pcie_aer: support configurable AER capa version
[qemu.git] / hw / char / 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/osdep.h"
14 #include "sysemu/char.h"
15 #include "qemu/error-report.h"
16 #include "trace.h"
17 #include "hw/virtio/virtio-serial.h"
18 #include "qapi-event.h"
19
20 #define TYPE_VIRTIO_CONSOLE_SERIAL_PORT "virtserialport"
21 #define VIRTIO_CONSOLE(obj) \
22 OBJECT_CHECK(VirtConsole, (obj), TYPE_VIRTIO_CONSOLE_SERIAL_PORT)
23
24 typedef struct VirtConsole {
25 VirtIOSerialPort parent_obj;
26
27 CharBackend chr;
28 guint watch;
29 } VirtConsole;
30
31 /*
32 * Callback function that's called from chardevs when backend becomes
33 * writable.
34 */
35 static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond,
36 void *opaque)
37 {
38 VirtConsole *vcon = opaque;
39
40 vcon->watch = 0;
41 virtio_serial_throttle_port(VIRTIO_SERIAL_PORT(vcon), false);
42 return FALSE;
43 }
44
45 /* Callback function that's called when the guest sends us data */
46 static ssize_t flush_buf(VirtIOSerialPort *port,
47 const uint8_t *buf, ssize_t len)
48 {
49 VirtConsole *vcon = VIRTIO_CONSOLE(port);
50 ssize_t ret;
51
52 if (!qemu_chr_fe_get_driver(&vcon->chr)) {
53 /* If there's no backend, we can just say we consumed all data. */
54 return len;
55 }
56
57 ret = qemu_chr_fe_write(&vcon->chr, buf, len);
58 trace_virtio_console_flush_buf(port->id, len, ret);
59
60 if (ret < len) {
61 VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
62
63 /*
64 * Ideally we'd get a better error code than just -1, but
65 * that's what the chardev interface gives us right now. If
66 * we had a finer-grained message, like -EPIPE, we could close
67 * this connection.
68 */
69 if (ret < 0)
70 ret = 0;
71
72 /* XXX we should be queuing data to send later for the
73 * console devices too rather than silently dropping
74 * console data on EAGAIN. The Linux virtio-console
75 * hvc driver though does sends with spinlocks held,
76 * so if we enable throttling that'll stall the entire
77 * guest kernel, not merely the process writing to the
78 * console.
79 *
80 * While we could queue data for later write without
81 * enabling throttling, this would result in the guest
82 * being able to trigger arbitrary memory usage in QEMU
83 * buffering data for later writes.
84 *
85 * So fixing this problem likely requires fixing the
86 * Linux virtio-console hvc driver to not hold spinlocks
87 * while writing, and instead merely block the process
88 * that's writing. QEMU would then need some way to detect
89 * if the guest had the fixed driver too, before we can
90 * use throttling on host side.
