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