Add qemu 2.4.0

Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>

1 files changed, 1638 insertions, 0 deletions

diff --git a/qemu/hw/virtio/virtio.c b/qemu/hw/virtio/virtio.c
new file mode 100644
index 000000000..788b556a7
--- /dev/null
+++ b/qemu/hw/virtio/virtio.c
@@ -0,0 +1,1638 @@
+/*
+ * 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 "exec/address-spaces.h"
+#include "qemu/error-report.h"
+#include "hw/virtio/virtio.h"
+#include "qemu/atomic.h"
+#include "hw/virtio/virtio-bus.h"
+#include "migration/migration.h"
+#include "hw/virtio/virtio-access.h"
+
+/*
+ * The alignment to use between consumer and producer parts of vring.
+ * x86 pagesize again. This is the default, used by transports like PCI
+ * which don't provide a means for the guest to tell the host the alignment.
+ */
+#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;
+    unsigned int align;
+    hwaddr desc;
+    hwaddr avail;
+    hwaddr used;
+} VRing;
+
+struct VirtQueue
+{
+    VRing vring;
+    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;
+    QLIST_ENTRY(VirtQueue) node;
+};
+
+/* virt queue functions */
+void virtio_queue_update_rings(VirtIODevice *vdev, int n)
+{
+    VRing *vring = &vdev->vq[n].vring;
+
+    if (!vring->desc) {
+        /* not yet setup -> nothing to do */
+        return;
+    }
+    vring->avail = vring->desc + vring->num * sizeof(VRingDesc);
+    vring->used = vring_align(vring->avail +
+                              offsetof(VRingAvail, ring[vring->num]),
+                              vring->align);
+}
+
+static inline uint64_t vring_desc_addr(VirtIODevice *vdev, hwaddr desc_pa,
+                                       int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, addr);
+    return virtio_ldq_phys(vdev, pa);
+}
+
+static inline uint32_t vring_desc_len(VirtIODevice *vdev, hwaddr desc_pa, int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, len);
+    return virtio_ldl_phys(vdev, pa);
+}
+
+static inline uint16_t vring_desc_flags(VirtIODevice *vdev, hwaddr desc_pa,
+                                        int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, flags);
+    return virtio_lduw_phys(vdev, pa);
+}
+
+static inline uint16_t vring_desc_next(VirtIODevice *vdev, hwaddr desc_pa,
+                                       int i)
+{
+    hwaddr pa;
+    pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, next);
+    return virtio_lduw_phys(vdev, pa);
+}
+
+static inline uint16_t vring_avail_flags(VirtQueue *vq)
+{
+    hwaddr pa;
+    pa = vq->vring.avail + offsetof(VRingAvail, flags);
+    return virtio_lduw_phys(vq->vdev, pa);
+}
+
+static inline uint16_t vring_avail_idx(VirtQueue *vq)
+{
+    hwaddr pa;
+    pa = vq->vring.avail + offsetof(VRingAvail, idx);
+    return virtio_lduw_phys(vq->vdev, pa);
+}
+
+static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
+{
+    hwaddr pa;
+    pa = vq->vring.avail + offsetof(VRingAvail, ring[i]);
+    return virtio_lduw_phys(vq->vdev, pa);
+}
+
+static inline uint16_t vring_get_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);
+    virtio_stl_phys(vq->vdev, 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);
+    virtio_stl_phys(vq->vdev, pa, val);
+}
+
+static uint16_t vring_used_idx(VirtQueue *vq)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, idx);
+    return virtio_lduw_phys(vq->vdev, pa);
+}
+
+static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
+{
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, idx);
+    virtio_stw_phys(vq->vdev, pa, val);
+}
+
+static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
+{
+    VirtIODevice *vdev = vq->vdev;
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, flags);
+    virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) | mask);
+}
+
+static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
+{
+    VirtIODevice *vdev = vq->vdev;
+    hwaddr pa;
+    pa = vq->vring.used + offsetof(VRingUsed, flags);
+    virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) & ~mask);
+}
+
+static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
+{
+    hwaddr pa;
+    if (!vq->notification) {
+        return;
+    }
+    pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]);
+    virtio_stw_phys(vq->vdev, pa, val);
+}
+
+void virtio_queue_set_notification(VirtQueue *vq, int enable)
+{
+    vq->notification = enable;
+    if (virtio_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
