xref: /openbmc/qemu/hw/char/sclpconsole-lm.c (revision a23797ef) 
1 /*
2  * SCLP event types
3  *    Operations Command - Line Mode input
4  *    Message            - Line Mode output
5  *
6  * Copyright IBM, Corp. 2013
7  *
8  * Authors:
9  *  Heinz Graalfs <graalfs@linux.vnet.ibm.com>
10  *
11  * This work is licensed under the terms of the GNU GPL, version 2 or (at your
12  * option) any later version.  See the COPYING file in the top-level directory.
13  *
14  */
15 
16 #include "hw/qdev.h"
17 #include "qemu/thread.h"
18 #include "qemu/error-report.h"
19 #include "sysemu/char.h"
20 
21 #include "hw/s390x/sclp.h"
22 #include "hw/s390x/event-facility.h"
23 #include "hw/s390x/ebcdic.h"
24 
25 #define SIZE_BUFFER 4096
26 #define NEWLINE     "\n"
27 
28 typedef struct OprtnsCommand {
29     EventBufferHeader header;
30     MDMSU message_unit;
31     char data[0];
32 } QEMU_PACKED OprtnsCommand;
33 
34 /* max size for line-mode data in 4K SCCB page */
35 #define SIZE_CONSOLE_BUFFER (SCCB_DATA_LEN - sizeof(OprtnsCommand))
36 
37 typedef struct SCLPConsoleLM {
38     SCLPEvent event;
39     CharDriverState *chr;
40     bool echo;                  /* immediate echo of input if true        */
41     uint32_t write_errors;      /* errors writing to char layer           */
42     uint32_t length;            /* length of byte stream in buffer        */
43     uint8_t buf[SIZE_CONSOLE_BUFFER];
44 } SCLPConsoleLM;
45 
46 /*
47 *  Character layer call-back functions
48  *
49  * Allow 1 character at a time
50  *
51  * Accumulate bytes from character layer in console buffer,
52  * event_pending is set when a newline character is encountered
53  *
54  * The maximum command line length is limited by the maximum
55  * space available in an SCCB. Line mode console input is sent
56  * truncated to the guest in case it doesn't fit into the SCCB.
57  */
58 
59 static int chr_can_read(void *opaque)
60 {
61     SCLPConsoleLM *scon = opaque;
62 
63     if (scon->event.event_pending) {
64         return 0;
65     }
66     return 1;
67 }
68 
69 static void chr_read(void *opaque, const uint8_t *buf, int size)
70 {
71     SCLPConsoleLM *scon = opaque;
72 
73     assert(size == 1);
74 
75     if (*buf == '\r' || *buf == '\n') {
76         scon->event.event_pending = true;
77         sclp_service_interrupt(0);
78         return;
79     }
80     if (scon->length == SIZE_CONSOLE_BUFFER) {
81         /* Eat the character, but still process CR and LF.  */
82         return;
83     }
84     scon->buf[scon->length] = *buf;
85     scon->length += 1;
86     if (scon->echo) {
87         qemu_chr_fe_write(scon->chr, buf, size);
88     }
89 }
90 
91 /* functions to be called by event facility */
92 
93 static bool can_handle_event(uint8_t type)
94 {
95     return type == SCLP_EVENT_MESSAGE || type == SCLP_EVENT_PMSGCMD;
96 }
97 
98 static unsigned int send_mask(void)
99 {
100     return SCLP_EVENT_MASK_OP_CMD | SCLP_EVENT_MASK_PMSGCMD;
101 }
102 
103 static unsigned int receive_mask(void)
104 {
105     return SCLP_EVENT_MASK_MSG | SCLP_EVENT_MASK_PMSGCMD;
106 }
107 
108 /*
109  * Triggered by SCLP's read_event_data
110  * - convert ASCII byte stream to EBCDIC and
111  * - copy converted data into provided (SCLP) buffer
112  */
113 static int get_console_data(SCLPEvent *event, uint8_t *buf, size_t *size,
114                             int avail)
115 {
116     int len;
117 
118     SCLPConsoleLM *cons = DO_UPCAST(SCLPConsoleLM, event, event);
119 
120     len = cons->length;
121     /* data need to fit into provided SCLP buffer */
122     if (len > avail) {
123         return 1;
124     }
125 
126     ebcdic_put(buf, (char *)&cons->buf, len);
127     *size = len;
128     cons->length = 0;
129     /* data provided and no more data pending */
130     event->event_pending = false;
131     qemu_notify_event();
132     return 0;
133 }
134 
135 static int read_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr,
136                            int *slen)
