hw: move virtio devices to hw/ subdirectories

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

7 files changed, 3122 insertions, 0 deletions

diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
index ed63495a7f..c7e801344b 100644
--- a/hw/virtio/Makefile.objs
+++ b/hw/virtio/Makefile.objs
@@ -1,4 +1,7 @@
 common-obj-$(CONFIG_VIRTIO) += virtio-rng.o
 common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
 common-obj-$(CONFIG_VIRTIO) += virtio-bus.o
+common-obj-$(CONFIG_VIRTIO_BLK_DATA_PLANE) += dataplane/
 
+obj-$(CONFIG_VIRTIO) += virtio.o virtio-balloon.o 
+obj-$(CONFIG_VHOST_NET) += vhost.o
diff --git a/hw/virtio/dataplane/Makefile.objs b/hw/virtio/dataplane/Makefile.objs
new file mode 100644
index 0000000000..a91bf33c8b
--- /dev/null
+++ b/hw/virtio/dataplane/Makefile.objs
@@ -0,0 +1 @@
+common-obj-y += hostmem.o vring.o
diff --git a/hw/virtio/dataplane/hostmem.c b/hw/virtio/dataplane/hostmem.c
new file mode 100644
index 0000000000..37292ffd00
--- /dev/null
+++ b/hw/virtio/dataplane/hostmem.c
@@ -0,0 +1,176 @@
+/*
+ * Thread-safe guest to host memory mapping
+ *
+ * Copyright 2012 Red Hat, Inc. and/or its affiliates
+ *
+ * Authors:
+ *   Stefan Hajnoczi <stefanha@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 "exec/address-spaces.h"
+#include "hw/virtio/dataplane/hostmem.h"
+
+static int hostmem_lookup_cmp(const void *phys_, const void *region_)
+{
+    hwaddr phys = *(const hwaddr *)phys_;
+    const HostMemRegion *region = region_;
+
+    if (phys < region->guest_addr) {
+        return -1;
+    } else if (phys >= region->guest_addr + region->size) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+/**
+ * Map guest physical address to host pointer
+ */
+void *hostmem_lookup(HostMem *hostmem, hwaddr phys, hwaddr len, bool is_write)
+{
+    HostMemRegion *region;
+    void *host_addr = NULL;
+    hwaddr offset_within_region;
+
+    qemu_mutex_lock(&hostmem->current_regions_lock);
+    region = bsearch(&phys, hostmem->current_regions,
+                     hostmem->num_current_regions,
+                     sizeof(hostmem->current_regions[0]),
+                     hostmem_lookup_cmp);
+    if (!region) {
+        goto out;
+    }
+    if (is_write && region->readonly) {
+        goto out;
+    }
+    offset_within_region = phys - region->guest_addr;
+    if (len <= region->size - offset_within_region) {
+        host_addr = region->host_addr + offset_within_region;
+    }
+out:
+    qemu_mutex_unlock(&hostmem->current_regions_lock);
+
+    return host_addr;
+}
+
+/**
+ * Install new regions list
+ */
+static void hostmem_listener_commit(MemoryListener *listener)
+{
+    HostMem *hostmem = container_of(listener, HostMem, listener);
+
+    qemu_mutex_lock(&hostmem->current_regions_lock);
+    g_free(hostmem->current_regions);
+    hostmem->current_regions = hostmem->new_regions;
+    hostmem->num_current_regions = hostmem->num_new_regions;
+    qemu_mutex_unlock(&hostmem->current_regions_lock);
+
+    /* Reset new regions list */
+    hostmem->new_regions = NULL;
+    hostmem->num_new_regions = 0;
+}
+
+/**
+ * Add a MemoryRegionSection to the new regions list
+ */
+static void hostmem_append_new_region(HostMem *hostmem,
+                                      MemoryRegionSection *section)
+{
+    void *ram_ptr = memory_region_get_ram_ptr(section->mr);
+    size_t num = hostmem->num_new_regions;
+    size_t new_size = (num + 1) * sizeof(hostmem->new_regions[0]);
+
+    hostmem->new_regions = g_realloc(hostmem->new_regions, new_size);
+    hostmem->new_regions[num] = (HostMemRegion){
+        .host_addr = ram_ptr + section->offset_within_region,
+        .guest_addr = section->offset_within_address_space,
+        .size = section->size,
+        .readonly = section->readonly,
+    };
+    hostmem->num_new_regions++;
+}
+
+static void hostmem_listener_append_region(MemoryListener *listener,
+                                           MemoryRegionSection *section)
+{
+    HostMem *hostmem = container_of(listener, HostMem, listener);
+
+    /* Ignore non-RAM regions, we may not be able to map them */
+    if (!memory_region_is_ram(section->mr)) {
+        return;
+    }
+
+    /* Ignore regions with dirty logging, we cannot mark them dirty */
+    if (memory_region_is_logging(section->mr)) {
+        return;
+    }
+
+    hostmem_append_new_region(hostmem, section);
+}
+
+/* We don't implement most MemoryListener callbacks, use these nop stubs */
+static void hostmem_listener_dummy(MemoryListener *listener)
+{
+}
+
+static void hostmem_listener_section_dummy(MemoryListener *listener,
+                                           MemoryRegionSection *section)
+{
+}
+
+static void hostmem_listener_eventfd_dummy(MemoryListener *listener,
+                                           MemoryRegionSection *section,
+                                           bool match_data, uint64_t data,
+                                           EventNotifier *e)
+{
+}
+
+static void hostmem_listener_coalesced_mmio_dummy(MemoryListener *listener,
+                                                  MemoryRegionSection *section,
+                                                  hwaddr addr, hwaddr len)
+{
+}
+
+void hostmem_init(HostMem *hostmem)
+{
+    memset(hostmem, 0, sizeof(*hostmem));
+
+    qemu_mutex_init(&hostmem->current_regions_lock);
+
+    hostmem->listener = (MemoryListener){
+        .begin = hostmem_listener_dummy,
+        .commit = hostmem_listener_commit,
+        .region_add = hostmem_listener_append_region,
+        .region_del = hostmem_listener_section_dummy,
+        .region_nop = hostmem_listener_append_region,
+        .log_start = hostmem_listener_section_dummy,
+        .log_stop = hostmem_listener_section_dummy,
+        .log_sync = hostmem_listener_section_dummy,
+        .log_global_start = hostmem_listener_dummy,
+        .log_global_stop = hostmem_listener_dummy,
+        .eventfd_add = hostmem_listener_eventfd_dummy,
+        .eventfd_del = hostmem_listener_eventfd_dummy,
+        .coalesced_mmio_add = hostmem_listener_coalesced_mmio_dummy,
+        .coalesced_mmio_del = hostmem_listener_coalesced_mmio_dummy,
+        .priority = 10,
+    };
+
+    memory_listener_register(&hostmem->listener, &address_space_memory);
+    if (hostmem->num_new_regions > 0) {
+        hostmem_listener_commit(&hostmem->listener);
+    }
+}
+
+void hostmem_finalize(HostMem *hostmem)
+{
+    memory_listener_unregister(&hostmem->listener);
+    g_free(hostmem->new_regions);
+    g_free(hostmem->current_regions);
+    qemu_mutex_destroy(&hostmem->current_regions_lock);
+}
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
new file mode 100644
index 0000000000..e0d6e83625
--- /dev/null
+++ b/hw/virtio/dataplane/vring.c
@@ -0,0 +1,363 @@
+/* Copyright 2012 Red Hat, Inc.
+ * Copyright IBM, Corp. 2012
+ *
+ * Based on Linux 2.6.39 vhost code:
+ * Copyright (C) 2009 Red Hat, Inc.
+ * Copyright (C) 2006 Rusty Russell IBM Corporation
+ *
+ * Author: Michael S. Tsirkin <mst@redhat.com>
+ *         Stefan Hajnoczi <stefanha@redhat.com>
+ *
+ * Inspiration, some code, and most witty comments come from
+ * Documentation/virtual/lguest/lguest.c, by Rusty Russell
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+
+#include "trace.h"
+#include "hw/virtio/dataplane/vring.h"
+#include "qemu/error-report.h"
+
+/* Map the guest's vring to host memory */
+bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
+{
+    hwaddr vring_addr = virtio_queue_get_ring_addr(vdev, n);
+    hwaddr vring_size = virtio_queue_get_ring_size(vdev, n);
+    void *vring_ptr;
+
+    vring->broken = false;
+
+    hostmem_init(&vring->hostmem);
+    vring_ptr = hostmem_lookup(&vring->hostmem, vring_addr, vring_size, true);
+    if (!vring_ptr) {
+        error_report("Failed to map vring "
+                     "addr %#" HWADDR_PRIx " size %" HWADDR_PRIu,
+                     vring_addr, vring_size);
+        vring->broken = true;
+        return false;
+    }
+
+    vring_init(&vring->vr, virtio_queue_get_num(vdev, n), vring_ptr, 4096);
+
+    vring->last_avail_idx = 0;
+    vring->last_used_idx = 0;
+    vring->signalled_used = 0;
+    vring->signalled_used_valid = false;
+
+    trace_vring_setup(virtio_queue_get_ring_addr(vdev, n),
+                      vring->vr.desc, vring->vr.avail, vring->vr.used);
+    return true;
+}
+
+void vring_teardown(Vring *vring)
+{
+    hostmem_finalize(&vring->hostmem);
+}
+
+/* Disable guest->host notifies */
+void vring_disable_notification(VirtIODevice *vdev, Vring *vring)
+{
+    if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
+        vring->vr.used->flags |= VRING_USED_F_NO_NOTIFY;
+    }
+}
+
+/* Enable guest->host notifies
+ *
+ * Return true if the vring is empty, false if there are more requests.
