xref: /openbmc/qemu/hw/acpi/erst.c (revision b21e2380)
1 /*
2  * ACPI Error Record Serialization Table, ERST, Implementation
3  *
4  * ACPI ERST introduced in ACPI 4.0, June 16, 2009.
5  * ACPI Platform Error Interfaces : Error Serialization
6  *
7  * Copyright (c) 2021 Oracle and/or its affiliates.
8  *
9  * SPDX-License-Identifier: GPL-2.0-or-later
10  */
11 
12 #include "qemu/osdep.h"
13 #include "qapi/error.h"
14 #include "hw/qdev-core.h"
15 #include "exec/memory.h"
16 #include "qom/object.h"
17 #include "hw/pci/pci.h"
18 #include "qom/object_interfaces.h"
19 #include "qemu/error-report.h"
20 #include "migration/vmstate.h"
21 #include "hw/qdev-properties.h"
22 #include "hw/acpi/acpi.h"
23 #include "hw/acpi/acpi-defs.h"
24 #include "hw/acpi/aml-build.h"
25 #include "hw/acpi/bios-linker-loader.h"
26 #include "exec/address-spaces.h"
27 #include "sysemu/hostmem.h"
28 #include "hw/acpi/erst.h"
29 #include "trace.h"
30 
31 /* ACPI 4.0: Table 17-16 Serialization Actions */
32 #define ACTION_BEGIN_WRITE_OPERATION         0x0
33 #define ACTION_BEGIN_READ_OPERATION          0x1
34 #define ACTION_BEGIN_CLEAR_OPERATION         0x2
35 #define ACTION_END_OPERATION                 0x3
36 #define ACTION_SET_RECORD_OFFSET             0x4
37 #define ACTION_EXECUTE_OPERATION             0x5
38 #define ACTION_CHECK_BUSY_STATUS             0x6
39 #define ACTION_GET_COMMAND_STATUS            0x7
40 #define ACTION_GET_RECORD_IDENTIFIER         0x8
41 #define ACTION_SET_RECORD_IDENTIFIER         0x9
42 #define ACTION_GET_RECORD_COUNT              0xA
43 #define ACTION_BEGIN_DUMMY_WRITE_OPERATION   0xB
44 #define ACTION_RESERVED                      0xC
45 #define ACTION_GET_ERROR_LOG_ADDRESS_RANGE   0xD
46 #define ACTION_GET_ERROR_LOG_ADDRESS_LENGTH  0xE
47 #define ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES 0xF
48 #define ACTION_GET_EXECUTE_OPERATION_TIMINGS 0x10 /* ACPI 6.3 */
49 
50 /* ACPI 4.0: Table 17-17 Command Status Definitions */
51 #define STATUS_SUCCESS                0x00
52 #define STATUS_NOT_ENOUGH_SPACE       0x01
53 #define STATUS_HARDWARE_NOT_AVAILABLE 0x02
54 #define STATUS_FAILED                 0x03
55 #define STATUS_RECORD_STORE_EMPTY     0x04
56 #define STATUS_RECORD_NOT_FOUND       0x05
57 
58 /* ACPI 4.0: Table 17-19 Serialization Instructions */
59 #define INST_READ_REGISTER                 0x00
60 #define INST_READ_REGISTER_VALUE           0x01
61 #define INST_WRITE_REGISTER                0x02
62 #define INST_WRITE_REGISTER_VALUE          0x03
63 #define INST_NOOP                          0x04
64 #define INST_LOAD_VAR1                     0x05
65 #define INST_LOAD_VAR2                     0x06
66 #define INST_STORE_VAR1                    0x07
67 #define INST_ADD                           0x08
68 #define INST_SUBTRACT                      0x09
69 #define INST_ADD_VALUE                     0x0A
70 #define INST_SUBTRACT_VALUE                0x0B
71 #define INST_STALL                         0x0C
72 #define INST_STALL_WHILE_TRUE              0x0D
73 #define INST_SKIP_NEXT_INSTRUCTION_IF_TRUE 0x0E
74 #define INST_GOTO                          0x0F
75 #define INST_SET_SRC_ADDRESS_BASE          0x10
76 #define INST_SET_DST_ADDRESS_BASE          0x11
77 #define INST_MOVE_DATA                     0x12
78 
79 /* UEFI 2.1: Appendix N Common Platform Error Record */
80 #define UEFI_CPER_RECORD_MIN_SIZE 128U
81 #define UEFI_CPER_RECORD_LENGTH_OFFSET 20U
82 #define UEFI_CPER_RECORD_ID_OFFSET 96U
83 
84 /*
85  * NOTE that when accessing CPER fields within a record, memcpy()
86  * is utilized to avoid a possible misaligned access on the host.
87  */
88 
89 /*
90  * This implementation is an ACTION (cmd) and VALUE (data)
91  * interface consisting of just two 64-bit registers.
92  */
93 #define ERST_REG_SIZE (16UL)
94 #define ERST_ACTION_OFFSET (0UL) /* action (cmd) */
95 #define ERST_VALUE_OFFSET  (8UL) /* argument/value (data) */
96 
97 /*
98  * ERST_RECORD_SIZE is the buffer size for exchanging ERST
99  * record contents. Thus, it defines the maximum record size.
