hw: move virtio devices to hw/ subdirectories

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

1 files changed, 1018 insertions, 0 deletions

diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
new file mode 100644
index 0000000000..1dba8ab2c6
--- /dev/null
+++ b/hw/char/virtio-serial-bus.c
@@ -0,0 +1,1018 @@
+/*
+ * A bus for connecting virtio serial and console ports
+ *
+ * Copyright (C) 2009, 2010 Red Hat, Inc.
+ *
+ * Author(s):
+ *  Amit Shah <amit.shah@redhat.com>
+ *
+ * Some earlier parts are:
+ *  Copyright IBM, Corp. 2008
+ * authored by
+ *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.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 "qemu/iov.h"
+#include "monitor/monitor.h"
+#include "qemu/queue.h"
+#include "hw/sysbus.h"
+#include "trace.h"
+#include "hw/virtio/virtio-serial.h"
+
+static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
+{
+    VirtIOSerialPort *port;
+
+    if (id == VIRTIO_CONSOLE_BAD_ID) {
+        return NULL;
+    }
+
+    QTAILQ_FOREACH(port, &vser->ports, next) {
+        if (port->id == id)
+            return port;
+    }
+    return NULL;
+}
+
+static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
+{
+    VirtIOSerialPort *port;
+
+    QTAILQ_FOREACH(port, &vser->ports, next) {
+        if (port->ivq == vq || port->ovq == vq)
+            return port;
+    }
+    return NULL;
+}
+
+static bool use_multiport(VirtIOSerial *vser)
+{
+    return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+}
+
+static size_t write_to_port(VirtIOSerialPort *port,
+                            const uint8_t *buf, size_t size)
+{
+    VirtQueueElement elem;
+    VirtQueue *vq;
+    size_t offset;
+
+    vq = port->ivq;
+    if (!virtio_queue_ready(vq)) {
+        return 0;
+    }
+
+    offset = 0;
+    while (offset < size) {
+        size_t len;
+
+        if (!virtqueue_pop(vq, &elem)) {
+            break;
+        }
+
+        len = iov_from_buf(elem.in_sg, elem.in_num, 0,
+                           buf + offset, size - offset);
+        offset += len;
+
+        virtqueue_push(vq, &elem, len);
+    }
+
+    virtio_notify(&port->vser->vdev, vq);
+    return offset;
+}
+
+static void discard_vq_data(VirtQueue *vq, VirtIODevice *vdev)
+{
+    VirtQueueElement elem;
+
+    if (!virtio_queue_ready(vq)) {
+        return;
+    }
+    while (virtqueue_pop(vq, &elem)) {
+        virtqueue_push(vq, &elem, 0);
+    }
+    virtio_notify(vdev, vq);
+}
+
+static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq,
+                                 VirtIODevice *vdev)
+{
+    VirtIOSerialPortClass *vsc;
+
+    assert(port);
+    assert(virtio_queue_ready(vq));
+
+    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+
+    while (!port->throttled) {
+        unsigned int i;
+
+        /* Pop an elem only if we haven't left off a previous one mid-way */
+        if (!port->elem.out_num) {
+            if (!virtqueue_pop(vq, &port->elem)) {
+                break;
+            }
+            port->iov_idx = 0;
+            port->iov_offset = 0;
+        }
+
+        for (i = port->iov_idx; i < port->elem.out_num; i++) {
+            size_t buf_size;
+            ssize_t ret;
+
+            buf_size = port->elem.out_sg[i].iov_len - port->iov_offset;
+            ret = vsc->have_data(port,
+                                  port->elem.out_sg[i].iov_base
+                                  + port->iov_offset,
+                                  buf_size);
+            if (port->throttled) {
+                port->iov_idx = i;
+                if (ret > 0) {
+                    port->iov_offset += ret;
+                }
+                break;
+            }
+            port->iov_offset = 0;
+        }
+        if (port->throttled) {
+            break;
+        }
+        virtqueue_push(vq, &port->elem, 0);
+        port->elem.out_num = 0;
+    }
+    virtio_notify(vdev, vq);
+}
+
+static void flush_queued_data(VirtIOSerialPort *port)
+{
+    assert(port);
+