+ */
+bool vring_enable_notification(VirtIODevice *vdev, Vring *vring)
+{
+    if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+        vring_avail_event(&vring->vr) = vring->vr.avail->idx;
+    } else {
+        vring->vr.used->flags &= ~VRING_USED_F_NO_NOTIFY;
+    }
+    smp_mb(); /* ensure update is seen before reading avail_idx */
+    return !vring_more_avail(vring);
+}
+
+/* This is stolen from linux/drivers/vhost/vhost.c:vhost_notify() */
+bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
+{
+    uint16_t old, new;
+    bool v;
+    /* Flush out used index updates. This is paired
+     * with the barrier that the Guest executes when enabling
+     * interrupts. */
+    smp_mb();
+
+    if ((vdev->guest_features & VIRTIO_F_NOTIFY_ON_EMPTY) &&
+        unlikely(vring->vr.avail->idx == vring->last_avail_idx)) {
+        return true;
+    }
+
+    if (!(vdev->guest_features & VIRTIO_RING_F_EVENT_IDX)) {
+        return !(vring->vr.avail->flags & VRING_AVAIL_F_NO_INTERRUPT);
+    }
+    old = vring->signalled_used;
+    v = vring->signalled_used_valid;
+    new = vring->signalled_used = vring->last_used_idx;
+    vring->signalled_used_valid = true;
+
+    if (unlikely(!v)) {
+        return true;
+    }
+
+    return vring_need_event(vring_used_event(&vring->vr), new, old);
+}
+
+/* This is stolen from linux/drivers/vhost/vhost.c. */
+static int get_indirect(Vring *vring,
+                        struct iovec iov[], struct iovec *iov_end,
+                        unsigned int *out_num, unsigned int *in_num,
+                        struct vring_desc *indirect)
+{
+    struct vring_desc desc;
+    unsigned int i = 0, count, found = 0;
+
+    /* Sanity check */
+    if (unlikely(indirect->len % sizeof(desc))) {
+        error_report("Invalid length in indirect descriptor: "
+                     "len %#x not multiple of %#zx",
+                     indirect->len, sizeof(desc));
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    count = indirect->len / sizeof(desc);
+    /* Buffers are chained via a 16 bit next field, so
+     * we can have at most 2^16 of these. */
+    if (unlikely(count > USHRT_MAX + 1)) {
+        error_report("Indirect buffer length too big: %d", indirect->len);
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    do {
+        struct vring_desc *desc_ptr;
+
+        /* Translate indirect descriptor */
+        desc_ptr = hostmem_lookup(&vring->hostmem,
+                                  indirect->addr + found * sizeof(desc),
+                                  sizeof(desc), false);
+        if (!desc_ptr) {
+            error_report("Failed to map indirect descriptor "
+                         "addr %#" PRIx64 " len %zu",
+                         (uint64_t)indirect->addr + found * sizeof(desc),
+                         sizeof(desc));
+            vring->broken = true;
+            return -EFAULT;
+        }
+        desc = *desc_ptr;
+
+        /* Ensure descriptor has been loaded before accessing fields */
+        barrier(); /* read_barrier_depends(); */
+
+        if (unlikely(++found > count)) {
+            error_report("Loop detected: last one at %u "
+                         "indirect size %u", i, count);
+            vring->broken = true;
+            return -EFAULT;
+        }
+
+        if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) {
+            error_report("Nested indirect descriptor");
+            vring->broken = true;
+            return -EFAULT;
+        }
+
+        /* Stop for now if there are not enough iovecs available. */
+        if (iov >= iov_end) {
+            return -ENOBUFS;
+        }
+
+        iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
+                                       desc.flags & VRING_DESC_F_WRITE);
+        if (!iov->iov_base) {
+            error_report("Failed to map indirect descriptor"
+                         "addr %#" PRIx64 " len %u",
+                         (uint64_t)desc.addr, desc.len);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        iov->iov_len = desc.len;
+        iov++;
+
+        /* If this is an input descriptor, increment that count. */
+        if (desc.flags & VRING_DESC_F_WRITE) {
+            *in_num += 1;
+        } else {
+            /* If it's an output descriptor, they're all supposed
+             * to come before any input descriptors. */
+            if (unlikely(*in_num)) {
+                error_report("Indirect descriptor "
+                             "has out after in: idx %u", i);
+                vring->broken = true;
+                return -EFAULT;
+            }
+            *out_num += 1;
+        }
+        i = desc.next;
+    } while (desc.flags & VRING_DESC_F_NEXT);
+    return 0;
+}
+
+/* This looks in the virtqueue and for the first available buffer, and converts
+ * it to an iovec for convenient access.  Since descriptors consist of some
+ * number of output then some number of input descriptors, it's actually two
+ * iovecs, but we pack them into one and note how many of each there were.
+ *
+ * This function returns the descriptor number found, or vq->num (which is
+ * never a valid descriptor number) if none was found.  A negative code is
+ * returned on error.
+ *
+ * Stolen from linux/drivers/vhost/vhost.c.
+ */
+int vring_pop(VirtIODevice *vdev, Vring *vring,
+              struct iovec iov[], struct iovec *iov_end,
+              unsigned int *out_num, unsigned int *in_num)
+{
+    struct vring_desc desc;
+    unsigned int i, head, found = 0, num = vring->vr.num;
+    uint16_t avail_idx, last_avail_idx;
+
+    /* If there was a fatal error then refuse operation */
+    if (vring->broken) {
+        return -EFAULT;
+    }
+
+    /* Check it isn't doing very strange things with descriptor numbers. */
+    last_avail_idx = vring->last_avail_idx;
+    avail_idx = vring->vr.avail->idx;
+    barrier(); /* load indices now and not again later */
+
+    if (unlikely((uint16_t)(avail_idx - last_avail_idx) > num)) {
+        error_report("Guest moved used index from %u to %u",
+                     last_avail_idx, avail_idx);
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    /* If there's nothing new since last we looked. */
+    if (avail_idx == last_avail_idx) {
+        return -EAGAIN;
+    }
+
+    /* Only get avail ring entries after they have been exposed by guest. */
+    smp_rmb();
+
+    /* Grab the next descriptor number they're advertising, and increment
+     * the index we've seen. */
+    head = vring->vr.avail->ring[last_avail_idx % num];
+
+    /* If their number is silly, that's an error. */
+    if (unlikely(head >= num)) {
+        error_report("Guest says index %u > %u is available", head, num);
+        vring->broken = true;
+        return -EFAULT;
+    }
+
+    if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+        vring_avail_event(&vring->vr) = vring->vr.avail->idx;
+    }
+
+    /* When we start there are none of either input nor output. */
+    *out_num = *in_num = 0;
+
+    i = head;
+    do {
+        if (unlikely(i >= num)) {
+            error_report("Desc index is %u > %u, head = %u", i, num, head);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        if (unlikely(++found > num)) {
+            error_report("Loop detected: last one at %u vq size %u head %u",
+                         i, num, head);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        desc = vring->vr.desc[i];
+
+        /* Ensure descriptor is loaded before accessing fields */
+        barrier();
+
+        if (desc.flags & VRING_DESC_F_INDIRECT) {
+            int ret = get_indirect(vring, iov, iov_end, out_num, in_num, &desc);
+            if (ret < 0) {
+                return ret;
+            }
+            continue;
+        }
+
+        /* If there are not enough iovecs left, stop for now.  The caller
+         * should check if there are more descs available once they have dealt
+         * with the current set.
+         */
+        if (iov >= iov_end) {
+            return -ENOBUFS;
+        }
+
+        /* TODO handle non-contiguous memory across region boundaries */
+        iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
+                                       desc.flags & VRING_DESC_F_WRITE);
+        if (!iov->iov_base) {
+            error_report("Failed to map vring desc addr %#" PRIx64 " len %u",
+                         (uint64_t)desc.addr, desc.len);
+            vring->broken = true;
+            return -EFAULT;
+        }
+        iov->iov_len  = desc.len;
+        iov++;
+
+        if (desc.flags & VRING_DESC_F_WRITE) {
+            /* If this is an input descriptor,
+             * increment that count. */
+            *in_num += 1;
+        } else {
+            /* If it's an output descriptor, they're all supposed
+             * to come before any input descriptors. */
+            if (unlikely(*in_num)) {
+                error_report("Descriptor has out after in: idx %d", i);
+                vring->broken = true;
+                return -EFAULT;
+            }
+            *out_num += 1;
+        }
+        i = desc.next;
+    } while (desc.flags & VRING_DESC_F_NEXT);
+
+    /* On success, increment avail index. */
+    vring->last_avail_idx++;
+    return head;
+}
+
+/* After we've used one of their buffers, we tell them about it.
+ *
+ * Stolen from linux/drivers/vhost/vhost.c.
+ */
+void vring_push(Vring *vring, unsigned int head, int len)
+{
+    struct vring_used_elem *used;
+    uint16_t new;
+
+    /* Don't touch vring if a fatal error occurred */
+    if (vring->broken) {
+        return;
+    }
+
+    /* The virtqueue contains a ring of used buffers.  Get a pointer to the
+     * next entry in that used ring. */
+    used = &vring->vr.used->ring[vring->last_used_idx % vring->vr.num];
+    used->id = head;
+    used->len = len;
+
+    /* Make sure buffer is written before we update index. */
+    smp_wmb();
+
+    new = vring->vr.used->idx = ++vring->last_used_idx;
+    if (unlikely((int16_t)(new - vring->signalled_used) < (uint16_t)1)) {
+        vring->signalled_used_valid = false;
+    }
+}
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
new file mode 100644
index 0000000000..636fad0f74
--- /dev/null
+++ b/hw/virtio/vhost.c
@@ -0,0 +1,1042 @@
+/*
+ * vhost support
+ *
+ * Copyright Red Hat, Inc. 2010
+ *
+ * Authors:
+ *  Michael S. Tsirkin <mst@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include <sys/ioctl.h>
+#include "hw/virtio/vhost.h"
+#include "hw/hw.h"
+#include "qemu/range.h"
+#include <linux/vhost.h>
+#include "exec/address-spaces.h"
+
+static void vhost_dev_sync_region(struct vhost_dev *dev,
+                                  MemoryRegionSection *section,
+                                  uint64_t mfirst, uint64_t mlast,
+                                  uint64_t rfirst, uint64_t rlast)
+{
+    uint64_t start = MAX(mfirst, rfirst);
+    uint64_t end = MIN(mlast, rlast);
+    vhost_log_chunk_t *from = dev->log + start / VHOST_LOG_CHUNK;
+    vhost_log_chunk_t *to = dev->log + end / VHOST_LOG_CHUNK + 1;
+    uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK;
+
+    if (end < start) {
+        return;
+    }
+    assert(end / VHOST_LOG_CHUNK < dev->log_size);
+    assert(start / VHOST_LOG_CHUNK < dev->log_size);
+
+    for (;from < to; ++from) {
+        vhost_log_chunk_t log;
+        int bit;
+        /* We first check with non-atomic: much cheaper,
+         * and we expect non-dirty to be the common case. */
+        if (!*from) {
+            addr += VHOST_LOG_CHUNK;
+            continue;
+        }
+        /* Data must be read atomically. We don't really
+         * need the barrier semantics of __sync
+         * builtins, but it's easier to use them than
+         * roll our own. */
+        log = __sync_fetch_and_and(from, 0);
+        while ((bit = sizeof(log) > sizeof(int) ?