100  * As this is mapped through a PCI BAR, it must be a power of
101  * two and larger than UEFI_CPER_RECORD_MIN_SIZE.
102  * The backing storage is divided into fixed size "slots",
103  * each ERST_RECORD_SIZE in length, and each "slot"
104  * storing a single record. No attempt at optimizing storage
105  * through compression, compaction, etc is attempted.
106  * NOTE that slot 0 is reserved for the backing storage header.
107  * Depending upon the size of the backing storage, additional
108  * slots will be part of the slot 0 header in order to account
109  * for a record_id for each available remaining slot.
110  */
111 /* 8KiB records, not too small, not too big */
112 #define ERST_RECORD_SIZE (8192UL)
113 
114 #define ACPI_ERST_MEMDEV_PROP "memdev"
115 #define ACPI_ERST_RECORD_SIZE_PROP "record_size"
116 
117 /*
118  * From the ACPI ERST spec sections:
119  * A record id of all 0s is used to indicate 'unspecified' record id.
120  * A record id of all 1s is used to indicate empty or end.
121  */
122 #define ERST_UNSPECIFIED_RECORD_ID (0UL)
123 #define ERST_EMPTY_END_RECORD_ID (~0UL)
124 
125 #define ERST_IS_VALID_RECORD_ID(rid) \
126     ((rid != ERST_UNSPECIFIED_RECORD_ID) && \
127      (rid != ERST_EMPTY_END_RECORD_ID))
128 
129 /*
130  * Implementation-specific definitions and types.
131  * Values are arbitrary and chosen for this implementation.
132  * See erst.rst documentation for details.
133  */
134 #define ERST_EXECUTE_OPERATION_MAGIC 0x9CUL
135 #define ERST_STORE_MAGIC 0x524F545354535245UL /* ERSTSTOR */
136 typedef struct {
137     uint64_t magic;
138     uint32_t record_size;
139     uint32_t storage_offset; /* offset to record storage beyond header */
140     uint16_t version;
141     uint16_t reserved;
142     uint32_t record_count;
143     uint64_t map[]; /* contains record_ids, and position indicates index */
144 } __attribute__((packed)) ERSTStorageHeader;
145 
146 /*
147  * Object cast macro
148  */
149 #define ACPIERST(obj) \
150     OBJECT_CHECK(ERSTDeviceState, (obj), TYPE_ACPI_ERST)
151 
152 /*
153  * Main ERST device state structure
154  */
155 typedef struct {
156     PCIDevice parent_obj;
157 
158     /* Backend storage */
159     HostMemoryBackend *hostmem;
160     MemoryRegion *hostmem_mr;
161     uint32_t storage_size;
162     uint32_t default_record_size;
163 
164     /* Programming registers */
165     MemoryRegion iomem_mr;
166 
167     /* Exchange buffer */
168     MemoryRegion exchange_mr;
169 
170     /* Interface state */
171     uint8_t operation;
172     uint8_t busy_status;
173     uint8_t command_status;
174     uint32_t record_offset;
175     uint64_t reg_action;
176     uint64_t reg_value;
177     uint64_t record_identifier;
178     ERSTStorageHeader *header;
179     unsigned first_record_index;
180     unsigned last_record_index;
181     unsigned next_record_index;
182 
183 } ERSTDeviceState;
184 
185 /*******************************************************************/
186 /*******************************************************************/
187 typedef struct {
188     GArray *table_data;
189     pcibus_t bar;
190     uint8_t instruction;
191     uint8_t flags;
192     uint8_t register_bit_width;
193     pcibus_t register_offset;
194 } BuildSerializationInstructionEntry;
195 
196 /* ACPI 4.0: 17.4.1.2 Serialization Instruction Entries */
197 static void build_serialization_instruction(
198     BuildSerializationInstructionEntry *e,
199     uint8_t serialization_action,
200     uint64_t value)
201 {
202     /* ACPI 4.0: Table 17-18 Serialization Instruction Entry */
203     struct AcpiGenericAddress gas;
204     uint64_t mask;
205 
206     /* Serialization Action */
207     build_append_int_noprefix(e->table_data, serialization_action, 1);
208     /* Instruction */
209     build_append_int_noprefix(e->table_data, e->instruction, 1);
210     /* Flags */
211     build_append_int_noprefix(e->table_data, e->flags, 1);
212     /* Reserved */
213     build_append_int_noprefix(e->table_data, 0, 1);
214     /* Register Region */
215     gas.space_id = AML_SYSTEM_MEMORY;
216     gas.bit_width = e->register_bit_width;
217     gas.bit_offset = 0;
218     gas.access_width = (uint8_t)ctz32(e->register_bit_width) - 2;
219     gas.address = (uint64_t)(e->bar + e->register_offset);
220     build_append_gas_from_struct(e->table_data, &gas);
221     /* Value */
222     build_append_int_noprefix(e->table_data, value, 8);
223     /* Mask */
224     mask = (1ULL << (e->register_bit_width - 1) << 1) - 1;
225     build_append_int_noprefix(e->table_data, mask, 8);
226 }
227 
228 /* ACPI 4.0: 17.4.1 Serialization Action Table */
229 void build_erst(GArray *table_data, BIOSLinker *linker, Object *erst_dev,
230     const char *oem_id, const char *oem_table_id)
231 {
232     /*
233      * Serialization Action Table
234      * The serialization action table must be generated first
235      * so that its size can be known in order to populate the
236      * Instruction Entry Count field.
