xref: /openbmc/qemu/hw/tpm/tpm_tis_common.c (revision efb91426)
1 /*
2  * tpm_tis_common.c - QEMU's TPM TIS interface emulator
3  * device agnostic functions
4  *
5  * Copyright (C) 2006,2010-2013 IBM Corporation
6  *
7  * Authors:
8  *  Stefan Berger <stefanb@us.ibm.com>
9  *  David Safford <safford@us.ibm.com>
10  *
11  * Xen 4 support: Andrease Niederl <andreas.niederl@iaik.tugraz.at>
12  *
13  * This work is licensed under the terms of the GNU GPL, version 2 or later.
14  * See the COPYING file in the top-level directory.
15  *
16  * Implementation of the TIS interface according to specs found at
17  * http://www.trustedcomputinggroup.org. This implementation currently
18  * supports version 1.3, 21 March 2013
19  * In the developers menu choose the PC Client section then find the TIS
20  * specification.
21  *
22  * TPM TIS for TPM 2 implementation following TCG PC Client Platform
23  * TPM Profile (PTP) Specification, Family 2.0, Revision 00.43
24  */
25 #include "qemu/osdep.h"
26 #include "hw/irq.h"
27 #include "hw/isa/isa.h"
28 #include "qapi/error.h"
29 #include "qemu/bswap.h"
30 #include "qemu/crc-ccitt.h"
31 #include "qemu/module.h"
32 
33 #include "hw/acpi/tpm.h"
34 #include "hw/pci/pci_ids.h"
35 #include "hw/qdev-properties.h"
36 #include "migration/vmstate.h"
37 #include "sysemu/tpm_backend.h"
38 #include "sysemu/tpm_util.h"
39 #include "tpm_ppi.h"
40 #include "trace.h"
41 
42 #include "tpm_tis.h"
43 
44 #define DEBUG_TIS 0
45 
46 /* local prototypes */
47 
48 static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr addr,
49                                   unsigned size);
50 
51 /* utility functions */
52 
53 static uint8_t tpm_tis_locality_from_addr(hwaddr addr)
54 {
55     uint8_t locty;
56 
57     locty = (uint8_t)((addr >> TPM_TIS_LOCALITY_SHIFT) & 0x7);
58     assert(TPM_TIS_IS_VALID_LOCTY(locty));
59 
60     return locty;
61 }
62 
63 
64 /*
65  * Set the given flags in the STS register by clearing the register but
66  * preserving the SELFTEST_DONE and TPM_FAMILY_MASK flags and then setting
67  * the new flags.
68  *
69  * The SELFTEST_DONE flag is acquired from the backend that determines it by
70  * peeking into TPM commands.
71  *
72  * A VM suspend/resume will preserve the flag by storing it into the VM
73  * device state, but the backend will not remember it when QEMU is started
74  * again. Therefore, we cache the flag here. Once set, it will not be unset
75  * except by a reset.
76  */
77 static void tpm_tis_sts_set(TPMLocality *l, uint32_t flags)
78 {
79     l->sts &= TPM_TIS_STS_SELFTEST_DONE | TPM_TIS_STS_TPM_FAMILY_MASK;
80     l->sts |= flags;
81 }
82 
83 /*
84  * Send a request to the TPM.