137 {
138     int avail, rc;
139     size_t src_len;
140     uint8_t *to;
141     OprtnsCommand *oc = (OprtnsCommand *) evt_buf_hdr;
142 
143     if (!event->event_pending) {
144         /* no data pending */
145         return 0;
146     }
147 
148     to = (uint8_t *)&oc->data;
149     avail = *slen - sizeof(OprtnsCommand);
150     rc = get_console_data(event, to, &src_len, avail);
151     if (rc) {
152         /* data didn't fit, try next SCCB */
153         return 1;
154     }
155 
156     oc->message_unit.mdmsu.gds_id = GDS_ID_MDSMU;
157     oc->message_unit.mdmsu.length = cpu_to_be16(sizeof(struct MDMSU));
158 
159     oc->message_unit.cpmsu.gds_id = GDS_ID_CPMSU;
160     oc->message_unit.cpmsu.length =
161         cpu_to_be16(sizeof(struct MDMSU) - sizeof(GdsVector));
162 
163     oc->message_unit.text_command.gds_id = GDS_ID_TEXTCMD;
164     oc->message_unit.text_command.length =
165         cpu_to_be16(sizeof(struct MDMSU) - (2 * sizeof(GdsVector)));
166 
167     oc->message_unit.self_def_text_message.key = GDS_KEY_SELFDEFTEXTMSG;
168     oc->message_unit.self_def_text_message.length =
169         cpu_to_be16(sizeof(struct MDMSU) - (3 * sizeof(GdsVector)));
170 
171     oc->message_unit.text_message.key = GDS_KEY_TEXTMSG;
172     oc->message_unit.text_message.length =
173         cpu_to_be16(sizeof(GdsSubvector) + src_len);
174 
175     oc->header.length = cpu_to_be16(sizeof(OprtnsCommand) + src_len);
176     oc->header.type = SCLP_EVENT_OPRTNS_COMMAND;
177     *slen = avail - src_len;
178 
179     return 1;
180 }
181 
182 /*
183  * Triggered by SCLP's write_event_data
184  *  - write console data to character layer
185  *  returns < 0 if an error occurred
186  */
187 static int write_console_data(SCLPEvent *event, const uint8_t *buf, int len)
188 {
189     int ret = 0;
190     const uint8_t *buf_offset;
191 
192     SCLPConsoleLM *scon = DO_UPCAST(SCLPConsoleLM, event, event);
193 
194     if (!scon->chr) {
195         /* If there's no backend, we can just say we consumed all data. */
196         return len;
197     }
198 
199     buf_offset = buf;
200     while (len > 0) {
201         ret = qemu_chr_fe_write(scon->chr, buf, len);
202         if (ret == 0) {
203             /* a pty doesn't seem to be connected - no error */
204             len = 0;
205         } else if (ret == -EAGAIN || (ret > 0 && ret < len)) {
206             len -= ret;
207             buf_offset += ret;
208         } else {
209             len = 0;
210         }
211     }
212 
213     return ret;
214 }
215 
216 static int process_mdb(SCLPEvent *event, MDBO *mdbo)
217 {
218     int rc;
219     int len;
220     uint8_t buffer[SIZE_BUFFER];
221 
222     len = be16_to_cpu(mdbo->length);
223     len -= sizeof(mdbo->length) + sizeof(mdbo->type)
224             + sizeof(mdbo->mto.line_type_flags)
225             + sizeof(mdbo->mto.alarm_control)
226             + sizeof(mdbo->mto._reserved);
227 
228     assert(len <= SIZE_BUFFER);
229 
230     /* convert EBCDIC SCLP contents to ASCII console message */
231     ascii_put(buffer, mdbo->mto.message, len);
232     rc = write_console_data(event, (uint8_t *)NEWLINE, 1);
233     if (rc < 0) {
234         return rc;
235     }
236     return write_console_data(event, buffer, len);
237 }
238 
239 static int write_event_data(SCLPEvent *event, EventBufferHeader *ebh)
240 {
241     int len;
242     int written;
243     int errors = 0;
244     MDBO *mdbo;
245     SclpMsg *data = (SclpMsg *) ebh;
246     SCLPConsoleLM *scon = DO_UPCAST(SCLPConsoleLM, event, event);
247 
248     len = be16_to_cpu(data->mdb.header.length);
249     if (len < sizeof(data->mdb.header)) {
250         return SCLP_RC_INCONSISTENT_LENGTHS;
251     }
252     len -= sizeof(data->mdb.header);
253 
254     /* first check message buffers */
255     mdbo = data->mdb.mdbo;
256     while (len > 0) {
257         if (be16_to_cpu(mdbo->length) > len
258                 || be16_to_cpu(mdbo->length) == 0) {