+        vring_set_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(VirtIODevice *vdev, 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(vdev, desc_pa, i) & VRING_DESC_F_NEXT)) {
+        return max;
+    }
+
+    /* Check they're not leading us off end of descriptors. */
+    next = vring_desc_next(vdev, 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)) {
+        VirtIODevice *vdev = vq->vdev;
+        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(vdev, desc_pa, i) & VRING_DESC_F_INDIRECT) {
+            if (vring_desc_len(vdev, 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(vdev, desc_pa, i) / sizeof(VRingDesc);
+            desc_pa = vring_desc_addr(vdev, desc_pa, i);
+            num_bufs = i = 0;
+        }
+
+        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(vdev, desc_pa, i) & VRING_DESC_F_WRITE) {
+                in_total += vring_desc_len(vdev, desc_pa, i);
+            } else {
+                out_total += vring_desc_len(vdev, desc_pa, i);
+            }
+            if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
+                goto done;
+            }
+        } while ((i = virtqueue_next_desc(vdev, 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;
+
+    if (num_sg > VIRTQUEUE_MAX_SIZE) {
+        error_report("virtio: map attempt out of bounds: %zd > %d",
+                     num_sg, VIRTQUEUE_MAX_SIZE);
+        exit(1);
+    }
+
+    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: error 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;
+    VirtIODevice *vdev = vq->vdev;
+
+    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 (virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
+        vring_set_avail_event(vq, vq->last_avail_idx);
+    }
+
+    if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_INDIRECT) {
+        if (vring_desc_len(vdev, 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(vdev, desc_pa, i) / sizeof(VRingDesc);
+        desc_pa = vring_desc_addr(vdev, desc_pa, i);
+        i = 0;
+    }
+
+    /* Collect all the descriptors */
+    do {
+        struct iovec *sg;
+
+        if (vring_desc_flags(vdev, 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(vdev, 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(vdev, desc_pa, i);
+            sg = &elem->out_sg[elem->out_num++];
+        }
+
+        sg->iov_len = vring_desc_len(vdev, 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(vdev, 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)
+{
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+
+    if (k->notify) {
+        k->notify(qbus->parent, vector);
+    }
+}
+
+void virtio_update_irq(VirtIODevice *vdev)
+{
+    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
+}
+
+static int virtio_validate_features(VirtIODevice *vdev)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+
+    if (k->validate_features) {
+        return k->validate_features(vdev);
+    } else {
+        return 0;
+    }
+}
+
+int virtio_set_status(VirtIODevice *vdev, uint8_t val)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    trace_virtio_set_status(vdev, val);
+
+    if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+        if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
+            val & VIRTIO_CONFIG_S_FEATURES_OK) {
+            int ret = virtio_validate_features(vdev);
+
+            if (ret) {
+                return ret;
+            }
+        }
+    }
+    if (k->set_status) {
+        k->set_status(vdev, val);
+    }
+    vdev->status = val;
+    return 0;
+}
+
+bool target_words_bigendian(void);
+static enum virtio_device_endian virtio_default_endian(void)
+{
+    if (target_words_bigendian()) {
+        return VIRTIO_DEVICE_ENDIAN_BIG;
+    } else {
+        return VIRTIO_DEVICE_ENDIAN_LITTLE;
+    }
+}
+
+static enum virtio_device_endian virtio_current_cpu_endian(void)
+{
+    CPUClass *cc = CPU_GET_CLASS(current_cpu);
+
+    if (cc->virtio_is_big_endian(current_cpu)) {
+        return VIRTIO_DEVICE_ENDIAN_BIG;
+    } else {
+        return VIRTIO_DEVICE_ENDIAN_LITTLE;
+    }
+}
+
+void virtio_reset(void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    int i;
+
+    virtio_set_status(vdev, 0);
+    if (current_cpu) {
+        /* Guest initiated reset */
+        vdev->device_endian = virtio_current_cpu_endian();
+    } else {
+        /* System reset */
