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 static void virtconsole_update_handlers(VirtConsole *vcon);
  24
  25 /* Callback function that's called when the guest sends us data */
  26 static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
  27 {
  28     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  29     ssize_t ret;
  30
  31     ret = qemu_chr_fe_write(vcon->chr, buf, len);
  32     trace_virtio_console_flush_buf(port->id, len, ret);
  33
  34     if (ret < 0) {
  35         /*
  36          * Ideally we'd get a better error code than just -1, but
  37          * that's what the chardev interface gives us right now.  If
  38          * we had a finer-grained message, like -EPIPE, we could close
  39          * this connection.  Absent such error messages, the most we
  40          * can do is to return 0 here.
  41          *
  42          * This will prevent stray -1 values to go to
  43          * virtio-serial-bus.c and cause abort()s in
  44          * do_flush_queued_data().
  45          */
  46         ret = 0;
  47     }
  48     return ret;
  49 }
  50
  51 /* Callback function that's called when the guest opens the port */
  52 static void guest_open(VirtIOSerialPort *port)
  53 {
  54     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  55
  56     qemu_chr_fe_open(vcon->chr);
  57     virtconsole_update_handlers(vcon);
  58 }
  59
  60 /* Callback function that's called when the guest closes the port */
  61 static void guest_close(VirtIOSerialPort *port)
  62 {
  63     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
  64
  65     qemu_chr_fe_close(vcon->chr);
  66 }
  67
  68 /* Send data from a char device over to the guest */
  69 static void chr_read_handler(void *opaque)
  70 {
  71     VirtConsole *vcon = opaque;
  72     uint8_t buf[4096];
  73     int size;
  74
  75     size = virtio_serial_guest_ready(&vcon->port);
  76     size = MIN(size, sizeof(buf));
  77     size = qemu_chr_fe_read(vcon->chr, buf, size);
  78
  79     trace_virtio_console_chr_read(vcon->port.id, size);
  80     virtio_serial_write(&vcon->port, buf, size);
  81 }
  82
  83 static int chr_event(void *opaque, int event, void *data)
  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     return 0;
  98 }
  99
 100 static void virtconsole_update_handlers(VirtConsole *vcon)
 101 {
 102     if (virtio_serial_guest_ready(&vcon->port) > 0) {
 103         qemu_chr_fe_set_handlers(vcon->chr, chr_read_handler, NULL, chr_event,
 104                                  vcon);
 105     } else {
 106         qemu_chr_fe_set_handlers(vcon->chr, NULL, NULL, chr_event,
 107                                  vcon);
 108     }
 109 }
 110
 111 static int virtconsole_initfn(VirtIOSerialPort *port)
 112 {
 113     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 114     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
 115                                            vcon->port.dev.info);
 116
 117     if (port->id == 0 && !info->is_console) {
 118         error_report("Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.");
 119         return -1;
 120     }
 121
 122     if (vcon->chr) {
 123         /* FIXME we need a notifier for when guest ready changes */
 124         info->have_data = flush_buf;
 125         info->guest_open = guest_open;
 126         info->guest_close = guest_close;
 127     }
 128
 129     return 0;
 130 }
 131
 132 static int virtconsole_exitfn(VirtIOSerialPort *port)
 133 {
 134     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 135
 136     if (vcon->chr) {
 137         qemu_chr_fe_close(vcon->chr);
 138     }
 139
 140     return 0;
 141 }
 142
 143 static VirtIOSerialPortInfo virtconsole_info = {
 144     .qdev.name     = "virtconsole",
 145     .qdev.size     = sizeof(VirtConsole),
 146     .is_console    = true,
 147     .init          = virtconsole_initfn,
 148     .exit          = virtconsole_exitfn,
 149     .qdev.props = (Property[]) {
 150         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 151         DEFINE_PROP_END_OF_LIST(),
 152     },
 153 };
 154
 155 static void virtconsole_register(void)
 156 {
 157     virtio_serial_port_qdev_register(&virtconsole_info);
 158 }
 159 device_init(virtconsole_register)
 160
 161 static VirtIOSerialPortInfo virtserialport_info = {
 162     .qdev.name     = "virtserialport",
 163     .qdev.size     = sizeof(VirtConsole),
 164     .init          = virtconsole_initfn,
 165     .exit          = virtconsole_exitfn,
 166     .qdev.props = (Property[]) {
 167         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 168         DEFINE_PROP_END_OF_LIST(),
 169     },
 170 };
 171
 172 static void virtserialport_register(void)
 173 {
 174     virtio_serial_port_qdev_register(&virtserialport_info);
 175 }
 176 device_init(virtserialport_register)