+                ffsll(log) : ffs(log))) {
+            hwaddr page_addr;
+            hwaddr section_offset;
+            hwaddr mr_offset;
+            bit -= 1;
+            page_addr = addr + bit * VHOST_LOG_PAGE;
+            section_offset = page_addr - section->offset_within_address_space;
+            mr_offset = section_offset + section->offset_within_region;
+            memory_region_set_dirty(section->mr, mr_offset, VHOST_LOG_PAGE);
+            log &= ~(0x1ull << bit);
+        }
+        addr += VHOST_LOG_CHUNK;
+    }
+}
+
+static int vhost_sync_dirty_bitmap(struct vhost_dev *dev,
+                                   MemoryRegionSection *section,
+                                   hwaddr first,
+                                   hwaddr last)
+{
+    int i;
+    hwaddr start_addr;
+    hwaddr end_addr;
+
+    if (!dev->log_enabled || !dev->started) {
+        return 0;
+    }
+    start_addr = section->offset_within_address_space;
+    end_addr = range_get_last(start_addr, section->size);
+    start_addr = MAX(first, start_addr);
+    end_addr = MIN(last, end_addr);
+
+    for (i = 0; i < dev->mem->nregions; ++i) {
+        struct vhost_memory_region *reg = dev->mem->regions + i;
+        vhost_dev_sync_region(dev, section, start_addr, end_addr,
+                              reg->guest_phys_addr,
+                              range_get_last(reg->guest_phys_addr,
+                                             reg->memory_size));
+    }
+    for (i = 0; i < dev->nvqs; ++i) {
+        struct vhost_virtqueue *vq = dev->vqs + i;
+        vhost_dev_sync_region(dev, section, start_addr, end_addr, vq->used_phys,
+                              range_get_last(vq->used_phys, vq->used_size));
+    }
+    return 0;
+}
+
+static void vhost_log_sync(MemoryListener *listener,
+                          MemoryRegionSection *section)
+{
+    struct vhost_dev *dev = container_of(listener, struct vhost_dev,
+                                         memory_listener);
+    vhost_sync_dirty_bitmap(dev, section, 0x0, ~0x0ULL);
+}
+
+static void vhost_log_sync_range(struct vhost_dev *dev,
+                                 hwaddr first, hwaddr last)
+{
+    int i;
+    /* FIXME: this is N^2 in number of sections */
+    for (i = 0; i < dev->n_mem_sections; ++i) {
+        MemoryRegionSection *section = &dev->mem_sections[i];
+        vhost_sync_dirty_bitmap(dev, section, first, last);
+    }
+}
+
+/* Assign/unassign. Keep an unsorted array of non-overlapping
+ * memory regions in dev->mem. */
+static void vhost_dev_unassign_memory(struct vhost_dev *dev,
+                                      uint64_t start_addr,
+                                      uint64_t size)
+{
+    int from, to, n = dev->mem->nregions;
+    /* Track overlapping/split regions for sanity checking. */
+    int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0;
+
+    for (from = 0, to = 0; from < n; ++from, ++to) {
+        struct vhost_memory_region *reg = dev->mem->regions + to;
+        uint64_t reglast;
+        uint64_t memlast;
+        uint64_t change;
+
+        /* clone old region */
+        if (to != from) {
+            memcpy(reg, dev->mem->regions + from, sizeof *reg);
+        }
+
+        /* No overlap is simple */
+        if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size,
+                            start_addr, size)) {
+            continue;
+        }
+
+        /* Split only happens if supplied region
+         * is in the middle of an existing one. Thus it can not
+         * overlap with any other existing region. */
+        assert(!split);
+
+        reglast = range_get_last(reg->guest_phys_addr, reg->memory_size);
+        memlast = range_get_last(start_addr, size);
+
+        /* Remove whole region */
+        if (start_addr <= reg->guest_phys_addr && memlast >= reglast) {
+            --dev->mem->nregions;
+            --to;
+            ++overlap_middle;
+            continue;
+        }
+
+        /* Shrink region */
+        if (memlast >= reglast) {
+            reg->memory_size = start_addr - reg->guest_phys_addr;
+            assert(reg->memory_size);
+            assert(!overlap_end);
+            ++overlap_end;
+            continue;
+        }
+
+        /* Shift region */
+        if (start_addr <= reg->guest_phys_addr) {
+            change = memlast + 1 - reg->guest_phys_addr;
+            reg->memory_size -= change;
+            reg->guest_phys_addr += change;
+            reg->userspace_addr += change;
+            assert(reg->memory_size);
+            assert(!overlap_start);
+            ++overlap_start;
+            continue;
+        }
+
+        /* This only happens if supplied region
+         * is in the middle of an existing one. Thus it can not
+         * overlap with any other existing region. */
+        assert(!overlap_start);
+        assert(!overlap_end);
+        assert(!overlap_middle);
+        /* Split region: shrink first part, shift second part. */
+        memcpy(dev->mem->regions + n, reg, sizeof *reg);
+        reg->memory_size = start_addr - reg->guest_phys_addr;
+        assert(reg->memory_size);
+        change = memlast + 1 - reg->guest_phys_addr;
+        reg = dev->mem->regions + n;
+        reg->memory_size -= change;
+        assert(reg->memory_size);
+        reg->guest_phys_addr += change;
+        reg->userspace_addr += change;
+        /* Never add more than 1 region */
+        assert(dev->mem->nregions == n);
+        ++dev->mem->nregions;
+        ++split;
+    }
+}
+
+/* Called after unassign, so no regions overlap the given range. */
+static void vhost_dev_assign_memory(struct vhost_dev *dev,
+                                    uint64_t start_addr,
+                                    uint64_t size,
+                                    uint64_t uaddr)
+{
+    int from, to;
+    struct vhost_memory_region *merged = NULL;
+    for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) {
+        struct vhost_memory_region *reg = dev->mem->regions + to;
+        uint64_t prlast, urlast;
+        uint64_t pmlast, umlast;
+        uint64_t s, e, u;
+
+        /* clone old region */
+        if (to != from) {
+            memcpy(reg, dev->mem->regions + from, sizeof *reg);
+        }
+        prlast = range_get_last(reg->guest_phys_addr, reg->memory_size);
+        pmlast = range_get_last(start_addr, size);
+        urlast = range_get_last(reg->userspace_addr, reg->memory_size);
+        umlast = range_get_last(uaddr, size);
+
+        /* check for overlapping regions: should never happen. */
+        assert(prlast < start_addr || pmlast < reg->guest_phys_addr);
+        /* Not an adjacent or overlapping region - do not merge. */
+        if ((prlast + 1 != start_addr || urlast + 1 != uaddr) &&
+            (pmlast + 1 != reg->guest_phys_addr ||
+             umlast + 1 != reg->userspace_addr)) {
+            continue;
+        }
+
+        if (merged) {
+            --to;
+            assert(to >= 0);
+        } else {
+            merged = reg;
+        }
+        u = MIN(uaddr, reg->userspace_addr);
+        s = MIN(start_addr, reg->guest_phys_addr);
+        e = MAX(pmlast, prlast);
+        uaddr = merged->userspace_addr = u;
+        start_addr = merged->guest_phys_addr = s;
+        size = merged->memory_size = e - s + 1;
+        assert(merged->memory_size);
+    }
+
+    if (!merged) {
+        struct vhost_memory_region *reg = dev->mem->regions + to;
+        memset(reg, 0, sizeof *reg);
+        reg->memory_size = size;
+        assert(reg->memory_size);
+        reg->guest_phys_addr = start_addr;
+        reg->userspace_addr = uaddr;
+        ++to;
+    }
+    assert(to <= dev->mem->nregions + 1);
+    dev->mem->nregions = to;
+}
+
+static uint64_t vhost_get_log_size(struct vhost_dev *dev)
+{
+    uint64_t log_size = 0;
+    int i;
+    for (i = 0; i < dev->mem->nregions; ++i) {
+        struct vhost_memory_region *reg = dev->mem->regions + i;
+        uint64_t last = range_get_last(reg->guest_phys_addr,
+                                       reg->memory_size);
+        log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
+    }
+    for (i = 0; i < dev->nvqs; ++i) {
+        struct vhost_virtqueue *vq = dev->vqs + i;
+        uint64_t last = vq->used_phys + vq->used_size - 1;
+        log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
+    }
+    return log_size;
+}
+
+static inline void vhost_dev_log_resize(struct vhost_dev* dev, uint64_t size)
+{
+    vhost_log_chunk_t *log;
+    uint64_t log_base;
+    int r;
+
+    log = g_malloc0(size * sizeof *log);
+    log_base = (uint64_t)(unsigned long)log;
+    r = ioctl(dev->control, VHOST_SET_LOG_BASE, &log_base);
+    assert(r >= 0);
+    /* Sync only the range covered by the old log */
+    if (dev->log_size) {
+        vhost_log_sync_range(dev, 0, dev->log_size * VHOST_LOG_CHUNK - 1);
+    }
+    if (dev->log) {
+        g_free(dev->log);
+    }
+    dev->log = log;
+    dev->log_size = size;
+}
+
+static int vhost_verify_ring_mappings(struct vhost_dev *dev,
+                                      uint64_t start_addr,
+                                      uint64_t size)
+{
+    int i;
+    for (i = 0; i < dev->nvqs; ++i) {
+        struct vhost_virtqueue *vq = dev->vqs + i;
+        hwaddr l;
+        void *p;
+
+        if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) {
+            continue;
+        }
+        l = vq->ring_size;
+        p = cpu_physical_memory_map(vq->ring_phys, &l, 1);
+        if (!p || l != vq->ring_size) {
+            fprintf(stderr, "Unable to map ring buffer for ring %d\n", i);
+            return -ENOMEM;
+        }
+        if (p != vq->ring) {
+            fprintf(stderr, "Ring buffer relocated for ring %d\n", i);
+            return -EBUSY;
+        }
+        cpu_physical_memory_unmap(p, l, 0, 0);
+    }
+    return 0;
+}
+
+static struct vhost_memory_region *vhost_dev_find_reg(struct vhost_dev *dev,
+						      uint64_t start_addr,
+						      uint64_t size)
+{
+    int i, n = dev->mem->nregions;
+    for (i = 0; i < n; ++i) {
+        struct vhost_memory_region *reg = dev->mem->regions + i;
+        if (ranges_overlap(reg->guest_phys_addr, reg->memory_size,
+                           start_addr, size)) {
+            return reg;
+        }
+    }
+    return NULL;
+}
+
+static bool vhost_dev_cmp_memory(struct vhost_dev *dev,
+                                 uint64_t start_addr,
+                                 uint64_t size,
+                                 uint64_t uaddr)
+{
+    struct vhost_memory_region *reg = vhost_dev_find_reg(dev, start_addr, size);
+    uint64_t reglast;
+    uint64_t memlast;
+
+    if (!reg) {
+        return true;
+    }
+
+    reglast = range_get_last(reg->guest_phys_addr, reg->memory_size);
+    memlast = range_get_last(start_addr, size);
+
+    /* Need to extend region? */
+    if (start_addr < reg->guest_phys_addr || memlast > reglast) {
+        return true;
+    }
+    /* userspace_addr changed? */
+    return uaddr != reg->userspace_addr + start_addr - reg->guest_phys_addr;
+}
+
+static void vhost_set_memory(MemoryListener *listener,
+                             MemoryRegionSection *section,
+                             bool add)
+{
+    struct vhost_dev *dev = container_of(listener, struct vhost_dev,
+                                         memory_listener);
+    hwaddr start_addr = section->offset_within_address_space;
+    ram_addr_t size = section->size;
+    bool log_dirty = memory_region_is_logging(section->mr);
+    int s = offsetof(struct vhost_memory, regions) +
+        (dev->mem->nregions + 1) * sizeof dev->mem->regions[0];
+    uint64_t log_size;
+    int r;
+    void *ram;
+
+    dev->mem = g_realloc(dev->mem, s);
+
+    if (log_dirty) {
+        add = false;
+    }
+
+    assert(size);
+
+    /* Optimize no-change case. At least cirrus_vga does this a lot at this time. */
+    ram = memory_region_get_ram_ptr(section->mr) + section->offset_within_region;
+    if (add) {
+        if (!vhost_dev_cmp_memory(dev, start_addr, size, (uintptr_t)ram)) {
+            /* Region exists with same address. Nothing to do. */
+            return;
+        }
+    } else {
+        if (!vhost_dev_find_reg(dev, start_addr, size)) {
+            /* Removing region that we don't access. Nothing to do. */
+            return;
+        }
+    }
+
+    vhost_dev_unassign_memory(dev, start_addr, size);
+    if (add) {
+        /* Add given mapping, merging adjacent regions if any */
+        vhost_dev_assign_memory(dev, start_addr, size, (uintptr_t)ram);
+    } else {
+        /* Remove old mapping for this memory, if any. */
+        vhost_dev_unassign_memory(dev, start_addr, size);
+    }
+
+    if (!dev->started) {
+        return;
+    }
+
+    if (dev->started) {
+        r = vhost_verify_ring_mappings(dev, start_addr, size);
+        assert(r >= 0);
+    }
+
+    if (!dev->log_enabled) {
+        r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
+        assert(r >= 0);
+        return;
+    }
+    log_size = vhost_get_log_size(dev);
+    /* We allocate an extra 4K bytes to log,