259             return SCLP_RC_INCONSISTENT_LENGTHS;
260         }
261         len -= be16_to_cpu(mdbo->length);
262         mdbo = (void *) mdbo + be16_to_cpu(mdbo->length);
263     }
264 
265     /* then execute */
266     len = be16_to_cpu(data->mdb.header.length) - sizeof(data->mdb.header);
267     mdbo = data->mdb.mdbo;
268     while (len > 0) {
269         switch (be16_to_cpu(mdbo->type)) {
270         case MESSAGE_TEXT:
271             /* message text object */
272             written = process_mdb(event, mdbo);
273             if (written < 0) {
274                 /* character layer error */
275                 errors++;
276             }
277             break;
278         default: /* ignore */
279             break;
280         }
281         len -= be16_to_cpu(mdbo->length);
282         mdbo = (void *) mdbo + be16_to_cpu(mdbo->length);
283     }
284     if (errors) {
285         scon->write_errors += errors;
286     }
287     data->header.flags = SCLP_EVENT_BUFFER_ACCEPTED;
288 
289     return SCLP_RC_NORMAL_COMPLETION;
290 }
291 
292 /* functions for live migration */
293 
294 static const VMStateDescription vmstate_sclplmconsole = {
295     .name = "sclplmconsole",
296     .version_id = 0,
297     .minimum_version_id = 0,
298     .fields = (VMStateField[]) {
299         VMSTATE_BOOL(event.event_pending, SCLPConsoleLM),
300         VMSTATE_UINT32(write_errors, SCLPConsoleLM),
301         VMSTATE_UINT32(length, SCLPConsoleLM),
302         VMSTATE_UINT8_ARRAY(buf, SCLPConsoleLM, SIZE_CONSOLE_BUFFER),
303         VMSTATE_END_OF_LIST()
304      }
305 };
306 
307 /* qemu object creation and initialization functions */
308 
309 /* tell character layer our call-back functions */
310 
311 static int console_init(SCLPEvent *event)
312 {
313     static bool console_available;
314 
315     SCLPConsoleLM *scon = DO_UPCAST(SCLPConsoleLM, event, event);
316 
317     if (console_available) {
318         error_report("Multiple line-mode operator consoles are not supported");
319         return -1;
320     }
321     console_available = true;
322 
323     if (scon->chr) {
324         qemu_chr_add_handlers(scon->chr, chr_can_read, chr_read, NULL, scon);
325     }
326 
327     return 0;
328 }
329 
330 static int console_exit(SCLPEvent *event)
331 {
332     return 0;
333 }
334 
335 static void console_reset(DeviceState *dev)
336 {
337    SCLPEvent *event = SCLP_EVENT(dev);
338    SCLPConsoleLM *scon = DO_UPCAST(SCLPConsoleLM, event, event);
339 
340    event->event_pending = false;
341    scon->length = 0;
342    scon->write_errors = 0;
343 }
344 
345 static Property console_properties[] = {
346     DEFINE_PROP_CHR("chardev", SCLPConsoleLM, chr),
347     DEFINE_PROP_UINT32("write_errors", SCLPConsoleLM, write_errors, 0),
348     DEFINE_PROP_BOOL("echo", SCLPConsoleLM, echo, true),
349     DEFINE_PROP_END_OF_LIST(),
350 };
351 
352 static void console_class_init(ObjectClass *klass, void *data)
353 {
354     DeviceClass *dc = DEVICE_CLASS(klass);
355     SCLPEventClass *ec = SCLP_EVENT_CLASS(klass);
356 
357     dc->props = console_properties;
358     dc->reset = console_reset;
359     dc->vmsd = &vmstate_sclplmconsole;
360     ec->init = console_init;
361     ec->exit = console_exit;
362     ec->get_send_mask = send_mask;
363     ec->get_receive_mask = receive_mask;
364     ec->can_handle_event = can_handle_event;
365     ec->read_event_data = read_event_data;
366     ec->write_event_data = write_event_data;
367     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
368 }
369 
370 static const TypeInfo sclp_console_info = {
371     .name          = "sclplmconsole",
372     .parent        = TYPE_SCLP_EVENT,
373     .instance_size = sizeof(SCLPConsoleLM),
374     .class_init    = console_class_init,
375     .class_size    = sizeof(SCLPEventClass),
376 };
377 
378 static void register_types(void)
379 {
380     type_register_static(&sclp_console_info);
381 }
382 
383 type_init(register_types)
384