMState *s = kvm_state;

    unsigned long size, allocated_size = 0;

    KVMDirtyLog d;

    KVMSlot *mem;

    int ret = 0;

    target_phys_addr_t start_addr = section->offset_within_address_space;

    target_phys_addr_t end_addr = start_addr + section->size;

    d.dirty_bitmap = NULL;

    while (start_addr < end_addr) {

        mem = kvm_lookup_overlapping_slot(s, start_addr, end_addr);

        if (mem == NULL) {

            break;

        }

        /* XXX bad kernel interface alert

         * For dirty bitmap, kernel allocates array of size aligned to

         * bits-per-long.  But for case when the kernel is 64bits and

         * the userspace is 32bits, userspace can't align to the same

         * bits-per-long, since sizeof(long) is different between kernel

         * and user space.  This way, userspace will provide buffer which

         * may be 4 bytes less than the kernel will use, resulting in

         * userspace memory corruption (which is not detectable by valgrind

         * too, in most cases).

         * So for now, let's align to 64 instead of HOST_LONG_BITS here, in

         * a hope that sizeof(long) wont become >8 any time soon.

         */

        size = ALIGN(((mem->memory_size) >> TARGET_PAGE_BITS),

                     /*HOST_LONG_BITS*/ 64) / 8;

        if (!d.dirty_bitmap) {

            d.dirty_bitmap = g_malloc(size);

        } else if (size > allocated_size) {

            d.dirty_bitmap = g_realloc(d.dirty_bitmap, size);

        }

        allocated_size = size;

        memset(d.dirty_bitmap, 0, allocated_size);

        d.slot = mem->slot;

        if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) {

            DPRINTF("ioctl failed %d\n", errno);

            ret = -1;

            break;

        }

        kvm_get_dirty_pages_log_range(section, d.dirty_bitmap);

        start_addr = mem->start_addr + mem->memory_size;

    }

    g_free(d.dirty_bitmap);

    return ret;

}

int kvm_coalesce_mmio_region(target_phys_addr_t start, ram_addr_t size)

{

    int ret = -ENOSYS;

    KVMState *s = kvm_state;

    if (s->coalesced_mmio) {

        struct kvm_coalesced_mmio_zone zone;

        zone.addr = start;

        zone.size = size;

        ret = kvm_vm_ioctl(s, KVM_REGISTER_COALESCED_MMIO, &zone);

    }

    return ret;

}

int kvm_uncoalesce_mmio_region(target_phys_addr_t start, ram_addr_t size)

{

    int ret = -ENOSYS;

    KVMState *s = kvm_state;

    if (s->coalesced_mmio) {

        struct kvm_coalesced_mmio_zone zone;

        zone.addr = start;

        zone.size = size;

        ret = kvm_vm_ioctl(s, KVM_UNREGISTER_COALESCED_MMIO, &zone);

    }

    return ret;

}

int kvm_check_extension(KVMState *s, unsigned int extension)

{

    int ret;

    ret = kvm_ioctl(s, KVM_CHECK_EXTENSION, extension);

    if (ret < 0) {

        ret = 0;

    }

    return ret;

}

static int kvm_check_many_ioeventfds(void)

{

    /* Userspace can use ioeventfd for io notification.  This requires a host

     * that supports eventfd(2) and an I/O thread; since eventfd does not

     * support SIGIO it cannot interrupt the vcpu.

     *

     * Older kernels have a 6 device limit on the KVM io bus.  Find out so we

     * can avoid creating too many ioeventfds.