237      */
238     unsigned action;
239     GArray *table_instruction_data = g_array_new(FALSE, FALSE, sizeof(char));
240     pcibus_t bar0 = pci_get_bar_addr(PCI_DEVICE(erst_dev), 0);
241     AcpiTable table = { .sig = "ERST", .rev = 1, .oem_id = oem_id,
242                         .oem_table_id = oem_table_id };
243     /* Contexts for the different ways ACTION and VALUE are accessed */
244     BuildSerializationInstructionEntry rd_value_32_val = {
245         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
246         .instruction = INST_READ_REGISTER_VALUE,
247         .register_bit_width = 32,
248         .register_offset = ERST_VALUE_OFFSET,
249     };
250     BuildSerializationInstructionEntry rd_value_32 = {
251         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
252         .instruction = INST_READ_REGISTER,
253         .register_bit_width = 32,
254         .register_offset = ERST_VALUE_OFFSET,
255     };
256     BuildSerializationInstructionEntry rd_value_64 = {
257         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
258         .instruction = INST_READ_REGISTER,
259         .register_bit_width = 64,
260         .register_offset = ERST_VALUE_OFFSET,
261     };
262     BuildSerializationInstructionEntry wr_value_32_val = {
263         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
264         .instruction = INST_WRITE_REGISTER_VALUE,
265         .register_bit_width = 32,
266         .register_offset = ERST_VALUE_OFFSET,
267     };
268     BuildSerializationInstructionEntry wr_value_32 = {
269         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
270         .instruction = INST_WRITE_REGISTER,
271         .register_bit_width = 32,
272         .register_offset = ERST_VALUE_OFFSET,
273     };
274     BuildSerializationInstructionEntry wr_value_64 = {
275         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
276         .instruction = INST_WRITE_REGISTER,
277         .register_bit_width = 64,
278         .register_offset = ERST_VALUE_OFFSET,
279     };
280     BuildSerializationInstructionEntry wr_action = {
281         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
282         .instruction = INST_WRITE_REGISTER_VALUE,
283         .register_bit_width = 32,
284         .register_offset = ERST_ACTION_OFFSET,
285     };
286 
287     trace_acpi_erst_pci_bar_0(bar0);
288 
289     /* Serialization Instruction Entries */
290     action = ACTION_BEGIN_WRITE_OPERATION;
291     build_serialization_instruction(&wr_action, action, action);
292 
293     action = ACTION_BEGIN_READ_OPERATION;
294     build_serialization_instruction(&wr_action, action, action);
295 
296     action = ACTION_BEGIN_CLEAR_OPERATION;
297     build_serialization_instruction(&wr_action, action, action);
298 
299     action = ACTION_END_OPERATION;
300     build_serialization_instruction(&wr_action, action, action);
301 
302     action = ACTION_SET_RECORD_OFFSET;
303     build_serialization_instruction(&wr_value_32, action, 0);
304     build_serialization_instruction(&wr_action, action, action);
305 
306     action = ACTION_EXECUTE_OPERATION;
307     build_serialization_instruction(&wr_value_32_val, action,
308         ERST_EXECUTE_OPERATION_MAGIC);
309     build_serialization_instruction(&wr_action, action, action);
310 
311     action = ACTION_CHECK_BUSY_STATUS;
312     build_serialization_instruction(&wr_action, action, action);
313     build_serialization_instruction(&rd_value_32_val, action, 0x01);
314 
315     action = ACTION_GET_COMMAND_STATUS;
316     build_serialization_instruction(&wr_action, action, action);
317     build_serialization_instruction(&rd_value_32, action, 0);
318 
319     action = ACTION_GET_RECORD_IDENTIFIER;
320     build_serialization_instruction(&wr_action, action, action);
321     build_serialization_instruction(&rd_value_64, action, 0);
322 
323     action = ACTION_SET_RECORD_IDENTIFIER;
324     build_serialization_instruction(&wr_value_64, action, 0);
325     build_serialization_instruction(&wr_action, action, action);
326 
327     action = ACTION_GET_RECORD_COUNT;
328     build_serialization_instruction(&wr_action, action, action);
329     build_serialization_instruction(&rd_value_32, action, 0);
330 
331     action = ACTION_BEGIN_DUMMY_WRITE_OPERATION;
332     build_serialization_instruction(&wr_action, action, action);
333 
334     action = ACTION_GET_ERROR_LOG_ADDRESS_RANGE;
335     build_serialization_instruction(&wr_action, action, action);
336     build_serialization_instruction(&rd_value_64, action, 0);
337 
338     action = ACTION_GET_ERROR_LOG_ADDRESS_LENGTH;
339     build_serialization_instruction(&wr_action, action, action);
340     build_serialization_instruction(&rd_value_64, action, 0);
341 
342     action = ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES;
343     build_serialization_instruction(&wr_action, action, action);
344     build_serialization_instruction(&rd_value_32, action, 0);
345 
346     action = ACTION_GET_EXECUTE_OPERATION_TIMINGS;
347     build_serialization_instruction(&wr_action, action, action);
