1 /* SPDX-License-Identifier: GPL-2.0 */
2 /******************************************************************************
3 * x86_emulate.h
4 *
5 * Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
6 *
7 * Copyright (c) 2005 Keir Fraser
8 *
9 * From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
10 */
11
12 #ifndef _ASM_X86_KVM_X86_EMULATE_H
13 #define _ASM_X86_KVM_X86_EMULATE_H
14
15 #include <asm/desc_defs.h>
16 #include "fpu.h"
17
18 struct x86_emulate_ctxt;
19 enum x86_intercept;
20 enum x86_intercept_stage;
21
22 struct x86_exception {
23 u8 vector;
24 bool error_code_valid;
25 u16 error_code;
26 bool nested_page_fault;
27 u64 address; /* cr2 or nested page fault gpa */
28 u8 async_page_fault;
29 unsigned long exit_qualification;
30 };
31
32 /*
33 * This struct is used to carry enough information from the instruction
34 * decoder to main KVM so that a decision can be made whether the
35 * instruction needs to be intercepted or not.
36 */
37 struct x86_instruction_info {
38 u8 intercept; /* which intercept */
39 u8 rep_prefix; /* rep prefix? */
40 u8 modrm_mod; /* mod part of modrm */
41 u8 modrm_reg; /* index of register used */
42 u8 modrm_rm; /* rm part of modrm */
43 u64 src_val; /* value of source operand */
44 u64 dst_val; /* value of destination operand */
45 u8 src_bytes; /* size of source operand */
46 u8 dst_bytes; /* size of destination operand */
47 u8 ad_bytes; /* size of src/dst address */
48 u64 next_rip; /* rip following the instruction */
49 };
50
51 /*
52 * x86_emulate_ops:
53 *
54 * These operations represent the instruction emulator's interface to memory.
55 * There are two categories of operation: those that act on ordinary memory
56 * regions (*_std), and those that act on memory regions known to require
57 * special treatment or emulation (*_emulated).
58 *
59 * The emulator assumes that an instruction accesses only one 'emulated memory'
60 * location, that this location is the given linear faulting address (cr2), and
61 * that this is one of the instruction's data operands. Instruction fetches and
62 * stack operations are assumed never to access emulated memory. The emulator
63 * automatically deduces which operand of a string-move operation is accessing
64 * emulated memory, and assumes that the other operand accesses normal memory.
65 *
66 * NOTES:
67 * 1. The emulator isn't very smart about emulated vs. standard memory.
68 * 'Emulated memory' access addresses should be checked for sanity.
69 * 'Normal memory' accesses may fault, and the caller must arrange to
70 * detect and handle reentrancy into the emulator via recursive faults.
71 * Accesses may be unaligned and may cross page boundaries.
72 * 2. If the access fails (cannot emulate, or a standard access faults) then
73 * it is up to the memop to propagate the fault to the guest VM via
74 * some out-of-band mechanism, unknown to the emulator. The memop signals
75 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
76 * then immediately bail.
77 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
78 * cmpxchg8b_emulated need support 8-byte accesses.
79 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
80 */
81 /* Access completed successfully: continue emulation as normal. */
82 #define X86EMUL_CONTINUE 0
83 /* Access is unhandleable: bail from emulation and return error to caller. */
84 #define X86EMUL_UNHANDLEABLE 1
85 /* Terminate emulation but return success to the caller. */
86 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
87 #define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */
88 #define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */
89 #define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */
90 #define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */
91
92 /* x86-specific emulation flags */
93 #define X86EMUL_F_WRITE BIT(0)
94 #define X86EMUL_F_FETCH BIT(1)
95 #define X86EMUL_F_IMPLICIT BIT(2)
96 #define X86EMUL_F_INVLPG BIT(3)
97
98 struct x86_emulate_ops {
99 void (*vm_bugged)(struct x86_emulate_ctxt *ctxt);
100 /*
101 * read_gpr: read a general purpose register (rax - r15)
102 *
103 * @reg: gpr number.