+     * to reduce the * number of reallocations. */
+#define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log)
+    /* To log more, must increase log size before table update. */
+    if (dev->log_size < log_size) {
+        vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER);
+    }
+    r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
+    assert(r >= 0);
+    /* To log less, can only decrease log size after table update. */
+    if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
+        vhost_dev_log_resize(dev, log_size);
+    }
+}
+
+static bool vhost_section(MemoryRegionSection *section)
+{
+    return memory_region_is_ram(section->mr);
+}
+
+static void vhost_begin(MemoryListener *listener)
+{
+}
+
+static void vhost_commit(MemoryListener *listener)
+{
+}
+
+static void vhost_region_add(MemoryListener *listener,
+                             MemoryRegionSection *section)
+{
+    struct vhost_dev *dev = container_of(listener, struct vhost_dev,
+                                         memory_listener);
+
+    if (!vhost_section(section)) {
+        return;
+    }
+
+    ++dev->n_mem_sections;
+    dev->mem_sections = g_renew(MemoryRegionSection, dev->mem_sections,
+                                dev->n_mem_sections);
+    dev->mem_sections[dev->n_mem_sections - 1] = *section;
+    vhost_set_memory(listener, section, true);
+}
+
+static void vhost_region_del(MemoryListener *listener,
+                             MemoryRegionSection *section)
+{
+    struct vhost_dev *dev = container_of(listener, struct vhost_dev,
+                                         memory_listener);
+    int i;
+
+    if (!vhost_section(section)) {
+        return;
+    }
+
+    vhost_set_memory(listener, section, false);
+    for (i = 0; i < dev->n_mem_sections; ++i) {
+        if (dev->mem_sections[i].offset_within_address_space
+            == section->offset_within_address_space) {
+            --dev->n_mem_sections;
+            memmove(&dev->mem_sections[i], &dev->mem_sections[i+1],
+                    (dev->n_mem_sections - i) * sizeof(*dev->mem_sections));
+            break;
+        }
+    }
+}
+
+static void vhost_region_nop(MemoryListener *listener,
+                             MemoryRegionSection *section)
+{
+}
+
+static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
+                                    struct vhost_virtqueue *vq,
+                                    unsigned idx, bool enable_log)
+{
+    struct vhost_vring_addr addr = {
+        .index = idx,
+        .desc_user_addr = (uint64_t)(unsigned long)vq->desc,
+        .avail_user_addr = (uint64_t)(unsigned long)vq->avail,
+        .used_user_addr = (uint64_t)(unsigned long)vq->used,
+        .log_guest_addr = vq->used_phys,
+        .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0,
+    };
+    int r = ioctl(dev->control, VHOST_SET_VRING_ADDR, &addr);
+    if (r < 0) {
+        return -errno;
+    }
+    return 0;
+}
+
+static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log)
+{
+    uint64_t features = dev->acked_features;
+    int r;
+    if (enable_log) {
+        features |= 0x1 << VHOST_F_LOG_ALL;
+    }
+    r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
+    return r < 0 ? -errno : 0;
+}
+
+static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
+{
+    int r, t, i;
+    r = vhost_dev_set_features(dev, enable_log);
+    if (r < 0) {
+        goto err_features;
+    }
+    for (i = 0; i < dev->nvqs; ++i) {
+        r = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
+                                     enable_log);
+        if (r < 0) {
+            goto err_vq;
+        }
+    }
+    return 0;
+err_vq:
+    for (; i >= 0; --i) {
+        t = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
+                                     dev->log_enabled);
+        assert(t >= 0);
+    }
+    t = vhost_dev_set_features(dev, dev->log_enabled);
+    assert(t >= 0);
+err_features:
+    return r;
+}
+
+static int vhost_migration_log(MemoryListener *listener, int enable)
+{
+    struct vhost_dev *dev = container_of(listener, struct vhost_dev,
+                                         memory_listener);
+    int r;
+    if (!!enable == dev->log_enabled) {
+        return 0;
+    }
+    if (!dev->started) {
+        dev->log_enabled = enable;
+        return 0;
+    }
+    if (!enable) {
+        r = vhost_dev_set_log(dev, false);
+        if (r < 0) {
+            return r;
+        }
+        if (dev->log) {
+            g_free(dev->log);
+        }
+        dev->log = NULL;
+        dev->log_size = 0;
+    } else {
+        vhost_dev_log_resize(dev, vhost_get_log_size(dev));
+        r = vhost_dev_set_log(dev, true);
+        if (r < 0) {
+            return r;
+        }
+    }
+    dev->log_enabled = enable;
+    return 0;
+}
+
+static void vhost_log_global_start(MemoryListener *listener)
+{
+    int r;
+
+    r = vhost_migration_log(listener, true);
+    if (r < 0) {
+        abort();
+    }
+}
+
+static void vhost_log_global_stop(MemoryListener *listener)
+{
+    int r;
+
+    r = vhost_migration_log(listener, false);
+    if (r < 0) {
+        abort();
+    }
+}
+
+static void vhost_log_start(MemoryListener *listener,
+                            MemoryRegionSection *section)
+{
+    /* FIXME: implement */
+}
+
+static void vhost_log_stop(MemoryListener *listener,
+                           MemoryRegionSection *section)
+{
+    /* FIXME: implement */
+}
+
+static int vhost_virtqueue_start(struct vhost_dev *dev,
+                                struct VirtIODevice *vdev,
+                                struct vhost_virtqueue *vq,
+                                unsigned idx)
+{
+    hwaddr s, l, a;
+    int r;
+    int vhost_vq_index = idx - dev->vq_index;
+    struct vhost_vring_file file = {
+        .index = vhost_vq_index
+    };
+    struct vhost_vring_state state = {
+        .index = vhost_vq_index
+    };
+    struct VirtQueue *vvq = virtio_get_queue(vdev, idx);
+
+    assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
+
+    vq->num = state.num = virtio_queue_get_num(vdev, idx);
+    r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state);
+    if (r) {
+        return -errno;
+    }
+
+    state.num = virtio_queue_get_last_avail_idx(vdev, idx);
+    r = ioctl(dev->control, VHOST_SET_VRING_BASE, &state);
+    if (r) {
+        return -errno;
+    }
+
+    s = l = virtio_queue_get_desc_size(vdev, idx);
+    a = virtio_queue_get_desc_addr(vdev, idx);
+    vq->desc = cpu_physical_memory_map(a, &l, 0);
+    if (!vq->desc || l != s) {
+        r = -ENOMEM;
+        goto fail_alloc_desc;
+    }
+    s = l = virtio_queue_get_avail_size(vdev, idx);
+    a = virtio_queue_get_avail_addr(vdev, idx);
+    vq->avail = cpu_physical_memory_map(a, &l, 0);
+    if (!vq->avail || l != s) {
+        r = -ENOMEM;
+        goto fail_alloc_avail;
+    }
+    vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx);
+    vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx);
+    vq->used = cpu_physical_memory_map(a, &l, 1);
+    if (!vq->used || l != s) {
+        r = -ENOMEM;
+        goto fail_alloc_used;
+    }
+
+    vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx);
+    vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx);
+    vq->ring = cpu_physical_memory_map(a, &l, 1);
+    if (!vq->ring || l != s) {
+        r = -ENOMEM;
+        goto fail_alloc_ring;
+    }
+
+    r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled);
+    if (r < 0) {
+        r = -errno;
+        goto fail_alloc;
+    }
+
+    file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq));
+    r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file);
+    if (r) {
+        r = -errno;
+        goto fail_kick;
+    }
+
+    /* Clear and discard previous events if any. */
+    event_notifier_test_and_clear(&vq->masked_notifier);
+
+    return 0;
+
+fail_kick:
+fail_alloc:
+    cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
+                              0, 0);
+fail_alloc_ring:
+    cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
+                              0, 0);
+fail_alloc_used:
+    cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
+                              0, 0);
+fail_alloc_avail:
+    cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
+                              0, 0);
+fail_alloc_desc:
+    return r;
+}
+
+static void vhost_virtqueue_stop(struct vhost_dev *dev,
+                                    struct VirtIODevice *vdev,
+                                    struct vhost_virtqueue *vq,
+                                    unsigned idx)
+{
+    struct vhost_vring_state state = {
+        .index = idx - dev->vq_index
+    };
+    int r;
+    assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
+    r = ioctl(dev->control, VHOST_GET_VRING_BASE, &state);
+    if (r < 0) {
+        fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r);
+        fflush(stderr);
+    }
+    virtio_queue_set_last_avail_idx(vdev, idx, state.num);
+    assert (r >= 0);
+    cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
+                              0, virtio_queue_get_ring_size(vdev, idx));
+    cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
+                              1, virtio_queue_get_used_size(vdev, idx));
+    cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
+                              0, virtio_queue_get_avail_size(vdev, idx));
+    cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
+                              0, virtio_queue_get_desc_size(vdev, idx));
+}
+
+static void vhost_eventfd_add(MemoryListener *listener,
+                              MemoryRegionSection *section,
+                              bool match_data, uint64_t data, EventNotifier *e)
+{
+}
+
+static void vhost_eventfd_del(MemoryListener *listener,
+                              MemoryRegionSection *section,
+                              bool match_data, uint64_t data, EventNotifier *e)
+{
+}
+
+static int vhost_virtqueue_init(struct vhost_dev *dev,
+                                struct vhost_virtqueue *vq, int n)
+{
+    struct vhost_vring_file file = {
+        .index = n,
+    };
+    int r = event_notifier_init(&vq->masked_notifier, 0);
+    if (r < 0) {
+        return r;
+    }
+
+    file.fd = event_notifier_get_fd(&vq->masked_notifier);
+    r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
+    if (r) {
+        r = -errno;
+        goto fail_call;
+    }
+    return 0;
+fail_call:
+    event_notifier_cleanup(&vq->masked_notifier);
+    return r;
+}
+
+static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
+{
+    event_notifier_cleanup(&vq->masked_notifier);
+}
+
+int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
+                   bool force)
+{
+    uint64_t features;
+    int i, r;
+    if (devfd >= 0) {
+        hdev->control = devfd;
+    } else {
+        hdev->control = open(devpath, O_RDWR);
+        if (hdev->control < 0) {
+            return -errno;
+        }
+    }
+    r = ioctl(hdev->control, VHOST_SET_OWNER, NULL);
+    if (r < 0) {
+        goto fail;
+    }
+
+    r = ioctl(hdev->control, VHOST_GET_FEATURES, &features);
+    if (r < 0) {
+        goto fail;
+    }
+
+    for (i = 0; i < hdev->nvqs; ++i) {
+        r = vhost_virtqueue_init(hdev, hdev->vqs + i, i);
+        if (r < 0) {
+            goto fail_vq;
+        }
+    }
+    hdev->features = features;
+
+    hdev->memory_listener = (MemoryListener) {
+        .begin = vhost_begin,
+        .commit = vhost_commit,
+        .region_add = vhost_region_add,
+        .region_del = vhost_region_del,
+        .region_nop = vhost_region_nop,
+        .log_start = vhost_log_start,
+        .log_stop = vhost_log_stop,
+        .log_sync = vhost_log_sync,
+        .log_global_start = vhost_log_global_start,
+        .log_global_stop = vhost_log_global_stop,
+        .eventfd_add = vhost_eventfd_add,
+        .eventfd_del = vhost_eventfd_del,
+        .priority = 10
+    };
+    hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions));
+    hdev->n_mem_sections = 0;
+    hdev->mem_sections = NULL;
+    hdev->log = NULL;
+    hdev->log_size = 0;
+    hdev->log_enabled = false;
+    hdev->started = false;
+    memory_listener_register(&hdev->memory_listener, &address_space_memory);
+    hdev->force = force;
+    return 0;
+fail_vq:
+    while (--i >= 0) {
+        vhost_virtqueue_cleanup(hdev->vqs + i);
+    }
+fail:
+    r = -errno;
+    close(hdev->control);
+    return r;
+}
+
+void vhost_dev_cleanup(struct vhost_dev *hdev)
+{
+    int i;
+    for (i = 0; i < hdev->nvqs; ++i) {
+        vhost_virtqueue_cleanup(hdev->vqs + i);
+    }
+    memory_listener_unregister(&hdev->memory_listener);
+    g_free(hdev->mem);
+    g_free(hdev->mem_sections);
+    close(hdev->control);
+}
+
+bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev)
+{
+    return !vdev->binding->query_guest_notifiers ||
+        vdev->binding->query_guest_notifiers(vdev->binding_opaque) ||
+        hdev->force;
+}
+
+/* Stop processing guest IO notifications in qemu.
