include/hw/virtio/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
  16 #ifndef QEMU_VIRTIO_SERIAL_H
  17 #define QEMU_VIRTIO_SERIAL_H
  18
  19 #include "standard-headers/linux/virtio_console.h"
  20 #include "hw/qdev.h"
  21 #include "hw/virtio/virtio.h"
  22
  23 struct virtio_serial_conf {
  24     /* Max. number of ports we can have for a virtio-serial device */
  25     uint32_t max_virtserial_ports;
  26 };
  27
  28 #define TYPE_VIRTIO_SERIAL_PORT "virtio-serial-port"
  29 #define VIRTIO_SERIAL_PORT(obj) \
  30      OBJECT_CHECK(VirtIOSerialPort, (obj), TYPE_VIRTIO_SERIAL_PORT)
  31 #define VIRTIO_SERIAL_PORT_CLASS(klass) \
  32      OBJECT_CLASS_CHECK(VirtIOSerialPortClass, (klass), TYPE_VIRTIO_SERIAL_PORT)
  33 #define VIRTIO_SERIAL_PORT_GET_CLASS(obj) \
  34      OBJECT_GET_CLASS(VirtIOSerialPortClass, (obj), TYPE_VIRTIO_SERIAL_PORT)
  35
  36 typedef struct VirtIOSerial VirtIOSerial;
  37 typedef struct VirtIOSerialBus VirtIOSerialBus;
  38 typedef struct VirtIOSerialPort VirtIOSerialPort;
  39
  40 typedef struct VirtIOSerialPortClass {
  41     DeviceClass parent_class;
  42
  43     /* Is this a device that binds with hvc in the guest? */
  44     bool is_console;
  45
  46     /*
  47      * The per-port (or per-app) realize function that's called when a
  48      * new device is found on the bus.
  49      */
  50     DeviceRealize realize;
  51     /*
  52      * Per-port unrealize function that's called when a port gets
  53      * hot-unplugged or removed.
  54      */
  55     DeviceUnrealize unrealize;
  56
  57     /* Callbacks for guest events */
  58         /* Guest opened/closed device. */
  59     void (*set_guest_connected)(VirtIOSerialPort *port, int guest_connected);
  60
  61     /* Enable/disable backend for virtio serial port */
  62     void (*enable_backend)(VirtIOSerialPort *port, bool enable);
  63
  64         /* Guest is now ready to accept data (virtqueues set up). */
  65     void (*guest_ready)(VirtIOSerialPort *port);
  66
  67         /*
  68          * Guest has enqueued a buffer for the host to write into.
  69          * Called each time a buffer is enqueued by the guest;
  70          * irrespective of whether there already were free buffers the
  71          * host could have consumed.
  72          *
  73          * This is dependent on both the guest and host end being
  74          * connected.
  75          */
  76     void (*guest_writable)(VirtIOSerialPort *port);
  77
  78     /*
  79      * Guest wrote some data to the port. This data is handed over to
  80      * the app via this callback.  The app can return a size less than
  81      * 'len'.  In this case, throttling will be enabled for this port.
  82      */
  83     ssize_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf,
  84                          ssize_t len);
  85 } VirtIOSerialPortClass;
  86
  87 /*
  88  * This is the state that's shared between all the ports.  Some of the
  89  * state is configurable via command-line options. Some of it can be
  90  * set by individual devices in their initfn routines. Some of the
  91  * state is set by the generic qdev device init routine.
  92  */
  93 struct VirtIOSerialPort {
  94     DeviceState dev;
  95
  96     QTAILQ_ENTRY(VirtIOSerialPort) next;
  97
  98     /*
  99      * This field gives us the virtio device as well as the qdev bus
 100      * that we are associated with
 101      */
 102     VirtIOSerial *vser;
 103
 104     VirtQueue *ivq, *ovq;
 105
 106     /*
 107      * This name is sent to the guest and exported via sysfs.
