Archipelago » qemu

/*

 * A bus for connecting virtio serial and console ports

 *

 * Copyright (C) 2009 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.

 */

#include "monitor.h"

#include "qemu-queue.h"

#include "sysbus.h"

#include "virtio-serial.h"

/* The virtio-serial bus on top of which the ports will ride as devices */

struct VirtIOSerialBus {

    BusState qbus;

    /* This is the parent device that provides the bus for ports. */

    VirtIOSerial *vser;

    /* The maximum number of ports that can ride on top of this bus */

    uint32_t max_nr_ports;

};

struct VirtIOSerial {

    VirtIODevice vdev;

    VirtQueue *c_ivq, *c_ovq;

    /* Arrays of ivqs and ovqs: one per port */

    VirtQueue **ivqs, **ovqs;

    VirtIOSerialBus *bus;

    QTAILQ_HEAD(, VirtIOSerialPort) ports;

    struct virtio_console_config config;

};

static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)

{

    VirtIOSerialPort *port;

    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 = 0;

    size_t len = 0;

    vq = port->ivq;

    if (!virtio_queue_ready(vq)) {

        return 0;

    }

    if (!size) {

        return 0;

    }

    while (offset < size) {

        int i;

        if (!virtqueue_pop(vq, &elem)) {

            break;

        }

        for (i = 0; offset < size && i < elem.in_num; i++) {

            len = MIN(elem.in_sg[i].iov_len, size - offset);

            memcpy(elem.in_sg[i].iov_base, buf + offset, len);

            offset += len;

        }

        virtqueue_push(vq, &elem, len);

    }

    virtio_notify(&port->vser->vdev, vq);

    return offset;

}

static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)

{

    VirtQueueElement elem;

    VirtQueue *vq;

    struct virtio_console_control *cpkt;

    vq = port->vser->c_ivq;

    if (!virtio_queue_ready(vq)) {

        return 0;

    }

    if (!virtqueue_pop(vq, &elem)) {

        return 0;

    }

    cpkt = (struct virtio_console_control *)buf;

    stl_p(&cpkt->id, port->id);

    memcpy(elem.in_sg[0].iov_base, buf, len);

    virtqueue_push(vq, &elem, len);

    virtio_notify(&port->vser->vdev, vq);

    return len;

}

static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,

                                 uint16_t value)

{

    struct virtio_console_control cpkt;

    stw_p(&cpkt.event, event);

    stw_p(&cpkt.value, value);

    return send_control_msg(port, &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, VIRTIO_CONSOLE_PORT_OPEN, 1);

    return 0;

}

int virtio_serial_close(VirtIOSerialPort *port)

{

    port->host_connected = false;

    send_control_event(port, 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;

    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;

    }

    if (virtqueue_avail_bytes(vq, 4096, 0)) {

        return 4096;

    }

    if (virtqueue_avail_bytes(vq, 1, 0)) {

        return 1;

    }

    return 0;

}

/* Guest wants to notify us of some event */

static void handle_control_message(VirtIOSerial *vser, void *buf)

{

    struct VirtIOSerialPort *port;

    struct virtio_console_control cpkt, *gcpkt;

    gcpkt = buf;

    port = find_port_by_id(vser, ldl_p(&gcpkt->id));

    if (!port)

        return;

    cpkt.event = lduw_p(&gcpkt->event);

    cpkt.value = lduw_p(&gcpkt->value);

    switch(cpkt.event) {

    case VIRTIO_CONSOLE_PORT_READY:

        /*

         * 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 (port->is_console) {

            send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);

        }

        if (port->host_connected) {

            send_control_event(port, 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 (port->info->guest_ready) {

            port->info->guest_ready(port);

        }

        break;

    case VIRTIO_CONSOLE_PORT_OPEN:

        port->guest_connected = cpkt.value;

        if (cpkt.value && port->info->guest_open) {

            /* Send the guest opened notification if an app is interested */

            port->info->guest_open(port);