91 */
92 if (!k->is_console) {
93 virtio_serial_throttle_port(port, true);
94 if (!vcon->watch) {
95 vcon->watch = qemu_chr_fe_add_watch(&vcon->chr,
96 G_IO_OUT|G_IO_HUP,
97 chr_write_unblocked, vcon);
98 }
99 }
100 }
101 return ret;
102 }
103
104 /* Callback function that's called when the guest opens/closes the port */
105 static void set_guest_connected(VirtIOSerialPort *port, int guest_connected)
106 {
107 VirtConsole *vcon = VIRTIO_CONSOLE(port);
108 DeviceState *dev = DEVICE(port);
109 VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
110
111 if (!k->is_console) {
112 qemu_chr_fe_set_open(&vcon->chr, guest_connected);
113 }
114
115 if (dev->id) {
116 qapi_event_send_vserport_change(dev->id, guest_connected,
117 &error_abort);
118 }
119 }
120
121 static void guest_writable(VirtIOSerialPort *port)
122 {
123 VirtConsole *vcon = VIRTIO_CONSOLE(port);
124
125 qemu_chr_fe_accept_input(&vcon->chr);
126 }
127
128 /* Readiness of the guest to accept data on a port */
129 static int chr_can_read(void *opaque)
130 {
131 VirtConsole *vcon = opaque;
132
133 return virtio_serial_guest_ready(VIRTIO_SERIAL_PORT(vcon));
134 }
135
136 /* Send data from a char device over to the guest */
137 static void chr_read(void *opaque, const uint8_t *buf, int size)
138 {
139 VirtConsole *vcon = opaque;
140 VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
141
142 trace_virtio_console_chr_read(port->id, size);
143 virtio_serial_write(port, buf, size);
144 }
145
146 static void chr_event(void *opaque, int event)
147 {
148 VirtConsole *vcon = opaque;
149 VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
150
151 trace_virtio_console_chr_event(port->id, event);
152 switch (event) {
153 case CHR_EVENT_OPENED:
154 virtio_serial_open(port);
155 break;
156 case CHR_EVENT_CLOSED:
157 if (vcon->watch) {
158 g_source_remove(vcon->watch);
159 vcon->watch = 0;
160 }
161 virtio_serial_close(port);
162 break;
163 }
164 }
165
166 static void virtconsole_realize(DeviceState *dev, Error **errp)
167 {
168 VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
169 VirtConsole *vcon = VIRTIO_CONSOLE(dev);
170 VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
171 CharDriverState *chr = qemu_chr_fe_get_driver(&vcon->chr);
172
173 if (port->id == 0 && !k->is_console) {
174 error_setg(errp, "Port number 0 on virtio-serial devices reserved "
175 "for virtconsole devices for backward compatibility.");
176 return;
177 }
178
179 if (chr) {
180 /*
181 * For consoles we don't block guest data transfer just
182 * because nothing is connected - we'll just let it go
183 * whetherever the chardev wants - /dev/null probably.
184 *
185 * For serial ports we need 100% reliable data transfer
186 * so we use the opened/closed signals from chardev to
187 * trigger open/close of the device
188 */
189 if (k->is_console) {
190 qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
191 NULL, vcon, NULL, true);
192 virtio_serial_open(port);
193 } else {
194 qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
195 chr_event, vcon, NULL, false);
196 }
197 }
198 }
199
200 static void virtconsole_unrealize(DeviceState *dev, Error **errp)
201 {
202 VirtConsole *vcon = VIRTIO_CONSOLE(dev);
203
204 if (vcon->watch) {
205 g_source_remove(vcon->watch);
206 }
207 }
208
209 static void virtconsole_class_init(ObjectClass *klass, void *data)
210 {
211 VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
212
213 k->is_console = true;
214 }
215
216 static const TypeInfo virtconsole_info = {
217 .name = "virtconsole",
218 .parent = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
219 .class_init = virtconsole_class_init,
220 };
221
222 static Property virtserialport_properties[] = {
223 DEFINE_PROP_CHR("chardev", VirtConsole, chr),
224 DEFINE_PROP_END_OF_LIST(),
225 };
226
227 static void virtserialport_class_init(ObjectClass *klass, void *data)
228 {
229 DeviceClass *dc = DEVICE_CLASS(klass);
230 VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass);
231
232 k->realize = virtconsole_realize;
233 k->unrealize = virtconsole_unrealize;
234 k->have_data = flush_buf;
235 k->set_guest_connected = set_guest_connected;
236 k->guest_writable = guest_writable;
237 dc->props = virtserialport_properties;
238 }
239
240 static const TypeInfo virtserialport_info = {
241 .name = TYPE_VIRTIO_CONSOLE_SERIAL_PORT,
242 .parent = TYPE_VIRTIO_SERIAL_PORT,
243 .instance_size = sizeof(VirtConsole),
244 .class_init = virtserialport_class_init,
245 };
246
247 static void virtconsole_register_types(void)
248 {
249 type_register_static(&virtserialport_info);
250 type_register_static(&virtconsole_info);
251 }
252
253 type_init(virtconsole_register_types)