     */

#if defined(CONFIG_EVENTFD)

    int ioeventfds[7];

    int i, ret = 0;

    for (i = 0; i < ARRAY_SIZE(ioeventfds); i++) {

        ioeventfds[i] = eventfd(0, EFD_CLOEXEC);

        if (ioeventfds[i] < 0) {

            break;

        }

        ret = kvm_set_ioeventfd_pio_word(ioeventfds[i], 0, i, true);

        if (ret < 0) {

            close(ioeventfds[i]);

            break;

        }

    }

    /* Decide whether many devices are supported or not */

    ret = i == ARRAY_SIZE(ioeventfds);

    while (i-- > 0) {

        kvm_set_ioeventfd_pio_word(ioeventfds[i], 0, i, false);

        close(ioeventfds[i]);

    }

    return ret;

#else

    return 0;

#endif

}

static const KVMCapabilityInfo *

kvm_check_extension_list(KVMState *s, const KVMCapabilityInfo *list)

{

    while (list->name) {

        if (!kvm_check_extension(s, list->value)) {

            return list;

        }

        list++;

    }

    return NULL;

}

static void kvm_set_phys_mem(MemoryRegionSection *section, bool add)

{

    KVMState *s = kvm_state;

    KVMSlot *mem, old;

    int err;

    MemoryRegion *mr = section->mr;

    bool log_dirty = memory_region_is_logging(mr);

    target_phys_addr_t start_addr = section->offset_within_address_space;

    ram_addr_t size = section->size;

    void *ram = NULL;

    /* kvm works in page size chunks, but the function may be called

       with sub-page size and unaligned start address. */

    size = TARGET_PAGE_ALIGN(size);

    start_addr = TARGET_PAGE_ALIGN(start_addr);

    if (!memory_region_is_ram(mr)) {

        return;

    }

    ram = memory_region_get_ram_ptr(mr) + section->offset_within_region;

    while (1) {

        mem = kvm_lookup_overlapping_slot(s, start_addr, start_addr + size);

        if (!mem) {

            break;

        }

        if (add && start_addr >= mem->start_addr &&

            (start_addr + size <= mem->start_addr + mem->memory_size) &&

            (ram - start_addr == mem->ram - mem->start_addr)) {

            /* The new slot fits into the existing one and comes with

             * identical parameters - update flags and done. */

            kvm_slot_dirty_pages_log_change(mem, log_dirty);

            return;

        }

        old = *mem;

        /* unregister the overlapping slot */

        mem->memory_size = 0;

        err = kvm_set_user_memory_region(s, mem);

        if (err) {

            fprintf(stderr, "%s: error unregistering overlapping slot: %s\n",

                    __func__, strerror(-err));

            abort();

        }

        /* Workaround for older KVM versions: we can't join slots, even not by

         * unregistering the previous ones and then registering the larger

         * slot. We have to maintain the existing fragmentation. Sigh.

         *

         * This workaround assumes that the new slot starts at the same

         * address as the first existing one. If not or if some overlapping

         * slot comes around later, we will fail (not seen in practice so far)

         * - and actually require a recent KVM version. */

        if (s->broken_set_mem_region &&

            old.start_addr == start_addr && old.memory_size < size && add) {

            mem = kvm_alloc_slot(s);

            mem->memory_size = old.memory_size;

            mem->start_addr = old.start_addr;

            mem->ram = old.ram;

            mem->flags = kvm_mem_flags(s, log_dirty);

            err = kvm_set_user_memory_region(s, mem);

            if (err) {

                fprintf(stderr, "%s: error updating slot: %s\n", __func__,

                        strerror(-err));

                abort();

            }

            start_addr += old.memory_size;

            ram += old.memory_size;

            size -= old.memory_size;

            continue;

        }

        /* register prefix slot */

        if (old.start_addr < start_addr) {

            mem = kvm_alloc_slot(s);

            mem->memory_size = start_addr - old.start_addr;

            mem->start_addr = old.start_addr;

            mem->ram = old.ram;

            mem->flags =  kvm_mem_flags(s, log_dirty);

            err = kvm_set_user_memory_region(s, mem);

            if (err) {

                fprintf(stderr, "%s: error registering prefix slot: %s\n",

                        __func__, strerror(-err));

#ifdef TARGET_PPC

                fprintf(stderr, "%s: This is probably because your kernel's " \

                                "PAGE_SIZE is too big. Please try to use 4k " \

                                "PAGE_SIZE!\n", __func__);

#endif

                abort();

