xref: /openbmc/qemu/hw/acpi/erst.c (revision 6c3a9247)
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 #define IS_UEFI_CPER_RECORD(ptr) \
84     (((ptr)[0] == 'C') && \
85      ((ptr)[1] == 'P') && \
86      ((ptr)[2] == 'E') && \
87      ((ptr)[3] == 'R'))
88 
89 /*
90  * NOTE that when accessing CPER fields within a record, memcpy()
91  * is utilized to avoid a possible misaligned access on the host.
92  */
93 
94 /*
95  * This implementation is an ACTION (cmd) and VALUE (data)
96  * interface consisting of just two 64-bit registers.
97  */
98 #define ERST_REG_SIZE (16UL)
99 #define ERST_ACTION_OFFSET (0UL) /* action (cmd) */
100 #define ERST_VALUE_OFFSET  (8UL) /* argument/value (data) */
101 
102 /*
103  * ERST_RECORD_SIZE is the buffer size for exchanging ERST
104  * record contents. Thus, it defines the maximum record size.
105  * As this is mapped through a PCI BAR, it must be a power of
106  * two and larger than UEFI_CPER_RECORD_MIN_SIZE.
107  * The backing storage is divided into fixed size "slots",
108  * each ERST_RECORD_SIZE in length, and each "slot"
109  * storing a single record. No attempt at optimizing storage
110  * through compression, compaction, etc is attempted.
111  * NOTE that slot 0 is reserved for the backing storage header.
112  * Depending upon the size of the backing storage, additional
113  * slots will be part of the slot 0 header in order to account
114  * for a record_id for each available remaining slot.
115  */
116 /* 8KiB records, not too small, not too big */
117 #define ERST_RECORD_SIZE (8192UL)
118 
119 #define ACPI_ERST_MEMDEV_PROP "memdev"
120 #define ACPI_ERST_RECORD_SIZE_PROP "record_size"
121 
122 /*
123  * From the ACPI ERST spec sections:
124  * A record id of all 0s is used to indicate 'unspecified' record id.
125  * A record id of all 1s is used to indicate empty or end.
126  */
127 #define ERST_UNSPECIFIED_RECORD_ID (0UL)
128 #define ERST_EMPTY_END_RECORD_ID (~0UL)
129 
130 #define ERST_IS_VALID_RECORD_ID(rid) \
131     ((rid != ERST_UNSPECIFIED_RECORD_ID) && \
132      (rid != ERST_EMPTY_END_RECORD_ID))
133 
134 /*
135  * Implementation-specific definitions and types.
136  * Values are arbitrary and chosen for this implementation.
137  * See erst.rst documentation for details.
138  */
139 #define ERST_EXECUTE_OPERATION_MAGIC 0x9CUL
140 #define ERST_STORE_MAGIC 0x524F545354535245UL /* ERSTSTOR */
141 typedef struct {
142     uint64_t magic;
143     uint32_t record_size;
144     uint32_t storage_offset; /* offset to record storage beyond header */
145     uint16_t version;
146     uint16_t reserved;
147     uint32_t record_count;
148     uint64_t map[]; /* contains record_ids, and position indicates index */
149 } __attribute__((packed)) ERSTStorageHeader;
150 
151 /*
152  * Object cast macro
153  */
154 #define ACPIERST(obj) \
155     OBJECT_CHECK(ERSTDeviceState, (obj), TYPE_ACPI_ERST)
156 
157 /*
158  * Main ERST device state structure
159  */
160 typedef struct {
161     PCIDevice parent_obj;
162 
163     /* Backend storage */
164     HostMemoryBackend *hostmem;
165     MemoryRegion *hostmem_mr;
166     uint32_t storage_size;
167     uint32_t default_record_size;
168 
169     /* Programming registers */
170     MemoryRegion iomem_mr;
171 
172     /* Exchange buffer */
173     MemoryRegion exchange_mr;
174 
175     /* Interface state */
176     uint8_t operation;
177     uint8_t busy_status;
178     uint8_t command_status;
179     uint32_t record_offset;
180     uint64_t reg_action;
181     uint64_t reg_value;
182     uint64_t record_identifier;
183     ERSTStorageHeader *header;
184     unsigned first_record_index;
185     unsigned last_record_index;
186     unsigned next_record_index;
187 
188 } ERSTDeviceState;
189 
190 /*******************************************************************/
191 /*******************************************************************/
192 typedef struct {
193     GArray *table_data;
194     pcibus_t bar;
195     uint8_t instruction;
196     uint8_t flags;
197     uint8_t register_bit_width;
198     pcibus_t register_offset;
199 } BuildSerializationInstructionEntry;
200 
201 /* ACPI 4.0: 17.4.1.2 Serialization Instruction Entries */
202 static void build_serialization_instruction(
203     BuildSerializationInstructionEntry *e,
204     uint8_t serialization_action,
205     uint64_t value)
206 {
207     /* ACPI 4.0: Table 17-18 Serialization Instruction Entry */