85  */
86 static void tpm_tis_tpm_send(TPMState *s, uint8_t locty)
87 {
88     tpm_util_show_buffer(s->buffer, s->be_buffer_size, "To TPM");
89 
90     /*
91      * rw_offset serves as length indicator for length of data;
92      * it's reset when the response comes back
93      */
94     s->loc[locty].state = TPM_TIS_STATE_EXECUTION;
95 
96     s->cmd = (TPMBackendCmd) {
97         .locty = locty,
98         .in = s->buffer,
99         .in_len = s->rw_offset,
100         .out = s->buffer,
101         .out_len = s->be_buffer_size,
102     };
103 
104     tpm_backend_deliver_request(s->be_driver, &s->cmd);
105 }
106 
107 /* raise an interrupt if allowed */
108 static void tpm_tis_raise_irq(TPMState *s, uint8_t locty, uint32_t irqmask)
109 {
110     if (!TPM_TIS_IS_VALID_LOCTY(locty)) {
111         return;
112     }
113 
114     if ((s->loc[locty].inte & TPM_TIS_INT_ENABLED) &&
115         (s->loc[locty].inte & irqmask)) {
116         trace_tpm_tis_raise_irq(irqmask);
117         qemu_irq_raise(s->irq);
118         s->loc[locty].ints |= irqmask;
119     }
120 }
121 
122 static uint32_t tpm_tis_check_request_use_except(TPMState *s, uint8_t locty)
123 {
124     uint8_t l;
125 
126     for (l = 0; l < TPM_TIS_NUM_LOCALITIES; l++) {
127         if (l == locty) {
128             continue;
129         }
130         if ((s->loc[l].access & TPM_TIS_ACCESS_REQUEST_USE)) {
131             return 1;
132         }
133     }
134 
135     return 0;
136 }
137 
138 static void tpm_tis_new_active_locality(TPMState *s, uint8_t new_active_locty)
139 {
140     bool change = (s->active_locty != new_active_locty);
141     bool is_seize;
142     uint8_t mask;
143 
144     if (change && TPM_TIS_IS_VALID_LOCTY(s->active_locty)) {
145         is_seize = TPM_TIS_IS_VALID_LOCTY(new_active_locty) &&
146                    s->loc[new_active_locty].access & TPM_TIS_ACCESS_SEIZE;
147 
148         if (is_seize) {
149             mask = ~(TPM_TIS_ACCESS_ACTIVE_LOCALITY);
150         } else {
151             mask = ~(TPM_TIS_ACCESS_ACTIVE_LOCALITY|
152                      TPM_TIS_ACCESS_REQUEST_USE);
153         }
154         /* reset flags on the old active locality */
155         s->loc[s->active_locty].access &= mask;
156 
157         if (is_seize) {
158             s->loc[s->active_locty].access |= TPM_TIS_ACCESS_BEEN_SEIZED;
159         }
160     }
161 
162     s->active_locty = new_active_locty;
163 
164     trace_tpm_tis_new_active_locality(s->active_locty);
165 
166     if (TPM_TIS_IS_VALID_LOCTY(new_active_locty)) {
167         /* set flags on the new active locality */
168         s->loc[new_active_locty].access |= TPM_TIS_ACCESS_ACTIVE_LOCALITY;
169         s->loc[new_active_locty].access &= ~(TPM_TIS_ACCESS_REQUEST_USE |
170                                                TPM_TIS_ACCESS_SEIZE);
171     }
172 
173     if (change) {
174         tpm_tis_raise_irq(s, s->active_locty, TPM_TIS_INT_LOCALITY_CHANGED);
175     }
176 }
177 
178 /* abort -- this function switches the locality */
179 static void tpm_tis_abort(TPMState *s)
180 {
181     s->rw_offset = 0;
182 
183     trace_tpm_tis_abort(s->next_locty);
184 
185     /*
186      * Need to react differently depending on who's aborting now and
187      * which locality will become active afterwards.
188      */
189     if (s->aborting_locty == s->next_locty) {
190         s->loc[s->aborting_locty].state = TPM_TIS_STATE_READY;
191         tpm_tis_sts_set(&s->loc[s->aborting_locty],
192                         TPM_TIS_STS_COMMAND_READY);
193         tpm_tis_raise_irq(s, s->aborting_locty, TPM_TIS_INT_COMMAND_READY);
194     }
195 
196     /* locality after abort is another one than the current one */
197     tpm_tis_new_active_locality(s, s->next_locty);
198 
199     s->next_locty = TPM_TIS_NO_LOCALITY;
200     /* nobody's aborting a command anymore */
201     s->aborting_locty = TPM_TIS_NO_LOCALITY;
202 }
203 
204 /* prepare aborting current command */
205 static void tpm_tis_prep_abort(TPMState *s, uint8_t locty, uint8_t newlocty)
206 {
207     uint8_t busy_locty;
208 
209     assert(TPM_TIS_IS_VALID_LOCTY(newlocty));
210 
211     s->aborting_locty = locty; /* may also be TPM_TIS_NO_LOCALITY */
212     s->next_locty = newlocty;  /* locality after successful abort */
213 
214     /*
215      * only abort a command using an interrupt if currently executing
216      * a command AND if there's a valid connection to the vTPM.
217      */
218     for (busy_locty = 0; busy_locty < TPM_TIS_NUM_LOCALITIES; busy_locty++) {
219         if (s->loc[busy_locty].state == TPM_TIS_STATE_EXECUTION) {
220             /*
221              * request the backend to cancel. Some backends may not
222              * support it
223              */
224             tpm_backend_cancel_cmd(s->be_driver);
225             return;
226         }
227     }
228 
229     tpm_tis_abort(s);
230 }
231 
232 /*
233  * Callback from the TPM to indicate that the response was received.