+    if (!virtio_queue_ready(port->ovq)) {
+        return;
+    }
+    do_flush_queued_data(port, port->ovq, &port->vser->vdev);
+}
+
+static size_t send_control_msg(VirtIOSerial *vser, void *buf, size_t len)
+{
+    VirtQueueElement elem;
+    VirtQueue *vq;
+
+    vq = vser->c_ivq;
+    if (!virtio_queue_ready(vq)) {
+        return 0;
+    }
+    if (!virtqueue_pop(vq, &elem)) {
+        return 0;
+    }
+
+    memcpy(elem.in_sg[0].iov_base, buf, len);
+
+    virtqueue_push(vq, &elem, len);
+    virtio_notify(&vser->vdev, vq);
+    return len;
+}
+
+static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
+                                 uint16_t event, uint16_t value)
+{
+    struct virtio_console_control cpkt;
+
+    stl_p(&cpkt.id, port_id);
+    stw_p(&cpkt.event, event);
+    stw_p(&cpkt.value, value);
+
+    trace_virtio_serial_send_control_event(port_id, event, value);
+    return send_control_msg(vser, &cpkt, sizeof(cpkt));
+}
+
+/* Functions for use inside qemu to open and read from/write to ports */
+int virtio_serial_open(VirtIOSerialPort *port)
+{
+    /* Don't allow opening an already-open port */
+    if (port->host_connected) {
+        return 0;
+    }
+    /* Send port open notification to the guest */
+    port->host_connected = true;
+    send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
+
+    return 0;
+}
+
+int virtio_serial_close(VirtIOSerialPort *port)
+{
+    port->host_connected = false;
+    /*
+     * If there's any data the guest sent which the app didn't
+     * consume, reset the throttling flag and discard the data.
+     */
+    port->throttled = false;
+    discard_vq_data(port->ovq, &port->vser->vdev);
+
+    send_control_event(port->vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 0);
+
+    return 0;
+}
+
+/* Individual ports/apps call this function to write to the guest. */
+ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
+                            size_t size)
+{
+    if (!port || !port->host_connected || !port->guest_connected) {
+        return 0;
+    }
+    return write_to_port(port, buf, size);
+}
+
+/*
+ * Readiness of the guest to accept data on a port.
+ * Returns max. data the guest can receive
+ */
+size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
+{
+    VirtQueue *vq = port->ivq;
+    unsigned int bytes;
+
+    if (!virtio_queue_ready(vq) ||
+        !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
+        virtio_queue_empty(vq)) {
+        return 0;
+    }
+    if (use_multiport(port->vser) && !port->guest_connected) {
+        return 0;
+    }
+    virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0);
+    return bytes;
+}
+
+static void flush_queued_data_bh(void *opaque)
+{
+    VirtIOSerialPort *port = opaque;
+
+    flush_queued_data(port);
+}
+
+void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
+{
+    if (!port) {
+        return;
+    }
+
+    trace_virtio_serial_throttle_port(port->id, throttle);
+    port->throttled = throttle;
+    if (throttle) {
+        return;
+    }
+    qemu_bh_schedule(port->bh);
+}
+
+/* Guest wants to notify us of some event */
+static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len)
+{
+    struct VirtIOSerialPort *port;
+    VirtIOSerialPortClass *vsc;
+    struct virtio_console_control cpkt, *gcpkt;
+    uint8_t *buffer;
+    size_t buffer_len;
+
+    gcpkt = buf;
+
+    if (len < sizeof(cpkt)) {
+        /* The guest sent an invalid control packet */
+        return;
+    }
+
+    cpkt.event = lduw_p(&gcpkt->event);
+    cpkt.value = lduw_p(&gcpkt->value);
+
+    trace_virtio_serial_handle_control_message(cpkt.event, cpkt.value);
+
+    if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) {
+        if (!cpkt.value) {
+            error_report("virtio-serial-bus: Guest failure in adding device %s",
+                         vser->bus.qbus.name);
+            return;
+        }
+        /*
+         * The device is up, we can now tell the device about all the
+         * ports we have here.
