virtio-serial-bus: use bh for unthrottling
[qemu.git] / 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 /*
123 * When unthrottling we use a bottom-half to call flush_queued_data.
124 */
125 QEMUBH *bh;
126
127 /* Identify if this is a port that binds with hvc in the guest */
128 uint8_t is_console;
129
130 /* Is the corresponding guest device open? */
131 bool guest_connected;
132 /* Is this device open for IO on the host? */
133 bool host_connected;
134 /* Do apps not want to receive data? */
135 bool throttled;
136 };
137
138 struct VirtIOSerialPortInfo {
139 DeviceInfo qdev;
140 /*
141 * The per-port (or per-app) init function that's called when a
142 * new device is found on the bus.
143 */
144 int (*init)(VirtIOSerialPort *port);
145 /*
146 * Per-port exit function that's called when a port gets
147 * hot-unplugged or removed.
148 */
149 int (*exit)(VirtIOSerialPort *port);
150
151 /* Callbacks for guest events */
152 /* Guest opened device. */
153 void (*guest_open)(VirtIOSerialPort *port);
154 /* Guest closed device. */
155 void (*guest_close)(VirtIOSerialPort *port);
156
157 /* Guest is now ready to accept data (virtqueues set up). */
158 void (*guest_ready)(VirtIOSerialPort *port);
159
160 /*
161 * Guest wrote some data to the port. This data is handed over to
162 * the app via this callback. The app can return a size less than
163 * 'len'. In this case, throttling will be enabled for this port.
164 */
165 ssize_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf,
166 size_t len);
167 };
168
169 /* Interface to the virtio-serial bus */
170
171 /*
172 * Individual ports/apps should call this function to register the port
173 * with the virtio-serial bus
174 */
175 void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info);
176
177 /*
178 * Open a connection to the port
179 * Returns 0 on success (always).
180 */
181 int virtio_serial_open(VirtIOSerialPort *port);
182
183 /*
184 * Close the connection to the port
185 * Returns 0 on success (always).
186 */
187 int virtio_serial_close(VirtIOSerialPort *port);
188
189 /*
190 * Send data to Guest
191 */
192 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
193 size_t size);
194
195 /*
196 * Query whether a guest is ready to receive data.
197 */
198 size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
199
200 /*
201 * Flow control: Ports can signal to the virtio-serial core to stop
202 * sending data or re-start sending data, depending on the 'throttle'
203 * value here.
204 */
205 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);
206
207 #endif