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98b19252 AS |
1 | /* |
2 | * Virtio Console and Generic Serial Port Devices | |
3 | * | |
71c092e9 | 4 | * Copyright Red Hat, Inc. 2009, 2010 |
98b19252 AS |
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 | ||
9b8bfe21 | 13 | #include "qemu/osdep.h" |
4d43a603 | 14 | #include "chardev/char-fe.h" |
1de7afc9 | 15 | #include "qemu/error-report.h" |
0b8fa32f | 16 | #include "qemu/module.h" |
d02e4fa4 | 17 | #include "trace.h" |
a27bd6c7 | 18 | #include "hw/qdev-properties.h" |
0d09e41a | 19 | #include "hw/virtio/virtio-serial.h" |
e688df6b | 20 | #include "qapi/error.h" |
9af23989 | 21 | #include "qapi/qapi-events-char.h" |
98b19252 | 22 | |
be21c336 | 23 | #define TYPE_VIRTIO_CONSOLE_SERIAL_PORT "virtserialport" |
0399a381 | 24 | #define VIRTIO_CONSOLE(obj) \ |
be21c336 | 25 | OBJECT_CHECK(VirtConsole, (obj), TYPE_VIRTIO_CONSOLE_SERIAL_PORT) |
0399a381 | 26 | |
98b19252 | 27 | typedef struct VirtConsole { |
0399a381 AF |
28 | VirtIOSerialPort parent_obj; |
29 | ||
becdfa00 | 30 | CharBackend chr; |
c3d6b96e | 31 | guint watch; |
98b19252 AS |
32 | } VirtConsole; |
33 | ||
7df4d457 AS |
34 | /* |
35 | * Callback function that's called from chardevs when backend becomes | |
36 | * writable. | |
37 | */ | |
38 | static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond, | |
39 | void *opaque) | |
40 | { | |
41 | VirtConsole *vcon = opaque; | |
42 | ||
c3d6b96e | 43 | vcon->watch = 0; |
0399a381 | 44 | virtio_serial_throttle_port(VIRTIO_SERIAL_PORT(vcon), false); |
7df4d457 AS |
45 | return FALSE; |
46 | } | |
98b19252 AS |
47 | |
48 | /* Callback function that's called when the guest sends us data */ | |
f9fb0532 HG |
49 | static ssize_t flush_buf(VirtIOSerialPort *port, |
50 | const uint8_t *buf, ssize_t len) | |
98b19252 | 51 | { |
0399a381 | 52 | VirtConsole *vcon = VIRTIO_CONSOLE(port); |
d02e4fa4 | 53 | ssize_t ret; |
98b19252 | 54 | |
30650701 | 55 | if (!qemu_chr_fe_backend_connected(&vcon->chr)) { |
6640422c AS |
56 | /* If there's no backend, we can just say we consumed all data. */ |
57 | return len; | |
58 | } | |
59 | ||
5345fdb4 | 60 | ret = qemu_chr_fe_write(&vcon->chr, buf, len); |
d02e4fa4 | 61 | trace_virtio_console_flush_buf(port->id, len, ret); |
0219d732 | 62 | |
f9fb0532 | 63 | if (ret < len) { |
d6258c93 AS |
64 | VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port); |
65 | ||
0219d732 AS |
66 | /* |
67 | * Ideally we'd get a better error code than just -1, but | |
68 | * that's what the chardev interface gives us right now. If | |
69 | * we had a finer-grained message, like -EPIPE, we could close | |
d6258c93 | 70 | * this connection. |
0219d732 | 71 | */ |
f9fb0532 HG |
72 | if (ret < 0) |
73 | ret = 0; | |
6ab3fc32 DB |
74 | |
75 | /* XXX we should be queuing data to send later for the | |
76 | * console devices too rather than silently dropping | |
77 | * console data on EAGAIN. The Linux virtio-console | |
78 | * hvc driver though does sends with spinlocks held, | |
79 | * so if we enable throttling that'll stall the entire | |
80 | * guest kernel, not merely the process writing to the | |
81 | * console. | |
82 | * | |
83 | * While we could queue data for later write without | |
84 | * enabling throttling, this would result in the guest | |
85 | * being able to trigger arbitrary memory usage in QEMU | |
86 | * buffering data for later writes. | |
87 | * | |
88 | * So fixing this problem likely requires fixing the | |
89 | * Linux virtio-console hvc driver to not hold spinlocks | |
90 | * while writing, and instead merely block the process | |
91 | * that's writing. QEMU would then need some way to detect | |
92 | * if the guest had the fixed driver too, before we can | |
93 | * use throttling on host side. | |
94 | */ | |
d6258c93 AS |
95 | if (!k->is_console) { |
96 | virtio_serial_throttle_port(port, true); | |
c3d6b96e | 97 | if (!vcon->watch) { |
5345fdb4 MAL |
98 | vcon->watch = qemu_chr_fe_add_watch(&vcon->chr, |
99 | G_IO_OUT|G_IO_HUP, | |
c3d6b96e HG |