+         */
+        QTAILQ_FOREACH(port, &vser->ports, next) {
+            send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_ADD, 1);
+        }
+        return;
+    }
+
+    port = find_port_by_id(vser, ldl_p(&gcpkt->id));
+    if (!port) {
+        error_report("virtio-serial-bus: Unexpected port id %u for device %s",
+                     ldl_p(&gcpkt->id), vser->bus.qbus.name);
+        return;
+    }
+
+    trace_virtio_serial_handle_control_message_port(port->id);
+
+    vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+
+    switch(cpkt.event) {
+    case VIRTIO_CONSOLE_PORT_READY:
+        if (!cpkt.value) {
+            error_report("virtio-serial-bus: Guest failure in adding port %u for device %s",
+                         port->id, vser->bus.qbus.name);
+            break;
+        }
+        /*
+         * Now that we know the guest asked for the port name, we're
+         * sure the guest has initialised whatever state is necessary
+         * for this port. Now's a good time to let the guest know if
+         * this port is a console port so that the guest can hook it
+         * up to hvc.
+         */
+        if (vsc->is_console) {
+            send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
+        }
+
+        if (port->name) {
+            stl_p(&cpkt.id, port->id);
+            stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
+            stw_p(&cpkt.value, 1);
+
+            buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
+            buffer = g_malloc(buffer_len);
+
+            memcpy(buffer, &cpkt, sizeof(cpkt));
+            memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
+            buffer[buffer_len - 1] = 0;
+
+            send_control_msg(vser, buffer, buffer_len);
+            g_free(buffer);
+        }
+
+        if (port->host_connected) {
+            send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_OPEN, 1);
+        }
+
+        /*
+         * When the guest has asked us for this information it means
+         * the guest is all setup and has its virtqueues
+         * initialised. If some app is interested in knowing about
+         * this event, let it know.
+         */
+        if (vsc->guest_ready) {
+            vsc->guest_ready(port);
+        }
+        break;
+
+    case VIRTIO_CONSOLE_PORT_OPEN:
+        port->guest_connected = cpkt.value;
+        if (vsc->set_guest_connected) {
+            /* Send the guest opened notification if an app is interested */
+            vsc->set_guest_connected(port, cpkt.value);
+        }
+        break;
+    }
+}
+
+static void control_in(VirtIODevice *vdev, VirtQueue *vq)
+{
+}
+
+static void control_out(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtQueueElement elem;
+    VirtIOSerial *vser;
+    uint8_t *buf;
+    size_t len;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+
+    len = 0;
+    buf = NULL;
+    while (virtqueue_pop(vq, &elem)) {
+        size_t cur_len;
+
+        cur_len = iov_size(elem.out_sg, elem.out_num);
+        /*
+         * Allocate a new buf only if we didn't have one previously or
+         * if the size of the buf differs
+         */
+        if (cur_len > len) {
+            g_free(buf);
+
+            buf = g_malloc(cur_len);
+            len = cur_len;
+        }
+        iov_to_buf(elem.out_sg, elem.out_num, 0, buf, cur_len);
+
+        handle_control_message(vser, buf, cur_len);
+        virtqueue_push(vq, &elem, 0);
+    }
+    g_free(buf);
+    virtio_notify(vdev, vq);
+}
+
+/* Guest wrote something to some port. */
+static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOSerial *vser;
+    VirtIOSerialPort *port;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+    port = find_port_by_vq(vser, vq);
+
+    if (!port || !port->host_connected) {
+        discard_vq_data(vq, vdev);
+        return;
+    }
+
+    if (!port->throttled) {
+        do_flush_queued_data(port, vq, vdev);
+        return;
+    }
+}
+
+static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
+{
+}
+
+static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
+{
+    VirtIOSerial *vser;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+
+    if (vser->bus.max_nr_ports > 1) {
+        features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+    }
+    return features;
+}
+
+/* Guest requested config info */
+static void get_config(VirtIODevice *vdev, uint8_t *config_data)
+{
+    VirtIOSerial *vser;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+    memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
+}
+
+static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
+{
+    struct virtio_console_config config;
+
+    memcpy(&config, config_data, sizeof(config));
+}
+
+static void guest_reset(VirtIOSerial *vser)
+{
+    VirtIOSerialPort *port;
+    VirtIOSerialPortClass *vsc;
+
+    QTAILQ_FOREACH(port, &vser->ports, next) {
+        vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+        if (port->guest_connected) {
+            port->guest_connected = false;
+            if (vsc->set_guest_connected) {
+                vsc->set_guest_connected(port, false);
+            }
+        }
+    }
+}
+
+static void set_status(VirtIODevice *vdev, uint8_t status)
+{
+    VirtIOSerial *vser;
+    VirtIOSerialPort *port;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+    port = find_port_by_id(vser, 0);
+
+    if (port && !use_multiport(port->vser)
+        && (status & VIRTIO_CONFIG_S_DRIVER_OK)) {
+        /*
+         * Non-multiport guests won't be able to tell us guest
+         * open/close status.  Such guests can only have a port at id
+         * 0, so set guest_connected for such ports as soon as guest
+         * is up.
