Merge remote-tracking branch 'remotes/philmd-gitlab/tags/renesas-20201027' into staging
[qemu.git] / hw / char / xen_console.c
1 /*
2 * Copyright (C) International Business Machines Corp., 2005
3 * Author(s): Anthony Liguori <aliguori@us.ibm.com>
4 *
5 * Copyright (C) Red Hat 2007
6 *
7 * Xen Console
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; under version 2 of the License.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, see <http://www.gnu.org/licenses/>.
20 */
21
22 #include "qemu/osdep.h"
23 #include <sys/select.h>
24 #include <termios.h>
25
26 #include "qapi/error.h"
27 #include "sysemu/sysemu.h"
28 #include "chardev/char-fe.h"
29 #include "hw/xen/xen-legacy-backend.h"
30
31 #include "hw/xen/interface/io/console.h"
32
33 struct buffer {
34 uint8_t *data;
35 size_t consumed;
36 size_t size;
37 size_t capacity;
38 size_t max_capacity;
39 };
40
41 struct XenConsole {
42 struct XenLegacyDevice xendev; /* must be first */
43 struct buffer buffer;
44 char console[XEN_BUFSIZE];
45 int ring_ref;
46 void *sring;
47 CharBackend chr;
48 int backlog;
49 };
50
51 static void buffer_append(struct XenConsole *con)
52 {
53 struct buffer *buffer = &con->buffer;
54 XENCONS_RING_IDX cons, prod, size;
55 struct xencons_interface *intf = con->sring;
56
57 cons = intf->out_cons;
58 prod = intf->out_prod;
59 xen_mb();
60
61 size = prod - cons;
62 if ((size == 0) || (size > sizeof(intf->out)))
63 return;
64
65 if ((buffer->capacity - buffer->size) < size) {
66 buffer->capacity += (size + 1024);
67 buffer->data = g_realloc(buffer->data, buffer->capacity);
68 }
69
70 while (cons != prod)
71 buffer->data[buffer->size++] = intf->out[
72 MASK_XENCONS_IDX(cons++, intf->out)];
73
74 xen_mb();
75 intf->out_cons = cons;
76 xen_pv_send_notify(&con->xendev);
77
78 if (buffer->max_capacity &&
79 buffer->size > buffer->max_capacity) {
80 /* Discard the middle of the data. */
81
82 size_t over = buffer->size - buffer->max_capacity;
83 uint8_t *maxpos = buffer->data + buffer->max_capacity;
84
85 memmove(maxpos - over, maxpos, over);
86 buffer->data = g_realloc(buffer->data, buffer->max_capacity);
87 buffer->size = buffer->capacity = buffer->max_capacity;
88
89 if (buffer->consumed > buffer->max_capacity - over)
90 buffer->consumed = buffer->max_capacity - over;
91 }
92 }
93
94 static void buffer_advance(struct buffer *buffer, size_t len)
95 {
96 buffer->consumed += len;
97 if (buffer->consumed == buffer->size) {
98 buffer->consumed = 0;
99 buffer->size = 0;
100 }
101 }
102
103 static int ring_free_bytes(struct XenConsole *con)
104 {
105 struct xencons_interface *intf = con->sring;
106 XENCONS_RING_IDX cons, prod, space;
107
108 cons = intf->in_cons;
109 prod = intf->in_prod;
110 xen_mb();
111
112 space = prod - cons;
113 if (space > sizeof(intf->in))
114 return 0; /* ring is screwed: ignore it */
115
116 return (sizeof(intf->in) - space);
117 }
118
119 static int xencons_can_receive(void *opaque)
120 {
121 struct XenConsole *con = opaque;
122 return ring_free_bytes(con);
123 }
124
125 static void xencons_receive(void *opaque, const uint8_t *buf, int len)
126 {
127 struct XenConsole *con = opaque;
128 struct xencons_interface *intf = con->sring;
129 XENCONS_RING_IDX prod;
130 int i, max;
131
132 max = ring_free_bytes(con);
133 /* The can_receive() func limits this, but check again anyway */
134 if (max < len)
135 len = max;
136
137 prod = intf->in_prod;
138 for (i = 0; i < len; i++) {
139 intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
140 buf[i];
141 }
142 xen_wmb();
143 intf->in_prod = prod;
144 xen_pv_send_notify(&con->xendev);
145 }
146
147 static void xencons_send(struct XenConsole *con)
148 {
149 ssize_t len, size;
150
151 size = con->buffer.size - con->buffer.consumed;
152 if (qemu_chr_fe_backend_connected(&con->chr)) {
153 len = qemu_chr_fe_write(&con->chr,
154 con->buffer.data + con->buffer.consumed,
155 size);
156 } else {