+        vdev->device_endian = virtio_default_endian();
+    }
+
+    if (k->reset) {
+        k->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_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;
+        virtio_queue_set_vector(vdev, i, 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)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint8_t val;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return (uint32_t)-1;
+    }
+
+    k->get_config(vdev, vdev->config);
+
+    val = ldub_p(vdev->config + addr);
+    return val;
+}
+
+uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint16_t val;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return (uint32_t)-1;
+    }
+
+    k->get_config(vdev, vdev->config);
+
+    val = lduw_p(vdev->config + addr);
+    return val;
+}
+
+uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint32_t val;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return (uint32_t)-1;
+    }
+
+    k->get_config(vdev, vdev->config);
+
+    val = ldl_p(vdev->config + addr);
+    return val;
+}
+
+void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint8_t val = data;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return;
+    }
+
+    stb_p(vdev->config + addr, val);
+
+    if (k->set_config) {
+        k->set_config(vdev, vdev->config);
+    }
+}
+
+void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint16_t val = data;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return;
+    }
+
+    stw_p(vdev->config + addr, val);
+
+    if (k->set_config) {
+        k->set_config(vdev, vdev->config);
+    }
+}
+
+void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint32_t val = data;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return;
+    }
+
+    stl_p(vdev->config + addr, val);
+
+    if (k->set_config) {
+        k->set_config(vdev, vdev->config);
+    }
+}
+
+uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint8_t val;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return (uint32_t)-1;
+    }
+
+    k->get_config(vdev, vdev->config);
+
+    val = ldub_p(vdev->config + addr);
+    return val;
+}
+
+uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint16_t val;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return (uint32_t)-1;
+    }
+
+    k->get_config(vdev, vdev->config);
+
+    val = lduw_le_p(vdev->config + addr);
+    return val;
+}
+
+uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint32_t val;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return (uint32_t)-1;
+    }
+
+    k->get_config(vdev, vdev->config);
+
+    val = ldl_le_p(vdev->config + addr);
+    return val;
+}
+
+void virtio_config_modern_writeb(VirtIODevice *vdev,
+                                 uint32_t addr, uint32_t data)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint8_t val = data;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return;
+    }
+
+    stb_p(vdev->config + addr, val);
+
+    if (k->set_config) {
+        k->set_config(vdev, vdev->config);
+    }
+}
+
+void virtio_config_modern_writew(VirtIODevice *vdev,
+                                 uint32_t addr, uint32_t data)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint16_t val = data;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return;
+    }
+
+    stw_le_p(vdev->config + addr, val);
+
+    if (k->set_config) {
+        k->set_config(vdev, vdev->config);
+    }
+}
+
+void virtio_config_modern_writel(VirtIODevice *vdev,
+                                 uint32_t addr, uint32_t data)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint32_t val = data;
+
+    if (addr + sizeof(val) > vdev->config_len) {
+        return;
+    }
+
+    stl_le_p(vdev->config + addr, val);
+
+    if (k->set_config) {
+        k->set_config(vdev, vdev->config);
+    }
+}
+
+void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
+{
+    vdev->vq[n].vring.desc = addr;
+    virtio_queue_update_rings(vdev, n);
+}
+
+hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.desc;
+}
+
+void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
+                            hwaddr avail, hwaddr used)
+{
+    vdev->vq[n].vring.desc = desc;
+    vdev->vq[n].vring.avail = avail;
+    vdev->vq[n].vring.used = used;
+}
+
+void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
+{
+    /* Don't allow guest to flip queue between existent and
+     * nonexistent states, or to set it to an invalid size.