208     struct AcpiGenericAddress gas;
209     uint64_t mask;
210 
211     /* Serialization Action */
212     build_append_int_noprefix(e->table_data, serialization_action, 1);
213     /* Instruction */
214     build_append_int_noprefix(e->table_data, e->instruction, 1);
215     /* Flags */
216     build_append_int_noprefix(e->table_data, e->flags, 1);
217     /* Reserved */
218     build_append_int_noprefix(e->table_data, 0, 1);
219     /* Register Region */
220     gas.space_id = AML_SYSTEM_MEMORY;
221     gas.bit_width = e->register_bit_width;
222     gas.bit_offset = 0;
223     gas.access_width = (uint8_t)ctz32(e->register_bit_width) - 2;
224     gas.address = (uint64_t)(e->bar + e->register_offset);
225     build_append_gas_from_struct(e->table_data, &gas);
226     /* Value */
227     build_append_int_noprefix(e->table_data, value, 8);
228     /* Mask */
229     mask = (1ULL << (e->register_bit_width - 1) << 1) - 1;
230     build_append_int_noprefix(e->table_data, mask, 8);
231 }
232 
233 /* ACPI 4.0: 17.4.1 Serialization Action Table */
234 void build_erst(GArray *table_data, BIOSLinker *linker, Object *erst_dev,
235     const char *oem_id, const char *oem_table_id)
236 {
237     /*
238      * Serialization Action Table
239      * The serialization action table must be generated first
240      * so that its size can be known in order to populate the
241      * Instruction Entry Count field.
242      */
243     unsigned action;
244     GArray *table_instruction_data = g_array_new(FALSE, FALSE, sizeof(char));
245     pcibus_t bar0 = pci_get_bar_addr(PCI_DEVICE(erst_dev), 0);
246     AcpiTable table = { .sig = "ERST", .rev = 1, .oem_id = oem_id,
247                         .oem_table_id = oem_table_id };
248     /* Contexts for the different ways ACTION and VALUE are accessed */
249     BuildSerializationInstructionEntry rd_value_32_val = {
250         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
251         .instruction = INST_READ_REGISTER_VALUE,
252         .register_bit_width = 32,
253         .register_offset = ERST_VALUE_OFFSET,
254     };
255     BuildSerializationInstructionEntry rd_value_32 = {
256         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
257         .instruction = INST_READ_REGISTER,
258         .register_bit_width = 32,
259         .register_offset = ERST_VALUE_OFFSET,
260     };
261     BuildSerializationInstructionEntry rd_value_64 = {
262         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
263         .instruction = INST_READ_REGISTER,
264         .register_bit_width = 64,
265         .register_offset = ERST_VALUE_OFFSET,
266     };
267     BuildSerializationInstructionEntry wr_value_32_val = {
268         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
269         .instruction = INST_WRITE_REGISTER_VALUE,
270         .register_bit_width = 32,
271         .register_offset = ERST_VALUE_OFFSET,
272     };
273     BuildSerializationInstructionEntry wr_value_32 = {
274         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
275         .instruction = INST_WRITE_REGISTER,
276         .register_bit_width = 32,
277         .register_offset = ERST_VALUE_OFFSET,
278     };
279     BuildSerializationInstructionEntry wr_value_64 = {
280         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
281         .instruction = INST_WRITE_REGISTER,
282         .register_bit_width = 64,
283         .register_offset = ERST_VALUE_OFFSET,
284     };
285     BuildSerializationInstructionEntry wr_action = {
286         .table_data = table_instruction_data, .bar = bar0, .flags = 0,
287         .instruction = INST_WRITE_REGISTER_VALUE,
288         .register_bit_width = 32,
289         .register_offset = ERST_ACTION_OFFSET,
290     };
291 
292     trace_acpi_erst_pci_bar_0(bar0);
293 
294     /* Serialization Instruction Entries */
295     action = ACTION_BEGIN_WRITE_OPERATION;
296     build_serialization_instruction(&wr_action, action, action);
297 
298     action = ACTION_BEGIN_READ_OPERATION;
299     build_serialization_instruction(&wr_action, action, action);
300 
301     action = ACTION_BEGIN_CLEAR_OPERATION;
302     build_serialization_instruction(&wr_action, action, action);
303 
304     action = ACTION_END_OPERATION;
305     build_serialization_instruction(&wr_action, action, action);
306 
307     action = ACTION_SET_RECORD_OFFSET;
308     build_serialization_instruction(&wr_value_32, action, 0);