348     build_serialization_instruction(&rd_value_64, action, 0);
349 
350     /* Serialization Header */
351     acpi_table_begin(&table, table_data);
352 
353     /* Serialization Header Size */
354     build_append_int_noprefix(table_data, 48, 4);
355 
356     /* Reserved */
357     build_append_int_noprefix(table_data,  0, 4);
358 
359     /*
360      * Instruction Entry Count
361      * Each instruction entry is 32 bytes
362      */
363     g_assert((table_instruction_data->len) % 32 == 0);
364     build_append_int_noprefix(table_data,
365         (table_instruction_data->len / 32), 4);
366 
367     /* Serialization Instruction Entries */
368     g_array_append_vals(table_data, table_instruction_data->data,
369         table_instruction_data->len);
370     g_array_free(table_instruction_data, TRUE);
371 
372     acpi_table_end(linker, &table);
373 }
374 
375 /*******************************************************************/
376 /*******************************************************************/
377 static uint8_t *get_nvram_ptr_by_index(ERSTDeviceState *s, unsigned index)
378 {
379     uint8_t *rc = NULL;
380     off_t offset = (index * le32_to_cpu(s->header->record_size));
381 
382     g_assert(offset < s->storage_size);
383 
384     rc = memory_region_get_ram_ptr(s->hostmem_mr);
385     rc += offset;
386 
387     return rc;
388 }
389 
390 static void make_erst_storage_header(ERSTDeviceState *s)
391 {
392     ERSTStorageHeader *header = s->header;
393     unsigned mapsz, headersz;
394 
395     header->magic = cpu_to_le64(ERST_STORE_MAGIC);
396     header->record_size = cpu_to_le32(s->default_record_size);
397     header->version = cpu_to_le16(0x0100);
398     header->reserved = cpu_to_le16(0x0000);
399 
400     /* Compute mapsize */
401     mapsz = s->storage_size / s->default_record_size;
402     mapsz *= sizeof(uint64_t);
403     /* Compute header+map size */
404     headersz = sizeof(ERSTStorageHeader) + mapsz;
405     /* Round up to nearest integer multiple of ERST_RECORD_SIZE */
406     headersz = QEMU_ALIGN_UP(headersz, s->default_record_size);
407     header->storage_offset = cpu_to_le32(headersz);
408 
409     /*
410      * The HostMemoryBackend initializes contents to zero,
411      * so all record_ids stashed in the map are zero'd.
412      * As well the record_count is zero. Properly initialized.
413      */
414 }
415 
416 static void check_erst_backend_storage(ERSTDeviceState *s, Error **errp)
417 {
418     ERSTStorageHeader *header;
419     uint32_t record_size;
420 
421     header = memory_region_get_ram_ptr(s->hostmem_mr);
422     s->header = header;
423 
424     /* Ensure pointer to header is 64-bit aligned */
425     g_assert(QEMU_PTR_IS_ALIGNED(header, sizeof(uint64_t)));
426 
427     /*
428      * Check if header is uninitialized; HostMemoryBackend inits to 0
429      */
430     if (le64_to_cpu(header->magic) == 0UL) {
431         make_erst_storage_header(s);
432     }
433 
434     /* Validity check record_size */
435     record_size = le32_to_cpu(header->record_size);
436     if (!(
437         (record_size) && /* non zero */
438         (record_size >= UEFI_CPER_RECORD_MIN_SIZE) &&
439         (((record_size - 1) & record_size) == 0) && /* is power of 2 */
440         (record_size >= 4096) /* PAGE_SIZE */
441         )) {
442         error_setg(errp, "ERST record_size %u is invalid", record_size);
443     }
444 
445     /* Validity check header */
446     if (!(
447         (le64_to_cpu(header->magic) == ERST_STORE_MAGIC) &&
448         ((le32_to_cpu(header->storage_offset) % record_size) == 0) &&
449         (le16_to_cpu(header->version) == 0x0100) &&
450         (le16_to_cpu(header->reserved) == 0)
451         )) {
452         error_setg(errp, "ERST backend storage header is invalid");
453     }
454 
455     /* Check storage_size against record_size */
456     if (((s->storage_size % record_size) != 0) ||
457          (record_size > s->storage_size)) {
458         error_setg(errp, "ACPI ERST requires storage size be multiple of "
459             "record size (%uKiB)", record_size);
460     }
461 
462     /* Compute offset of first and last record storage slot */
463     s->first_record_index = le32_to_cpu(header->storage_offset)
464         / record_size;
465     s->last_record_index = (s->storage_size / record_size);
466 }
467 
468 static void update_map_entry(ERSTDeviceState *s, unsigned index,
469     uint64_t record_id)
470 {
471     if (index < s->last_record_index) {
472         s->header->map[index] = cpu_to_le64(record_id);
473     }
474 }
475 
476 static unsigned find_next_empty_record_index(ERSTDeviceState *s)
477 {
478     unsigned rc = 0; /* 0 not a valid index */
479     unsigned index = s->first_record_index;
480 
481     for (; index < s->last_record_index; ++index) {
482         if (le64_to_cpu(s->header->map[index]) == ERST_UNSPECIFIED_RECORD_ID) {
483             rc = index;
484             break;
485         }
486     }
487 
488     return rc;
489 }
490 
491 static unsigned lookup_erst_record(ERSTDeviceState *s,
492     uint64_t record_identifier)
