hw/virtio-serial.h

   1 /*
   2  * Virtio Serial / Console Support
   3  *
   4  * Copyright IBM, Corp. 2008
   5  * Copyright Red Hat, Inc. 2009, 2010
   6  *
   7  * Authors:
   8  *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
   9  *  Amit Shah <amit.shah@redhat.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2.  See
  12  * the COPYING file in the top-level directory.
  13  *
  14  */
  15 #ifndef _QEMU_VIRTIO_SERIAL_H
  16 #define _QEMU_VIRTIO_SERIAL_H
  17
  18 #include "qdev.h"
  19 #include "virtio.h"
  20
  21 /* == Interface shared between the guest kernel and qemu == */
  22
  23 /* The Virtio ID for virtio console / serial ports */
  24 #define VIRTIO_ID_CONSOLE               3
  25
  26 /* Features supported */
  27 #define VIRTIO_CONSOLE_F_MULTIPORT      1
  28
  29 #define VIRTIO_CONSOLE_BAD_ID           (~(uint32_t)0)
  30
  31 struct virtio_console_config {
  32     /*
  33      * These two fields are used by VIRTIO_CONSOLE_F_SIZE which
  34      * isn't implemented here yet
  35      */
  36     uint16_t cols;
  37     uint16_t rows;
  38
  39     uint32_t max_nr_ports;
  40 } __attribute__((packed));
  41
  42 struct virtio_console_control {
  43     uint32_t id;                /* Port number */
  44     uint16_t event;             /* The kind of control event (see below) */
  45     uint16_t value;             /* Extra information for the key */
  46 };
  47
  48 /* Some events for the internal messages (control packets) */
  49 #define VIRTIO_CONSOLE_DEVICE_READY     0
  50 #define VIRTIO_CONSOLE_PORT_ADD         1
  51 #define VIRTIO_CONSOLE_PORT_REMOVE      2
  52 #define VIRTIO_CONSOLE_PORT_READY       3
  53 #define VIRTIO_CONSOLE_CONSOLE_PORT     4
  54 #define VIRTIO_CONSOLE_RESIZE           5
  55 #define VIRTIO_CONSOLE_PORT_OPEN        6
  56 #define VIRTIO_CONSOLE_PORT_NAME        7
  57
  58 /* == In-qemu interface == */
  59
  60 typedef struct VirtIOSerial VirtIOSerial;
  61 typedef struct VirtIOSerialBus VirtIOSerialBus;
  62 typedef struct VirtIOSerialPort VirtIOSerialPort;
  63 typedef struct VirtIOSerialPortInfo VirtIOSerialPortInfo;
  64
  65 /*
  66  * This is the state that's shared between all the ports.  Some of the
  67  * state is configurable via command-line options. Some of it can be
  68  * set by individual devices in their initfn routines. Some of the
  69  * state is set by the generic qdev device init routine.
  70  */
  71 struct VirtIOSerialPort {
  72     DeviceState dev;
  73     VirtIOSerialPortInfo *info;
  74
  75     QTAILQ_ENTRY(VirtIOSerialPort) next;
  76
  77     /*
  78      * This field gives us the virtio device as well as the qdev bus
  79      * that we are associated with
  80      */
  81     VirtIOSerial *vser;
  82
  83     VirtQueue *ivq, *ovq;
  84
  85     /*
  86      * This name is sent to the guest and exported via sysfs.
  87      * The guest could create symlinks based on this information.
  88      * The name is in the reverse fqdn format, like org.qemu.console.0
  89      */
  90     char *name;
  91
  92     /*
  93      * This id helps identify ports between the guest and the host.
  94      * The guest sends a "header" with this id with each data packet
  95      * that it sends and the host can then find out which associated
  96      * device to send out this data to
  97      */
  98     uint32_t id;
  99
 100     /*
 101      * This is the elem that we pop from the virtqueue.  A slow
 102      * backend that consumes guest data (e.g. the file backend for
 103      * qemu chardevs) can cause the guest to block till all the output
 104      * is flushed.  This isn't desired, so we keep a note of the last
 105      * element popped and continue consuming it once the backend
 106      * becomes writable again.
 107      */
 108     VirtQueueElement elem;
 109
 110     /*
 111      * The index and the offset into the iov buffer that was popped in
 112      * elem above.
 113      */
 114     uint32_t iov_idx;
 115     uint64_t iov_offset;
 116
 117     /* Identify if this is a port that binds with hvc in the guest */
 118     uint8_t is_console;
 119
 120     /* Is the corresponding guest device open? */
 121     bool guest_connected;
 122     /* Is this device open for IO on the host? */
 123     bool host_connected;
 124     /* Do apps not want to receive data? */
 125     bool throttled;
 126 };
 127
 128 struct VirtIOSerialPortInfo {
 129     DeviceInfo qdev;
 130     /*
 131      * The per-port (or per-app) init function that's called when a
 132      * new device is found on the bus.
 133      */
 134     int (*init)(VirtIOSerialPort *port);
 135     /*
 136      * Per-port exit function that's called when a port gets
 137      * hot-unplugged or removed.
 138      */
 139     int (*exit)(VirtIOSerialPort *port);
 140
 141     /* Callbacks for guest events */
 142         /* Guest opened device. */
 143     void (*guest_open)(VirtIOSerialPort *port);
 144         /* Guest closed device. */
 145     void (*guest_close)(VirtIOSerialPort *port);
 146
 147         /* Guest is now ready to accept data (virtqueues set up). */
 148     void (*guest_ready)(VirtIOSerialPort *port);
 149
 150     /*
 151      * Guest wrote some data to the port. This data is handed over to
 152      * the app via this callback.  The app can return a size less than
 153      * 'len'.  In this case, throttling will be enabled for this port.
 154      */
 155     ssize_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf,
 156                          size_t len);
 157 };
 158
 159 /* Interface to the virtio-serial bus */
 160
 161 /*
 162  * Individual ports/apps should call this function to register the port
 163  * with the virtio-serial bus
 164  */
 165 void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info);
 166
 167 /*
 168  * Open a connection to the port
 169  *   Returns 0 on success (always).
 170  */
 171 int virtio_serial_open(VirtIOSerialPort *port);
 172
 173 /*
 174  * Close the connection to the port
 175  *   Returns 0 on success (always).
 176  */
 177 int virtio_serial_close(VirtIOSerialPort *port);
 178
 179 /*
 180  * Send data to Guest
 181  */
 182 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 183                             size_t size);
 184
 185 /*
 186  * Query whether a guest is ready to receive data.
 187  */
 188 size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
 189
 190 /*
 191  * Flow control: Ports can signal to the virtio-serial core to stop
 192  * sending data or re-start sending data, depending on the 'throttle'
 193  * value here.
 194  */
 195 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);
 196
 197 #endif