100 | chr_write_unblocked, vcon); |
101 | } | |
d6258c93 | 102 | } |
0219d732 | 103 | } |
d02e4fa4 | 104 | return ret; |
98b19252 AS |
105 | } |
106 | ||
b2c1394a HG |
107 | /* Callback function that's called when the guest opens/closes the port */ |
108 | static void set_guest_connected(VirtIOSerialPort *port, int guest_connected) | |
0b6d2266 | 109 | { |
0399a381 | 110 | VirtConsole *vcon = VIRTIO_CONSOLE(port); |
e2ae6159 | 111 | DeviceState *dev = DEVICE(port); |
bce6261e | 112 | VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port); |
0b6d2266 | 113 | |
fa394ed6 | 114 | if (!k->is_console) { |
5345fdb4 | 115 | qemu_chr_fe_set_open(&vcon->chr, guest_connected); |
e2ae6159 LE |
116 | } |
117 | ||
118 | if (dev->id) { | |
3ab72385 | 119 | qapi_event_send_vserport_change(dev->id, guest_connected); |
6640422c | 120 | } |
0b6d2266 HG |
121 | } |
122 | ||
246ca55f MAL |
123 | static void guest_writable(VirtIOSerialPort *port) |
124 | { | |
125 | VirtConsole *vcon = VIRTIO_CONSOLE(port); | |
126 | ||
fa394ed6 | 127 | qemu_chr_fe_accept_input(&vcon->chr); |
246ca55f MAL |
128 | } |
129 | ||
98b19252 AS |
130 | /* Readiness of the guest to accept data on a port */ |
131 | static int chr_can_read(void *opaque) | |
132 | { | |
133 | VirtConsole *vcon = opaque; | |
134 | ||
0399a381 | 135 | return virtio_serial_guest_ready(VIRTIO_SERIAL_PORT(vcon)); |
98b19252 AS |
136 | } |
137 | ||
138 | /* Send data from a char device over to the guest */ | |
139 | static void chr_read(void *opaque, const uint8_t *buf, int size) | |
140 | { | |
141 | VirtConsole *vcon = opaque; | |
0399a381 | 142 | VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon); |
98b19252 | 143 | |
0399a381 AF |
144 | trace_virtio_console_chr_read(port->id, size); |
145 | virtio_serial_write(port, buf, size); | |
98b19252 AS |
146 | } |
147 | ||
083b266f | 148 | static void chr_event(void *opaque, QEMUChrEvent event) |
98b19252 AS |
149 | { |
150 | VirtConsole *vcon = opaque; | |
0399a381 | 151 | VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon); |
98b19252 | 152 | |
0399a381 | 153 | trace_virtio_console_chr_event(port->id, event); |
98b19252 | 154 | switch (event) { |
28eaf465 | 155 | case CHR_EVENT_OPENED: |
0399a381 | 156 | virtio_serial_open(port); |
98b19252 | 157 | break; |
98b19252 | 158 | case CHR_EVENT_CLOSED: |
c3d6b96e HG |
159 | if (vcon->watch) { |
160 | g_source_remove(vcon->watch); | |
161 | vcon->watch = 0; | |
162 | } | |
0399a381 | 163 | virtio_serial_close(port); |
98b19252 | 164 | break; |
3042bd34 PMD |
165 | case CHR_EVENT_BREAK: |
166 | case CHR_EVENT_MUX_IN: | |
167 | case CHR_EVENT_MUX_OUT: | |
168 | /* Ignore */ | |
169 | break; | |
98b19252 AS |
170 | } |
171 | } | |
172 | ||
af50855c AN |
173 | static int chr_be_change(void *opaque) |
174 | { | |
175 | VirtConsole *vcon = opaque; | |
176 | VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon); | |
177 | VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port); | |
178 | ||
179 | if (k->is_console) { | |
180 | qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read, | |
181 | NULL, chr_be_change, vcon, NULL, true); | |
182 | } else { | |
183 | qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read, | |
184 | chr_event, chr_be_change, vcon, NULL, false); | |
185 | } | |
186 | ||
187 | if (vcon->watch) { | |
188 | g_source_remove(vcon->watch); | |
189 | vcon->watch = qemu_chr_fe_add_watch(&vcon->chr, | |
190 | G_IO_OUT | G_IO_HUP, | |
191 | chr_write_unblocked, vcon); | |
192 | } | |
193 | ||
194 | return 0; | |
195 | } | |
196 | ||
55289fb0 PB |
197 | static void virtconsole_enable_backend(VirtIOSerialPort *port, bool enable) |
198 | { | |
199 | VirtConsole *vcon = VIRTIO_CONSOLE(port); | |
200 | ||
201 | if (!qemu_chr_fe_backend_connected(&vcon->chr)) { | |
202 | return; | |
203 | } | |
204 | ||
205 | if (enable) { | |
206 | VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port); | |
207 | ||
208 | qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read, | |
209 | k->is_console ? NULL : chr_event, | |