493 {
494     unsigned rc = 0; /* 0 not a valid index */
495 
496     /* Find the record_identifier in the map */
497     if (record_identifier != ERST_UNSPECIFIED_RECORD_ID) {
498         /*
499          * Count number of valid records encountered, and
500          * short-circuit the loop if identifier not found
501          */
502         uint32_t record_count = le32_to_cpu(s->header->record_count);
503         unsigned count = 0;
504         unsigned index;
505         for (index = s->first_record_index; index < s->last_record_index &&
506                 count < record_count; ++index) {
507             if (le64_to_cpu(s->header->map[index]) == record_identifier) {
508                 rc = index;
509                 break;
510             }
511             if (le64_to_cpu(s->header->map[index]) !=
512                 ERST_UNSPECIFIED_RECORD_ID) {
513                 ++count;
514             }
515         }
516     }
517 
518     return rc;
519 }
520 
521 /*
522  * ACPI 4.0: 17.4.1.1 Serialization Actions, also see
523  * ACPI 4.0: 17.4.2.2 Operations - Reading 6.c and 2.c
524  */
525 static unsigned get_next_record_identifier(ERSTDeviceState *s,
526     uint64_t *record_identifier, bool first)
527 {
528     unsigned found = 0;
529     unsigned index;
530 
531     /* For operations needing to return 'first' record identifier */
532     if (first) {
533         /* Reset initial index to beginning */
534         s->next_record_index = s->first_record_index;
535     }
536     index = s->next_record_index;
537 
538     *record_identifier = ERST_EMPTY_END_RECORD_ID;
539 
540     if (le32_to_cpu(s->header->record_count)) {
541         for (; index < s->last_record_index; ++index) {
542             if (le64_to_cpu(s->header->map[index]) !=
543                     ERST_UNSPECIFIED_RECORD_ID) {
544                     /* where to start next time */
545                     s->next_record_index = index + 1;
546                     *record_identifier = le64_to_cpu(s->header->map[index]);
547                     found = 1;
548                     break;
549             }
550         }
551     }
552     if (!found) {
553         /* at end (ie scan complete), reset */
554         s->next_record_index = s->first_record_index;
555     }
556 
557     return STATUS_SUCCESS;
558 }
559 
560 /* ACPI 4.0: 17.4.2.3 Operations - Clearing */
561 static unsigned clear_erst_record(ERSTDeviceState *s)
562 {
563     unsigned rc = STATUS_RECORD_NOT_FOUND;
564     unsigned index;
565 
566     /* Check for valid record identifier */
567     if (!ERST_IS_VALID_RECORD_ID(s->record_identifier)) {
568         return STATUS_FAILED;
569     }
570 
571     index = lookup_erst_record(s, s->record_identifier);
572     if (index) {
573         /* No need to wipe record, just invalidate its map entry */
574         uint32_t record_count;
575         update_map_entry(s, index, ERST_UNSPECIFIED_RECORD_ID);
576         record_count = le32_to_cpu(s->header->record_count);
577         record_count -= 1;
578         s->header->record_count = cpu_to_le32(record_count);
579         rc = STATUS_SUCCESS;
580     }
581 
582     return rc;
583 }
584 
585 /* ACPI 4.0: 17.4.2.2 Operations - Reading */
586 static unsigned read_erst_record(ERSTDeviceState *s)
587 {
588     unsigned rc = STATUS_RECORD_NOT_FOUND;
589     unsigned exchange_length;
590     unsigned index;
591 
592     /* Check if backend storage is empty */
593     if (le32_to_cpu(s->header->record_count) == 0) {
594         return STATUS_RECORD_STORE_EMPTY;
595     }
596 
597     exchange_length = memory_region_size(&s->exchange_mr);
598 
599     /* Check for record identifier of all 0s */
600     if (s->record_identifier == ERST_UNSPECIFIED_RECORD_ID) {
601         /* Set to 'first' record in storage */
602         get_next_record_identifier(s, &s->record_identifier, true);
603         /* record_identifier is now a valid id, or all 1s */
604     }
605 
606     /* Check for record identifier of all 1s */
607     if (s->record_identifier == ERST_EMPTY_END_RECORD_ID) {
608         return STATUS_FAILED;
609     }
610 
611     /* Validate record_offset */
612     if (s->record_offset > (exchange_length - UEFI_CPER_RECORD_MIN_SIZE)) {
613         return STATUS_FAILED;
614     }
615 
616     index = lookup_erst_record(s, s->record_identifier);
617     if (index) {
618         uint8_t *nvram;
619         uint8_t *exchange;
620         uint32_t record_length;
621 
622         /* Obtain pointer to the exchange buffer */
623         exchange = memory_region_get_ram_ptr(&s->exchange_mr);
624         exchange += s->record_offset;
625         /* Obtain pointer to slot in storage */
626         nvram = get_nvram_ptr_by_index(s, index);
627         /* Validate CPER record_length */
628         memcpy((uint8_t *)&record_length,
629             &nvram[UEFI_CPER_RECORD_LENGTH_OFFSET],
630             sizeof(uint32_t));
631         record_length = le32_to_cpu(record_length);
632         if (record_length < UEFI_CPER_RECORD_MIN_SIZE) {
633             rc = STATUS_FAILED;
634         }