 108      * The guest could create symlinks based on this information.
 109      * The name is in the reverse fqdn format, like org.qemu.console.0
 110      */
 111     char *name;
 112
 113     /*
 114      * This id helps identify ports between the guest and the host.
 115      * The guest sends a "header" with this id with each data packet
 116      * that it sends and the host can then find out which associated
 117      * device to send out this data to
 118      */
 119     uint32_t id;
 120
 121     /*
 122      * This is the elem that we pop from the virtqueue.  A slow
 123      * backend that consumes guest data (e.g. the file backend for
 124      * qemu chardevs) can cause the guest to block till all the output
 125      * is flushed.  This isn't desired, so we keep a note of the last
 126      * element popped and continue consuming it once the backend
 127      * becomes writable again.
 128      */
 129     VirtQueueElement *elem;
 130
 131     /*
 132      * The index and the offset into the iov buffer that was popped in
 133      * elem above.
 134      */
 135     uint32_t iov_idx;
 136     uint64_t iov_offset;
 137
 138     /*
 139      * When unthrottling we use a bottom-half to call flush_queued_data.
 140      */
 141     QEMUBH *bh;
 142
 143     /* Is the corresponding guest device open? */
 144     bool guest_connected;
 145     /* Is this device open for IO on the host? */
 146     bool host_connected;
 147     /* Do apps not want to receive data? */
 148     bool throttled;
 149 };
 150
 151 /* The virtio-serial bus on top of which the ports will ride as devices */
 152 struct VirtIOSerialBus {
 153     BusState qbus;
 154
 155     /* This is the parent device that provides the bus for ports. */
 156     VirtIOSerial *vser;
 157
 158     /* The maximum number of ports that can ride on top of this bus */
 159     uint32_t max_nr_ports;
 160 };
 161
 162 typedef struct VirtIOSerialPostLoad {
 163     QEMUTimer *timer;
 164     uint32_t nr_active_ports;
 165     struct {
 166         VirtIOSerialPort *port;
 167         uint8_t host_connected;
 168     } *connected;
 169 } VirtIOSerialPostLoad;
 170
 171 struct VirtIOSerial {
 172     VirtIODevice parent_obj;
 173
 174     VirtQueue *c_ivq, *c_ovq;
 175     /* Arrays of ivqs and ovqs: one per port */
 176     VirtQueue **ivqs, **ovqs;
 177
 178     VirtIOSerialBus bus;
 179
 180     QTAILQ_HEAD(, VirtIOSerialPort) ports;
 181
 182     QLIST_ENTRY(VirtIOSerial) next;
 183
 184     /* bitmap for identifying active ports */
 185     uint32_t *ports_map;
 186
 187     struct VirtIOSerialPostLoad *post_load;
 188
 189     virtio_serial_conf serial;
 190
 191     uint64_t host_features;
 192 };
 193
 194 /* Interface to the virtio-serial bus */
 195
 196 /*
 197  * Open a connection to the port
 198  *   Returns 0 on success (always).
 199  */
 200 int virtio_serial_open(VirtIOSerialPort *port);
 201
 202 /*
 203  * Close the connection to the port
 204  *   Returns 0 on success (always).
 205  */
 206 int virtio_serial_close(VirtIOSerialPort *port);
 207
 208 /*
 209  * Send data to Guest
 210  */
 211 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 212                             size_t size);
 213
 214 /*
 215  * Query whether a guest is ready to receive data.
 216  */
 217 size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
 218
 219 /*
 220  * Flow control: Ports can signal to the virtio-serial core to stop
 221  * sending data or re-start sending data, depending on the 'throttle'
 222  * value here.
 223  */
 224 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);
 225
 226 #define TYPE_VIRTIO_SERIAL "virtio-serial-device"
 227 #define VIRTIO_SERIAL(obj) \
 228         OBJECT_CHECK(VirtIOSerial, (obj), TYPE_VIRTIO_SERIAL)
 229
 230 #endif