234  */
235 void tpm_tis_request_completed(TPMState *s, int ret)
236 {
237     uint8_t locty = s->cmd.locty;
238     uint8_t l;
239 
240     assert(TPM_TIS_IS_VALID_LOCTY(locty));
241 
242     if (s->cmd.selftest_done) {
243         for (l = 0; l < TPM_TIS_NUM_LOCALITIES; l++) {
244             s->loc[l].sts |= TPM_TIS_STS_SELFTEST_DONE;
245         }
246     }
247 
248     /* FIXME: report error if ret != 0 */
249     tpm_tis_sts_set(&s->loc[locty],
250                     TPM_TIS_STS_VALID | TPM_TIS_STS_DATA_AVAILABLE);
251     s->loc[locty].state = TPM_TIS_STATE_COMPLETION;
252     s->rw_offset = 0;
253 
254     tpm_util_show_buffer(s->buffer, s->be_buffer_size, "From TPM");
255 
256     if (TPM_TIS_IS_VALID_LOCTY(s->next_locty)) {
257         tpm_tis_abort(s);
258     }
259 
260     tpm_tis_raise_irq(s, locty,
261                       TPM_TIS_INT_DATA_AVAILABLE | TPM_TIS_INT_STS_VALID);
262 }
263 
264 /*
265  * Read a byte of response data
266  */
267 static uint32_t tpm_tis_data_read(TPMState *s, uint8_t locty)
268 {
269     uint32_t ret = TPM_TIS_NO_DATA_BYTE;
270     uint16_t len;
271 
272     if ((s->loc[locty].sts & TPM_TIS_STS_DATA_AVAILABLE)) {
273         len = MIN(tpm_cmd_get_size(&s->buffer),
274                   s->be_buffer_size);
275 
276         ret = s->buffer[s->rw_offset++];
277         if (s->rw_offset >= len) {
278             /* got last byte */
279             tpm_tis_sts_set(&s->loc[locty], TPM_TIS_STS_VALID);
280             tpm_tis_raise_irq(s, locty, TPM_TIS_INT_STS_VALID);
281         }
282         trace_tpm_tis_data_read(ret, s->rw_offset - 1);
283     }
284 
285     return ret;
286 }
287 
288 #ifdef DEBUG_TIS
289 static void tpm_tis_dump_state(TPMState *s, hwaddr addr)
290 {
291     static const unsigned regs[] = {
292         TPM_TIS_REG_ACCESS,
293         TPM_TIS_REG_INT_ENABLE,
294         TPM_TIS_REG_INT_VECTOR,
295         TPM_TIS_REG_INT_STATUS,
296         TPM_TIS_REG_INTF_CAPABILITY,
297         TPM_TIS_REG_STS,
298         TPM_TIS_REG_DID_VID,
299         TPM_TIS_REG_RID,
300         0xfff};
301     int idx;
302     uint8_t locty = tpm_tis_locality_from_addr(addr);
303     hwaddr base = addr & ~0xfff;
304 
305     printf("tpm_tis: active locality      : %d\n"
306            "tpm_tis: state of locality %d : %d\n"
307            "tpm_tis: register dump:\n",
308            s->active_locty,
309            locty, s->loc[locty].state);
310 
311     for (idx = 0; regs[idx] != 0xfff; idx++) {
312         printf("tpm_tis: 0x%04x : 0x%08x\n", regs[idx],
313                (int)tpm_tis_mmio_read(s, base + regs[idx], 4));
314     }
315 
316     printf("tpm_tis: r/w offset    : %d\n"
317            "tpm_tis: result buffer : ",
318            s->rw_offset);
319     for (idx = 0;
320          idx < MIN(tpm_cmd_get_size(&s->buffer), s->be_buffer_size);
321          idx++) {
322         printf("%c%02x%s",
323                s->rw_offset == idx ? '>' : ' ',
324                s->buffer[idx],
325                ((idx & 0xf) == 0xf) ? "\ntpm_tis:                 " : "");
326     }
327     printf("\n");
328 }
329 #endif
330 
331 /*
332  * Read a register of the TIS interface
333  * See specs pages 33-63 for description of the registers
334  */
335 static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr addr,
336                                   unsigned size)
337 {
338     TPMState *s = opaque;
339     uint16_t offset = addr & 0xffc;
340     uint8_t shift = (addr & 0x3) * 8;
341     uint32_t val = 0xffffffff;
342     uint8_t locty = tpm_tis_locality_from_addr(addr);
343     uint32_t avail;
344     uint8_t v;
345 
346     if (tpm_backend_had_startup_error(s->be_driver)) {