309     build_serialization_instruction(&wr_action, action, action);
310 
311     action = ACTION_EXECUTE_OPERATION;
312     build_serialization_instruction(&wr_value_32_val, action,
313         ERST_EXECUTE_OPERATION_MAGIC);
314     build_serialization_instruction(&wr_action, action, action);
315 
316     action = ACTION_CHECK_BUSY_STATUS;
317     build_serialization_instruction(&wr_action, action, action);
318     build_serialization_instruction(&rd_value_32_val, action, 0x01);
319 
320     action = ACTION_GET_COMMAND_STATUS;
321     build_serialization_instruction(&wr_action, action, action);
322     build_serialization_instruction(&rd_value_32, action, 0);
323 
324     action = ACTION_GET_RECORD_IDENTIFIER;
325     build_serialization_instruction(&wr_action, action, action);
326     build_serialization_instruction(&rd_value_64, action, 0);
327 
328     action = ACTION_SET_RECORD_IDENTIFIER;
329     build_serialization_instruction(&wr_value_64, action, 0);
330     build_serialization_instruction(&wr_action, action, action);
331 
332     action = ACTION_GET_RECORD_COUNT;
333     build_serialization_instruction(&wr_action, action, action);
334     build_serialization_instruction(&rd_value_32, action, 0);
335 
336     action = ACTION_BEGIN_DUMMY_WRITE_OPERATION;
337     build_serialization_instruction(&wr_action, action, action);
338 
339     action = ACTION_GET_ERROR_LOG_ADDRESS_RANGE;
340     build_serialization_instruction(&wr_action, action, action);
341     build_serialization_instruction(&rd_value_64, action, 0);
342 
343     action = ACTION_GET_ERROR_LOG_ADDRESS_LENGTH;
344     build_serialization_instruction(&wr_action, action, action);
345     build_serialization_instruction(&rd_value_64, action, 0);
346 
347     action = ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES;
348     build_serialization_instruction(&wr_action, action, action);
349     build_serialization_instruction(&rd_value_32, action, 0);
350 
351     action = ACTION_GET_EXECUTE_OPERATION_TIMINGS;
352     build_serialization_instruction(&wr_action, action, action);
353     build_serialization_instruction(&rd_value_64, action, 0);
354 
355     /* Serialization Header */
356     acpi_table_begin(&table, table_data);
357 
358     /* Serialization Header Size */
359     build_append_int_noprefix(table_data, 48, 4);
360 
361     /* Reserved */
362     build_append_int_noprefix(table_data,  0, 4);
363 
364     /*
365      * Instruction Entry Count
366      * Each instruction entry is 32 bytes
367      */
368     g_assert((table_instruction_data->len) % 32 == 0);
369     build_append_int_noprefix(table_data,
370         (table_instruction_data->len / 32), 4);
371 
372     /* Serialization Instruction Entries */
373     g_array_append_vals(table_data, table_instruction_data->data,
374         table_instruction_data->len);
375     g_array_free(table_instruction_data, TRUE);
376 
377     acpi_table_end(linker, &table);
378 }
379 
380 /*******************************************************************/
381 /*******************************************************************/
382 static uint8_t *get_nvram_ptr_by_index(ERSTDeviceState *s, unsigned index)
383 {
384     uint8_t *rc = NULL;
385     off_t offset = (index * le32_to_cpu(s->header->record_size));
386 
387     g_assert(offset < s->storage_size);
388 
389     rc = memory_region_get_ram_ptr(s->hostmem_mr);
390     rc += offset;
391 
392     return rc;
393 }
394 
395 static void make_erst_storage_header(ERSTDeviceState *s)
396 {
397     ERSTStorageHeader *header = s->header;
398     unsigned mapsz, headersz;
399 
400     header->magic = cpu_to_le64(ERST_STORE_MAGIC);
401     header->record_size = cpu_to_le32(s->default_record_size);
402     header->version = cpu_to_le16(0x0100);
403     header->reserved = cpu_to_le16(0x0000);
404 
405     /* Compute mapsize */
406     mapsz = s->storage_size / s->default_record_size;
407     mapsz *= sizeof(uint64_t);
408     /* Compute header+map size */
409     headersz = sizeof(ERSTStorageHeader) + mapsz;
410     /* Round up to nearest integer multiple of ERST_RECORD_SIZE */
411     headersz = QEMU_ALIGN_UP(headersz, s->default_record_size);
412     header->storage_offset = cpu_to_le32(headersz);
413 
414     /*
415      * The HostMemoryBackend initializes contents to zero,
416      * so all record_ids stashed in the map are zero'd.
417      * As well the record_count is zero. Properly initialized.