            }

        }

        /* register suffix slot */

        if (old.start_addr + old.memory_size > start_addr + size) {

            ram_addr_t size_delta;

            mem = kvm_alloc_slot(s);

            mem->start_addr = start_addr + size;

            size_delta = mem->start_addr - old.start_addr;

            mem->memory_size = old.memory_size - size_delta;

            mem->ram = old.ram + size_delta;

            mem->flags = kvm_mem_flags(s, log_dirty);

            err = kvm_set_user_memory_region(s, mem);

            if (err) {

                fprintf(stderr, "%s: error registering suffix slot: %s\n",

                        __func__, strerror(-err));

                abort();

            }

        }

    }

    /* in case the KVM bug workaround already "consumed" the new slot */

    if (!size) {

        return;

    }

    if (!add) {

        return;

    }

    mem = kvm_alloc_slot(s);

    mem->memory_size = size;

    mem->start_addr = start_addr;

    mem->ram = ram;

    mem->flags = kvm_mem_flags(s, log_dirty);

    err = kvm_set_user_memory_region(s, mem);

    if (err) {

        fprintf(stderr, "%s: error registering slot: %s\n", __func__,

                strerror(-err));

        abort();

    }

}

static void kvm_region_add(MemoryListener *listener,

                           MemoryRegionSection *section)

{

    kvm_set_phys_mem(section, true);

}

static void kvm_region_del(MemoryListener *listener,

                           MemoryRegionSection *section)

{

    kvm_set_phys_mem(section, false);

}

static void kvm_log_sync(MemoryListener *listener,

                         MemoryRegionSection *section)

{

    int r;

    r = kvm_physical_sync_dirty_bitmap(section);

    if (r < 0) {

        abort();

    }

}

static void kvm_log_global_start(struct MemoryListener *listener)

{

    int r;

    r = kvm_set_migration_log(1);

    assert(r >= 0);

}

static void kvm_log_global_stop(struct MemoryListener *listener)

{

    int r;

    r = kvm_set_migration_log(0);

    assert(r >= 0);

}

static MemoryListener kvm_memory_listener = {

    .region_add = kvm_region_add,

    .region_del = kvm_region_del,

    .log_start = kvm_log_start,

    .log_stop = kvm_log_stop,

    .log_sync = kvm_log_sync,

    .log_global_start = kvm_log_global_start,

    .log_global_stop = kvm_log_global_stop,

};

static void kvm_handle_interrupt(CPUState *env, int mask)

{

    env->interrupt_request |= mask;

    if (!qemu_cpu_is_self(env)) {

        qemu_cpu_kick(env);

    }

}

int kvm_init(void)

{

    static const char upgrade_note[] =

        "Please upgrade to at least kernel 2.6.29 or recent kvm-kmod\n"

        "(see http://sourceforge.net/projects/kvm).\n";

    KVMState *s;

    const KVMCapabilityInfo *missing_cap;

    int ret;

    int i;

    s = g_malloc0(sizeof(KVMState));

#ifdef KVM_CAP_SET_GUEST_DEBUG

    QTAILQ_INIT(&s->kvm_sw_breakpoints);

#endif

    for (i = 0; i < ARRAY_SIZE(s->slots); i++) {

        s->slots[i].slot = i;

    }

    s->vmfd = -1;

    s->fd = qemu_open("/dev/kvm", O_RDWR);

    if (s->fd == -1) {

        fprintf(stderr, "Could not access KVM kernel module: %m\n");

        ret = -errno;

        goto err;

    }

    ret = kvm_ioctl(s, KVM_GET_API_VERSION, 0);

    if (ret < KVM_API_VERSION) {

        if (ret > 0) {

            ret = -EINVAL;

        }

        fprintf(stderr, "kvm version too old\n");

        goto err;

    }

    if (ret > KVM_API_VERSION) {

        ret = -EINVAL;

        fprintf(stderr, "kvm version not supported\n");

        goto err;

    }

    s->vmfd = kvm_ioctl(s, KVM_CREATE_VM, 0);

    if (s->vmfd < 0) {

#ifdef TARGET_S390X

        fprintf(stderr, "Please add the 'switch_amode' kernel parameter to "

