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68396ea @rmustacc Initial commit of d32e8d0b8d9e0ef7cf7ab2e74548982972789dfc from qemu-kvm
rmustacc authored
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 <stdlib.h>
23 #include <errno.h>
24 #include <string.h>
25 #include <sys/select.h>
26 #include <fcntl.h>
27 #include <unistd.h>
28 #include <termios.h>
29 #include <stdarg.h>
30 #include <sys/mman.h>
31 #include <xs.h>
32 #include <xen/io/console.h>
33 #include <xenctrl.h>
34
35 #include "hw.h"
36 #include "sysemu.h"
37 #include "qemu-char.h"
38 #include "xen_backend.h"
39
40 struct buffer {
41 uint8_t *data;
42 size_t consumed;
43 size_t size;
44 size_t capacity;
45 size_t max_capacity;
46 };
47
48 struct XenConsole {
49 struct XenDevice xendev; /* must be first */
50 struct buffer buffer;
51 char console[XEN_BUFSIZE];
52 int ring_ref;
53 void *sring;
54 CharDriverState *chr;
55 int backlog;
56 };
57
58 static void buffer_append(struct XenConsole *con)
59 {
60 struct buffer *buffer = &con->buffer;
61 XENCONS_RING_IDX cons, prod, size;
62 struct xencons_interface *intf = con->sring;
63
64 cons = intf->out_cons;
65 prod = intf->out_prod;
66 xen_mb();
67
68 size = prod - cons;
69 if ((size == 0) || (size > sizeof(intf->out)))
70 return;
71
72 if ((buffer->capacity - buffer->size) < size) {
73 buffer->capacity += (size + 1024);
74 buffer->data = qemu_realloc(buffer->data, buffer->capacity);
75 }
76
77 while (cons != prod)
78 buffer->data[buffer->size++] = intf->out[
79 MASK_XENCONS_IDX(cons++, intf->out)];
80
81 xen_mb();
82 intf->out_cons = cons;
83 xen_be_send_notify(&con->xendev);
84
85 if (buffer->max_capacity &&
86 buffer->size > buffer->max_capacity) {
87 /* Discard the middle of the data. */
88
89 size_t over = buffer->size - buffer->max_capacity;
90 uint8_t *maxpos = buffer->data + buffer->max_capacity;
91
92 memmove(maxpos - over, maxpos, over);
93 buffer->data = qemu_realloc(buffer->data, buffer->max_capacity);
94 buffer->size = buffer->capacity = buffer->max_capacity;
95
96 if (buffer->consumed > buffer->max_capacity - over)
97 buffer->consumed = buffer->max_capacity - over;
98 }
99 }
100
101 static void buffer_advance(struct buffer *buffer, size_t len)
102 {
103 buffer->consumed += len;
104 if (buffer->consumed == buffer->size) {
105 buffer->consumed = 0;
106 buffer->size = 0;
107 }
108 }
109
110 static int ring_free_bytes(struct XenConsole *con)
111 {
112 struct xencons_interface *intf = con->sring;
113 XENCONS_RING_IDX cons, prod, space;
114
115 cons = intf->in_cons;
116 prod = intf->in_prod;
117 xen_mb();
118
119 space = prod - cons;
120 if (space > sizeof(intf->in))
121 return 0; /* ring is screwed: ignore it */
122
123 return (sizeof(intf->in) - space);
124 }
125
126 static int xencons_can_receive(void *opaque)
127 {
128 struct XenConsole *con = opaque;
129 return ring_free_bytes(con);
130 }
131
132 static void xencons_receive(void *opaque, const uint8_t *buf, int len)
133 {
134 struct XenConsole *con = opaque;
135 struct xencons_interface *intf = con->sring;
136 XENCONS_RING_IDX prod;
137 int i, max;
138
139 max = ring_free_bytes(con);
140 /* The can_receive() func limits this, but check again anyway */
141 if (max < len)
142 len = max;
143
144 prod = intf->in_prod;
145 for (i = 0; i < len; i++) {
146 intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
147 buf[i];
148 }
149 xen_wmb();
150 intf->in_prod = prod;
151 xen_be_send_notify(&con->xendev);
152 }
153
154 static void xencons_send(struct XenConsole *con)
155 {
156 ssize_t len, size;
157
158 size = con->buffer.size - con->buffer.consumed;
159 if (con->chr)
160 len = qemu_chr_write(con->chr, con->buffer.data + con->buffer.consumed,
161 size);
162 else
163 len = size;
164 if (len < 1) {
165 if (!con->backlog) {
166 con->backlog = 1;
167 xen_be_printf(&con->xendev, 1, "backlog piling up, nobody listening?\n");
168 }
169 } else {
170 buffer_advance(&con->buffer, len);
171 if (con->backlog && len == size) {
172 con->backlog = 0;
173 xen_be_printf(&con->xendev, 1, "backlog is gone\n");
174 }
175 }
176 }
177
178 /* -------------------------------------------------------------------- */
179
180 static int con_init(struct XenDevice *xendev)
181 {
182 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
183 char *type, *dom;
184
185 /* setup */
186 dom = xs_get_domain_path(xenstore, con->xendev.dom);
187 snprintf(con->console, sizeof(con->console), "%s/console", dom);
188 free(dom);
189
190 type = xenstore_read_str(con->console, "type");
191 if (!type || strcmp(type, "ioemu") != 0) {
192 xen_be_printf(xendev, 1, "not for me (type=%s)\n", type);
193 return -1;
194 }
195
196 if (!serial_hds[con->xendev.dev])
197 xen_be_printf(xendev, 1, "WARNING: serial line %d not configured\n",
198 con->xendev.dev);
199 else
200 con->chr = serial_hds[con->xendev.dev];
201
202 return 0;
203 }
204
205 static int con_connect(struct XenDevice *xendev)
206 {
207 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
208 int limit;
209
210 if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
211 return -1;
212 if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
213 return -1;
214 if (xenstore_read_int(con->console, "limit", &limit) == 0)
215 con->buffer.max_capacity = limit;
216
217 con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom,
218 XC_PAGE_SIZE,
219 PROT_READ|PROT_WRITE,
220 con->ring_ref);
221 if (!con->sring)
222 return -1;
223
224 xen_be_bind_evtchn(&con->xendev);
225 if (con->chr)
226 qemu_chr_add_handlers(con->chr, xencons_can_receive, xencons_receive,
227 NULL, con);
228
229 xen_be_printf(xendev, 1, "ring mfn %d, remote port %d, local port %d, limit %zd\n",
230 con->ring_ref,
231 con->xendev.remote_port,
232 con->xendev.local_port,
233 con->buffer.max_capacity);
234 return 0;
235 }
236
237 static void con_disconnect(struct XenDevice *xendev)
238 {
239 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
240
241 if (con->chr)
242 qemu_chr_add_handlers(con->chr, NULL, NULL, NULL, NULL);
243 xen_be_unbind_evtchn(&con->xendev);
244
245 if (con->sring) {
246 munmap(con->sring, XC_PAGE_SIZE);
247 con->sring = NULL;
248 }
249 }
250
251 static void con_event(struct XenDevice *xendev)
252 {
253 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
254
255 buffer_append(con);
256 if (con->buffer.size - con->buffer.consumed)
257 xencons_send(con);
258 }
259
260 /* -------------------------------------------------------------------- */
261
262 struct XenDevOps xen_console_ops = {
263 .size = sizeof(struct XenConsole),
264 .flags = DEVOPS_FLAG_IGNORE_STATE,
265 .init = con_init,
266 .connect = con_connect,
267 .event = con_event,
268 .disconnect = con_disconnect,
269 };
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