418      */
419 }
420 
421 static void check_erst_backend_storage(ERSTDeviceState *s, Error **errp)
422 {
423     ERSTStorageHeader *header;
424     uint32_t record_size;
425 
426     header = memory_region_get_ram_ptr(s->hostmem_mr);
427     s->header = header;
428 
429     /* Ensure pointer to header is 64-bit aligned */
430     g_assert(QEMU_PTR_IS_ALIGNED(header, sizeof(uint64_t)));
431 
432     /*
433      * Check if header is uninitialized; HostMemoryBackend inits to 0
434      */
435     if (le64_to_cpu(header->magic) == 0UL) {
436         make_erst_storage_header(s);
437     }
438 
439     /* Validity check record_size */
440     record_size = le32_to_cpu(header->record_size);
441     if (!(
442         (record_size) && /* non zero */
443         (record_size >= UEFI_CPER_RECORD_MIN_SIZE) &&
444         (((record_size - 1) & record_size) == 0) && /* is power of 2 */
445         (record_size >= 4096) /* PAGE_SIZE */
446         )) {
447         error_setg(errp, "ERST record_size %u is invalid", record_size);
448     }
449 
450     /* Validity check header */
451     if (!(
452         (le64_to_cpu(header->magic) == ERST_STORE_MAGIC) &&
453         ((le32_to_cpu(header->storage_offset) % record_size) == 0) &&
454         (le16_to_cpu(header->version) == 0x0100) &&
455         (le16_to_cpu(header->reserved) == 0)
456         )) {
457         error_setg(errp, "ERST backend storage header is invalid");
458     }
459 
460     /* Check storage_size against record_size */
461     if (((s->storage_size % record_size) != 0) ||
462          (record_size > s->storage_size)) {
463         error_setg(errp, "ACPI ERST requires storage size be multiple of "
464             "record size (%uKiB)", record_size);
465     }
466 
467     /* Compute offset of first and last record storage slot */
468     s->first_record_index = le32_to_cpu(header->storage_offset)
469         / record_size;
470     s->last_record_index = (s->storage_size / record_size);
471 }
472 
473 static void update_map_entry(ERSTDeviceState *s, unsigned index,
474     uint64_t record_id)
475 {
476     if (index < s->last_record_index) {
477         s->header->map[index] = cpu_to_le64(record_id);
478     }
479 }
480 
481 static unsigned find_next_empty_record_index(ERSTDeviceState *s)
482 {
483     unsigned rc = 0; /* 0 not a valid index */
484     unsigned index = s->first_record_index;
485 
486     for (; index < s->last_record_index; ++index) {
487         if (le64_to_cpu(s->header->map[index]) == ERST_UNSPECIFIED_RECORD_ID) {
488             rc = index;
489             break;
490         }
491     }
492 
493     return rc;
494 }
495 
496 static unsigned lookup_erst_record(ERSTDeviceState *s,
497     uint64_t record_identifier)
498 {
499     unsigned rc = 0; /* 0 not a valid index */
500 
501     /* Find the record_identifier in the map */
502     if (record_identifier != ERST_UNSPECIFIED_RECORD_ID) {
503         /*
504          * Count number of valid records encountered, and
505          * short-circuit the loop if identifier not found
506          */
507         uint32_t record_count = le32_to_cpu(s->header->record_count);
508         unsigned count = 0;
509         unsigned index;
510         for (index = s->first_record_index; index < s->last_record_index &&
511                 count < record_count; ++index) {
512             if (le64_to_cpu(s->header->map[index]) == record_identifier) {
513                 rc = index;
514                 break;
515             }
516             if (le64_to_cpu(s->header->map[index]) !=
517                 ERST_UNSPECIFIED_RECORD_ID) {
518                 ++count;
519             }
520         }
521     }
522 
523     return rc;
524 }
525 
526 /*
527  * ACPI 4.0: 17.4.1.1 Serialization Actions, also see
528  * ACPI 4.0: 17.4.2.2 Operations - Reading 6.c and 2.c
529  */
530 static unsigned get_next_record_identifier(ERSTDeviceState *s,
531     uint64_t *record_identifier, bool first)
532 {
533     unsigned found = 0;
534     unsigned index;
535 
536     /* For operations needing to return 'first' record identifier */
537     if (first) {
538         /* Reset initial index to beginning */
539         s->next_record_index = s->first_record_index;
540     }
541     index = s->next_record_index;
542 
543     *record_identifier = ERST_EMPTY_END_RECORD_ID;
544 
545     if (le32_to_cpu(s->header->record_count)) {
546         for (; index < s->last_record_index; ++index) {
547             if (le64_to_cpu(s->header->map[index]) !=