104 */
105 ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
106 /*
107 * write_gpr: write a general purpose register (rax - r15)
108 *
109 * @reg: gpr number.
110 * @val: value to write.
111 */
112 void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val);
113 /*
114 * read_std: Read bytes of standard (non-emulated/special) memory.
115 * Used for descriptor reading.
116 * @addr: [IN ] Linear address from which to read.
117 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
118 * @bytes: [IN ] Number of bytes to read from memory.
119 * @system:[IN ] Whether the access is forced to be at CPL0.
120 */
121 int (*read_std)(struct x86_emulate_ctxt *ctxt,
122 unsigned long addr, void *val,
123 unsigned int bytes,
124 struct x86_exception *fault, bool system);
125
126 /*
127 * write_std: Write bytes of standard (non-emulated/special) memory.
128 * Used for descriptor writing.
129 * @addr: [IN ] Linear address to which to write.
130 * @val: [OUT] Value write to memory, zero-extended to 'u_long'.
131 * @bytes: [IN ] Number of bytes to write to memory.
132 * @system:[IN ] Whether the access is forced to be at CPL0.
133 */
134 int (*write_std)(struct x86_emulate_ctxt *ctxt,
135 unsigned long addr, void *val, unsigned int bytes,
136 struct x86_exception *fault, bool system);
137 /*
138 * fetch: Read bytes of standard (non-emulated/special) memory.
139 * Used for instruction fetch.
140 * @addr: [IN ] Linear address from which to read.
141 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
142 * @bytes: [IN ] Number of bytes to read from memory.
143 */
144 int (*fetch)(struct x86_emulate_ctxt *ctxt,
145 unsigned long addr, void *val, unsigned int bytes,
146 struct x86_exception *fault);
147
148 /*
149 * read_emulated: Read bytes from emulated/special memory area.
150 * @addr: [IN ] Linear address from which to read.
151 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
152 * @bytes: [IN ] Number of bytes to read from memory.
153 */
154 int (*read_emulated)(struct x86_emulate_ctxt *ctxt,
155 unsigned long addr, void *val, unsigned int bytes,
156 struct x86_exception *fault);
157
158 /*
159 * write_emulated: Write bytes to emulated/special memory area.
160 * @addr: [IN ] Linear address to which to write.
161 * @val: [IN ] Value to write to memory (low-order bytes used as
162 * required).
163 * @bytes: [IN ] Number of bytes to write to memory.
164 */
165 int (*write_emulated)(struct x86_emulate_ctxt *ctxt,
166 unsigned long addr, const void *val,
167 unsigned int bytes,
168 struct x86_exception *fault);
169
170 /*
171 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
172 * emulated/special memory area.
173 * @addr: [IN ] Linear address to access.
174 * @old: [IN ] Value expected to be current at @addr.
175 * @new: [IN ] Value to write to @addr.
176 * @bytes: [IN ] Number of bytes to access using CMPXCHG.