+         */
+        port->guest_connected = true;
+    }
+    if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
+        guest_reset(vser);
+    }
+}
+
+static void vser_reset(VirtIODevice *vdev)
+{
+    VirtIOSerial *vser;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+    guest_reset(vser);
+}
+
+static void virtio_serial_save(QEMUFile *f, void *opaque)
+{
+    VirtIOSerial *s = opaque;
+    VirtIOSerialPort *port;
+    uint32_t nr_active_ports;
+    unsigned int i, max_nr_ports;
+
+    /* The virtio device */
+    virtio_save(&s->vdev, f);
+
+    /* The config space */
+    qemu_put_be16s(f, &s->config.cols);
+    qemu_put_be16s(f, &s->config.rows);
+
+    qemu_put_be32s(f, &s->config.max_nr_ports);
+
+    /* The ports map */
+    max_nr_ports = tswap32(s->config.max_nr_ports);
+    for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
+        qemu_put_be32s(f, &s->ports_map[i]);
+    }
+
+    /* Ports */
+
+    nr_active_ports = 0;
+    QTAILQ_FOREACH(port, &s->ports, next) {
+        nr_active_ports++;
+    }
+
+    qemu_put_be32s(f, &nr_active_ports);
+
+    /*
+     * Items in struct VirtIOSerialPort.
+     */
+    QTAILQ_FOREACH(port, &s->ports, next) {
+        uint32_t elem_popped;
+
+        qemu_put_be32s(f, &port->id);
+        qemu_put_byte(f, port->guest_connected);
+        qemu_put_byte(f, port->host_connected);
+
+	elem_popped = 0;
+        if (port->elem.out_num) {
+            elem_popped = 1;
+        }
+        qemu_put_be32s(f, &elem_popped);
+        if (elem_popped) {
+            qemu_put_be32s(f, &port->iov_idx);
+            qemu_put_be64s(f, &port->iov_offset);
+
+            qemu_put_buffer(f, (unsigned char *)&port->elem,
+                            sizeof(port->elem));
+        }
+    }
+}
+
+static void virtio_serial_post_load_timer_cb(void *opaque)
+{
+    uint32_t i;
+    VirtIOSerial *s = opaque;
+    VirtIOSerialPort *port;
+    uint8_t host_connected;
+    VirtIOSerialPortClass *vsc;
+
+    if (!s->post_load) {
+        return;
+    }
+    for (i = 0 ; i < s->post_load->nr_active_ports; ++i) {
+        port = s->post_load->connected[i].port;
+        host_connected = s->post_load->connected[i].host_connected;
+        if (host_connected != port->host_connected) {
+            /*
+             * We have to let the guest know of the host connection
+             * status change
+             */
+            send_control_event(s, port->id, VIRTIO_CONSOLE_PORT_OPEN,
+                               port->host_connected);
+        }
+        vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+        if (vsc->set_guest_connected) {
+            vsc->set_guest_connected(port, port->guest_connected);
+        }
+    }
+    g_free(s->post_load->connected);
+    qemu_free_timer(s->post_load->timer);
+    g_free(s->post_load);
+    s->post_load = NULL;
+}
+
+static int fetch_active_ports_list(QEMUFile *f, int version_id,
+                                   VirtIOSerial *s, uint32_t nr_active_ports)
+{
+    uint32_t i;
+
+    s->post_load = g_malloc0(sizeof(*s->post_load));
+    s->post_load->nr_active_ports = nr_active_ports;
+    s->post_load->connected =
+        g_malloc0(sizeof(*s->post_load->connected) * nr_active_ports);
+
+    s->post_load->timer = qemu_new_timer_ns(vm_clock,
+                                            virtio_serial_post_load_timer_cb,
+                                            s);
+
+    /* Items in struct VirtIOSerialPort */
+    for (i = 0; i < nr_active_ports; i++) {
+        VirtIOSerialPort *port;
+        uint32_t id;
+
+        id = qemu_get_be32(f);
+        port = find_port_by_id(s, id);
+        if (!port) {
+            return -EINVAL;
+        }
+
+        port->guest_connected = qemu_get_byte(f);
+        s->post_load->connected[i].port = port;
+        s->post_load->connected[i].host_connected = qemu_get_byte(f);
+
+        if (version_id > 2) {