347         return 0;
348     }
349 
350     switch (offset) {
351     case TPM_TIS_REG_ACCESS:
352         /* never show the SEIZE flag even though we use it internally */
353         val = s->loc[locty].access & ~TPM_TIS_ACCESS_SEIZE;
354         /* the pending flag is always calculated */
355         if (tpm_tis_check_request_use_except(s, locty)) {
356             val |= TPM_TIS_ACCESS_PENDING_REQUEST;
357         }
358         val |= !tpm_backend_get_tpm_established_flag(s->be_driver);
359         break;
360     case TPM_TIS_REG_INT_ENABLE:
361         val = s->loc[locty].inte;
362         break;
363     case TPM_TIS_REG_INT_VECTOR:
364         val = s->irq_num;
365         break;
366     case TPM_TIS_REG_INT_STATUS:
367         val = s->loc[locty].ints;
368         break;
369     case TPM_TIS_REG_INTF_CAPABILITY:
370         switch (s->be_tpm_version) {
371         case TPM_VERSION_UNSPEC:
372             val = 0;
373             break;
374         case TPM_VERSION_1_2:
375             val = TPM_TIS_CAPABILITIES_SUPPORTED1_3;
376             break;
377         case TPM_VERSION_2_0:
378             val = TPM_TIS_CAPABILITIES_SUPPORTED2_0;
379             break;
380         }
381         break;
382     case TPM_TIS_REG_STS:
383         if (s->active_locty == locty) {
384             if ((s->loc[locty].sts & TPM_TIS_STS_DATA_AVAILABLE)) {
385                 val = TPM_TIS_BURST_COUNT(
386                        MIN(tpm_cmd_get_size(&s->buffer),
387                            s->be_buffer_size)
388                        - s->rw_offset) | s->loc[locty].sts;
389             } else {
390                 avail = s->be_buffer_size - s->rw_offset;
391                 /*
392                  * byte-sized reads should not return 0x00 for 0x100
393                  * available bytes.
394                  */
395                 if (size == 1 && avail > 0xff) {
396                     avail = 0xff;
397                 }
398                 val = TPM_TIS_BURST_COUNT(avail) | s->loc[locty].sts;
399             }
400         }
401         break;
402     case TPM_TIS_REG_DATA_FIFO:
403     case TPM_TIS_REG_DATA_XFIFO ... TPM_TIS_REG_DATA_XFIFO_END:
404         if (s->active_locty == locty) {
405             if (size > 4 - (addr & 0x3)) {
406                 /* prevent access beyond FIFO */
407                 size = 4 - (addr & 0x3);
408             }
409             val = 0;
410             shift = 0;
411             while (size > 0) {
412                 switch (s->loc[locty].state) {
413                 case TPM_TIS_STATE_COMPLETION:
414                     v = tpm_tis_data_read(s, locty);
415                     break;
416                 default:
417                     v = TPM_TIS_NO_DATA_BYTE;
418                     break;
419                 }
420                 val |= (v << shift);
421                 shift += 8;
422                 size--;
423             }
424             shift = 0; /* no more adjustments */
425         }
426         break;
427     case TPM_TIS_REG_INTERFACE_ID:
428         val = s->loc[locty].iface_id;
429         break;
430     case TPM_TIS_REG_DID_VID:
431         val = (TPM_TIS_TPM_DID << 16) | TPM_TIS_TPM_VID;
432         break;
433     case TPM_TIS_REG_RID:
434         val = TPM_TIS_TPM_RID;
435         break;
436 #ifdef DEBUG_TIS
437     case TPM_TIS_REG_DEBUG:
438         tpm_tis_dump_state(s, addr);
439         break;
440 #endif
441     }
442 
443     if (shift) {
444         val >>= shift;
445     }
446 
447     trace_tpm_tis_mmio_read(size, addr, val);
448 
449     return val;
450 }
451 
452 /*
453  * A wrapper read function so that it can be directly called without
454  * mmio.