        }

        if (!cpkt.value && port->info->guest_close) {

            /* Send the guest closed notification if an app is interested */

            port->info->guest_close(port);

        }

        break;

    }

}

static void control_in(VirtIODevice *vdev, VirtQueue *vq)

{

}

static void control_out(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtQueueElement elem;

    VirtIOSerial *vser;

    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);

    while (virtqueue_pop(vq, &elem)) {

        handle_control_message(vser, elem.out_sg[0].iov_base);

        virtqueue_push(vq, &elem, elem.out_sg[0].iov_len);

    }

    virtio_notify(vdev, vq);

}

/* Guest wrote something to some port. */

static void handle_output(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtIOSerial *vser;

    VirtQueueElement elem;

    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);

    while (virtqueue_pop(vq, &elem)) {

        VirtIOSerialPort *port;

        size_t ret;

        port = find_port_by_vq(vser, vq);

        if (!port) {

            ret = 0;

            goto next_buf;

        }

        /*

         * A port may not have any handler registered for consuming the

         * data that the guest sends or it may not have a chardev associated

         * with it. Just ignore the data in that case.

         */

        if (!port->info->have_data) {

            ret = 0;

            goto next_buf;

        }

        /* The guest always sends only one sg */

        ret = port->info->have_data(port, elem.out_sg[0].iov_base,

                                    elem.out_sg[0].iov_len);

    next_buf:

        virtqueue_push(vq, &elem, ret);

    }

    virtio_notify(vdev, vq);

}

static void handle_input(VirtIODevice *vdev, VirtQueue *vq)

{

}

static uint32_t get_features(VirtIODevice *vdev, uint32_t features)

{

    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 virtio_serial_save(QEMUFile *f, void *opaque)

{

    VirtIOSerial *s = opaque;

    VirtIOSerialPort *port;

    uint32_t nr_active_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.nr_ports);

    /* Items in struct VirtIOSerial */

    /* Do this because we might have hot-unplugged some 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) {

        /*

         * We put the port number because we may not have an active

         * port at id 0 that's reserved for a console port, or in case

         * of ports that might have gotten unplugged

         */

        qemu_put_be32s(f, &port->id);

        qemu_put_byte(f, port->guest_connected);

    }

}

static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)

{

    VirtIOSerial *s = opaque;

    VirtIOSerialPort *port;

    uint32_t nr_active_ports;

    unsigned int i;

    if (version_id > 2) {

        return -EINVAL;

    }

    /* The virtio device */

    virtio_load(&s->vdev, f);

    if (version_id < 2) {

        return 0;

    }

    /* The config space */

    qemu_get_be16s(f, &s->config.cols);

    qemu_get_be16s(f, &s->config.rows);

    s->config.nr_ports = qemu_get_be32(f);

    /* Items in struct VirtIOSerial */

    qemu_get_be32s(f, &nr_active_ports);

    /* Items in struct VirtIOSerialPort */

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

        uint32_t id;

        id = qemu_get_be32(f);

        port = find_port_by_id(s, id);

        port->guest_connected = qemu_get_byte(f);

    }

    return 0;

}

static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);

static struct BusInfo virtser_bus_info = {

    .name      = "virtio-serial-bus",

    .size      = sizeof(VirtIOSerialBus),

    .print_dev = virtser_bus_dev_print,

};

static VirtIOSerialBus *virtser_bus_new(DeviceState *dev)

{

    VirtIOSerialBus *bus;

    bus = FROM_QBUS(VirtIOSerialBus, qbus_create(&virtser_bus_info, dev,

                                                 "virtio-serial-bus"));

    bus->qbus.allow_hotplug = 1;

    return bus;

}

static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)

{

    VirtIOSerialDevice *dev = DO_UPCAST(VirtIOSerialDevice, qdev, qdev);