+            uint32_t elem_popped;
+
+            qemu_get_be32s(f, &elem_popped);
+            if (elem_popped) {
+                qemu_get_be32s(f, &port->iov_idx);
+                qemu_get_be64s(f, &port->iov_offset);
+
+                qemu_get_buffer(f, (unsigned char *)&port->elem,
+                                sizeof(port->elem));
+                virtqueue_map_sg(port->elem.in_sg, port->elem.in_addr,
+                                 port->elem.in_num, 1);
+                virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
+                                 port->elem.out_num, 1);
+
+                /*
+                 *  Port was throttled on source machine.  Let's
+                 *  unthrottle it here so data starts flowing again.
+                 */
+                virtio_serial_throttle_port(port, false);
+            }
+        }
+    }
+    qemu_mod_timer(s->post_load->timer, 1);
+    return 0;
+}
+
+static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VirtIOSerial *s = opaque;
+    uint32_t max_nr_ports, nr_active_ports, ports_map;
+    unsigned int i;
+    int ret;
+
+    if (version_id > 3) {
+        return -EINVAL;
+    }
+
+    /* The virtio device */
+    ret = virtio_load(&s->vdev, f);
+    if (ret) {
+        return ret;
+    }
+
+    if (version_id < 2) {
+        return 0;
+    }
+
+    /* The config space */
+    qemu_get_be16s(f, &s->config.cols);
+    qemu_get_be16s(f, &s->config.rows);
+
+    qemu_get_be32s(f, &max_nr_ports);
+    tswap32s(&max_nr_ports);
+    if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
+        /* Source could have had more ports than us. Fail migration. */
+        return -EINVAL;
+    }
+
+    for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
+        qemu_get_be32s(f, &ports_map);
+
+        if (ports_map != s->ports_map[i]) {
+            /*
+             * Ports active on source and destination don't
+             * match. Fail migration.
+             */
+            return -EINVAL;
+        }
+    }
+
+    qemu_get_be32s(f, &nr_active_ports);
+
+    if (nr_active_ports) {
+        ret = fetch_active_ports_list(f, version_id, s, nr_active_ports);
+        if (ret) {
+            return ret;
+        }
+    }
+    return 0;
+}
+
+static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
+
+static Property virtser_props[] = {
+    DEFINE_PROP_UINT32("nr", VirtIOSerialPort, id, VIRTIO_CONSOLE_BAD_ID),
+    DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
+    DEFINE_PROP_END_OF_LIST()
+};
+
+#define TYPE_VIRTIO_SERIAL_BUS "virtio-serial-bus"
+#define VIRTIO_SERIAL_BUS(obj) \
+      OBJECT_CHECK(VirtIOSerialBus, (obj), TYPE_VIRTIO_SERIAL_BUS)
+
+static void virtser_bus_class_init(ObjectClass *klass, void *data)
+{
+    BusClass *k = BUS_CLASS(klass);
+    k->print_dev = virtser_bus_dev_print;
+}
+
+static const TypeInfo virtser_bus_info = {
+    .name = TYPE_VIRTIO_SERIAL_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(VirtIOSerialBus),
+    .class_init = virtser_bus_class_init,
+};
+
+static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
+{
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
+
+    monitor_printf(mon, "%*sport %d, guest %s, host %s, throttle %s\n",
+                   indent, "", port->id,
+                   port->guest_connected ? "on" : "off",
+                   port->host_connected ? "on" : "off",
+                   port->throttled ? "on" : "off");
+}
+
+/* This function is only used if a port id is not provided by the user */
+static uint32_t find_free_port_id(VirtIOSerial *vser)
+{
+    unsigned int i, max_nr_ports;
+
+    max_nr_ports = tswap32(vser->config.max_nr_ports);
+    for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
+        uint32_t map, bit;
+
+        map = vser->ports_map[i];
+        bit = ffs(~map);
+        if (bit) {
+            return (bit - 1) + i * 32;
