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     ret = qemu_chr_fe_write(vcon->chr, buf, len);
  31     trace_virtio_console_flush_buf(port->id, len, ret);
  32
  33     if (ret < 0) {
  34         /*
  35          * Ideally we'd get a better error code than just -1, but
  36          * that's what the chardev interface gives us right now.  If
  37          * we had a finer-grained message, like -EPIPE, we could close
  38          * this connection.  Absent such error messages, the most we
  39          * can do is to return 0 here.
  40          *
  41          * This will prevent stray -1 values to go to
  42          * virtio-serial-bus.c and cause abort()s in
  43          * do_flush_queued_data().
  44          */
  45         ret = 0;
  46     }
  47     return ret;
  48 }
  49
  50 /* Callback function that's called when the guest opens the port */
  51 static void guest_open(VirtIOSerialPort *port)
  52 {
  53     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  54
  55     qemu_chr_fe_open(vcon->chr);
  56 }
  57
  58 /* Callback function that's called when the guest closes the port */
  59 static void guest_close(VirtIOSerialPort *port)
  60 {
  61     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  62
  63     qemu_chr_fe_close(vcon->chr);
  64 }
  65
  66 /* Readiness of the guest to accept data on a port */
  67 static int chr_can_read(void *opaque)
  68 {
  69     VirtConsole *vcon = opaque;
  70
  71     return virtio_serial_guest_ready(&vcon->port);
  72 }
  73
  74 /* Send data from a char device over to the guest */
  75 static void chr_read(void *opaque, const uint8_t *buf, int size)
  76 {
  77     VirtConsole *vcon = opaque;
  78
  79     trace_virtio_console_chr_read(vcon->port.id, size);
  80     virtio_serial_write(&vcon->port, buf, size);
  81 }
  82
  83 static void chr_event(void *opaque, int event)
  84 {
  85     VirtConsole *vcon = opaque;
  86
  87     trace_virtio_console_chr_event(vcon->port.id, event);
  88     switch (event) {
  89     case CHR_EVENT_OPENED:
  90         virtio_serial_open(&vcon->port);
  91         break;
  92     case CHR_EVENT_CLOSED:
  93         virtio_serial_close(&vcon->port);
  94         break;
  95     }
  96 }
  97
  98 static int virtconsole_initfn(VirtIOSerialPort *port)
  99 {
 100     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 101     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
 102                                            vcon->port.dev.info);
 103
 104     if (port->id == 0 && !info->is_console) {
 105         error_report("Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.");
 106         return -1;
 107     }
 108
 109     if (vcon->chr) {
 110         qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
 111                               vcon);
 112         info->have_data = flush_buf;
 113         info->guest_open = guest_open;
 114         info->guest_close = guest_close;
 115     }
 116
 117     return 0;
 118 }
 119
 120 static int virtconsole_exitfn(VirtIOSerialPort *port)
 121 {
 122     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 123
 124     if (vcon->chr) {
 125         /*
 126          * Instead of closing the chardev, free it so it can be used
 127          * for other purposes.
 128          */
 129         qemu_chr_add_handlers(vcon->chr, NULL, NULL, NULL, NULL);
 130     }
 131
 132     return 0;
 133 }
 134
 135 static VirtIOSerialPortInfo virtconsole_info = {
 136     .qdev.name     = "virtconsole",
 137     .qdev.size     = sizeof(VirtConsole),
 138     .is_console    = true,
 139     .init          = virtconsole_initfn,
 140     .exit          = virtconsole_exitfn,
 141     .qdev.props = (Property[]) {
 142         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 143         DEFINE_PROP_END_OF_LIST(),
 144     },
 145 };
 146
 147 static void virtconsole_register(void)
 148 {
 149     virtio_serial_port_qdev_register(&virtconsole_info);
 150 }
 151 device_init(virtconsole_register)
 152
 153 static VirtIOSerialPortInfo virtserialport_info = {
 154     .qdev.name     = "virtserialport",
 155     .qdev.size     = sizeof(VirtConsole),
 156     .init          = virtconsole_initfn,
 157     .exit          = virtconsole_exitfn,
 158     .qdev.props = (Property[]) {
 159         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 160         DEFINE_PROP_END_OF_LIST(),
 161     },
 162 };
 163
 164 static void virtserialport_register(void)
 165 {
 166     virtio_serial_port_qdev_register(&virtserialport_info);
 167 }
 168 device_init(virtserialport_register)