635         if ((s->record_offset + record_length) > exchange_length) {
636             rc = STATUS_FAILED;
637         }
638         /* If all is ok, copy the record to the exchange buffer */
639         if (rc != STATUS_FAILED) {
640             memcpy(exchange, nvram, record_length);
641             rc = STATUS_SUCCESS;
642         }
643     } else {
644         /*
645          * See "Reading : 'The steps performed by the platform ...' 2.c"
646          * Set to 'first' record in storage
647          */
648         get_next_record_identifier(s, &s->record_identifier, true);
649     }
650 
651     return rc;
652 }
653 
654 /* ACPI 4.0: 17.4.2.1 Operations - Writing */
655 static unsigned write_erst_record(ERSTDeviceState *s)
656 {
657     unsigned rc = STATUS_FAILED;
658     unsigned exchange_length;
659     unsigned index;
660     uint64_t record_identifier;
661     uint32_t record_length;
662     uint8_t *exchange;
663     uint8_t *nvram = NULL;
664     bool record_found = false;
665 
666     exchange_length = memory_region_size(&s->exchange_mr);
667 
668     /* Validate record_offset */
669     if (s->record_offset > (exchange_length - UEFI_CPER_RECORD_MIN_SIZE)) {
670         return STATUS_FAILED;
671     }
672 
673     /* Obtain pointer to record in the exchange buffer */
674     exchange = memory_region_get_ram_ptr(&s->exchange_mr);
675     exchange += s->record_offset;
676 
677     /* Validate CPER record_length */
678     memcpy((uint8_t *)&record_length, &exchange[UEFI_CPER_RECORD_LENGTH_OFFSET],
679         sizeof(uint32_t));
680     record_length = le32_to_cpu(record_length);
681     if (record_length < UEFI_CPER_RECORD_MIN_SIZE) {
682         return STATUS_FAILED;
683     }
684     if ((s->record_offset + record_length) > exchange_length) {
685         return STATUS_FAILED;
686     }
687 
688     /* Extract record identifier */
689     memcpy((uint8_t *)&record_identifier, &exchange[UEFI_CPER_RECORD_ID_OFFSET],
690         sizeof(uint64_t));
691     record_identifier = le64_to_cpu(record_identifier);
692 
693     /* Check for valid record identifier */
694     if (!ERST_IS_VALID_RECORD_ID(record_identifier)) {
695         return STATUS_FAILED;
696     }
697 
698     index = lookup_erst_record(s, record_identifier);
699     if (index) {
700         /* Record found, overwrite existing record */
701         nvram = get_nvram_ptr_by_index(s, index);
702         record_found = true;
703     } else {
704         /* Record not found, not an overwrite, allocate for write */
705         index = find_next_empty_record_index(s);
706         if (index) {
707             nvram = get_nvram_ptr_by_index(s, index);
708         } else {
709             /* All slots are occupied */
710             rc = STATUS_NOT_ENOUGH_SPACE;
711         }
712     }
713     if (nvram) {
714         /* Write the record into the slot */
715         memcpy(nvram, exchange, record_length);
716         memset(nvram + record_length, exchange_length - record_length, 0xFF);
717         /* If a new record, increment the record_count */
718         if (!record_found) {
719             uint32_t record_count;
720             record_count = le32_to_cpu(s->header->record_count);
721             record_count += 1; /* writing new record */
722             s->header->record_count = cpu_to_le32(record_count);
723         }
724         update_map_entry(s, index, record_identifier);
725         rc = STATUS_SUCCESS;
726     }
727 
728     return rc;
729 }
730 
731 /*******************************************************************/
732 
733 static uint64_t erst_rd_reg64(hwaddr addr,
734     uint64_t reg, unsigned size)
735 {
736     uint64_t rdval;
737     uint64_t mask;
738     unsigned shift;
739 
740     if (size == sizeof(uint64_t)) {
741         /* 64b access */
742         mask = 0xFFFFFFFFFFFFFFFFUL;
743         shift = 0;
744     } else {
745         /* 32b access */
746         mask = 0x00000000FFFFFFFFUL;
747         shift = ((addr & 0x4) == 0x4) ? 32 : 0;
748     }
749 
750     rdval = reg;
751     rdval >>= shift;
752     rdval &= mask;
753 
754     return rdval;
755 }
756 
757 static uint64_t erst_wr_reg64(hwaddr addr,
758     uint64_t reg, uint64_t val, unsigned size)
759 {
760     uint64_t wrval;
761     uint64_t mask;
762     unsigned shift;
763 
764     if (size == sizeof(uint64_t)) {
765         /* 64b access */
766         mask = 0xFFFFFFFFFFFFFFFFUL;
767         shift = 0;
768     } else {
769         /* 32b access */
770         mask = 0x00000000FFFFFFFFUL;
771         shift = ((addr & 0x4) == 0x4) ? 32 : 0;
772     }
773 
774     val &= mask;
775     val <<= shift;
776     mask <<= shift;
777     wrval = reg;
778     wrval &= ~mask;
779     wrval |= val;
780 
781     return wrval;
782 }
783 
784 static void erst_reg_write(void *opaque, hwaddr addr,
785     uint64_t val, unsigned size)
786 {
787     ERSTDeviceState *s = (ERSTDeviceState *)opaque;
788 
789     /*
790      * NOTE: All actions/operations/side effects happen on the WRITE,
791      * by this implementation's design. The READs simply return the
792      * reg_value contents.