+        }
+    }
+    return VIRTIO_CONSOLE_BAD_ID;
+}
+
+static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
+{
+    unsigned int i;
+
+    i = port_id / 32;
+    vser->ports_map[i] |= 1U << (port_id % 32);
+}
+
+static void add_port(VirtIOSerial *vser, uint32_t port_id)
+{
+    mark_port_added(vser, port_id);
+    send_control_event(vser, port_id, VIRTIO_CONSOLE_PORT_ADD, 1);
+}
+
+static void remove_port(VirtIOSerial *vser, uint32_t port_id)
+{
+    VirtIOSerialPort *port;
+    unsigned int i;
+
+    i = port_id / 32;
+    vser->ports_map[i] &= ~(1U << (port_id % 32));
+
+    port = find_port_by_id(vser, port_id);
+    /*
+     * This function is only called from qdev's unplug callback; if we
+     * get a NULL port here, we're in trouble.
+     */
+    assert(port);
+
+    /* Flush out any unconsumed buffers first */
+    discard_vq_data(port->ovq, &port->vser->vdev);
+
+    send_control_event(vser, port->id, VIRTIO_CONSOLE_PORT_REMOVE, 1);
+}
+
+static int virtser_port_qdev_init(DeviceState *qdev)
+{
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
+    VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+    VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
+    int ret, max_nr_ports;
+    bool plugging_port0;
+
+    port->vser = bus->vser;
+    port->bh = qemu_bh_new(flush_queued_data_bh, port);
+
+    assert(vsc->have_data);
+
+    /*
+     * Is the first console port we're seeing? If so, put it up at
+     * location 0. This is done for backward compatibility (old
+     * kernel, new qemu).
+     */
+    plugging_port0 = vsc->is_console && !find_port_by_id(port->vser, 0);
+
+    if (find_port_by_id(port->vser, port->id)) {
+        error_report("virtio-serial-bus: A port already exists at id %u",
+                     port->id);
+        return -1;
+    }
+
+    if (port->id == VIRTIO_CONSOLE_BAD_ID) {
+        if (plugging_port0) {
+            port->id = 0;
+        } else {
+            port->id = find_free_port_id(port->vser);
+            if (port->id == VIRTIO_CONSOLE_BAD_ID) {
+                error_report("virtio-serial-bus: Maximum port limit for this device reached");
+                return -1;
+            }
+        }
+    }
+
+    max_nr_ports = tswap32(port->vser->config.max_nr_ports);
+    if (port->id >= max_nr_ports) {
+        error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u",
+                     max_nr_ports - 1);
+        return -1;
+    }
+
+    ret = vsc->init(port);
+    if (ret) {
+        return ret;
+    }
+
+    port->elem.out_num = 0;
+
+    QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
+    port->ivq = port->vser->ivqs[port->id];
+    port->ovq = port->vser->ovqs[port->id];
+
+    add_port(port->vser, port->id);
+
+    /* Send an update to the guest about this new port added */
+    virtio_notify_config(&port->vser->vdev);
+
+    return ret;
+}
+
+static int virtser_port_qdev_exit(DeviceState *qdev)
+{
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, qdev);
+    VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+    VirtIOSerial *vser = port->vser;
+
+    qemu_bh_delete(port->bh);
+    remove_port(port->vser, port->id);
+
+    QTAILQ_REMOVE(&vser->ports, port, next);
+
+    if (vsc->exit) {
+        vsc->exit(port);
+    }
+    return 0;
+}
+
+VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
+{
+    VirtIOSerial *vser;
+    VirtIODevice *vdev;
+    uint32_t i, max_supported_ports;
+
+    if (!conf->max_virtserial_ports)
+        return NULL;
+
+    /* Each port takes 2 queues, and one pair is for the control queue */
+    max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
+
+    if (conf->max_virtserial_ports > max_supported_ports) {
+        error_report("maximum ports supported: %u", max_supported_ports);
+        return NULL;
+    }
+
+    vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