+ * Start processing them in vhost in kernel.
+ */
+int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
+{
+    int i, r;
+    if (!vdev->binding->set_host_notifier) {
+        fprintf(stderr, "binding does not support host notifiers\n");
+        r = -ENOSYS;
+        goto fail;
+    }
+
+    for (i = 0; i < hdev->nvqs; ++i) {
+        r = vdev->binding->set_host_notifier(vdev->binding_opaque,
+                                             hdev->vq_index + i,
+                                             true);
+        if (r < 0) {
+            fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r);
+            goto fail_vq;
+        }
+    }
+
+    return 0;
+fail_vq:
+    while (--i >= 0) {
+        r = vdev->binding->set_host_notifier(vdev->binding_opaque,
+                                             hdev->vq_index + i,
+                                             false);
+        if (r < 0) {
+            fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r);
+            fflush(stderr);
+        }
+        assert (r >= 0);
+    }
+fail:
+    return r;
+}
+
+/* Stop processing guest IO notifications in vhost.
+ * Start processing them in qemu.
+ * This might actually run the qemu handlers right away,
+ * so virtio in qemu must be completely setup when this is called.
+ */
+void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
+{
+    int i, r;
+
+    for (i = 0; i < hdev->nvqs; ++i) {
+        r = vdev->binding->set_host_notifier(vdev->binding_opaque,
+                                             hdev->vq_index + i,
+                                             false);
+        if (r < 0) {
+            fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r);
+            fflush(stderr);
+        }
+        assert (r >= 0);
+    }
+}
+
+/* Test and clear event pending status.
+ * Should be called after unmask to avoid losing events.
+ */
+bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n)
+{
+    struct vhost_virtqueue *vq = hdev->vqs + n - hdev->vq_index;
+    assert(hdev->started);
+    assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs);
+    return event_notifier_test_and_clear(&vq->masked_notifier);
+}
+
+/* Mask/unmask events from this vq. */
+void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
+                         bool mask)
+{
+    struct VirtQueue *vvq = virtio_get_queue(vdev, n);
+    int r, index = n - hdev->vq_index;
+
+    assert(hdev->started);
+    assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs);
+
+    struct vhost_vring_file file = {
+        .index = index
+    };
+    if (mask) {
+        file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier);
+    } else {
+        file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
+    }
+    r = ioctl(hdev->control, VHOST_SET_VRING_CALL, &file);
+    assert(r >= 0);
+}
+
+/* Host notifiers must be enabled at this point. */
+int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
+{
+    int i, r;
+
+    hdev->started = true;
+
+    r = vhost_dev_set_features(hdev, hdev->log_enabled);
+    if (r < 0) {
+        goto fail_features;
+    }
+    r = ioctl(hdev->control, VHOST_SET_MEM_TABLE, hdev->mem);
+    if (r < 0) {
+        r = -errno;
+        goto fail_mem;
+    }
+    for (i = 0; i < hdev->nvqs; ++i) {
+        r = vhost_virtqueue_start(hdev,
+                                  vdev,
+                                  hdev->vqs + i,
+                                  hdev->vq_index + i);
+        if (r < 0) {
+            goto fail_vq;
+        }
+    }
+
+    if (hdev->log_enabled) {
+        hdev->log_size = vhost_get_log_size(hdev);
+        hdev->log = hdev->log_size ?
+            g_malloc0(hdev->log_size * sizeof *hdev->log) : NULL;
+        r = ioctl(hdev->control, VHOST_SET_LOG_BASE,
+                  (uint64_t)(unsigned long)hdev->log);
+        if (r < 0) {
+            r = -errno;
+            goto fail_log;
+        }
+    }
+
+    return 0;
+fail_log:
+fail_vq:
+    while (--i >= 0) {
+        vhost_virtqueue_stop(hdev,
+                             vdev,
+                             hdev->vqs + i,
+                             hdev->vq_index + i);
+    }
+    i = hdev->nvqs;
+fail_mem:
+fail_features:
+
+    hdev->started = false;
+    return r;
+}
+
+/* Host notifiers must be enabled at this point. */
+void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
+{
+    int i;
+
+    for (i = 0; i < hdev->nvqs; ++i) {
+        vhost_virtqueue_stop(hdev,
+                             vdev,
+                             hdev->vqs + i,
+                             hdev->vq_index + i);
+    }
+    vhost_log_sync_range(hdev, 0, ~0x0ull);
+
+    hdev->started = false;
+    g_free(hdev->log);
+    hdev->log = NULL;
+    hdev->log_size = 0;
+}
+
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
new file mode 100644
index 0000000000..c2c446eb9b
--- /dev/null
+++ b/hw/virtio/virtio-balloon.c
@@ -0,0 +1,416 @@
+/*
+ * Virtio Balloon Device
+ *
+ * Copyright IBM, Corp. 2008
+ * Copyright (C) 2011 Red Hat, Inc.
+ * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/iov.h"
+#include "qemu/timer.h"
+#include "qemu-common.h"
+#include "hw/virtio/virtio.h"
+#include "hw/i386/pc.h"
+#include "cpu.h"
+#include "sysemu/balloon.h"
+#include "hw/virtio/virtio-balloon.h"
+#include "sysemu/kvm.h"
+#include "exec/address-spaces.h"
+#include "qapi/visitor.h"
+
+#if defined(__linux__)
+#include <sys/mman.h>
+#endif
+
+#include "hw/virtio/virtio-bus.h"
+
+static void balloon_page(void *addr, int deflate)
+{
+#if defined(__linux__)
+    if (!kvm_enabled() || kvm_has_sync_mmu())
+        qemu_madvise(addr, TARGET_PAGE_SIZE,
+                deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
+#endif
+}
+
+static const char *balloon_stat_names[] = {
+   [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
+   [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
+   [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
+   [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
+   [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
+   [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
+   [VIRTIO_BALLOON_S_NR] = NULL
+};
+
+/*
+ * reset_stats - Mark all items in the stats array as unset
+ *
+ * This function needs to be called at device intialization and before
+ * before updating to a set of newly-generated stats.  This will ensure that no
+ * stale values stick around in case the guest reports a subset of the supported
+ * statistics.
+ */
+static inline void reset_stats(VirtIOBalloon *dev)
+{
+    int i;
+    for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
+}
+
+static bool balloon_stats_supported(const VirtIOBalloon *s)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+    return vdev->guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
+}
+
+static bool balloon_stats_enabled(const VirtIOBalloon *s)
+{
+    return s->stats_poll_interval > 0;
+}
+
+static void balloon_stats_destroy_timer(VirtIOBalloon *s)
+{
+    if (balloon_stats_enabled(s)) {
+        qemu_del_timer(s->stats_timer);
+        qemu_free_timer(s->stats_timer);
+        s->stats_timer = NULL;
+        s->stats_poll_interval = 0;
+    }
+}
+
+static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
+{
+    qemu_mod_timer(s->stats_timer, qemu_get_clock_ms(vm_clock) + secs * 1000);
+}
+
+static void balloon_stats_poll_cb(void *opaque)
+{
+    VirtIOBalloon *s = opaque;
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+    if (!balloon_stats_supported(s)) {
+        /* re-schedule */
+        balloon_stats_change_timer(s, s->stats_poll_interval);
+        return;
+    }
+
+    virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
+    virtio_notify(vdev, s->svq);
+}
+
+static void balloon_stats_get_all(Object *obj, struct Visitor *v,
+                                  void *opaque, const char *name, Error **errp)
+{
+    VirtIOBalloon *s = opaque;
+    int i;
+
+    if (!s->stats_last_update) {
+        error_setg(errp, "guest hasn't updated any stats yet");
+        return;
+    }
+
+    visit_start_struct(v, NULL, "guest-stats", name, 0, errp);
+    visit_type_int(v, &s->stats_last_update, "last-update", errp);
+
+    visit_start_struct(v, NULL, NULL, "stats", 0, errp);
+    for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
+        visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
+                         errp);
+    }
+    visit_end_struct(v, errp);
+
+    visit_end_struct(v, errp);
+}
+
+static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
+                                            void *opaque, const char *name,
+                                            Error **errp)
+{
+    VirtIOBalloon *s = opaque;
+    visit_type_int(v, &s->stats_poll_interval, name, errp);
+}
+
+static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
+                                            void *opaque, const char *name,
+                                            Error **errp)
+{
+    VirtIOBalloon *s = opaque;
+    int64_t value;
+
+    visit_type_int(v, &value, name, errp);
+    if (error_is_set(errp)) {
+        return;
+    }
+
+    if (value < 0) {
+        error_setg(errp, "timer value must be greater than zero");
+        return;
+    }
+
+    if (value == s->stats_poll_interval) {
+        return;
+    }
+
+    if (value == 0) {
+        /* timer=0 disables the timer */
+        balloon_stats_destroy_timer(s);
+        return;
+    }
+
+    if (balloon_stats_enabled(s)) {
+        /* timer interval change */
+        s->stats_poll_interval = value;
+        balloon_stats_change_timer(s, value);
+        return;
+    }
+
+    /* create a new timer */
+    g_assert(s->stats_timer == NULL);
+    s->stats_timer = qemu_new_timer_ms(vm_clock, balloon_stats_poll_cb, s);
+    s->stats_poll_interval = value;
+    balloon_stats_change_timer(s, 0);
+}
+
+static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+    VirtQueueElement elem;
+    MemoryRegionSection section;
+
+    while (virtqueue_pop(vq, &elem)) {
+        size_t offset = 0;
+        uint32_t pfn;
+
+        while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
+            ram_addr_t pa;
+            ram_addr_t addr;
+
+            pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
+            offset += 4;
+
+            /* FIXME: remove get_system_memory(), but how? */
+            section = memory_region_find(get_system_memory(), pa, 1);
+            if (!section.size || !memory_region_is_ram(section.mr))
+                continue;
+
+            /* Using memory_region_get_ram_ptr is bending the rules a bit, but
+               should be OK because we only want a single page.  */
+            addr = section.offset_within_region;
+            balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
+                         !!(vq == s->dvq));
+        }
+
+        virtqueue_push(vq, &elem, offset);
+        virtio_notify(vdev, vq);
+    }
+}
+
+static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+    VirtQueueElement *elem = &s->stats_vq_elem;
+    VirtIOBalloonStat stat;
+    size_t offset = 0;
+    qemu_timeval tv;
+
+    if (!virtqueue_pop(vq, elem)) {
+        goto out;
+    }
+
+    /* Initialize the stats to get rid of any stale values.  This is only
+     * needed to handle the case where a guest supports fewer stats than it
+     * used to (ie. it has booted into an old kernel).
