1 files changed, 507 insertions, 0 deletions

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
new file mode 100644
index 0000000..e8bbd7d
--- /dev/null
+++ b/hw/virtio-serial-bus.c
@@ -0,0 +1,507 @@
+/*
+ * 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 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)
+{
+    return 0;
+}
+
+int virtio_serial_close(VirtIOSerialPort *port)
+{
+    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)
+{
+    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 (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);
+        }
+        /*
+         * 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;
+    }
+}
+
+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;
+
+    /* 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);
+}
+
+static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VirtIOSerial *s = opaque;
+
+    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);
+
+    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);
+}
+
+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++;
+
+    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;
+}