+                              sizeof(struct virtio_console_config),
+                              sizeof(VirtIOSerial));
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+
+    /* Spawn a new virtio-serial bus on which the ports will ride as devices */
+    qbus_create_inplace(&vser->bus.qbus, TYPE_VIRTIO_SERIAL_BUS, dev, NULL);
+    vser->bus.qbus.allow_hotplug = 1;
+    vser->bus.vser = vser;
+    QTAILQ_INIT(&vser->ports);
+
+    vser->bus.max_nr_ports = conf->max_virtserial_ports;
+    vser->ivqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
+    vser->ovqs = g_malloc(conf->max_virtserial_ports * sizeof(VirtQueue *));
+
+    /* Add a queue for host to guest transfers for port 0 (backward compat) */
+    vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
+    /* Add a queue for guest to host transfers for port 0 (backward compat) */
+    vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
+
+    /* TODO: host to guest notifications can get dropped
+     * if the queue fills up. Implement queueing in host,
+     * this might also make it possible to reduce the control
+     * queue size: as guest preposts buffers there,
+     * this will save 4Kbyte of guest memory per entry. */
+
+    /* control queue: host to guest */
+    vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
+    /* control queue: guest to host */
+    vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
+
+    for (i = 1; i < vser->bus.max_nr_ports; i++) {
+        /* Add a per-port queue for host to guest transfers */
+        vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
+        /* Add a per-per queue for guest to host transfers */
+        vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
+    }
+
+    vser->config.max_nr_ports = tswap32(conf->max_virtserial_ports);
+    vser->ports_map = g_malloc0(((conf->max_virtserial_ports + 31) / 32)
+        * sizeof(vser->ports_map[0]));
+    /*
+     * Reserve location 0 for a console port for backward compat
+     * (old kernel, new qemu)
+     */
+    mark_port_added(vser, 0);
+
+    vser->vdev.get_features = get_features;
+    vser->vdev.get_config = get_config;
+    vser->vdev.set_config = set_config;
+    vser->vdev.set_status = set_status;
+    vser->vdev.reset = vser_reset;
+
+    vser->qdev = dev;
+
+    vser->post_load = NULL;
+
+    /*
+     * Register for the savevm section with the virtio-console name
+     * to preserve backward compat
+     */
+    register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
+                    virtio_serial_load, vser);
+
+    return vdev;
+}
+
+void virtio_serial_exit(VirtIODevice *vdev)
+{
+    VirtIOSerial *vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+
+    unregister_savevm(vser->qdev, "virtio-console", vser);
+
+    g_free(vser->ivqs);
+    g_free(vser->ovqs);
+    g_free(vser->ports_map);
+    if (vser->post_load) {
+        g_free(vser->post_load->connected);
+        qemu_del_timer(vser->post_load->timer);
+        qemu_free_timer(vser->post_load->timer);
+        g_free(vser->post_load);
+    }
+    virtio_cleanup(vdev);
+}
+
+static void virtio_serial_port_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *k = DEVICE_CLASS(klass);
+    k->init = virtser_port_qdev_init;
+    k->bus_type = TYPE_VIRTIO_SERIAL_BUS;
+    k->exit = virtser_port_qdev_exit;
+    k->unplug = qdev_simple_unplug_cb;
+    k->props = virtser_props;
+}
+
+static const TypeInfo virtio_serial_port_type_info = {
+    .name = TYPE_VIRTIO_SERIAL_PORT,
+    .parent = TYPE_DEVICE,
+    .instance_size = sizeof(VirtIOSerialPort),
+    .abstract = true,
+    .class_size = sizeof(VirtIOSerialPortClass),
+    .class_init = virtio_serial_port_class_init,
+};
+
+static void virtio_serial_register_types(void)
+{
+    type_register_static(&virtser_bus_info);
+    type_register_static(&virtio_serial_port_type_info);
+}
+
+type_init(virtio_serial_register_types)