hw/char/virtio-console.c

   1 /*
   2  * Virtio Console and Generic Serial Port Devices
   3  *
   4  * Copyright Red Hat, Inc. 2009, 2010
   5  *
   6  * Authors:
   7  *  Amit Shah <amit.shah@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "sysemu/char.h"
  15 #include "qemu/error-report.h"
  16 #include "trace.h"
  17 #include "hw/virtio/virtio-serial.h"
  18 #include "qapi-event.h"
  19
  20 #define TYPE_VIRTIO_CONSOLE_SERIAL_PORT "virtserialport"
  21 #define VIRTIO_CONSOLE(obj) \
  22     OBJECT_CHECK(VirtConsole, (obj), TYPE_VIRTIO_CONSOLE_SERIAL_PORT)
  23
  24 typedef struct VirtConsole {
  25     VirtIOSerialPort parent_obj;
  26
  27     CharDriverState *chr;
  28     guint watch;
  29 } VirtConsole;
  30
  31 /*
  32  * Callback function that's called from chardevs when backend becomes
  33  * writable.
  34  */
  35 static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond,
  36                                     void *opaque)
  37 {
  38     VirtConsole *vcon = opaque;
  39
  40     vcon->watch = 0;
  41     virtio_serial_throttle_port(VIRTIO_SERIAL_PORT(vcon), false);
  42     return FALSE;
  43 }
  44
  45 /* Callback function that's called when the guest sends us data */
  46 static ssize_t flush_buf(VirtIOSerialPort *port,
  47                          const uint8_t *buf, ssize_t len)
  48 {
  49     VirtConsole *vcon = VIRTIO_CONSOLE(port);
  50     ssize_t ret;
  51
  52     if (!vcon->chr) {
  53         /* If there's no backend, we can just say we consumed all data. */
  54         return len;
  55     }
  56
  57     ret = qemu_chr_fe_write(vcon->chr, buf, len);
  58     trace_virtio_console_flush_buf(port->id, len, ret);
  59
  60     if (ret < len) {
  61         VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  62
  63         /*
  64          * Ideally we'd get a better error code than just -1, but
  65          * that's what the chardev interface gives us right now.  If
  66          * we had a finer-grained message, like -EPIPE, we could close
  67          * this connection.
  68          */
  69         if (ret < 0)
  70             ret = 0;
  71         if (!k->is_console) {
  72             virtio_serial_throttle_port(port, true);
  73             if (!vcon->watch) {
  74                 vcon->watch = qemu_chr_fe_add_watch(vcon->chr,
  75                                                     G_IO_OUT|G_IO_HUP,
  76                                                     chr_write_unblocked, vcon);
  77             }
  78         }
  79     }
  80     return ret;
  81 }
  82
  83 /* Callback function that's called when the guest opens/closes the port */
  84 static void set_guest_connected(VirtIOSerialPort *port, int guest_connected)
  85 {
  86     VirtConsole *vcon = VIRTIO_CONSOLE(port);
  87     DeviceState *dev = DEVICE(port);
  88     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  89
  90     if (vcon->chr && !k->is_console) {
  91         qemu_chr_fe_set_open(vcon->chr, guest_connected);
  92     }
  93
  94     if (dev->id) {
  95         qapi_event_send_vserport_change(dev->id, guest_connected,
  96                                         &error_abort);
  97     }
  98 }
  99
 100 static void guest_writable(VirtIOSerialPort *port)
 101 {
 102     VirtConsole *vcon = VIRTIO_CONSOLE(port);
 103
 104     if (vcon->chr) {
 105         qemu_chr_accept_input(vcon->chr);
 106     }
 107 }
 108
 109 /* Readiness of the guest to accept data on a port */
 110 static int chr_can_read(void *opaque)
 111 {
 112     VirtConsole *vcon = opaque;
 113
 114     return virtio_serial_guest_ready(VIRTIO_SERIAL_PORT(vcon));
 115 }
 116
 117 /* Send data from a char device over to the guest */
 118 static void chr_read(void *opaque, const uint8_t *buf, int size)
 119 {
 120     VirtConsole *vcon = opaque;
 121     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
 122
 123     trace_virtio_console_chr_read(port->id, size);