548                     ERST_UNSPECIFIED_RECORD_ID) {
549                     /* where to start next time */
550                     s->next_record_index = index + 1;
551                     *record_identifier = le64_to_cpu(s->header->map[index]);
552                     found = 1;
553                     break;
554             }
555         }
556     }
557     if (!found) {
558         /* at end (ie scan complete), reset */
559         s->next_record_index = s->first_record_index;
560     }
561 
562     return STATUS_SUCCESS;
563 }
564 
565 /* ACPI 4.0: 17.4.2.3 Operations - Clearing */
566 static unsigned clear_erst_record(ERSTDeviceState *s)
567 {
568     unsigned rc = STATUS_RECORD_NOT_FOUND;
569     unsigned index;
570 
571     /* Check for valid record identifier */
572     if (!ERST_IS_VALID_RECORD_ID(s->record_identifier)) {
573         return STATUS_FAILED;
574     }
575 
576     index = lookup_erst_record(s, s->record_identifier);
577     if (index) {
578         /* No need to wipe record, just invalidate its map entry */
579         uint32_t record_count;
580         update_map_entry(s, index, ERST_UNSPECIFIED_RECORD_ID);
581         record_count = le32_to_cpu(s->header->record_count);
582         record_count -= 1;
583         s->header->record_count = cpu_to_le32(record_count);
584         rc = STATUS_SUCCESS;
585     }
586 
587     return rc;
588 }
589 
590 /* ACPI 4.0: 17.4.2.2 Operations - Reading */
591 static unsigned read_erst_record(ERSTDeviceState *s)
592 {
593     unsigned rc = STATUS_RECORD_NOT_FOUND;
594     unsigned exchange_length;
595     unsigned index;
596 
597     /* Check if backend storage is empty */
598     if (le32_to_cpu(s->header->record_count) == 0) {
599         return STATUS_RECORD_STORE_EMPTY;
600     }
601 
602     exchange_length = memory_region_size(&s->exchange_mr);
603 
604     /* Check for record identifier of all 0s */
605     if (s->record_identifier == ERST_UNSPECIFIED_RECORD_ID) {
606         /* Set to 'first' record in storage */
607         get_next_record_identifier(s, &s->record_identifier, true);
608         /* record_identifier is now a valid id, or all 1s */
609     }
610 
611     /* Check for record identifier of all 1s */
612     if (s->record_identifier == ERST_EMPTY_END_RECORD_ID) {
613         return STATUS_FAILED;
614     }
615 
616     /* Validate record_offset */
617     if (s->record_offset > (exchange_length - UEFI_CPER_RECORD_MIN_SIZE)) {
618         return STATUS_FAILED;
619     }
620 
621     index = lookup_erst_record(s, s->record_identifier);
622     if (index) {
623         uint8_t *nvram;
624         uint8_t *exchange;
625         uint32_t record_length;
626 
627         /* Obtain pointer to the exchange buffer */
628         exchange = memory_region_get_ram_ptr(&s->exchange_mr);
629         exchange += s->record_offset;
630         /* Obtain pointer to slot in storage */
631         nvram = get_nvram_ptr_by_index(s, index);
632         /* Validate CPER record_length */
633         memcpy((uint8_t *)&record_length,
634             &nvram[UEFI_CPER_RECORD_LENGTH_OFFSET],
635             sizeof(uint32_t));
636         record_length = le32_to_cpu(record_length);
637         if (record_length < UEFI_CPER_RECORD_MIN_SIZE) {
638             rc = STATUS_FAILED;
639         }
640         if ((s->record_offset + record_length) > exchange_length) {
641             rc = STATUS_FAILED;
642         }
643         /* If all is ok, copy the record to the exchange buffer */
644         if (rc != STATUS_FAILED) {
645             memcpy(exchange, nvram, record_length);
646             rc = STATUS_SUCCESS;
647         }
648     } else {
649         /*
650          * See "Reading : 'The steps performed by the platform ...' 2.c"
651          * Set to 'first' record in storage
652          */
653         get_next_record_identifier(s, &s->record_identifier, true);
654     }
655 
656     return rc;
657 }
658 
659 /* ACPI 4.0: 17.4.2.1 Operations - Writing */
660 static unsigned write_erst_record(ERSTDeviceState *s)
661 {
662     unsigned rc = STATUS_FAILED;
663     unsigned exchange_length;
664     unsigned index;
665     uint64_t record_identifier;
666     uint32_t record_length;
667     uint8_t *exchange;
668     uint8_t *nvram = NULL;
669     bool record_found = false;
670 
671     exchange_length = memory_region_size(&s->exchange_mr);
672 
673     /* Validate record_offset */
674     if (s->record_offset > (exchange_length - UEFI_CPER_RECORD_MIN_SIZE)) {