157 len = size;
158 }
159 if (len < 1) {
160 if (!con->backlog) {
161 con->backlog = 1;
162 xen_pv_printf(&con->xendev, 1,
163 "backlog piling up, nobody listening?\n");
164 }
165 } else {
166 buffer_advance(&con->buffer, len);
167 if (con->backlog && len == size) {
168 con->backlog = 0;
169 xen_pv_printf(&con->xendev, 1, "backlog is gone\n");
170 }
171 }
172 }
173
174 /* -------------------------------------------------------------------- */
175
176 static int con_init(struct XenLegacyDevice *xendev)
177 {
178 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
179 char *type, *dom, label[32];
180 int ret = 0;
181 const char *output;
182
183 /* setup */
184 dom = xs_get_domain_path(xenstore, con->xendev.dom);
185 if (!xendev->dev) {
186 snprintf(con->console, sizeof(con->console), "%s/console", dom);
187 } else {
188 snprintf(con->console, sizeof(con->console), "%s/device/console/%d", dom, xendev->dev);
189 }
190 free(dom);
191
192 type = xenstore_read_str(con->console, "type");
193 if (!type || strcmp(type, "ioemu") != 0) {
194 xen_pv_printf(xendev, 1, "not for me (type=%s)\n", type);
195 ret = -1;
196 goto out;
197 }
198
199 output = xenstore_read_str(con->console, "output");
200
201 /* no Xen override, use qemu output device */
202 if (output == NULL) {
203 if (con->xendev.dev) {
204 qemu_chr_fe_init(&con->chr, serial_hd(con->xendev.dev),
205 &error_abort);
206 }
207 } else {
208 snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
209 qemu_chr_fe_init(&con->chr,
210 /*
211 * FIXME: sure we want to support implicit
212 * muxed monitors here?
213 */
214 qemu_chr_new_mux_mon(label, output, NULL),
215 &error_abort);
216 }
217
218 xenstore_store_pv_console_info(con->xendev.dev,
219 qemu_chr_fe_get_driver(&con->chr));
220
221 out:
222 g_free(type);
223 return ret;
224 }
225
226 static int con_initialise(struct XenLegacyDevice *xendev)
227 {
228 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
229 int limit;
230
231 if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
232 return -1;
233 if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
234 return -1;
235 if (xenstore_read_int(con->console, "limit", &limit) == 0)
236 con->buffer.max_capacity = limit;
237
238 if (!xendev->dev) {
239 xen_pfn_t mfn = con->ring_ref;
240 con->sring = xenforeignmemory_map(xen_fmem, con->xendev.dom,
241 PROT_READ | PROT_WRITE,
242 1, &mfn, NULL);
243 } else {
244 con->sring = xen_be_map_grant_ref(xendev, con->ring_ref,
245 PROT_READ | PROT_WRITE);
246 }
247 if (!con->sring)
248 return -1;
249
250 xen_be_bind_evtchn(&con->xendev);
251 qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
252 xencons_receive, NULL, NULL, con, NULL, true);
253
254 xen_pv_printf(xendev, 1,
255 "ring mfn %d, remote port %d, local port %d, limit %zd\n",
256 con->ring_ref,
257 con->xendev.remote_port,
258 con->xendev.local_port,
259 con->buffer.max_capacity);
260 return 0;
261 }
262
263 static void con_disconnect(struct XenLegacyDevice *xendev)
264 {
265 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
266
267 qemu_chr_fe_deinit(&con->chr, false);
268 xen_pv_unbind_evtchn(&con->xendev);
269
270 if (con->sring) {
271 if (!xendev->dev) {
272 xenforeignmemory_unmap(xen_fmem, con->sring, 1);
273 } else {
274 xen_be_unmap_grant_ref(xendev, con->sring);
275 }
276 con->sring = NULL;
277 }
278 }
279
280 static void con_event(struct XenLegacyDevice *xendev)
281 {
282 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
283
284 buffer_append(con);
285 if (con->buffer.size - con->buffer.consumed)
286 xencons_send(con);
287 }
288
289 /* -------------------------------------------------------------------- */
290
291 struct XenDevOps xen_console_ops = {
292 .size = sizeof(struct XenConsole),
293 .flags = DEVOPS_FLAG_IGNORE_STATE|DEVOPS_FLAG_NEED_GNTDEV,
294 .init = con_init,
295 .initialise = con_initialise,
296 .event = con_event,
297 .disconnect = con_disconnect,
298 };