                        "your host kernel command line\n");

#endif

        ret = s->vmfd;

        goto err;

    }

    missing_cap = kvm_check_extension_list(s, kvm_required_capabilites);

    if (!missing_cap) {

        missing_cap =

            kvm_check_extension_list(s, kvm_arch_required_capabilities);

    }

    if (missing_cap) {

        ret = -EINVAL;

        fprintf(stderr, "kvm does not support %s\n%s",

                missing_cap->name, upgrade_note);

        goto err;

    }

    s->coalesced_mmio = kvm_check_extension(s, KVM_CAP_COALESCED_MMIO);

    s->broken_set_mem_region = 1;

    ret = kvm_check_extension(s, KVM_CAP_JOIN_MEMORY_REGIONS_WORKS);

    if (ret > 0) {

        s->broken_set_mem_region = 0;

    }

#ifdef KVM_CAP_VCPU_EVENTS

    s->vcpu_events = kvm_check_extension(s, KVM_CAP_VCPU_EVENTS);

#endif

    s->robust_singlestep =

        kvm_check_extension(s, KVM_CAP_X86_ROBUST_SINGLESTEP);

#ifdef KVM_CAP_DEBUGREGS

    s->debugregs = kvm_check_extension(s, KVM_CAP_DEBUGREGS);

#endif

#ifdef KVM_CAP_XSAVE

    s->xsave = kvm_check_extension(s, KVM_CAP_XSAVE);

#endif

#ifdef KVM_CAP_XCRS

    s->xcrs = kvm_check_extension(s, KVM_CAP_XCRS);

#endif

    ret = kvm_arch_init(s);

    if (ret < 0) {

        goto err;

    }

    kvm_state = s;

    memory_listener_register(&kvm_memory_listener);

    s->many_ioeventfds = kvm_check_many_ioeventfds();

    cpu_interrupt_handler = kvm_handle_interrupt;

    return 0;

err:

    if (s) {

        if (s->vmfd >= 0) {

            close(s->vmfd);

        }

        if (s->fd != -1) {

            close(s->fd);

        }

    }

    g_free(s);

    return ret;

}

static void kvm_handle_io(uint16_t port, void *data, int direction, int size,

                          uint32_t count)

{

    int i;

    uint8_t *ptr = data;

    for (i = 0; i < count; i++) {

        if (direction == KVM_EXIT_IO_IN) {

            switch (size) {

            case 1:

                stb_p(ptr, cpu_inb(port));

                break;

            case 2:

                stw_p(ptr, cpu_inw(port));

                break;

            case 4:

                stl_p(ptr, cpu_inl(port));

                break;

            }

        } else {

            switch (size) {

            case 1:

                cpu_outb(port, ldub_p(ptr));

                break;

            case 2:

                cpu_outw(port, lduw_p(ptr));

                break;

            case 4:

                cpu_outl(port, ldl_p(ptr));

                break;

            }

        }

        ptr += size;

    }

}

static int kvm_handle_internal_error(CPUState *env, struct kvm_run *run)

{

    fprintf(stderr, "KVM internal error.");

    if (kvm_check_extension(kvm_state, KVM_CAP_INTERNAL_ERROR_DATA)) {

        int i;

        fprintf(stderr, " Suberror: %d\n", run->internal.suberror);

        for (i = 0; i < run->internal.ndata; ++i) {

            fprintf(stderr, "extra data[%d]: %"PRIx64"\n",

                    i, (uint64_t)run->internal.data[i]);

        }

    } else {

        fprintf(stderr, "\n");

    }

    if (run->internal.suberror == KVM_INTERNAL_ERROR_EMULATION) {

        fprintf(stderr, "emulation failure\n");

        if (!kvm_arch_stop_on_emulation_error(env)) {

            cpu_dump_state(env, stderr, fprintf, CPU_DUMP_CODE);

            return EXCP_INTERRUPT;

        }

    }

    /* FIXME: Should trigger a qmp message to let management know

     * something went wrong.

     */

    return -1;