675         return STATUS_FAILED;
676     }
677 
678     /* Obtain pointer to record in the exchange buffer */
679     exchange = memory_region_get_ram_ptr(&s->exchange_mr);
680     exchange += s->record_offset;
681 
682     /* Validate CPER record_length */
683     memcpy((uint8_t *)&record_length, &exchange[UEFI_CPER_RECORD_LENGTH_OFFSET],
684         sizeof(uint32_t));
685     record_length = le32_to_cpu(record_length);
686     if (record_length < UEFI_CPER_RECORD_MIN_SIZE) {
687         return STATUS_FAILED;
688     }
689     if ((s->record_offset + record_length) > exchange_length) {
690         return STATUS_FAILED;
691     }
692 
693     /* Extract record identifier */
694     memcpy((uint8_t *)&record_identifier, &exchange[UEFI_CPER_RECORD_ID_OFFSET],
695         sizeof(uint64_t));
696     record_identifier = le64_to_cpu(record_identifier);
697 
698     /* Check for valid record identifier */
699     if (!ERST_IS_VALID_RECORD_ID(record_identifier)) {
700         return STATUS_FAILED;
701     }
702 
703     index = lookup_erst_record(s, record_identifier);
704     if (index) {
705         /* Record found, overwrite existing record */
706         nvram = get_nvram_ptr_by_index(s, index);
707         record_found = true;
708     } else {
709         /* Record not found, not an overwrite, allocate for write */
710         index = find_next_empty_record_index(s);
711         if (index) {
712             nvram = get_nvram_ptr_by_index(s, index);
713         } else {
714             /* All slots are occupied */
715             rc = STATUS_NOT_ENOUGH_SPACE;
716         }
717     }
718     if (nvram) {
719         /* Write the record into the slot */
720         memcpy(nvram, exchange, record_length);
721         memset(nvram + record_length, exchange_length - record_length, 0xFF);
722         /* If a new record, increment the record_count */
723         if (!record_found) {
724             uint32_t record_count;
725             record_count = le32_to_cpu(s->header->record_count);
726             record_count += 1; /* writing new record */
727             s->header->record_count = cpu_to_le32(record_count);
728         }
729         update_map_entry(s, index, record_identifier);
730         rc = STATUS_SUCCESS;
731     }
732 
733     return rc;
734 }
735 
736 /*******************************************************************/
737 
738 static uint64_t erst_rd_reg64(hwaddr addr,
739     uint64_t reg, unsigned size)
740 {
741     uint64_t rdval;
742     uint64_t mask;
743     unsigned shift;
744 
745     if (size == sizeof(uint64_t)) {
746         /* 64b access */
747         mask = 0xFFFFFFFFFFFFFFFFUL;
748         shift = 0;
749     } else {
750         /* 32b access */
751         mask = 0x00000000FFFFFFFFUL;
752         shift = ((addr & 0x4) == 0x4) ? 32 : 0;
753     }
754 
755     rdval = reg;
756     rdval >>= shift;
757     rdval &= mask;
758 
759     return rdval;
760 }
761 
762 static uint64_t erst_wr_reg64(hwaddr addr,
763     uint64_t reg, uint64_t val, unsigned size)
764 {
765     uint64_t wrval;
766     uint64_t mask;
767     unsigned shift;
768 
769     if (size == sizeof(uint64_t)) {
770         /* 64b access */
771         mask = 0xFFFFFFFFFFFFFFFFUL;
772         shift = 0;
773     } else {
774         /* 32b access */
775         mask = 0x00000000FFFFFFFFUL;
776         shift = ((addr & 0x4) == 0x4) ? 32 : 0;
777     }
778 
779     val &= mask;
780     val <<= shift;
781     mask <<= shift;
782     wrval = reg;
783     wrval &= ~mask;
784     wrval |= val;
785 
786     return wrval;
787 }
788 
789 static void erst_reg_write(void *opaque, hwaddr addr,
790     uint64_t val, unsigned size)
791 {
792     ERSTDeviceState *s = (ERSTDeviceState *)opaque;
793 
794     /*
795      * NOTE: All actions/operations/side effects happen on the WRITE,
796      * by this implementation's design. The READs simply return the
797      * reg_value contents.
798      */
799     trace_acpi_erst_reg_write(addr, val, size);
800 
801     switch (addr) {
802     case ERST_VALUE_OFFSET + 0:
803     case ERST_VALUE_OFFSET + 4:
804         s->reg_value = erst_wr_reg64(addr, s->reg_value, val, size);
805         break;
806     case ERST_ACTION_OFFSET + 0:
807         /*
808          * NOTE: all valid values written to this register are of the
809          * ACTION_* variety. Thus there is no need to make this a 64-bit
810          * register, 32-bits is appropriate. As such ERST_ACTION_OFFSET+4
811          * is not needed.