793      */
794     trace_acpi_erst_reg_write(addr, val, size);
795 
796     switch (addr) {
797     case ERST_VALUE_OFFSET + 0:
798     case ERST_VALUE_OFFSET + 4:
799         s->reg_value = erst_wr_reg64(addr, s->reg_value, val, size);
800         break;
801     case ERST_ACTION_OFFSET + 0:
802         /*
803          * NOTE: all valid values written to this register are of the
804          * ACTION_* variety. Thus there is no need to make this a 64-bit
805          * register, 32-bits is appropriate. As such ERST_ACTION_OFFSET+4
806          * is not needed.
807          */
808         switch (val) {
809         case ACTION_BEGIN_WRITE_OPERATION:
810         case ACTION_BEGIN_READ_OPERATION:
811         case ACTION_BEGIN_CLEAR_OPERATION:
812         case ACTION_BEGIN_DUMMY_WRITE_OPERATION:
813         case ACTION_END_OPERATION:
814             s->operation = val;
815             break;
816         case ACTION_SET_RECORD_OFFSET:
817             s->record_offset = s->reg_value;
818             break;
819         case ACTION_EXECUTE_OPERATION:
820             if ((uint8_t)s->reg_value == ERST_EXECUTE_OPERATION_MAGIC) {
821                 s->busy_status = 1;
822                 switch (s->operation) {
823                 case ACTION_BEGIN_WRITE_OPERATION:
824                     s->command_status = write_erst_record(s);
825                     break;
826                 case ACTION_BEGIN_READ_OPERATION:
827                     s->command_status = read_erst_record(s);
828                     break;
829                 case ACTION_BEGIN_CLEAR_OPERATION:
830                     s->command_status = clear_erst_record(s);
831                     break;
832                 case ACTION_BEGIN_DUMMY_WRITE_OPERATION:
833                     s->command_status = STATUS_SUCCESS;
834                     break;
835                 case ACTION_END_OPERATION:
836                     s->command_status = STATUS_SUCCESS;
837                     break;
838                 default:
839                     s->command_status = STATUS_FAILED;
840                     break;
841                 }
842                 s->busy_status = 0;
843             }
844             break;
845         case ACTION_CHECK_BUSY_STATUS:
846             s->reg_value = s->busy_status;
847             break;
848         case ACTION_GET_COMMAND_STATUS:
849             s->reg_value = s->command_status;
850             break;
851         case ACTION_GET_RECORD_IDENTIFIER:
852             s->command_status = get_next_record_identifier(s,
853                                     &s->reg_value, false);
854             break;
855         case ACTION_SET_RECORD_IDENTIFIER:
856             s->record_identifier = s->reg_value;
857             break;
858         case ACTION_GET_RECORD_COUNT:
859             s->reg_value = le32_to_cpu(s->header->record_count);
860             break;
861         case ACTION_GET_ERROR_LOG_ADDRESS_RANGE:
862             s->reg_value = (hwaddr)pci_get_bar_addr(PCI_DEVICE(s), 1);
863             break;
864         case ACTION_GET_ERROR_LOG_ADDRESS_LENGTH:
865             s->reg_value = le32_to_cpu(s->header->record_size);
866             break;
867         case ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES:
868             s->reg_value = 0x0; /* intentional, not NVRAM mode */
869             break;
870         case ACTION_GET_EXECUTE_OPERATION_TIMINGS:
871             s->reg_value =
872                 (100ULL << 32) | /* 100us max time */
873                 (10ULL  <<  0) ; /*  10us min time */
874             break;
875         default:
876             /* Unknown action/command, NOP */
877             break;
878         }
879         break;
880     default:
881         /* This should not happen, but if it does, NOP */
882         break;
883     }
884 }
885 
886 static uint64_t erst_reg_read(void *opaque, hwaddr addr,
887                                 unsigned size)
888 {
889     ERSTDeviceState *s = (ERSTDeviceState *)opaque;
890     uint64_t val = 0;
891 
892     switch (addr) {
893     case ERST_ACTION_OFFSET + 0:
894     case ERST_ACTION_OFFSET + 4:
895         val = erst_rd_reg64(addr, s->reg_action, size);
896         break;
897     case ERST_VALUE_OFFSET + 0:
898     case ERST_VALUE_OFFSET + 4:
899         val = erst_rd_reg64(addr, s->reg_value, size);
900         break;
901     default:
902         break;
903     }
904     trace_acpi_erst_reg_read(addr, val, size);
905     return val;
906 }
907 
908 static const MemoryRegionOps erst_reg_ops = {
909     .read = erst_reg_read,
910     .write = erst_reg_write,
911     .endianness = DEVICE_NATIVE_ENDIAN,
912 };
913 
914 /*******************************************************************/
915 /*******************************************************************/
916 static int erst_post_load(void *opaque, int version_id)
917 {
918     ERSTDeviceState *s = opaque;
919 
920     /* Recompute pointer to header */
