hw/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 "char/char.h"
  14 #include "qemu/error-report.h"
  15 #include "trace.h"
  16 #include "hw/virtio-serial.h"
  17
  18 typedef struct VirtConsole {
  19     VirtIOSerialPort port;
  20     CharDriverState *chr;
  21 } VirtConsole;
  22
  23 /*
  24  * Callback function that's called from chardevs when backend becomes
  25  * writable.
  26  */
  27 static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond,
  28                                     void *opaque)
  29 {
  30     VirtConsole *vcon = opaque;
  31
  32     virtio_serial_throttle_port(&vcon->port, false);
  33     return FALSE;
  34 }
  35
  36 /* Callback function that's called when the guest sends us data */
  37 static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
  38 {
  39     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  40     ssize_t ret;
  41
  42     if (!vcon->chr) {
  43         /* If there's no backend, we can just say we consumed all data. */
  44         return len;
  45     }
  46
  47     ret = qemu_chr_fe_write(vcon->chr, buf, len);
  48     trace_virtio_console_flush_buf(port->id, len, ret);
  49
  50     if (ret <= 0) {
  51         VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
  52
  53         /*
  54          * Ideally we'd get a better error code than just -1, but
  55          * that's what the chardev interface gives us right now.  If
  56          * we had a finer-grained message, like -EPIPE, we could close
  57          * this connection.
  58          */
  59         ret = 0;
  60         if (!k->is_console) {
  61             virtio_serial_throttle_port(port, true);
  62             qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT, chr_write_unblocked,
  63                                   vcon);
  64         }
  65     }
  66     return ret;
  67 }
  68
  69 /* Callback function that's called when the guest opens the port */
  70 static void guest_open(VirtIOSerialPort *port)
  71 {
  72     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  73
  74     if (!vcon->chr) {
  75         return;
  76     }
  77     qemu_chr_fe_open(vcon->chr);
  78 }
  79
  80 /* Callback function that's called when the guest closes the port */
  81 static void guest_close(VirtIOSerialPort *port)
  82 {
  83     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  84
  85     if (!vcon->chr) {
  86         return;
  87     }
  88     qemu_chr_fe_close(vcon->chr);
  89 }
  90
  91 /* Readiness of the guest to accept data on a port */
  92 static int chr_can_read(void *opaque)
  93 {
  94     VirtConsole *vcon = opaque;
  95
  96     return virtio_serial_guest_ready(&vcon->port);
  97 }
  98
  99 /* Send data from a char device over to the guest */
 100 static void chr_read(void *opaque, const uint8_t *buf, int size)
 101 {
 102     VirtConsole *vcon = opaque;
 103
 104     trace_virtio_console_chr_read(vcon->port.id, size);
 105     virtio_serial_write(&vcon->port, buf, size);
 106 }
 107
 108 static void chr_event(void *opaque, int event)
 109 {
 110     VirtConsole *vcon = opaque;
 111
 112     trace_virtio_console_chr_event(vcon->port.id, event);
 113     switch (event) {
 114     case CHR_EVENT_OPENED:
 115         virtio_serial_open(&vcon->port);
 116         break;
 117     case CHR_EVENT_CLOSED:
 118         virtio_serial_close(&vcon->port);
 119         break;
 120     }
 121 }
 122
 123 static int virtconsole_initfn(VirtIOSerialPort *port)
 124 {
 125     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 126     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 127
 128     if (port->id == 0 && !k->is_console) {
 129         error_report("Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.");
 130         return -1;
 131     }
 132
 133     if (vcon->chr) {
 134         vcon->chr->explicit_fe_open = 1;
 135         qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
 136                               vcon);
 137     }
 138
 139     return 0;
 140 }
 141
 142 static Property virtconsole_properties[] = {
 143     DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 144     DEFINE_PROP_END_OF_LIST(),
 145 };
 146
 147 static void virtconsole_class_init(ObjectClass *klass, void *data)
 148 {
 149     DeviceClass *dc = DEVICE_CLASS(klass);
 150     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
 151
 152     k->is_console = true;
 153     k->init = virtconsole_initfn;
 154     k->have_data = flush_buf;
 155     k->guest_open = guest_open;
 156     k->guest_close = guest_close;
 157     dc->props = virtconsole_properties;
 158 }
 159
 160 static const TypeInfo virtconsole_info = {
 161     .name          = "virtconsole",
 162     .parent        = TYPE_VIRTIO_SERIAL_PORT,
 163     .instance_size = sizeof(VirtConsole),
 164     .class_init    = virtconsole_class_init,
 165 };
 166
 167 static Property virtserialport_properties[] = {
 168     DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 169     DEFINE_PROP_END_OF_LIST(),
 170 };
 171
 172 static void virtserialport_class_init(ObjectClass *klass, void *data)
 173 {
 174     DeviceClass *dc = DEVICE_CLASS(klass);
 175     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
 176
 177     k->init = virtconsole_initfn;
 178     k->have_data = flush_buf;
 179     k->guest_open = guest_open;
 180     k->guest_close = guest_close;
 181     dc->props = virtserialport_properties;
 182 }
 183
 184 static const TypeInfo virtserialport_info = {
 185     .name          = "virtserialport",
 186     .parent        = TYPE_VIRTIO_SERIAL_PORT,
 187     .instance_size = sizeof(VirtConsole),
 188     .class_init    = virtserialport_class_init,
 189 };
 190
 191 static void virtconsole_register_types(void)
 192 {
 193     type_register_static(&virtconsole_info);
 194     type_register_static(&virtserialport_info);
 195 }
 196
 197 type_init(virtconsole_register_types)