812          */
813         switch (val) {
814         case ACTION_BEGIN_WRITE_OPERATION:
815         case ACTION_BEGIN_READ_OPERATION:
816         case ACTION_BEGIN_CLEAR_OPERATION:
817         case ACTION_BEGIN_DUMMY_WRITE_OPERATION:
818         case ACTION_END_OPERATION:
819             s->operation = val;
820             break;
821         case ACTION_SET_RECORD_OFFSET:
822             s->record_offset = s->reg_value;
823             break;
824         case ACTION_EXECUTE_OPERATION:
825             if ((uint8_t)s->reg_value == ERST_EXECUTE_OPERATION_MAGIC) {
826                 s->busy_status = 1;
827                 switch (s->operation) {
828                 case ACTION_BEGIN_WRITE_OPERATION:
829                     s->command_status = write_erst_record(s);
830                     break;
831                 case ACTION_BEGIN_READ_OPERATION:
832                     s->command_status = read_erst_record(s);
833                     break;
834                 case ACTION_BEGIN_CLEAR_OPERATION:
835                     s->command_status = clear_erst_record(s);
836                     break;
837                 case ACTION_BEGIN_DUMMY_WRITE_OPERATION:
838                     s->command_status = STATUS_SUCCESS;
839                     break;
840                 case ACTION_END_OPERATION:
841                     s->command_status = STATUS_SUCCESS;
842                     break;
843                 default:
844                     s->command_status = STATUS_FAILED;
845                     break;
846                 }
847                 s->busy_status = 0;
848             }
849             break;
850         case ACTION_CHECK_BUSY_STATUS:
851             s->reg_value = s->busy_status;
852             break;
853         case ACTION_GET_COMMAND_STATUS:
854             s->reg_value = s->command_status;
855             break;
856         case ACTION_GET_RECORD_IDENTIFIER:
857             s->command_status = get_next_record_identifier(s,
858                                     &s->reg_value, false);
859             break;
860         case ACTION_SET_RECORD_IDENTIFIER:
861             s->record_identifier = s->reg_value;
862             break;
863         case ACTION_GET_RECORD_COUNT:
864             s->reg_value = le32_to_cpu(s->header->record_count);
865             break;
866         case ACTION_GET_ERROR_LOG_ADDRESS_RANGE:
867             s->reg_value = (hwaddr)pci_get_bar_addr(PCI_DEVICE(s), 1);
868             break;
869         case ACTION_GET_ERROR_LOG_ADDRESS_LENGTH:
870             s->reg_value = le32_to_cpu(s->header->record_size);
871             break;
872         case ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES:
873             s->reg_value = 0x0; /* intentional, not NVRAM mode */
874             break;
875         case ACTION_GET_EXECUTE_OPERATION_TIMINGS:
876             s->reg_value =
877                 (100ULL << 32) | /* 100us max time */
878                 (10ULL  <<  0) ; /*  10us min time */
879             break;
880         default:
881             /* Unknown action/command, NOP */
882             break;
883         }
884         break;
885     default:
886         /* This should not happen, but if it does, NOP */
887         break;
888     }
889 }
890 
891 static uint64_t erst_reg_read(void *opaque, hwaddr addr,
892                                 unsigned size)
893 {
894     ERSTDeviceState *s = (ERSTDeviceState *)opaque;
895     uint64_t val = 0;
896 
897     switch (addr) {
898     case ERST_ACTION_OFFSET + 0:
899     case ERST_ACTION_OFFSET + 4:
900         val = erst_rd_reg64(addr, s->reg_action, size);
901         break;
902     case ERST_VALUE_OFFSET + 0:
903     case ERST_VALUE_OFFSET + 4:
904         val = erst_rd_reg64(addr, s->reg_value, size);
905         break;
906     default:
907         break;
908     }
909     trace_acpi_erst_reg_read(addr, val, size);
910     return val;
911 }
912 
913 static const MemoryRegionOps erst_reg_ops = {
914     .read = erst_reg_read,
915     .write = erst_reg_write,
916     .endianness = DEVICE_NATIVE_ENDIAN,
917 };
918 
919 /*******************************************************************/
920 /*******************************************************************/
921 static int erst_post_load(void *opaque, int version_id)
922 {
923     ERSTDeviceState *s = opaque;
924 
925     /* Recompute pointer to header */
926     s->header = (ERSTStorageHeader *)get_nvram_ptr_by_index(s, 0);
927     trace_acpi_erst_post_load(s->header, le32_to_cpu(s->header->record_size));
928 
929     return 0;
930 }
931 
932 static const VMStateDescription erst_vmstate  = {
933     .name = "acpi-erst",
934     .version_id = 1,