177 */
178 int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt,
179 unsigned long addr,
180 const void *old,
181 const void *new,
182 unsigned int bytes,
183 struct x86_exception *fault);
184 void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr);
185
186 int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt,
187 int size, unsigned short port, void *val,
188 unsigned int count);
189
190 int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt,
191 int size, unsigned short port, const void *val,
192 unsigned int count);
193
194 bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector,
195 struct desc_struct *desc, u32 *base3, int seg);
196 void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector,
197 struct desc_struct *desc, u32 base3, int seg);
198 unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt,
199 int seg);
200 void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
201 void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
202 void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
203 void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
204 ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
205 int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
206 int (*cpl)(struct x86_emulate_ctxt *ctxt);
207 ulong (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr);
208 int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
209 int (*set_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
210 int (*get_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
211 int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
212 int (*check_rdpmc_early)(struct x86_emulate_ctxt *ctxt, u32 pmc);
213 int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata);
214 void (*halt)(struct x86_emulate_ctxt *ctxt);
215 void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
216 int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
217 int (*intercept)(struct x86_emulate_ctxt *ctxt,
218 struct x86_instruction_info *info,
219 enum x86_intercept_stage stage);
220
221 bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, u32 *eax, u32 *ebx,
222 u32 *ecx, u32 *edx, bool exact_only);
223 bool (*guest_has_movbe)(struct x86_emulate_ctxt *ctxt);
224 bool (*guest_has_fxsr)(struct x86_emulate_ctxt *ctxt);
225 bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt);
226 bool (*guest_cpuid_is_intel_compatible)(struct x86_emulate_ctxt *ctxt);
227
228 void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
229
230 bool (*is_smm)(struct x86_emulate_ctxt *ctxt);
231 bool (*is_guest_mode)(struct x86_emulate_ctxt *ctxt);
232 int (*leave_smm)(struct x86_emulate_ctxt *ctxt);
233 void (*triple_fault)(struct x86_emulate_ctxt *ctxt);
234 int (*set_xcr)(struct x86_emulate_ctxt *ctxt, u32 index, u64 xcr);
235
236 gva_t (*get_untagged_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr,
237 unsigned int flags);
238 };
239
240 /* Type, address-of, and value of an instruction's operand. */
241 struct operand {
242 enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
243 unsigned int bytes;
244 unsigned int count;
245 union {
246 unsigned long orig_val;
247 u64 orig_val64;
248 };
249 union {
250 unsigned long *reg;
251 struct segmented_address {
252 ulong ea;
253 unsigned seg;
254 } mem;
255 unsigned xmm;
256 unsigned mm;
257 } addr;
258 union {
259 unsigned long val;
260 u64 val64;
261 char valptr[sizeof(sse128_t)];
262 sse128_t vec_val;
263 u64 mm_val;
264 void *data;
265 };
266 };
267
268 struct fetch_cache {
269 u8 data[15];
270 u8 *ptr;
271 u8 *end;
272 };
273
274 struct read_cache {
275 u8 data[1024];
276 unsigned long pos;
277 unsigned long end;
278 };
279
280 /* Execution mode, passed to the emulator. */
281 enum x86emul_mode {
282 X86EMUL_MODE_REAL, /* Real mode. */
283 X86EMUL_MODE_VM86, /* Virtual 8086 mode. */
284 X86EMUL_MODE_PROT16, /* 16-bit protected mode. */
285 X86EMUL_MODE_PROT32, /* 32-bit protected mode. */
286 X86EMUL_MODE_PROT64, /* 64-bit (long) mode. */
287 };
288
289 /*
290 * fastop functions are declared as taking a never-defined fastop parameter,
291 * so they can't be called from C directly.
292 */
293 struct fastop;
294
295 typedef void (*fastop_t)(struct fastop *);
296
297 /*
298 * The emulator's _regs array tracks only the GPRs, i.e. excludes RIP. RIP is
299 * tracked/accessed via _eip, and except for RIP relative addressing, which
300 * also uses _eip, RIP cannot be a register operand nor can it be an operand in
301 * a ModRM or SIB byte.