455  */
456 uint32_t tpm_tis_read_data(TPMState *s, hwaddr addr, unsigned size)
457 {
458     return tpm_tis_mmio_read(s, addr, size);
459 }
460 
461 /*
462  * Calculate current data buffer checksum
463  */
464 uint16_t tpm_tis_get_checksum(TPMState *s)
465 {
466     return bswap16(crc_ccitt(0, s->buffer, s->rw_offset));
467 }
468 
469 /*
470  * Write a value to a register of the TIS interface
471  * See specs pages 33-63 for description of the registers
472  */
473 static void tpm_tis_mmio_write(void *opaque, hwaddr addr,
474                                uint64_t val, unsigned size)
475 {
476     TPMState *s = opaque;
477     uint16_t off = addr & 0xffc;
478     uint8_t shift = (addr & 0x3) * 8;
479     uint8_t locty = tpm_tis_locality_from_addr(addr);
480     uint8_t active_locty, l;
481     int c, set_new_locty = 1;
482     uint16_t len;
483     uint32_t mask = (size == 1) ? 0xff : ((size == 2) ? 0xffff : ~0);
484 
485     trace_tpm_tis_mmio_write(size, addr, val);
486 
487     if (locty == 4) {
488         trace_tpm_tis_mmio_write_locty4();
489         return;
490     }
491 
492     if (tpm_backend_had_startup_error(s->be_driver)) {
493         return;
494     }
495 
496     val &= mask;
497 
498     if (shift) {
499         val <<= shift;
500         mask <<= shift;
501     }
502 
503     mask ^= 0xffffffff;
504 
505     switch (off) {
506     case TPM_TIS_REG_ACCESS:
507 
508         if ((val & TPM_TIS_ACCESS_SEIZE)) {
509             val &= ~(TPM_TIS_ACCESS_REQUEST_USE |
510                      TPM_TIS_ACCESS_ACTIVE_LOCALITY);
511         }
512 
513         active_locty = s->active_locty;
514 
515         if ((val & TPM_TIS_ACCESS_ACTIVE_LOCALITY)) {
516             /* give up locality if currently owned */
517             if (s->active_locty == locty) {
518                 trace_tpm_tis_mmio_write_release_locty(locty);
519 
520                 uint8_t newlocty = TPM_TIS_NO_LOCALITY;
521                 /* anybody wants the locality ? */
522                 for (c = TPM_TIS_NUM_LOCALITIES - 1; c >= 0; c--) {
523                     if ((s->loc[c].access & TPM_TIS_ACCESS_REQUEST_USE)) {
524                         trace_tpm_tis_mmio_write_locty_req_use(c);
525                         newlocty = c;
526                         break;
527                     }
528                 }
529                 trace_tpm_tis_mmio_write_next_locty(newlocty);
530 
531                 if (TPM_TIS_IS_VALID_LOCTY(newlocty)) {
532                     set_new_locty = 0;
533                     tpm_tis_prep_abort(s, locty, newlocty);
534                 } else {
535                     active_locty = TPM_TIS_NO_LOCALITY;
536                 }
537             } else {
538                 /* not currently the owner; clear a pending request */
539                 s->loc[locty].access &= ~TPM_TIS_ACCESS_REQUEST_USE;
540             }
541         }
542 
543         if ((val & TPM_TIS_ACCESS_BEEN_SEIZED)) {
544             s->loc[locty].access &= ~TPM_TIS_ACCESS_BEEN_SEIZED;
545         }
546 
547         if ((val & TPM_TIS_ACCESS_SEIZE)) {
548             /*
549              * allow seize if a locality is active and the requesting
550              * locality is higher than the one that's active
551              * OR
552              * allow seize for requesting locality if no locality is
553              * active
554              */
555             while ((TPM_TIS_IS_VALID_LOCTY(s->active_locty) &&
556                     locty > s->active_locty) ||
557                     !TPM_TIS_IS_VALID_LOCTY(s->active_locty)) {
558                 bool higher_seize = false;
559 
560                 /* already a pending SEIZE ? */
561                 if ((s->loc[locty].access & TPM_TIS_ACCESS_SEIZE)) {
562                     break;
563                 }
564 
565                 /* check for ongoing seize by a higher locality */
566                 for (l = locty + 1; l < TPM_TIS_NUM_LOCALITIES; l++) {
567                     if ((s->loc[l].access & TPM_TIS_ACCESS_SEIZE)) {
568                         higher_seize = true;
569                         break;
570                     }
571                 }
572 
573                 if (higher_seize) {