+     */
+    if (!!num != !!vdev->vq[n].vring.num ||
+        num > VIRTQUEUE_MAX_SIZE ||
+        num < 0) {
+        return;
+    }
+    vdev->vq[n].vring.num = num;
+}
+
+VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
+{
+    return QLIST_FIRST(&vdev->vector_queues[vector]);
+}
+
+VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
+{
+    return QLIST_NEXT(vq, node);
+}
+
+int virtio_queue_get_num(VirtIODevice *vdev, int n)
+{
+    return vdev->vq[n].vring.num;
+}
+
+int virtio_get_num_queues(VirtIODevice *vdev)
+{
+    int i;
+
+    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
+        if (!virtio_queue_get_num(vdev, i)) {
+            break;
+        }
+    }
+
+    return i;
+}
+
+int virtio_queue_get_id(VirtQueue *vq)
+{
+    VirtIODevice *vdev = vq->vdev;
+    assert(vq >= &vdev->vq[0] && vq < &vdev->vq[VIRTIO_QUEUE_MAX]);
+    return vq - &vdev->vq[0];
+}
+
+void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
+{
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+
+    /* virtio-1 compliant devices cannot change the alignment */
+    if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+        error_report("tried to modify queue alignment for virtio-1 device");
+        return;
+    }
+    /* Check that the transport told us it was going to do this
+     * (so a buggy transport will immediately assert rather than
+     * silently failing to migrate this state)
+     */
+    assert(k->has_variable_vring_alignment);
+
+    vdev->vq[n].vring.align = align;
+    virtio_queue_update_rings(vdev, n);
+}
+
+void virtio_queue_notify_vq(VirtQueue *vq)
+{
+    if (vq->vring.desc && vq->handle_output) {
+        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_QUEUE_MAX ? vdev->vq[n].vector :
+        VIRTIO_NO_VECTOR;
+}
+
+void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
+{
+    VirtQueue *vq = &vdev->vq[n];
+
+    if (n < VIRTIO_QUEUE_MAX) {
+        if (vdev->vector_queues &&
+            vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
+            QLIST_REMOVE(vq, node);
+        }
+        vdev->vq[n].vector = vector;
+        if (vdev->vector_queues &&
+            vector != VIRTIO_NO_VECTOR) {
+            QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
+        }
+    }
+}
+
+VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
+                            void (*handle_output)(VirtIODevice *, VirtQueue *))
+{
+    int i;
+
+    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
+        if (vdev->vq[i].vring.num == 0)
+            break;
+    }
+
+    if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
+        abort();
+
+    vdev->vq[i].vring.num = queue_size;
+    vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
+    vdev->vq[i].handle_output = handle_output;
+
+    return &vdev->vq[i];
+}
+
+void virtio_del_queue(VirtIODevice *vdev, int n)
+{
+    if (n < 0 || n >= VIRTIO_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);
+}
+
+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 (virtio_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
+        !vq->inuse && vring_avail_idx(vq) == vq->last_avail_idx) {
+        return true;
+    }
+
+    if (!virtio_has_feature(vdev, 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_get_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;
+    vdev->generation++;
+    virtio_notify_vector(vdev, vdev->config_vector);
+}
+
+static bool virtio_device_endian_needed(void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+
+    assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
+    if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+        return vdev->device_endian != virtio_default_endian();
+    }
+    /* Devices conforming to VIRTIO 1.0 or later are always LE. */
+    return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
+}
+
+static bool virtio_64bit_features_needed(void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+
+    return (vdev->host_features >> 32) != 0;
+}
+
+static bool virtio_virtqueue_needed(void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+
+    return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1);
+}
+
+static void put_virtqueue_state(QEMUFile *f, void *pv, size_t size)
+{
+    VirtIODevice *vdev = pv;
+    int i;
+
+    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
+        qemu_put_be64(f, vdev->vq[i].vring.avail);
+        qemu_put_be64(f, vdev->vq[i].vring.used);
+    }
+}
+
+static int get_virtqueue_state(QEMUFile *f, void *pv, size_t size)
+{
+    VirtIODevice *vdev = pv;
+    int i;
+
+    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
+        vdev->vq[i].vring.avail = qemu_get_be64(f);
+        vdev->vq[i].vring.used = qemu_get_be64(f);
+    }
+    return 0;
+}
+
+static VMStateInfo vmstate_info_virtqueue = {
+    .name = "virtqueue_state",
+    .get = get_virtqueue_state,
+    .put = put_virtqueue_state,
+};
+
+static const VMStateDescription vmstate_virtio_virtqueues = {
+    .name = "virtio/virtqueues",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = &virtio_virtqueue_needed,
+    .fields = (VMStateField[]) {
+        {
+            .name         = "virtqueues",
+            .version_id   = 0,
+            .field_exists = NULL,
+            .size         = 0,
+            .info         = &vmstate_info_virtqueue,
+            .flags        = VMS_SINGLE,
+            .offset       = 0,
+        },