+     */
+    reset_stats(s);
+
+    while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
+           == sizeof(stat)) {
+        uint16_t tag = tswap16(stat.tag);
+        uint64_t val = tswap64(stat.val);
+
+        offset += sizeof(stat);
+        if (tag < VIRTIO_BALLOON_S_NR)
+            s->stats[tag] = val;
+    }
+    s->stats_vq_offset = offset;
+
+    if (qemu_gettimeofday(&tv) < 0) {
+        fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
+        goto out;
+    }
+
+    s->stats_last_update = tv.tv_sec;
+
+out:
+    if (balloon_stats_enabled(s)) {
+        balloon_stats_change_timer(s, s->stats_poll_interval);
+    }
+}
+
+static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
+{
+    VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
+    struct virtio_balloon_config config;
+
+    config.num_pages = cpu_to_le32(dev->num_pages);
+    config.actual = cpu_to_le32(dev->actual);
+
+    memcpy(config_data, &config, 8);
+}
+
+static void virtio_balloon_set_config(VirtIODevice *vdev,
+                                      const uint8_t *config_data)
+{
+    VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
+    struct virtio_balloon_config config;
+    uint32_t oldactual = dev->actual;
+    memcpy(&config, config_data, 8);
+    dev->actual = le32_to_cpu(config.actual);
+    if (dev->actual != oldactual) {
+        qemu_balloon_changed(ram_size -
+                             (dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
+    }
+}
+
+static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
+{
+    f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
+    return f;
+}
+
+static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
+{
+    VirtIOBalloon *dev = opaque;
+    info->actual = ram_size - ((uint64_t) dev->actual <<
+                               VIRTIO_BALLOON_PFN_SHIFT);
+}
+
+static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
+{
+    VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+
+    if (target > ram_size) {
+        target = ram_size;
+    }
+    if (target) {
+        dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
+        virtio_notify_config(vdev);
+    }
+}
+
+static void virtio_balloon_save(QEMUFile *f, void *opaque)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+    virtio_save(vdev, f);
+
+    qemu_put_be32(f, s->num_pages);
+    qemu_put_be32(f, s->actual);
+}
+
+static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+    int ret;
+
+    if (version_id != 1)
+        return -EINVAL;
+
+    ret = virtio_load(vdev, f);
+    if (ret) {
+        return ret;
+    }
+
+    s->num_pages = qemu_get_be32(f);
+    s->actual = qemu_get_be32(f);
+    return 0;
+}
+
+static int virtio_balloon_device_init(VirtIODevice *vdev)
+{
+    DeviceState *qdev = DEVICE(vdev);
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+    int ret;
+
+    virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 8);
+
+    vdev->get_config = virtio_balloon_get_config;
+    vdev->set_config = virtio_balloon_set_config;
+    vdev->get_features = virtio_balloon_get_features;
+
+    ret = qemu_add_balloon_handler(virtio_balloon_to_target,
+                                   virtio_balloon_stat, s);
+
+    if (ret < 0) {
+        virtio_common_cleanup(VIRTIO_DEVICE(s));
+        return -1;
+    }
+
+    s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
+    s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
+    s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
+
+    register_savevm(qdev, "virtio-balloon", -1, 1,
+                    virtio_balloon_save, virtio_balloon_load, s);
+
+    object_property_add(OBJECT(qdev), "guest-stats", "guest statistics",
+                        balloon_stats_get_all, NULL, NULL, s, NULL);
+
+    object_property_add(OBJECT(qdev), "guest-stats-polling-interval", "int",
+                        balloon_stats_get_poll_interval,
+                        balloon_stats_set_poll_interval,
+                        NULL, s, NULL);
+    return 0;
+}
+
+static int virtio_balloon_device_exit(DeviceState *qdev)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(qdev);
+    VirtIODevice *vdev = VIRTIO_DEVICE(qdev);
+
+    balloon_stats_destroy_timer(s);
+    qemu_remove_balloon_handler(s);
+    unregister_savevm(qdev, "virtio-balloon", s);
+    virtio_common_cleanup(vdev);
+    return 0;
+}
+
+static Property virtio_balloon_properties[] = {
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtio_balloon_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+    dc->exit = virtio_balloon_device_exit;
+    dc->props = virtio_balloon_properties;
+    vdc->init = virtio_balloon_device_init;
+    vdc->get_config = virtio_balloon_get_config;
+    vdc->set_config = virtio_balloon_set_config;
+    vdc->get_features = virtio_balloon_get_features;
+}
+
+static const TypeInfo virtio_balloon_info = {
+    .name = TYPE_VIRTIO_BALLOON,
+    .parent = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VirtIOBalloon),
+    .class_init = virtio_balloon_class_init,
+};
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_balloon_info);
+}
+
+type_init(virtio_register_types)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
new file mode 100644
index 0000000000..1c2282c54f
--- /dev/null
+++ b/hw/virtio/virtio.c
@@ -0,0 +1,1121 @@
+/*
+ * Virtio Support
+ *
+ * Copyright IBM, Corp. 2007
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include <inttypes.h>
+
+#include "trace.h"
+#include "qemu/error-report.h"
+#include "hw/virtio/virtio.h"
+#include "qemu/atomic.h"
+#include "hw/virtio/virtio-bus.h"
+
+/* The alignment to use between consumer and producer parts of vring.
+ * x86 pagesize again. */
+#define VIRTIO_PCI_VRING_ALIGN         4096
+
+typedef struct VRingDesc
+{
+    uint64_t addr;
+    uint32_t len;
+    uint16_t flags;
+    uint16_t next;
+} VRingDesc;
+
+typedef struct VRingAvail
+{
+    uint16_t flags;
+    uint16_t idx;
+    uint16_t ring[0];
+} VRingAvail;
+
+typedef struct VRingUsedElem
+{
+    uint32_t id;
+    uint32_t len;
+} VRingUsedElem;
+
+typedef struct VRingUsed
+{
+    uint16_t flags;
+    uint16_t idx;
+    VRingUsedElem ring[0];
+} VRingUsed;
+
+typedef struct VRing
+{
+    unsigned int num;
+    hwaddr desc;
+    hwaddr avail;
+    hwaddr used;
+} VRing;
+
+struct VirtQueue
+{
+    VRing vring;
+    hwaddr pa;
+    uint16_t last_avail_idx;
+    /* Last used index value we have signalled on */
+    uint16_t signalled_used;
+
+    /* Last used index value we have signalled on */
+    bool signalled_used_valid;
+
+    /* Notification enabled? */
+    bool notification;
+
+    uint16_t queue_index;
+
+    int inuse;
+
+    uint16_t vector;
+    void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
+    VirtIODevice *vdev;
+    EventNotifier guest_notifier;
+    EventNotifier host_notifier;
+};
+
+/* virt queue functions */
+static void virtqueue_init(VirtQueue *vq)
+{
+    hwaddr pa = vq->pa;
+
+    vq->vring.desc = pa;
+    vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc);
+    vq->vring.used = vring_align(vq->vring.avail +
+                                 offsetof(VRingAvail, ring[vq->vring.num]),
+                                 VIRTIO_PCI_VRING_ALIGN);
+}
+
+static inline uint64_t vring_desc_addr(hwaddr desc_pa, int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, addr);
+    return ldq_phys(pa);
+}
+
+static inline uint32_t vring_desc_len(hwaddr desc_pa, int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, len);
+    return ldl_phys(pa);
+}
+
+static inline uint16_t vring_desc_flags(hwaddr desc_pa, int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, flags);
+    return lduw_phys(pa);
+}
+
+static inline uint16_t vring_desc_next(hwaddr desc_pa, int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, next);
+    return lduw_phys(pa);
+}
+
+static inline uint16_t vring_avail_flags(VirtQueue *vq)
+{
+    hwaddr pa;
+    pa = vq->vring.avail + offsetof(VRingAvail, flags);
+    return lduw_phys(pa);
+}
+
+static inline uint16_t vring_avail_idx(VirtQueue *vq)
+{
+    hwaddr pa;
+    pa = vq->vring.avail + offsetof(VRingAvail, idx);
+    return lduw_phys(pa);
+}
+
+static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
+{
+    hwaddr pa;
+    pa = vq->vring.avail + offsetof(VRingAvail, ring[i]);
+    return lduw_phys(pa);
+}
+
+static inline uint16_t vring_used_event(VirtQueue *vq)
+{
+    return vring_avail_ring(vq, vq->vring.num);
+}
+
+static inline void vring_used_ring_id(VirtQueue *vq, int i, uint32_t val)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, ring[i].id);
+    stl_phys(pa, val);
+}
+
+static inline void vring_used_ring_len(VirtQueue *vq, int i, uint32_t val)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, ring[i].len);
+    stl_phys(pa, val);
+}
+
+static uint16_t vring_used_idx(VirtQueue *vq)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, idx);
+    return lduw_phys(pa);
+}
+
+static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, idx);
+    stw_phys(pa, val);
+}
+
+static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, flags);
+    stw_phys(pa, lduw_phys(pa) | mask);
+}
+
+static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, flags);
+    stw_phys(pa, lduw_phys(pa) & ~mask);
+}
+
+static inline void vring_avail_event(VirtQueue *vq, uint16_t val)
+{
+    hwaddr pa;
+    if (!vq->notification) {
+        return;
+    }
+    pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]);
+    stw_phys(pa, val);
+}
+
+void virtio_queue_set_notification(VirtQueue *vq, int enable)
+{
+    vq->notification = enable;
+    if (vq->vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+        vring_avail_event(vq, vring_avail_idx(vq));
+    } else if (enable) {
+        vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
+    } else {
+        vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
+    }
+    if (enable) {
+        /* Expose avail event/used flags before caller checks the avail idx. */
+        smp_mb();
+    }
+}
+
+int virtio_queue_ready(VirtQueue *vq)
+{
+    return vq->vring.avail != 0;
+}
+
+int virtio_queue_empty(VirtQueue *vq)
+{
+    return vring_avail_idx(vq) == vq->last_avail_idx;
+}
+
+void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
+                    unsigned int len, unsigned int idx)
+{
+    unsigned int offset;
+    int i;
+
+    trace_virtqueue_fill(vq, elem, len, idx);
+
+    offset = 0;
+    for (i = 0; i < elem->in_num; i++) {
+        size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
+
+        cpu_physical_memory_unmap(elem->in_sg[i].iov_base,
+                                  elem->in_sg[i].iov_len,
+                                  1, size);
+
+        offset += size;
+    }
+
+    for (i = 0; i < elem->out_num; i++)
+        cpu_physical_memory_unmap(elem->out_sg[i].iov_base,
+                                  elem->out_sg[i].iov_len,
+                                  0, elem->out_sg[i].iov_len);
+
+    idx = (idx + vring_used_idx(vq)) % vq->vring.num;
+
+    /* Get a pointer to the next entry in the used ring. */
+    vring_used_ring_id(vq, idx, elem->index);
+    vring_used_ring_len(vq, idx, len);
+}
+
+void virtqueue_flush(VirtQueue *vq, unsigned int count)
+{
+    uint16_t old, new;
+    /* Make sure buffer is written before we update index. */
+    smp_wmb();
+    trace_virtqueue_flush(vq, count);
+    old = vring_used_idx(vq);
+    new = old + count;
+    vring_used_idx_set(vq, new);
+    vq->inuse -= count;
+    if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
+        vq->signalled_used_valid = false;
+}
+
+void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
+                    unsigned int len)
+{
+    virtqueue_fill(vq, elem, len, 0);
+    virtqueue_flush(vq, 1);
+}
+
+static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
+{
+    uint16_t num_heads = vring_avail_idx(vq) - idx;
+
+    /* Check it isn't doing very strange things with descriptor numbers. */
+    if (num_heads > vq->vring.num) {
+        error_report("Guest moved used index from %u to %u",
+                     idx, vring_avail_idx(vq));
+        exit(1);
+    }
+    /* On success, callers read a descriptor at vq->last_avail_idx.