574                     break;
575                 }
576 
577                 /* cancel any seize by a lower locality */
578                 for (l = 0; l < locty; l++) {
579                     s->loc[l].access &= ~TPM_TIS_ACCESS_SEIZE;
580                 }
581 
582                 s->loc[locty].access |= TPM_TIS_ACCESS_SEIZE;
583 
584                 trace_tpm_tis_mmio_write_locty_seized(locty, s->active_locty);
585                 trace_tpm_tis_mmio_write_init_abort();
586 
587                 set_new_locty = 0;
588                 tpm_tis_prep_abort(s, s->active_locty, locty);
589                 break;
590             }
591         }
592 
593         if ((val & TPM_TIS_ACCESS_REQUEST_USE)) {
594             if (s->active_locty != locty) {
595                 if (TPM_TIS_IS_VALID_LOCTY(s->active_locty)) {
596                     s->loc[locty].access |= TPM_TIS_ACCESS_REQUEST_USE;
597                 } else {
598                     /* no locality active -> make this one active now */
599                     active_locty = locty;
600                 }
601             }
602         }
603 
604         if (set_new_locty) {
605             tpm_tis_new_active_locality(s, active_locty);
606         }
607 
608         break;
609     case TPM_TIS_REG_INT_ENABLE:
610         s->loc[locty].inte &= mask;
611         s->loc[locty].inte |= (val & (TPM_TIS_INT_ENABLED |
612                                         TPM_TIS_INT_POLARITY_MASK |
613                                         TPM_TIS_INTERRUPTS_SUPPORTED));
614         break;
615     case TPM_TIS_REG_INT_VECTOR:
616         /* hard wired -- ignore */
617         break;
618     case TPM_TIS_REG_INT_STATUS:
619         /* clearing of interrupt flags */
620         if (((val & TPM_TIS_INTERRUPTS_SUPPORTED)) &&
621             (s->loc[locty].ints & TPM_TIS_INTERRUPTS_SUPPORTED)) {
622             s->loc[locty].ints &= ~val;
623             if (s->loc[locty].ints == 0) {
624                 qemu_irq_lower(s->irq);
625                 trace_tpm_tis_mmio_write_lowering_irq();
626             }
627         }
628         s->loc[locty].ints &= ~(val & TPM_TIS_INTERRUPTS_SUPPORTED);
629         break;
630     case TPM_TIS_REG_STS:
631         if (s->active_locty != locty) {
632             break;
633         }
634 
635         if (s->be_tpm_version == TPM_VERSION_2_0) {
636             /* some flags that are only supported for TPM 2 */
637             if (val & TPM_TIS_STS_COMMAND_CANCEL) {
638                 if (s->loc[locty].state == TPM_TIS_STATE_EXECUTION) {
639                     /*
640                      * request the backend to cancel. Some backends may not
641                      * support it
642                      */
643                     tpm_backend_cancel_cmd(s->be_driver);
644                 }
645             }
646 
647             if (val & TPM_TIS_STS_RESET_ESTABLISHMENT_BIT) {
648                 if (locty == 3 || locty == 4) {
649                     tpm_backend_reset_tpm_established_flag(s->be_driver, locty);
650                 }
651             }
652         }
653 
654         val &= (TPM_TIS_STS_COMMAND_READY | TPM_TIS_STS_TPM_GO |
655                 TPM_TIS_STS_RESPONSE_RETRY);
656 
657         if (val == TPM_TIS_STS_COMMAND_READY) {
658             switch (s->loc[locty].state) {
659 
660             case TPM_TIS_STATE_READY:
661                 s->rw_offset = 0;
662             break;
663 
664             case TPM_TIS_STATE_IDLE:
665                 tpm_tis_sts_set(&s->loc[locty], TPM_TIS_STS_COMMAND_READY);
666                 s->loc[locty].state = TPM_TIS_STATE_READY;
667                 tpm_tis_raise_irq(s, locty, TPM_TIS_INT_COMMAND_READY);
668             break;
669 
670             case TPM_TIS_STATE_EXECUTION:
671             case TPM_TIS_STATE_RECEPTION:
672                 /* abort currently running command */
673                 trace_tpm_tis_mmio_write_init_abort();
674                 tpm_tis_prep_abort(s, locty, locty);
675             break;
676 
677             case TPM_TIS_STATE_COMPLETION:
678                 s->rw_offset = 0;
679                 /* shortcut to ready state with C/R set */
