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 struct virtio_serial_conf {
  49     /* Max. number of ports we can have for a virtio-serial device */
  50     uint32_t max_virtserial_ports;
  51 };
  52
  53 /* Some events for the internal messages (control packets) */
  54 #define VIRTIO_CONSOLE_DEVICE_READY     0
  55 #define VIRTIO_CONSOLE_PORT_ADD         1
  56 #define VIRTIO_CONSOLE_PORT_REMOVE      2
  57 #define VIRTIO_CONSOLE_PORT_READY       3
  58 #define VIRTIO_CONSOLE_CONSOLE_PORT     4
  59 #define VIRTIO_CONSOLE_RESIZE           5
  60 #define VIRTIO_CONSOLE_PORT_OPEN        6
  61 #define VIRTIO_CONSOLE_PORT_NAME        7
  62
  63 /* == In-qemu interface == */
  64
  65 typedef struct VirtIOSerial VirtIOSerial;
  66 typedef struct VirtIOSerialBus VirtIOSerialBus;
  67 typedef struct VirtIOSerialPort VirtIOSerialPort;
  68 typedef struct VirtIOSerialPortInfo VirtIOSerialPortInfo;
  69
  70 /*
  71  * This is the state that's shared between all the ports.  Some of the
  72  * state is configurable via command-line options. Some of it can be
  73  * set by individual devices in their initfn routines. Some of the
  74  * state is set by the generic qdev device init routine.
  75  */
  76 struct VirtIOSerialPort {
  77     DeviceState dev;
  78     VirtIOSerialPortInfo *info;
  79
  80     QTAILQ_ENTRY(VirtIOSerialPort) next;
  81
  82     /*
  83      * This field gives us the virtio device as well as the qdev bus
  84      * that we are associated with
  85      */
  86     VirtIOSerial *vser;
  87
  88     VirtQueue *ivq, *ovq;
  89
  90     /*
  91      * This name is sent to the guest and exported via sysfs.
  92      * The guest could create symlinks based on this information.
  93      * The name is in the reverse fqdn format, like org.qemu.console.0
  94      */
  95     char *name;
  96
  97     /*
  98      * This id helps identify ports between the guest and the host.
  99      * The guest sends a "header" with this id with each data packet
 100      * that it sends and the host can then find out which associated
 101      * device to send out this data to
 102      */
 103     uint32_t id;
 104
 105     /*
 106      * This is the elem that we pop from the virtqueue.  A slow
 107      * backend that consumes guest data (e.g. the file backend for
 108      * qemu chardevs) can cause the guest to block till all the output
 109      * is flushed.  This isn't desired, so we keep a note of the last
 110      * element popped and continue consuming it once the backend
 111      * becomes writable again.
 112      */
 113     VirtQueueElement elem;
 114
 115     /*
 116      * The index and the offset into the iov buffer that was popped in
 117      * elem above.
 118      */
 119     uint32_t iov_idx;
 120     uint64_t iov_offset;
 121
 122     /* Identify if this is a port that binds with hvc in the guest */
 123     uint8_t is_console;
 124
 125     /* Is the corresponding guest device open? */
 126     bool guest_connected;
 127     /* Is this device open for IO on the host? */
 128     bool host_connected;
 129     /* Do apps not want to receive data? */
 130     bool throttled;
 131 };
 132
 133 struct VirtIOSerialPortInfo {
 134     DeviceInfo qdev;
 135     /*
 136      * The per-port (or per-app) init function that's called when a
 137      * new device is found on the bus.
 138      */
 139     int (*init)(VirtIOSerialPort *port);
 140     /*
 141      * Per-port exit function that's called when a port gets
 142      * hot-unplugged or removed.
 143      */
 144     int (*exit)(VirtIOSerialPort *port);
 145
 146     /* Callbacks for guest events */
 147         /* Guest opened device. */
 148     void (*guest_open)(VirtIOSerialPort *port);
 149         /* Guest closed device. */
 150     void (*guest_close)(VirtIOSerialPort *port);
 151
 152         /* Guest is now ready to accept data (virtqueues set up). */
 153     void (*guest_ready)(VirtIOSerialPort *port);
 154
 155     /*
 156      * Guest wrote some data to the port. This data is handed over to
 157      * the app via this callback.  The app can return a size less than
 158      * 'len'.  In this case, throttling will be enabled for this port.
 159      */
 160     ssize_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf,
 161                          size_t len);
 162 };
 163
 164 /* Interface to the virtio-serial bus */
 165
 166 /*
 167  * Individual ports/apps should call this function to register the port
 168  * with the virtio-serial bus
 169  */
 170 void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info);
 171
 172 /*
 173  * Open a connection to the port
 174  *   Returns 0 on success (always).
 175  */
 176 int virtio_serial_open(VirtIOSerialPort *port);
 177
 178 /*
 179  * Close the connection to the port
 180  *   Returns 0 on success (always).
 181  */
 182 int virtio_serial_close(VirtIOSerialPort *port);
 183
 184 /*
 185  * Send data to Guest
 186  */
 187 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 188                             size_t size);
 189
 190 /*
 191  * Query whether a guest is ready to receive data.
 192  */
 193 size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
 194
 195 /*
 196  * Flow control: Ports can signal to the virtio-serial core to stop
 197  * sending data or re-start sending data, depending on the 'throttle'
 198  * value here.
 199  */
 200 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);
 201
 202 #endif