210 | chr_be_change, vcon, NULL, false); | |
211 | } else { | |
212 | qemu_chr_fe_set_handlers(&vcon->chr, NULL, NULL, NULL, | |
213 | NULL, NULL, NULL, false); | |
214 | } | |
215 | } | |
216 | ||
2ef66625 | 217 | static void virtconsole_realize(DeviceState *dev, Error **errp) |
98b19252 | 218 | { |
2ef66625 AF |
219 | VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev); |
220 | VirtConsole *vcon = VIRTIO_CONSOLE(dev); | |
221 | VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(dev); | |
a15bb0d6 | 222 | |
f82e35e3 | 223 | if (port->id == 0 && !k->is_console) { |
2ef66625 AF |
224 | error_setg(errp, "Port number 0 on virtio-serial devices reserved " |
225 | "for virtconsole devices for backward compatibility."); | |
226 | return; | |
7edfe652 MA |
227 | } |
228 | ||
30650701 | 229 | if (qemu_chr_fe_backend_connected(&vcon->chr)) { |
bce6261e DB |
230 | /* |
231 | * For consoles we don't block guest data transfer just | |
232 | * because nothing is connected - we'll just let it go | |
233 | * whetherever the chardev wants - /dev/null probably. | |
234 | * | |
235 | * For serial ports we need 100% reliable data transfer | |
236 | * so we use the opened/closed signals from chardev to | |
237 | * trigger open/close of the device | |
238 | */ | |
239 | if (k->is_console) { | |
5345fdb4 | 240 | qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read, |
af50855c AN |
241 | NULL, chr_be_change, |
242 | vcon, NULL, true); | |
bce6261e DB |
243 | virtio_serial_open(port); |
244 | } else { | |
5345fdb4 | 245 | qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read, |
af50855c AN |
246 | chr_event, chr_be_change, |
247 | vcon, NULL, false); | |
bce6261e | 248 | } |
98b19252 | 249 | } |
cbe77b61 AS |
250 | } |
251 | ||
2ef66625 | 252 | static void virtconsole_unrealize(DeviceState *dev, Error **errp) |
c3d6b96e | 253 | { |
2ef66625 | 254 | VirtConsole *vcon = VIRTIO_CONSOLE(dev); |
c3d6b96e HG |
255 | |
256 | if (vcon->watch) { | |
257 | g_source_remove(vcon->watch); | |
258 | } | |
c3d6b96e HG |
259 | } |
260 | ||
f82e35e3 AL |
261 | static void virtconsole_class_init(ObjectClass *klass, void *data) |
262 | { | |
263 | VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass); | |
264 | ||
265 | k->is_console = true; | |
f82e35e3 AL |
266 | } |
267 | ||
8c43a6f0 | 268 | static const TypeInfo virtconsole_info = { |
be21c336 AF |
269 | .name = "virtconsole", |
270 | .parent = TYPE_VIRTIO_CONSOLE_SERIAL_PORT, | |
39bffca2 | 271 | .class_init = virtconsole_class_init, |
98b19252 AS |
272 | }; |
273 | ||
f82e35e3 AL |
274 | static Property virtserialport_properties[] = { |
275 | DEFINE_PROP_CHR("chardev", VirtConsole, chr), | |
276 | DEFINE_PROP_END_OF_LIST(), | |
277 | }; | |
278 | ||
279 | static void virtserialport_class_init(ObjectClass *klass, void *data) | |
280 | { | |
39bffca2 | 281 | DeviceClass *dc = DEVICE_CLASS(klass); |
f82e35e3 AL |
282 | VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_CLASS(klass); |
283 | ||
2ef66625 AF |
284 | k->realize = virtconsole_realize; |
285 | k->unrealize = virtconsole_unrealize; | |
f82e35e3 | 286 | k->have_data = flush_buf; |
b2c1394a | 287 | k->set_guest_connected = set_guest_connected; |
55289fb0 | 288 | k->enable_backend = virtconsole_enable_backend; |
246ca55f | 289 | k->guest_writable = guest_writable; |
4f67d30b | 290 | device_class_set_props(dc, virtserialport_properties); |
f82e35e3 AL |
291 | } |
292 | ||
8c43a6f0 | 293 | static const TypeInfo virtserialport_info = { |
be21c336 | 294 | .name = TYPE_VIRTIO_CONSOLE_SERIAL_PORT, |
39bffca2 AL |
295 | .parent = TYPE_VIRTIO_SERIAL_PORT, |
296 | .instance_size = sizeof(VirtConsole), | |
297 | .class_init = virtserialport_class_init, | |
b60c470b AS |
298 | }; |
299 | ||
83f7d43a | 300 | static void virtconsole_register_types(void) |
b60c470b | 301 | { |
39bffca2 | 302 | type_register_static(&virtserialport_info); |
be21c336 | 303 | type_register_static(&virtconsole_info); |
b60c470b | 304 | } |
83f7d43a AF |
305 | |
306 | type_init(virtconsole_register_types) |