680                 s->loc[locty].state = TPM_TIS_STATE_READY;
681                 if (!(s->loc[locty].sts & TPM_TIS_STS_COMMAND_READY)) {
682                     tpm_tis_sts_set(&s->loc[locty],
683                                     TPM_TIS_STS_COMMAND_READY);
684                     tpm_tis_raise_irq(s, locty, TPM_TIS_INT_COMMAND_READY);
685                 }
686                 s->loc[locty].sts &= ~(TPM_TIS_STS_DATA_AVAILABLE);
687             break;
688 
689             }
690         } else if (val == TPM_TIS_STS_TPM_GO) {
691             switch (s->loc[locty].state) {
692             case TPM_TIS_STATE_RECEPTION:
693                 if ((s->loc[locty].sts & TPM_TIS_STS_EXPECT) == 0) {
694                     tpm_tis_tpm_send(s, locty);
695                 }
696                 break;
697             default:
698                 /* ignore */
699                 break;
700             }
701         } else if (val == TPM_TIS_STS_RESPONSE_RETRY) {
702             switch (s->loc[locty].state) {
703             case TPM_TIS_STATE_COMPLETION:
704                 s->rw_offset = 0;
705                 tpm_tis_sts_set(&s->loc[locty],
706                                 TPM_TIS_STS_VALID|
707                                 TPM_TIS_STS_DATA_AVAILABLE);
708                 break;
709             default:
710                 /* ignore */
711                 break;
712             }
713         }
714         break;
715     case TPM_TIS_REG_DATA_FIFO:
716     case TPM_TIS_REG_DATA_XFIFO ... TPM_TIS_REG_DATA_XFIFO_END:
717         /* data fifo */
718         if (s->active_locty != locty) {
719             break;
720         }
721 
722         if (s->loc[locty].state == TPM_TIS_STATE_IDLE ||
723             s->loc[locty].state == TPM_TIS_STATE_EXECUTION ||
724             s->loc[locty].state == TPM_TIS_STATE_COMPLETION) {
725             /* drop the byte */
726         } else {
727             trace_tpm_tis_mmio_write_data2send(val, size);
728             if (s->loc[locty].state == TPM_TIS_STATE_READY) {
729                 s->loc[locty].state = TPM_TIS_STATE_RECEPTION;
730                 tpm_tis_sts_set(&s->loc[locty],
731                                 TPM_TIS_STS_EXPECT | TPM_TIS_STS_VALID);
732             }
733 
734             val >>= shift;
735             if (size > 4 - (addr & 0x3)) {
736                 /* prevent access beyond FIFO */
737                 size = 4 - (addr & 0x3);
738             }
739 
740             while ((s->loc[locty].sts & TPM_TIS_STS_EXPECT) && size > 0) {
741                 if (s->rw_offset < s->be_buffer_size) {
742                     s->buffer[s->rw_offset++] =
743                         (uint8_t)val;
744                     val >>= 8;
745                     size--;
746                 } else {
747                     tpm_tis_sts_set(&s->loc[locty], TPM_TIS_STS_VALID);
748                 }
749             }
750 
751             /* check for complete packet */
752             if (s->rw_offset > 5 &&
753                 (s->loc[locty].sts & TPM_TIS_STS_EXPECT)) {
754                 /* we have a packet length - see if we have all of it */
755                 bool need_irq = !(s->loc[locty].sts & TPM_TIS_STS_VALID);
756 
757                 len = tpm_cmd_get_size(&s->buffer);
758                 if (len > s->rw_offset) {
759                     tpm_tis_sts_set(&s->loc[locty],
760                                     TPM_TIS_STS_EXPECT | TPM_TIS_STS_VALID);
761                 } else {
762                     /* packet complete */
763                     tpm_tis_sts_set(&s->loc[locty], TPM_TIS_STS_VALID);
764                 }
765                 if (need_irq) {
766                     tpm_tis_raise_irq(s, locty, TPM_TIS_INT_STS_VALID);
767                 }
768             }
769         }
770         break;
771     case TPM_TIS_REG_INTERFACE_ID:
772         if (val & TPM_TIS_IFACE_ID_INT_SEL_LOCK) {
773             for (l = 0; l < TPM_TIS_NUM_LOCALITIES; l++) {
774                 s->loc[l].iface_id |= TPM_TIS_IFACE_ID_INT_SEL_LOCK;
775             }
776         }
777         break;
778     }
779 }
780 
781 /*
782  * A wrapper write function so that it can be directly called without
783  * mmio.