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_virtio_device_endian = {
+    .name = "virtio/device_endian",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = &virtio_device_endian_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8(device_endian, VirtIODevice),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_virtio_64bit_features = {
+    .name = "virtio/64bit_features",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = &virtio_64bit_features_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(guest_features, VirtIODevice),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_virtio = {
+    .name = "virtio",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_virtio_device_endian,
+        &vmstate_virtio_64bit_features,
+        &vmstate_virtio_virtqueues,
+        NULL
+    }
+};
+
+void virtio_save(VirtIODevice *vdev, QEMUFile *f)
+{
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+    uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
+    int i;
+
+    if (k->save_config) {
+        k->save_config(qbus->parent, f);
+    }
+
+    qemu_put_8s(f, &vdev->status);
+    qemu_put_8s(f, &vdev->isr);
+    qemu_put_be16s(f, &vdev->queue_sel);
+    qemu_put_be32s(f, &guest_features_lo);
+    qemu_put_be32(f, vdev->config_len);
+    qemu_put_buffer(f, vdev->config, vdev->config_len);
+
+    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
+        if (vdev->vq[i].vring.num == 0)
+            break;
+    }
+
+    qemu_put_be32(f, i);
+
+    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
+        if (vdev->vq[i].vring.num == 0)
+            break;
+
+        qemu_put_be32(f, vdev->vq[i].vring.num);
+        if (k->has_variable_vring_alignment) {
+            qemu_put_be32(f, vdev->vq[i].vring.align);
+        }
+        /* XXX virtio-1 devices */
+        qemu_put_be64(f, vdev->vq[i].vring.desc);
+        qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
+        if (k->save_queue) {
+            k->save_queue(qbus->parent, i, f);
+        }
+    }
+
+    if (vdc->save != NULL) {
+        vdc->save(vdev, f);
+    }
+
+    /* Subsections */
+    vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
+}
+
+static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
+{
+    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+    bool bad = (val & ~(vdev->host_features)) != 0;
+
+    val &= vdev->host_features;
+    if (k->set_features) {
+        k->set_features(vdev, val);
+    }
+    vdev->guest_features = val;
+    return bad ? -1 : 0;
+}
+
+int virtio_set_features(VirtIODevice *vdev, uint64_t val)
+{
+   /*
+     * The driver must not attempt to set features after feature negotiation
+     * has finished.
+     */
+    if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
+        return -EINVAL;
+    }
+    return virtio_set_features_nocheck(vdev, val);
+}
+
+int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
+{
+    int i, ret;
+    int32_t config_len;
+    uint32_t num;
+    uint32_t features;
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+
+    /*
+     * We poison the endianness to ensure it does not get used before
+     * subsections have been loaded.
+     */
+    vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
+
+    if (k->load_config) {
+        ret = k->load_config(qbus->parent, f);
+        if (ret)
+            return ret;
+    }
+
+    qemu_get_8s(f, &vdev->status);
+    qemu_get_8s(f, &vdev->isr);
+    qemu_get_be16s(f, &vdev->queue_sel);
+    if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) {
+        return -1;
+    }
+    qemu_get_be32s(f, &features);
+
+    config_len = qemu_get_be32(f);
+
+    /*
+     * There are cases where the incoming config can be bigger or smaller
+     * than what we have; so load what we have space for, and skip
+     * any excess that's in the stream.
+     */
+    qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
+
+    while (config_len > vdev->config_len) {
+        qemu_get_byte(f);
+        config_len--;
+    }
+
+    num = qemu_get_be32(f);
+
+    if (num > VIRTIO_QUEUE_MAX) {
+        error_report("Invalid number of PCI queues: 0x%x", num);
+        return -1;
+    }
+
+    for (i = 0; i < num; i++) {
+        vdev->vq[i].vring.num = qemu_get_be32(f);
+        if (k->has_variable_vring_alignment) {
+            vdev->vq[i].vring.align = qemu_get_be32(f);
+        }
+        vdev->vq[i].vring.desc = 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].vring.desc) {
+            /* XXX virtio-1 devices */
+            virtio_queue_update_rings(vdev, i);
+        } 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 (k->load_queue) {
+            ret = k->load_queue(qbus->parent, i, f);
+            if (ret)
+                return ret;
+        }
+    }
+
+    virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
+
+    if (vdc->load != NULL) {
+        ret = vdc->load(vdev, f, version_id);
+        if (ret) {
+            return ret;
+        }
+    }
+
+    /* Subsections */
+    ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
+    if (ret) {
+        return ret;
+    }
+
+    if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
+        vdev->device_endian = virtio_default_endian();
+    }
+
+    if (virtio_64bit_features_needed(vdev)) {
+        /*
+         * Subsection load filled vdev->guest_features.  Run them
+         * through virtio_set_features to sanity-check them against
+         * host_features.