+     * Make sure descriptor read does not bypass avail index read. */
+    if (num_heads) {
+        smp_rmb();
+    }
+
+    return num_heads;
+}
+
+static unsigned int virtqueue_get_head(VirtQueue *vq, unsigned int idx)
+{
+    unsigned int head;
+
+    /* Grab the next descriptor number they're advertising, and increment
+     * the index we've seen. */
+    head = vring_avail_ring(vq, idx % vq->vring.num);
+
+    /* If their number is silly, that's a fatal mistake. */
+    if (head >= vq->vring.num) {
+        error_report("Guest says index %u is available", head);
+        exit(1);
+    }
+
+    return head;
+}
+
+static unsigned virtqueue_next_desc(hwaddr desc_pa,
+                                    unsigned int i, unsigned int max)
+{
+    unsigned int next;
+
+    /* If this descriptor says it doesn't chain, we're done. */
+    if (!(vring_desc_flags(desc_pa, i) & VRING_DESC_F_NEXT))
+        return max;
+
+    /* Check they're not leading us off end of descriptors. */
+    next = vring_desc_next(desc_pa, i);
+    /* Make sure compiler knows to grab that: we don't want it changing! */
+    smp_wmb();
+
+    if (next >= max) {
+        error_report("Desc next is %u", next);
+        exit(1);
+    }
+
+    return next;
+}
+
+void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
+                               unsigned int *out_bytes,
+                               unsigned max_in_bytes, unsigned max_out_bytes)
+{
+    unsigned int idx;
+    unsigned int total_bufs, in_total, out_total;
+
+    idx = vq->last_avail_idx;
+
+    total_bufs = in_total = out_total = 0;
+    while (virtqueue_num_heads(vq, idx)) {
+        unsigned int max, num_bufs, indirect = 0;
+        hwaddr desc_pa;
+        int i;
+
+        max = vq->vring.num;
+        num_bufs = total_bufs;
+        i = virtqueue_get_head(vq, idx++);
+        desc_pa = vq->vring.desc;
+
+        if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
+            if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
+                error_report("Invalid size for indirect buffer table");
+                exit(1);
+            }
+
+            /* If we've got too many, that implies a descriptor loop. */
+            if (num_bufs >= max) {
+                error_report("Looped descriptor");
+                exit(1);
+            }
+
+            /* loop over the indirect descriptor table */
+            indirect = 1;
+            max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
+            num_bufs = i = 0;
+            desc_pa = vring_desc_addr(desc_pa, i);
+        }
+
+        do {
+            /* If we've got too many, that implies a descriptor loop. */
+            if (++num_bufs > max) {
+                error_report("Looped descriptor");
+                exit(1);
+            }
+
+            if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
+                in_total += vring_desc_len(desc_pa, i);
+            } else {
+                out_total += vring_desc_len(desc_pa, i);
+            }
+            if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
+                goto done;
+            }
+        } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);
+
+        if (!indirect)
+            total_bufs = num_bufs;
+        else
+            total_bufs++;
+    }
+done:
+    if (in_bytes) {
+        *in_bytes = in_total;
+    }
+    if (out_bytes) {
+        *out_bytes = out_total;
+    }
+}
+
+int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
+                          unsigned int out_bytes)
+{
+    unsigned int in_total, out_total;
+
+    virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
+    return in_bytes <= in_total && out_bytes <= out_total;
+}
+
+void virtqueue_map_sg(struct iovec *sg, hwaddr *addr,
+    size_t num_sg, int is_write)
+{
+    unsigned int i;
+    hwaddr len;
+
+    for (i = 0; i < num_sg; i++) {
+        len = sg[i].iov_len;
+        sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write);
+        if (sg[i].iov_base == NULL || len != sg[i].iov_len) {
+            error_report("virtio: trying to map MMIO memory");
+            exit(1);
+        }
+    }
+}
+
+int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
+{
+    unsigned int i, head, max;
+    hwaddr desc_pa = vq->vring.desc;
+
+    if (!virtqueue_num_heads(vq, vq->last_avail_idx))
+        return 0;
+
+    /* When we start there are none of either input nor output. */
+    elem->out_num = elem->in_num = 0;
+
+    max = vq->vring.num;
+
+    i = head = virtqueue_get_head(vq, vq->last_avail_idx++);
+    if (vq->vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+        vring_avail_event(vq, vring_avail_idx(vq));
+    }
+
+    if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
+        if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
+            error_report("Invalid size for indirect buffer table");
+            exit(1);
+        }
+
+        /* loop over the indirect descriptor table */
+        max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
+        desc_pa = vring_desc_addr(desc_pa, i);
+        i = 0;
+    }
+
+    /* Collect all the descriptors */
+    do {
+        struct iovec *sg;
+
+        if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
+            if (elem->in_num >= ARRAY_SIZE(elem->in_sg)) {
+                error_report("Too many write descriptors in indirect table");
+                exit(1);
+            }
+            elem->in_addr[elem->in_num] = vring_desc_addr(desc_pa, i);
+            sg = &elem->in_sg[elem->in_num++];
+        } else {
+            if (elem->out_num >= ARRAY_SIZE(elem->out_sg)) {
+                error_report("Too many read descriptors in indirect table");
+                exit(1);
+            }
+            elem->out_addr[elem->out_num] = vring_desc_addr(desc_pa, i);
+            sg = &elem->out_sg[elem->out_num++];
+        }
+
+        sg->iov_len = vring_desc_len(desc_pa, i);
+
+        /* If we've got too many, that implies a descriptor loop. */
+        if ((elem->in_num + elem->out_num) > max) {
+            error_report("Looped descriptor");
+            exit(1);
+        }
+    } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);
+
+    /* Now map what we have collected */
+    virtqueue_map_sg(elem->in_sg, elem->in_addr, elem->in_num, 1);
+    virtqueue_map_sg(elem->out_sg, elem->out_addr, elem->out_num, 0);
+
+    elem->index = head;
+
+    vq->inuse++;
+
+    trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
+    return elem->in_num + elem->out_num;
+}
+
+/* virtio device */
+static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
+{
+    if (vdev->binding->notify) {
+        vdev->binding->notify(vdev->binding_opaque, vector);
+    }
+}
+
+void virtio_update_irq(VirtIODevice *vdev)
+{
+    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
+}
+
+void virtio_set_status(VirtIODevice *vdev, uint8_t val)
+{
+    trace_virtio_set_status(vdev, val);
+
+    if (vdev->set_status) {
+        vdev->set_status(vdev, val);
+    }
+    vdev->status = val;
+}
+
+void virtio_reset(void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+    int i;
+
+    virtio_set_status(vdev, 0);
+
+    if (vdev->reset)
+        vdev->reset(vdev);
+
+    vdev->guest_features = 0;
+    vdev->queue_sel = 0;
+    vdev->status = 0;
+    vdev->isr = 0;
+    vdev->config_vector = VIRTIO_NO_VECTOR;
+    virtio_notify_vector(vdev, vdev->config_vector);
+
+    for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+        vdev->vq[i].vring.desc = 0;
+        vdev->vq[i].vring.avail = 0;
+        vdev->vq[i].vring.used = 0;
+        vdev->vq[i].last_avail_idx = 0;
+        vdev->vq[i].pa = 0;
+        vdev->vq[i].vector = VIRTIO_NO_VECTOR;
+        vdev->vq[i].signalled_used = 0;
+        vdev->vq[i].signalled_used_valid = false;
+        vdev->vq[i].notification = true;
+    }
+}
+
+uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
+{
+    uint8_t val;
+
+    vdev->get_config(vdev, vdev->config);
+
+    if (addr > (vdev->config_len - sizeof(val)))
+        return (uint32_t)-1;
+
+    val = ldub_p(vdev->config + addr);
+    return val;
+}
+
+uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
+{
+    uint16_t val;
+
+    vdev->get_config(vdev, vdev->config);
+
+    if (addr > (vdev->config_len - sizeof(val)))
+        return (uint32_t)-1;
+
+    val = lduw_p(vdev->config + addr);
+    return val;
+}
+
+uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
+{
+    uint32_t val;
+
+    vdev->get_config(vdev, vdev->config);
+
+    if (addr > (vdev->config_len - sizeof(val)))
+        return (uint32_t)-1;
+
+    val = ldl_p(vdev->config + addr);
+    return val;
+}
+
+void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
+{
+    uint8_t val = data;
+
+    if (addr > (vdev->config_len - sizeof(val)))
+        return;
+
+    stb_p(vdev->config + addr, val);
+
+    if (vdev->set_config)
+        vdev->set_config(vdev, vdev->config);
+}
+
+void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
+{
+    uint16_t val = data;
+
+    if (addr > (vdev->config_len - sizeof(val)))
+        return;
+
+    stw_p(vdev->config + addr, val);
+
+    if (vdev->set_config)
+        vdev->set_config(vdev, vdev->config);
+}
+
+void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
+{
+    uint32_t val = data;
+
+    if (addr > (vdev->config_len - sizeof(val)))
+        return;
+
+    stl_p(vdev->config + addr, val);
+
+    if (vdev->set_config)
+        vdev->set_config(vdev, vdev->config);
+}
+
+void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
+{
+    vdev->vq[n].pa = addr;
+    virtqueue_init(&vdev->vq[n]);
+}
+
+hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].pa;
+}
+
+int virtio_queue_get_num(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.num;
+}
+
+int virtio_queue_get_id(VirtQueue *vq)
+{
+    VirtIODevice *vdev = vq->vdev;
+    assert(vq >= &vdev->vq[0] && vq < &vdev->vq[VIRTIO_PCI_QUEUE_MAX]);
+    return vq - &vdev->vq[0];
+}
+
+void virtio_queue_notify_vq(VirtQueue *vq)
+{
+    if (vq->vring.desc) {
+        VirtIODevice *vdev = vq->vdev;
+        trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
+        vq->handle_output(vdev, vq);
+    }
+}
+
+void virtio_queue_notify(VirtIODevice *vdev, int n)
+{
+    virtio_queue_notify_vq(&vdev->vq[n]);
+}
+
+uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
+{
+    return n < VIRTIO_PCI_QUEUE_MAX ? vdev->vq[n].vector :
+        VIRTIO_NO_VECTOR;
+}
+
+void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
+{
+    if (n < VIRTIO_PCI_QUEUE_MAX)
+        vdev->vq[n].vector = vector;
+}
+
+VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
+                            void (*handle_output)(VirtIODevice *, VirtQueue *))
+{
+    int i;
+
+    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+        if (vdev->vq[i].vring.num == 0)
+            break;
+    }
+
+    if (i == VIRTIO_PCI_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
+        abort();
+
+    vdev->vq[i].vring.num = queue_size;
+    vdev->vq[i].handle_output = handle_output;
+
+    return &vdev->vq[i];
+}
+
+void virtio_del_queue(VirtIODevice *vdev, int n)
+{
+    if (n < 0 || n >= VIRTIO_PCI_QUEUE_MAX) {
+        abort();
+    }
+
+    vdev->vq[n].vring.num = 0;
+}
+
+void virtio_irq(VirtQueue *vq)
+{
+    trace_virtio_irq(vq);
+    vq->vdev->isr |= 0x01;
+    virtio_notify_vector(vq->vdev, vq->vector);
+}
+
+/* Assuming a given event_idx value from the other size, if
+ * we have just incremented index from old to new_idx,
+ * should we trigger an event? */
+static inline int vring_need_event(uint16_t event, uint16_t new, uint16_t old)
+{
+	/* Note: Xen has similar logic for notification hold-off
+	 * in include/xen/interface/io/ring.h with req_event and req_prod
+	 * corresponding to event_idx + 1 and new respectively.