302 */
303 #ifdef CONFIG_X86_64
304 #define NR_EMULATOR_GPRS 16
305 #else
306 #define NR_EMULATOR_GPRS 8
307 #endif
308
309 struct x86_emulate_ctxt {
310 void *vcpu;
311 const struct x86_emulate_ops *ops;
312
313 /* Register state before/after emulation. */
314 unsigned long eflags;
315 unsigned long eip; /* eip before instruction emulation */
316 /* Emulated execution mode, represented by an X86EMUL_MODE value. */
317 enum x86emul_mode mode;
318
319 /* interruptibility state, as a result of execution of STI or MOV SS */
320 int interruptibility;
321
322 bool perm_ok; /* do not check permissions if true */
323 bool tf; /* TF value before instruction (after for syscall/sysret) */
324
325 bool have_exception;
326 struct x86_exception exception;
327
328 /* GPA available */
329 bool gpa_available;
330 gpa_t gpa_val;
331
332 /*
333 * decode cache
334 */
335
336 /* current opcode length in bytes */
337 u8 opcode_len;
338 u8 b;
339 u8 intercept;
340 u8 op_bytes;
341 u8 ad_bytes;
342 union {
343 int (*execute)(struct x86_emulate_ctxt *ctxt);
344 fastop_t fop;
345 };
346 int (*check_perm)(struct x86_emulate_ctxt *ctxt);
347
348 bool rip_relative;
349 u8 rex_prefix;
350 u8 lock_prefix;
351 u8 rep_prefix;
352 /* bitmaps of registers in _regs[] that can be read */
353 u16 regs_valid;
354 /* bitmaps of registers in _regs[] that have been written */
355 u16 regs_dirty;
356 /* modrm */
357 u8 modrm;
358 u8 modrm_mod;
359 u8 modrm_reg;
360 u8 modrm_rm;
361 u8 modrm_seg;
362 u8 seg_override;
363 u64 d;
364 unsigned long _eip;
365
366 /* Here begins the usercopy section. */
367 struct operand src;
368 struct operand src2;
369 struct operand dst;
370 struct operand memop;
371 unsigned long _regs[NR_EMULATOR_GPRS];
372 struct operand *memopp;
373 struct fetch_cache fetch;
374 struct read_cache io_read;
375 struct read_cache mem_read;
376 bool is_branch;
377 };
378
379 #define KVM_EMULATOR_BUG_ON(cond, ctxt) \
380 ({ \
381 int __ret = (cond); \
382 \
383 if (WARN_ON_ONCE(__ret)) \
384 ctxt->ops->vm_bugged(ctxt); \
385 unlikely(__ret); \
386 })
387
388 /* Repeat String Operation Prefix */
389 #define REPE_PREFIX 0xf3
390 #define REPNE_PREFIX 0xf2
391
392 /* CPUID vendors */
393 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
394 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
395 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
396
397 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
398 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
399 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
400
401 #define X86EMUL_CPUID_VENDOR_HygonGenuine_ebx 0x6f677948
402 #define X86EMUL_CPUID_VENDOR_HygonGenuine_ecx 0x656e6975
403 #define X86EMUL_CPUID_VENDOR_HygonGenuine_edx 0x6e65476e
404
405 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
406 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
407 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
408
409 #define X86EMUL_CPUID_VENDOR_CentaurHauls_ebx 0x746e6543
410 #define X86EMUL_CPUID_VENDOR_CentaurHauls_ecx 0x736c7561
411 #define X86EMUL_CPUID_VENDOR_CentaurHauls_edx 0x48727561
412
413 static inline bool is_guest_vendor_intel(u32 ebx, u32 ecx, u32 edx)
414 {
415 return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx &&
416 ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx &&
417 edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx;
418 }
419
420 static inline bool is_guest_vendor_amd(u32 ebx, u32 ecx, u32 edx)
421 {
422 return (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx &&
423 ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx &&
424 edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx) ||
425 (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx &&
426 ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx &&
427 edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx);