+         */
+        uint64_t features64 = vdev->guest_features;
+        if (virtio_set_features_nocheck(vdev, features64) < 0) {
+            error_report("Features 0x%" PRIx64 " unsupported. "
+                         "Allowed features: 0x%" PRIx64,
+                         features64, vdev->host_features);
+            return -1;
+        }
+    } else {
+        if (virtio_set_features_nocheck(vdev, features) < 0) {
+            error_report("Features 0x%x unsupported. "
+                         "Allowed features: 0x%" PRIx64,
+                         features, vdev->host_features);
+            return -1;
+        }
+    }
+
+    for (i = 0; i < num; i++) {
+        if (vdev->vq[i].vring.desc) {
+            uint16_t nheads;
+            nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
+            /* Check it isn't doing 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;
+            }
+        }
+    }
+
+    return 0;
+}
+
+void virtio_cleanup(VirtIODevice *vdev)
+{
+    qemu_del_vm_change_state_handler(vdev->vmstate);
+    g_free(vdev->config);
+    g_free(vdev->vq);
+    g_free(vdev->vector_queues);
+}
+
+static void virtio_vmstate_change(void *opaque, int running, RunState state)
+{
+    VirtIODevice *vdev = opaque;
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    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 (k->vmstate_change) {
+        k->vmstate_change(qbus->parent, backend_run);
+    }
+
+    if (!backend_run) {
+        virtio_set_status(vdev, vdev->status);
+    }
+}
+
+void virtio_instance_init_common(Object *proxy_obj, void *data,
+                                 size_t vdev_size, const char *vdev_name)
+{
+    DeviceState *vdev = data;
+
+    object_initialize(vdev, vdev_size, vdev_name);
+    object_property_add_child(proxy_obj, "virtio-backend", OBJECT(vdev), NULL);
+    object_unref(OBJECT(vdev));
+    qdev_alias_all_properties(vdev, proxy_obj);
+}
+
+void virtio_init(VirtIODevice *vdev, const char *name,
+                 uint16_t device_id, size_t config_size)
+{
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    int i;
+    int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
+
+    if (nvectors) {
+        vdev->vector_queues =
+            g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
+    }
+
+    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_QUEUE_MAX);
+    vdev->vm_running = runstate_is_running();
+    for (i = 0; i < VIRTIO_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);
+    vdev->device_endian = virtio_default_endian();
+}
+
+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;
+}
+
+void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
+{
+    vdev->vq[n].signalled_used_valid = false;
+}
+
+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;
+}
+
+void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
+{
+    g_free(vdev->bus_name);
+    vdev->bus_name = g_strdup(bus_name);
+}
+
+static void virtio_device_realize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
+    Error *err = NULL;
+
+    if (vdc->realize != NULL) {
+        vdc->realize(dev, &err);
+        if (err != NULL) {
+            error_propagate(errp, err);
+            return;
+        }
+    }
+
+    virtio_bus_device_plugged(vdev, &err);
+    if (err != NULL) {
+        error_propagate(errp, err);
+        return;
+    }
+}
+
+static void virtio_device_unrealize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
+    Error *err = NULL;
+
+    virtio_bus_device_unplugged(vdev);
+
+    if (vdc->unrealize != NULL) {
+        vdc->unrealize(dev, &err);
+        if (err != NULL) {
+            error_propagate(errp, err);
+            return;
+        }
+    }
+
+    g_free(vdev->bus_name);
+    vdev->bus_name = NULL;
+}
+
+static Property virtio_properties[] = {
+    DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtio_device_class_init(ObjectClass *klass, void *data)
+{
+    /* Set the default value here. */
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = virtio_device_realize;
+    dc->unrealize = virtio_device_unrealize;
+    dc->bus_type = TYPE_VIRTIO_BUS;
+    dc->props = virtio_properties;
+}
+
+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)