+	 * Note also that req_event and req_prod in Xen start at 1,
+	 * event indexes in virtio start at 0. */
+	return (uint16_t)(new - event - 1) < (uint16_t)(new - old);
+}
+
+static bool vring_notify(VirtIODevice *vdev, VirtQueue *vq)
+{
+    uint16_t old, new;
+    bool v;
+    /* We need to expose used array entries before checking used event. */
+    smp_mb();
+    /* Always notify when queue is empty (when feature acknowledge) */
+    if (((vdev->guest_features & (1 << VIRTIO_F_NOTIFY_ON_EMPTY)) &&
+         !vq->inuse && vring_avail_idx(vq) == vq->last_avail_idx)) {
+        return true;
+    }
+
+    if (!(vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX))) {
+        return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
+    }
+
+    v = vq->signalled_used_valid;
+    vq->signalled_used_valid = true;
+    old = vq->signalled_used;
+    new = vq->signalled_used = vring_used_idx(vq);
+    return !v || vring_need_event(vring_used_event(vq), new, old);
+}
+
+void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
+{
+    if (!vring_notify(vdev, vq)) {
+        return;
+    }
+
+    trace_virtio_notify(vdev, vq);
+    vdev->isr |= 0x01;
+    virtio_notify_vector(vdev, vq->vector);
+}
+
+void virtio_notify_config(VirtIODevice *vdev)
+{
+    if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
+        return;
+
+    vdev->isr |= 0x03;
+    virtio_notify_vector(vdev, vdev->config_vector);
+}
+
+void virtio_save(VirtIODevice *vdev, QEMUFile *f)
+{
+    int i;
+
+    if (vdev->binding->save_config)
+        vdev->binding->save_config(vdev->binding_opaque, f);
+
+    qemu_put_8s(f, &vdev->status);
+    qemu_put_8s(f, &vdev->isr);
+    qemu_put_be16s(f, &vdev->queue_sel);
+    qemu_put_be32s(f, &vdev->guest_features);
+    qemu_put_be32(f, vdev->config_len);
+    qemu_put_buffer(f, vdev->config, vdev->config_len);
+
+    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+        if (vdev->vq[i].vring.num == 0)
+            break;
+    }
+
+    qemu_put_be32(f, i);
+
+    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+        if (vdev->vq[i].vring.num == 0)
+            break;
+
+        qemu_put_be32(f, vdev->vq[i].vring.num);
+        qemu_put_be64(f, vdev->vq[i].pa);
+        qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
+        if (vdev->binding->save_queue)
+            vdev->binding->save_queue(vdev->binding_opaque, i, f);
+    }
+}
+
+int virtio_set_features(VirtIODevice *vdev, uint32_t val)
+{
+    uint32_t supported_features =
+        vdev->binding->get_features(vdev->binding_opaque);
+    bool bad = (val & ~supported_features) != 0;
+
+    val &= supported_features;
+    if (vdev->set_features) {
+        vdev->set_features(vdev, val);
+    }
+    vdev->guest_features = val;
+    return bad ? -1 : 0;
+}
+
+int virtio_load(VirtIODevice *vdev, QEMUFile *f)
+{
+    int num, i, ret;
+    uint32_t features;
+    uint32_t supported_features;
+
+    if (vdev->binding->load_config) {
+        ret = vdev->binding->load_config(vdev->binding_opaque, f);
+        if (ret)
+            return ret;
+    }
+
+    qemu_get_8s(f, &vdev->status);
+    qemu_get_8s(f, &vdev->isr);
+    qemu_get_be16s(f, &vdev->queue_sel);
+    qemu_get_be32s(f, &features);
+
+    if (virtio_set_features(vdev, features) < 0) {
+        supported_features = vdev->binding->get_features(vdev->binding_opaque);
+        error_report("Features 0x%x unsupported. Allowed features: 0x%x",
+                     features, supported_features);
+        return -1;
+    }
+    vdev->config_len = qemu_get_be32(f);
+    qemu_get_buffer(f, vdev->config, vdev->config_len);
+
+    num = qemu_get_be32(f);
+
+    for (i = 0; i < num; i++) {
+        vdev->vq[i].vring.num = qemu_get_be32(f);
+        vdev->vq[i].pa = qemu_get_be64(f);
+        qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
+        vdev->vq[i].signalled_used_valid = false;
+        vdev->vq[i].notification = true;
+
+        if (vdev->vq[i].pa) {
+            uint16_t nheads;
+            virtqueue_init(&vdev->vq[i]);
+            nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
+            /* Check it isn't doing very strange things with descriptor numbers. */
+            if (nheads > vdev->vq[i].vring.num) {
+                error_report("VQ %d size 0x%x Guest index 0x%x "
+                             "inconsistent with Host index 0x%x: delta 0x%x",
+                             i, vdev->vq[i].vring.num,
+                             vring_avail_idx(&vdev->vq[i]),
+                             vdev->vq[i].last_avail_idx, nheads);
+                return -1;
+            }
+        } else if (vdev->vq[i].last_avail_idx) {
+            error_report("VQ %d address 0x0 "
+                         "inconsistent with Host index 0x%x",
+                         i, vdev->vq[i].last_avail_idx);
+                return -1;
+	}
+        if (vdev->binding->load_queue) {
+            ret = vdev->binding->load_queue(vdev->binding_opaque, i, f);
+            if (ret)
+                return ret;
+        }
+    }
+
+    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
+    return 0;
+}
+
+void virtio_common_cleanup(VirtIODevice *vdev)
+{
+    qemu_del_vm_change_state_handler(vdev->vmstate);
+    g_free(vdev->config);
+    g_free(vdev->vq);
+}
+
+void virtio_cleanup(VirtIODevice *vdev)
+{
+    virtio_common_cleanup(vdev);
+    g_free(vdev);
+}
+
+static void virtio_vmstate_change(void *opaque, int running, RunState state)
+{
+    VirtIODevice *vdev = opaque;
+    bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
+    vdev->vm_running = running;
+
+    if (backend_run) {
+        virtio_set_status(vdev, vdev->status);
+    }
+
+    if (vdev->binding->vmstate_change) {
+        vdev->binding->vmstate_change(vdev->binding_opaque, backend_run);
+    }
+
+    if (!backend_run) {
+        virtio_set_status(vdev, vdev->status);
+    }
+}
+
+void virtio_init(VirtIODevice *vdev, const char *name,
+                 uint16_t device_id, size_t config_size)
+{
+    int i;
+    vdev->device_id = device_id;
+    vdev->status = 0;
+    vdev->isr = 0;
+    vdev->queue_sel = 0;
+    vdev->config_vector = VIRTIO_NO_VECTOR;
+    vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_PCI_QUEUE_MAX);
+    vdev->vm_running = runstate_is_running();
+    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+        vdev->vq[i].vector = VIRTIO_NO_VECTOR;
+        vdev->vq[i].vdev = vdev;
+        vdev->vq[i].queue_index = i;
+    }
+
+    vdev->name = name;
+    vdev->config_len = config_size;
+    if (vdev->config_len) {
+        vdev->config = g_malloc0(config_size);
+    } else {
+        vdev->config = NULL;
+    }
+    vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
+                                                     vdev);
+}
+
+VirtIODevice *virtio_common_init(const char *name, uint16_t device_id,
+                                 size_t config_size, size_t struct_size)
+{
+    VirtIODevice *vdev;
+    vdev = g_malloc0(struct_size);
+    virtio_init(vdev, name, device_id, config_size);
+    return vdev;
+}
+
+void virtio_bind_device(VirtIODevice *vdev, const VirtIOBindings *binding,
+                        DeviceState *opaque)
+{
+    vdev->binding = binding;
+    vdev->binding_opaque = opaque;
+}
+
+hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.desc;
+}
+
+hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.avail;
+}
+
+hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.used;
+}
+
+hwaddr virtio_queue_get_ring_addr(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.desc;
+}
+
+hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
+{
+    return sizeof(VRingDesc) * vdev->vq[n].vring.num;
+}
+
+hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
+{
+    return offsetof(VRingAvail, ring) +
+        sizeof(uint64_t) * vdev->vq[n].vring.num;
+}
+
+hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
+{
+    return offsetof(VRingUsed, ring) +
+        sizeof(VRingUsedElem) * vdev->vq[n].vring.num;
+}
+
+hwaddr virtio_queue_get_ring_size(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.used - vdev->vq[n].vring.desc +
+	    virtio_queue_get_used_size(vdev, n);
+}
+
+uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].last_avail_idx;
+}
+
+void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
+{
+    vdev->vq[n].last_avail_idx = idx;
+}
+
+VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
+{
+    return vdev->vq + n;
+}
+
+uint16_t virtio_get_queue_index(VirtQueue *vq)
+{
+    return vq->queue_index;
+}
+
+static void virtio_queue_guest_notifier_read(EventNotifier *n)
+{
+    VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
+    if (event_notifier_test_and_clear(n)) {
+        virtio_irq(vq);
+    }
+}
+
+void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
+                                                bool with_irqfd)
+{
+    if (assign && !with_irqfd) {
+        event_notifier_set_handler(&vq->guest_notifier,
+                                   virtio_queue_guest_notifier_read);
+    } else {
+        event_notifier_set_handler(&vq->guest_notifier, NULL);
+    }
+    if (!assign) {
+        /* Test and clear notifier before closing it,
+         * in case poll callback didn't have time to run. */
+        virtio_queue_guest_notifier_read(&vq->guest_notifier);
+    }
+}
+
+EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
+{
+    return &vq->guest_notifier;
+}
+
+static void virtio_queue_host_notifier_read(EventNotifier *n)
+{
+    VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
+    if (event_notifier_test_and_clear(n)) {
+        virtio_queue_notify_vq(vq);
+    }
+}
+
+void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign,
+                                               bool set_handler)
+{
+    if (assign && set_handler) {
+        event_notifier_set_handler(&vq->host_notifier,
+                                   virtio_queue_host_notifier_read);
+    } else {
+        event_notifier_set_handler(&vq->host_notifier, NULL);
+    }
+    if (!assign) {
+        /* Test and clear notifier before after disabling event,
+         * in case poll callback didn't have time to run. */
+        virtio_queue_host_notifier_read(&vq->host_notifier);
+    }
+}
+
+EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
+{
+    return &vq->host_notifier;
+}
+
+static int virtio_device_init(DeviceState *qdev)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(qdev);
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(qdev);
+    assert(k->init != NULL);
+    if (k->init(vdev) < 0) {
+        return -1;
+    }
+    virtio_bus_plug_device(vdev);
+    return 0;
+}
+
+static void virtio_device_class_init(ObjectClass *klass, void *data)
+{
+    /* Set the default value here. */
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    dc->init = virtio_device_init;
+    dc->bus_type = TYPE_VIRTIO_BUS;
+}
+
+static const TypeInfo virtio_device_info = {
+    .name = TYPE_VIRTIO_DEVICE,
+    .parent = TYPE_DEVICE,
+    .instance_size = sizeof(VirtIODevice),
+    .class_init = virtio_device_class_init,
+    .abstract = true,
+    .class_size = sizeof(VirtioDeviceClass),
+};
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_device_info);
+}
+
+type_init(virtio_register_types)