428 }
429
430 static inline bool is_guest_vendor_hygon(u32 ebx, u32 ecx, u32 edx)
431 {
432 return ebx == X86EMUL_CPUID_VENDOR_HygonGenuine_ebx &&
433 ecx == X86EMUL_CPUID_VENDOR_HygonGenuine_ecx &&
434 edx == X86EMUL_CPUID_VENDOR_HygonGenuine_edx;
435 }
436
437 enum x86_intercept_stage {
438 X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */
439 X86_ICPT_PRE_EXCEPT,
440 X86_ICPT_POST_EXCEPT,
441 X86_ICPT_POST_MEMACCESS,
442 };
443
444 enum x86_intercept {
445 x86_intercept_none,
446 x86_intercept_cr_read,
447 x86_intercept_cr_write,
448 x86_intercept_clts,
449 x86_intercept_lmsw,
450 x86_intercept_smsw,
451 x86_intercept_dr_read,
452 x86_intercept_dr_write,
453 x86_intercept_lidt,
454 x86_intercept_sidt,
455 x86_intercept_lgdt,
456 x86_intercept_sgdt,
457 x86_intercept_lldt,
458 x86_intercept_sldt,
459 x86_intercept_ltr,
460 x86_intercept_str,
461 x86_intercept_rdtsc,
462 x86_intercept_rdpmc,
463 x86_intercept_pushf,
464 x86_intercept_popf,
465 x86_intercept_cpuid,
466 x86_intercept_rsm,
467 x86_intercept_iret,
468 x86_intercept_intn,
469 x86_intercept_invd,
470 x86_intercept_pause,
471 x86_intercept_hlt,
472 x86_intercept_invlpg,
473 x86_intercept_invlpga,
474 x86_intercept_vmrun,
475 x86_intercept_vmload,
476 x86_intercept_vmsave,
477 x86_intercept_vmmcall,
478 x86_intercept_stgi,
479 x86_intercept_clgi,
480 x86_intercept_skinit,
481 x86_intercept_rdtscp,
482 x86_intercept_rdpid,
483 x86_intercept_icebp,
484 x86_intercept_wbinvd,
485 x86_intercept_monitor,
486 x86_intercept_mwait,
487 x86_intercept_rdmsr,
488 x86_intercept_wrmsr,
489 x86_intercept_in,
490 x86_intercept_ins,
491 x86_intercept_out,
492 x86_intercept_outs,
493 x86_intercept_xsetbv,
494
495 nr_x86_intercepts
496 };
497
498 /* Host execution mode. */
499 #if defined(CONFIG_X86_32)
500 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
501 #elif defined(CONFIG_X86_64)
502 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
503 #endif
504
505 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int emulation_type);
506 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
507 #define EMULATION_FAILED -1
508 #define EMULATION_OK 0
509 #define EMULATION_RESTART 1
510 #define EMULATION_INTERCEPTED 2
511 void init_decode_cache(struct x86_emulate_ctxt *ctxt);
512 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
513 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
514 u16 tss_selector, int idt_index, int reason,
515 bool has_error_code, u32 error_code);
516 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
517 void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
518 void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
519 bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt);
520
521 static inline ulong reg_read(struct x86_emulate_ctxt *ctxt, unsigned nr)
522 {
523 if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt))
524 nr &= NR_EMULATOR_GPRS - 1;
525
526 if (!(ctxt->regs_valid & (1 << nr))) {
527 ctxt->regs_valid |= 1 << nr;
528 ctxt->_regs[nr] = ctxt->ops->read_gpr(ctxt, nr);
529 }
530 return ctxt->_regs[nr];
531 }
532
533 static inline ulong *reg_write(struct x86_emulate_ctxt *ctxt, unsigned nr)
534 {
535 if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt))
536 nr &= NR_EMULATOR_GPRS - 1;
537
538 BUILD_BUG_ON(sizeof(ctxt->regs_dirty) * BITS_PER_BYTE < NR_EMULATOR_GPRS);
539 BUILD_BUG_ON(sizeof(ctxt->regs_valid) * BITS_PER_BYTE < NR_EMULATOR_GPRS);
540
541 ctxt->regs_valid |= 1 << nr;
542 ctxt->regs_dirty |= 1 << nr;
543 return &ctxt->_regs[nr];
544 }
545
546 static inline ulong *reg_rmw(struct x86_emulate_ctxt *ctxt, unsigned nr)
547 {
548 reg_read(ctxt, nr);
549 return reg_write(ctxt, nr);
550 }
551
552 #endif /* _ASM_X86_KVM_X86_EMULATE_H */
553
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