    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);

    monitor_printf(mon, "%*s dev-prop-int: id: %u\n",

                   indent, "", port->id);

    monitor_printf(mon, "%*s dev-prop-int: guest_connected: %d\n",

                   indent, "", port->guest_connected);

    monitor_printf(mon, "%*s dev-prop-int: host_connected: %d\n",

                   indent, "", port->host_connected);

}

static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)

{

    VirtIOSerialDevice *dev = DO_UPCAST(VirtIOSerialDevice, qdev, qdev);

    VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev, base);

    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);

    VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);

    int ret;

    bool plugging_port0;

    port->vser = bus->vser;

    /*

     * 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 = port->is_console && !find_port_by_id(port->vser, 0);

    if (port->vser->config.nr_ports == bus->max_nr_ports && !plugging_port0) {

        qemu_error("virtio-serial-bus: Maximum device limit reached\n");

        return -1;

    }

    dev->info = info;

    ret = info->init(dev);

    if (ret) {

        return ret;

    }

    port->id = plugging_port0 ? 0 : port->vser->config.nr_ports++;

    if (!use_multiport(port->vser)) {

        /*

         * Allow writes to guest in this case; we have no way of

         * knowing if a guest port is connected.

         */

        port->guest_connected = true;

    }

    QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);

    port->ivq = port->vser->ivqs[port->id];

    port->ovq = port->vser->ovqs[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)

{

    VirtIOSerialDevice *dev = DO_UPCAST(VirtIOSerialDevice, qdev, qdev);

    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);

    VirtIOSerial *vser = port->vser;

    /*

     * Don't decrement nr_ports here; thus we keep a linearly

     * increasing port id. Not utilising an id again saves us a couple

     * of complications:

     *

     * - Not having to bother about sending the port id to the guest

     *   kernel on hotplug or on addition of new ports; the guest can

     *   also linearly increment the port number. This is preferable

     *   because the config space won't have the need to store a

     *   ports_map.

     *

     * - Extra state to be stored for all the "holes" that got created

     *   so that we keep filling in the ids from the least available

     *   index.

     *

     * When such a functionality is desired, a control message to add

     * a port can be introduced.

     */

    QTAILQ_REMOVE(&vser->ports, port, next);

    if (port->info->exit)

        port->info->exit(dev);

    return 0;

}

void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info)

{

    info->qdev.init = virtser_port_qdev_init;

    info->qdev.bus_info = &virtser_bus_info;

    info->qdev.exit = virtser_port_qdev_exit;

    info->qdev.unplug = qdev_simple_unplug_cb;

    qdev_register(&info->qdev);

}

VirtIODevice *virtio_serial_init(DeviceState *dev, uint32_t max_nr_ports)

{

    VirtIOSerial *vser;

    VirtIODevice *vdev;

    uint32_t i;

    if (!max_nr_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 */

    vser->bus = virtser_bus_new(dev);

    vser->bus->vser = vser;

    QTAILQ_INIT(&vser->ports);

    vser->bus->max_nr_ports = max_nr_ports;

    vser->ivqs = qemu_malloc(max_nr_ports * sizeof(VirtQueue *));

    vser->ovqs = qemu_malloc(max_nr_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);

    /* control queue: host to guest */

    vser->c_ivq = virtio_add_queue(vdev, 16, control_in);

    /* control queue: guest to host */

    vser->c_ovq = virtio_add_queue(vdev, 16, 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 = max_nr_ports;

    /*

     * Reserve location 0 for a console port for backward compat

     * (old kernel, new qemu)

     */

    vser->config.nr_ports = 1;

    vser->vdev.get_features = get_features;

    vser->vdev.get_config = get_config;

    vser->vdev.set_config = set_config;

    /*

     * Register for the savevm section with the virtio-console name

     * to preserve backward compat

     */

    register_savevm("virtio-console", -1, 2, virtio_serial_save,

                    virtio_serial_load, vser);

    return vdev;

}