 124     virtio_serial_write(port, buf, size);
 125 }
 126
 127 static void chr_event(void *opaque, int event)
 128 {
 129     VirtConsole *vcon = opaque;
 130     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
 131
 132     trace_virtio_console_chr_event(port->id, event);
 133     switch (event) {
 134     case CHR_EVENT_OPENED:
 135         virtio_serial_open(port);
 136         break;
 137     case CHR_EVENT_CLOSED:
 138         if (vcon->watch) {
 139             g_source_remove(vcon->watch);
 140             vcon->watch = 0;
 141         }
 142         virtio_serial_close(port);
 143         break;
 144     }
 145 }
 146
 147 static void virtconsole_realize(DeviceState *dev, Error **errp)
 148 {
 149     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
 150     VirtConsole *vcon = VIRTIO_CONSOLE(dev);
 151     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
 152
 153     if (port->id == 0 && !k->is_console) {
 154         error_setg(errp, "Port number 0 on virtio-serial devices reserved "
 155                    "for virtconsole devices for backward compatibility.");
 156         return;
 157     }
 158
 159     if (vcon->chr) {
 160         /*
 161          * For consoles we don't block guest data transfer just
 162          * because nothing is connected - we'll just let it go
 163          * whetherever the chardev wants - /dev/null probably.
 164          *
 165          * For serial ports we need 100% reliable data transfer
 166          * so we use the opened/closed signals from chardev to
 167          * trigger open/close of the device
 168          */
 169         if (k->is_console) {
 170             vcon->chr->explicit_fe_open = 0;
 171             qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read,
 172                                   NULL, vcon);
 173             virtio_serial_open(port);
 174         } else {
 175             vcon->chr->explicit_fe_open = 1;
 176             qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read,
 177                                   chr_event, vcon);
 178         }
 179     }
 180 }
 181
 182 static void virtconsole_unrealize(DeviceState *dev, Error **errp)
 183 {
 184     VirtConsole *vcon = VIRTIO_CONSOLE(dev);
 185
 186     if (vcon->watch) {
 187         g_source_remove(vcon->watch);
 188     }
 189 }
 190
 191 static void virtconsole_class_init(ObjectClass *klass, void *data)
 192 {
 193     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
 194
 195     k->is_console = true;
 196 }
 197
 198 static const TypeInfo virtconsole_info = {
 199     .name          = "virtconsole",
 200     .parent        = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
 201     .class_init    = virtconsole_class_init,
 202 };
 203
 204 static Property virtserialport_properties[] = {
 205     DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 206     DEFINE_PROP_END_OF_LIST(),
 207 };
 208
 209 static void virtserialport_class_init(ObjectClass *klass, void *data)
 210 {
 211     DeviceClass *dc = DEVICE_CLASS(klass);
 212     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
 213
 214     k->realize = virtconsole_realize;
 215     k->unrealize = virtconsole_unrealize;
 216     k->have_data = flush_buf;
 217     k->set_guest_connected = set_guest_connected;
 218     k->guest_writable = guest_writable;
 219     dc->props = virtserialport_properties;
 220 }
 221
 222 static const TypeInfo virtserialport_info = {
 223     .name          = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
 224     .parent        = TYPE_VIRTIO_SERIAL_PORT,
 225     .instance_size = sizeof(VirtConsole),
 226     .class_init    = virtserialport_class_init,
 227 };
 228
 229 static void virtconsole_register_types(void)
 230 {
 231     type_register_static(&virtserialport_info);
 232     type_register_static(&virtconsole_info);
 233 }
 234
 235 type_init(virtconsole_register_types)