diff options
Diffstat (limited to 'hw/virtio-serial-bus.c')
| -rw-r--r-- | hw/virtio-serial-bus.c | 507 |
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 0000000000..e8bbd7d3ee --- /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; +} |