921     s->header = (ERSTStorageHeader *)get_nvram_ptr_by_index(s, 0);
922     trace_acpi_erst_post_load(s->header, le32_to_cpu(s->header->record_size));
923 
924     return 0;
925 }
926 
927 static const VMStateDescription erst_vmstate  = {
928     .name = "acpi-erst",
929     .version_id = 1,
930     .minimum_version_id = 1,
931     .post_load = erst_post_load,
932     .fields = (VMStateField[]) {
933         VMSTATE_UINT8(operation, ERSTDeviceState),
934         VMSTATE_UINT8(busy_status, ERSTDeviceState),
935         VMSTATE_UINT8(command_status, ERSTDeviceState),
936         VMSTATE_UINT32(record_offset, ERSTDeviceState),
937         VMSTATE_UINT64(reg_action, ERSTDeviceState),
938         VMSTATE_UINT64(reg_value, ERSTDeviceState),
939         VMSTATE_UINT64(record_identifier, ERSTDeviceState),
940         VMSTATE_UINT32(next_record_index, ERSTDeviceState),
941         VMSTATE_END_OF_LIST()
942     }
943 };
944 
945 static void erst_realizefn(PCIDevice *pci_dev, Error **errp)
946 {
947     ERSTDeviceState *s = ACPIERST(pci_dev);
948 
949     trace_acpi_erst_realizefn_in();
950 
951     if (!s->hostmem) {
952         error_setg(errp, "'" ACPI_ERST_MEMDEV_PROP "' property is not set");
953         return;
954     } else if (host_memory_backend_is_mapped(s->hostmem)) {
955         error_setg(errp, "can't use already busy memdev: %s",
956                    object_get_canonical_path_component(OBJECT(s->hostmem)));
957         return;
958     }
959 
960     s->hostmem_mr = host_memory_backend_get_memory(s->hostmem);
961 
962     /* HostMemoryBackend size will be multiple of PAGE_SIZE */
963     s->storage_size = object_property_get_int(OBJECT(s->hostmem), "size", errp);
964 
965     /* Initialize backend storage and record_count */
966     check_erst_backend_storage(s, errp);
967 
968     /* BAR 0: Programming registers */
969     memory_region_init_io(&s->iomem_mr, OBJECT(pci_dev), &erst_reg_ops, s,
970                           TYPE_ACPI_ERST, ERST_REG_SIZE);
971     pci_register_bar(pci_dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->iomem_mr);
972 
973     /* BAR 1: Exchange buffer memory */
974     memory_region_init_ram(&s->exchange_mr, OBJECT(pci_dev),
975                             "erst.exchange",
976                             le32_to_cpu(s->header->record_size), errp);
977     pci_register_bar(pci_dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY,
978                         &s->exchange_mr);
979 
980     /* Include the backend storage in the migration stream */
981     vmstate_register_ram_global(s->hostmem_mr);
982 
983     trace_acpi_erst_realizefn_out(s->storage_size);
984 }
985 
986 static void erst_reset(DeviceState *dev)
987 {
988     ERSTDeviceState *s = ACPIERST(dev);
989 
990     trace_acpi_erst_reset_in(le32_to_cpu(s->header->record_count));
991     s->operation = 0;
992     s->busy_status = 0;
993     s->command_status = STATUS_SUCCESS;
994     s->record_identifier = ERST_UNSPECIFIED_RECORD_ID;
995     s->record_offset = 0;
996     s->next_record_index = s->first_record_index;
997     /* NOTE: first/last_record_index are computed only once */
998     trace_acpi_erst_reset_out(le32_to_cpu(s->header->record_count));
999 }
1000 
1001 static Property erst_properties[] = {
1002     DEFINE_PROP_LINK(ACPI_ERST_MEMDEV_PROP, ERSTDeviceState, hostmem,
1003                      TYPE_MEMORY_BACKEND, HostMemoryBackend *),
1004     DEFINE_PROP_UINT32(ACPI_ERST_RECORD_SIZE_PROP, ERSTDeviceState,
1005                      default_record_size, ERST_RECORD_SIZE),
1006     DEFINE_PROP_END_OF_LIST(),
1007 };
1008 
1009 static void erst_class_init(ObjectClass *klass, void *data)
1010 {
1011     DeviceClass *dc = DEVICE_CLASS(klass);
1012     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
1013 
1014     trace_acpi_erst_class_init_in();
1015     k->realize = erst_realizefn;
1016     k->vendor_id = PCI_VENDOR_ID_REDHAT;
1017     k->device_id = PCI_DEVICE_ID_REDHAT_ACPI_ERST;
1018     k->revision = 0x00;
1019     k->class_id = PCI_CLASS_OTHERS;
1020     dc->reset = erst_reset;
1021     dc->vmsd = &erst_vmstate;
1022     dc->user_creatable = true;
1023     dc->hotpluggable = false;
1024     device_class_set_props(dc, erst_properties);
1025     dc->desc = "ACPI Error Record Serialization Table (ERST) device";
1026     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
1027     trace_acpi_erst_class_init_out();
1028 }
1029 
1030 static const TypeInfo erst_type_info = {
1031     .name          = TYPE_ACPI_ERST,
1032     .parent        = TYPE_PCI_DEVICE,
1033     .class_init    = erst_class_init,
1034     .instance_size = sizeof(ERSTDeviceState),
1035     .interfaces = (InterfaceInfo[]) {
1036         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
1037         { }
1038     }
1039 };
1040 
1041 static void erst_register_types(void)
1042 {
1043     type_register_static(&erst_type_info);
1044 }
1045 
1046 type_init(erst_register_types)
1047