935     .minimum_version_id = 1,
936     .post_load = erst_post_load,
937     .fields = (VMStateField[]) {
938         VMSTATE_UINT8(operation, ERSTDeviceState),
939         VMSTATE_UINT8(busy_status, ERSTDeviceState),
940         VMSTATE_UINT8(command_status, ERSTDeviceState),
941         VMSTATE_UINT32(record_offset, ERSTDeviceState),
942         VMSTATE_UINT64(reg_action, ERSTDeviceState),
943         VMSTATE_UINT64(reg_value, ERSTDeviceState),
944         VMSTATE_UINT64(record_identifier, ERSTDeviceState),
945         VMSTATE_UINT32(next_record_index, ERSTDeviceState),
946         VMSTATE_END_OF_LIST()
947     }
948 };
949 
950 static void erst_realizefn(PCIDevice *pci_dev, Error **errp)
951 {
952     ERSTDeviceState *s = ACPIERST(pci_dev);
953 
954     trace_acpi_erst_realizefn_in();
955 
956     if (!s->hostmem) {
957         error_setg(errp, "'" ACPI_ERST_MEMDEV_PROP "' property is not set");
958         return;
959     } else if (host_memory_backend_is_mapped(s->hostmem)) {
960         error_setg(errp, "can't use already busy memdev: %s",
961                    object_get_canonical_path_component(OBJECT(s->hostmem)));
962         return;
963     }
964 
965     s->hostmem_mr = host_memory_backend_get_memory(s->hostmem);
966 
967     /* HostMemoryBackend size will be multiple of PAGE_SIZE */
968     s->storage_size = object_property_get_int(OBJECT(s->hostmem), "size", errp);
969 
970     /* Initialize backend storage and record_count */
971     check_erst_backend_storage(s, errp);
972 
973     /* BAR 0: Programming registers */
974     memory_region_init_io(&s->iomem_mr, OBJECT(pci_dev), &erst_reg_ops, s,
975                           TYPE_ACPI_ERST, ERST_REG_SIZE);
976     pci_register_bar(pci_dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->iomem_mr);
977 
978     /* BAR 1: Exchange buffer memory */
979     memory_region_init_ram(&s->exchange_mr, OBJECT(pci_dev),
980                             "erst.exchange",
981                             le32_to_cpu(s->header->record_size), errp);
982     pci_register_bar(pci_dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY,
983                         &s->exchange_mr);
984 
985     /* Include the backend storage in the migration stream */
986     vmstate_register_ram_global(s->hostmem_mr);
987 
988     trace_acpi_erst_realizefn_out(s->storage_size);
989 }
990 
991 static void erst_reset(DeviceState *dev)
992 {
993     ERSTDeviceState *s = ACPIERST(dev);
994 
995     trace_acpi_erst_reset_in(le32_to_cpu(s->header->record_count));
996     s->operation = 0;
997     s->busy_status = 0;
998     s->command_status = STATUS_SUCCESS;
999     s->record_identifier = ERST_UNSPECIFIED_RECORD_ID;
1000     s->record_offset = 0;
1001     s->next_record_index = s->first_record_index;
1002     /* NOTE: first/last_record_index are computed only once */
1003     trace_acpi_erst_reset_out(le32_to_cpu(s->header->record_count));
1004 }
1005 
1006 static Property erst_properties[] = {
1007     DEFINE_PROP_LINK(ACPI_ERST_MEMDEV_PROP, ERSTDeviceState, hostmem,
1008                      TYPE_MEMORY_BACKEND, HostMemoryBackend *),
1009     DEFINE_PROP_UINT32(ACPI_ERST_RECORD_SIZE_PROP, ERSTDeviceState,
1010                      default_record_size, ERST_RECORD_SIZE),
1011     DEFINE_PROP_END_OF_LIST(),
1012 };
1013 
1014 static void erst_class_init(ObjectClass *klass, void *data)
1015 {
1016     DeviceClass *dc = DEVICE_CLASS(klass);
1017     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
1018 
1019     trace_acpi_erst_class_init_in();
1020     k->realize = erst_realizefn;
1021     k->vendor_id = PCI_VENDOR_ID_REDHAT;
1022     k->device_id = PCI_DEVICE_ID_REDHAT_ACPI_ERST;
1023     k->revision = 0x00;
1024     k->class_id = PCI_CLASS_OTHERS;
1025     dc->reset = erst_reset;
1026     dc->vmsd = &erst_vmstate;
1027     dc->user_creatable = true;
1028     dc->hotpluggable = false;
1029     device_class_set_props(dc, erst_properties);
1030     dc->desc = "ACPI Error Record Serialization Table (ERST) device";
1031     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
1032     trace_acpi_erst_class_init_out();
1033 }
1034 
1035 static const TypeInfo erst_type_info = {
1036     .name          = TYPE_ACPI_ERST,
1037     .parent        = TYPE_PCI_DEVICE,
1038     .class_init    = erst_class_init,
1039     .instance_size = sizeof(ERSTDeviceState),
1040     .interfaces = (InterfaceInfo[]) {
1041         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
1042         { }
1043     }
1044 };
1045 
1046 static void erst_register_types(void)
1047 {
1048     type_register_static(&erst_type_info);
1049 }
1050 
1051 type_init(erst_register_types)
1052