784  */
785 void tpm_tis_write_data(TPMState *s, hwaddr addr, uint64_t val, uint32_t size)
786 {
787     tpm_tis_mmio_write(s, addr, val, size);
788 }
789 
790 const MemoryRegionOps tpm_tis_memory_ops = {
791     .read = tpm_tis_mmio_read,
792     .write = tpm_tis_mmio_write,
793     .endianness = DEVICE_LITTLE_ENDIAN,
794     .valid = {
795         .min_access_size = 1,
796         .max_access_size = 4,
797     },
798 };
799 
800 /*
801  * Get the TPMVersion of the backend device being used
802  */
803 enum TPMVersion tpm_tis_get_tpm_version(TPMState *s)
804 {
805     if (tpm_backend_had_startup_error(s->be_driver)) {
806         return TPM_VERSION_UNSPEC;
807     }
808 
809     return tpm_backend_get_tpm_version(s->be_driver);
810 }
811 
812 /*
813  * This function is called when the machine starts, resets or due to
814  * S3 resume.
815  */
816 void tpm_tis_reset(TPMState *s)
817 {
818     int c;
819 
820     s->be_tpm_version = tpm_backend_get_tpm_version(s->be_driver);
821     s->be_buffer_size = MIN(tpm_backend_get_buffer_size(s->be_driver),
822                             TPM_TIS_BUFFER_MAX);
823 
824     if (s->ppi_enabled) {
825         tpm_ppi_reset(&s->ppi);
826     }
827     tpm_backend_reset(s->be_driver);
828 
829     s->active_locty = TPM_TIS_NO_LOCALITY;
830     s->next_locty = TPM_TIS_NO_LOCALITY;
831     s->aborting_locty = TPM_TIS_NO_LOCALITY;
832 
833     for (c = 0; c < TPM_TIS_NUM_LOCALITIES; c++) {
834         s->loc[c].access = TPM_TIS_ACCESS_TPM_REG_VALID_STS;
835         switch (s->be_tpm_version) {
836         case TPM_VERSION_UNSPEC:
837             break;
838         case TPM_VERSION_1_2:
839             s->loc[c].sts = TPM_TIS_STS_TPM_FAMILY1_2;
840             s->loc[c].iface_id = TPM_TIS_IFACE_ID_SUPPORTED_FLAGS1_3;
841             break;
842         case TPM_VERSION_2_0:
843             s->loc[c].sts = TPM_TIS_STS_TPM_FAMILY2_0;
844             s->loc[c].iface_id = TPM_TIS_IFACE_ID_SUPPORTED_FLAGS2_0;
845             break;
846         }
847         s->loc[c].inte = TPM_TIS_INT_POLARITY_LOW_LEVEL;
848         s->loc[c].ints = 0;
849         s->loc[c].state = TPM_TIS_STATE_IDLE;
850 
851         s->rw_offset = 0;
852     }
853 
854     if (tpm_backend_startup_tpm(s->be_driver, s->be_buffer_size) < 0) {
855         exit(1);
856     }
857 }
858 
859 /* persistent state handling */
860 
861 int tpm_tis_pre_save(TPMState *s)
862 {
863     uint8_t locty = s->active_locty;
864 
865     trace_tpm_tis_pre_save(locty, s->rw_offset);
866 
867     if (DEBUG_TIS) {
868         tpm_tis_dump_state(s, 0);
869     }
870 
871     /*
872      * Synchronize with backend completion.
873      */
874     tpm_backend_finish_sync(s->be_driver);
875 
876     return 0;
877 }
878 
879 const VMStateDescription vmstate_locty = {
880     .name = "tpm-tis/locty",
881     .version_id = 0,
882     .fields = (const VMStateField[]) {
883         VMSTATE_UINT32(state, TPMLocality),
884         VMSTATE_UINT32(inte, TPMLocality),
885         VMSTATE_UINT32(ints, TPMLocality),
886         VMSTATE_UINT8(access, TPMLocality),
887         VMSTATE_UINT32(sts, TPMLocality),
888         VMSTATE_UINT32(iface_id, TPMLocality),
889         VMSTATE_END_OF_LIST(),
890     }
891 };
892 
893