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     VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev,
 113                                            vcon->port.dev.info);
 114
 115     if (port->id == 0 && !info->is_console) {
 116         error_report("Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.");
 117         return -1;
 118     }
 119
 120     if (vcon->chr) {
 121         qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
 122                               vcon);
 123     }
 124
 125     return 0;
 126 }
 127
 128 static VirtIOSerialPortInfo virtconsole_info = {
 129     .qdev.name     = "virtconsole",
 130     .qdev.size     = sizeof(VirtConsole),
 131     .is_console    = true,
 132     .init          = virtconsole_initfn,
 133     .have_data     = flush_buf,
 134     .guest_open    = guest_open,
 135     .guest_close   = guest_close,
 136     .qdev.props = (Property[]) {
 137         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 138         DEFINE_PROP_END_OF_LIST(),
 139     },
 140 };
 141
 142 static void virtconsole_register(void)
 143 {
 144     virtio_serial_port_qdev_register(&virtconsole_info);
 145 }
 146 device_init(virtconsole_register)
 147
 148 static VirtIOSerialPortInfo virtserialport_info = {
 149     .qdev.name     = "virtserialport",
 150     .qdev.size     = sizeof(VirtConsole),
 151     .init          = virtconsole_initfn,
 152     .have_data     = flush_buf,
 153     .guest_open    = guest_open,
 154     .guest_close   = guest_close,
 155     .qdev.props = (Property[]) {
 156         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
 157         DEFINE_PROP_END_OF_LIST(),
 158     },
 159 };
 160
 161 static void virtserialport_register(void)
 162 {
 163     virtio_serial_port_qdev_register(&virtserialport_info);
 164 }
 165 device_init(virtserialport_register)