Merge remote-tracking branch 'remotes/alistair23/tags/pull-riscv-to-apply-20211022...
[qemu.git] / scripts / dump-guest-memory.py
1 """
2 This python script adds a new gdb command, "dump-guest-memory". It
3 should be loaded with "source dump-guest-memory.py" at the (gdb)
4 prompt.
5
6 Copyright (C) 2013, Red Hat, Inc.
7
8 Authors:
9 Laszlo Ersek <lersek@redhat.com>
10 Janosch Frank <frankja@linux.vnet.ibm.com>
11
12 This work is licensed under the terms of the GNU GPL, version 2 or later. See
13 the COPYING file in the top-level directory.
14 """
15
16 import ctypes
17 import struct
18
19 try:
20 UINTPTR_T = gdb.lookup_type("uintptr_t")
21 except Exception as inst:
22 raise gdb.GdbError("Symbols must be loaded prior to sourcing dump-guest-memory.\n"
23 "Symbols may be loaded by 'attach'ing a QEMU process id or by "
24 "'load'ing a QEMU binary.")
25
26 TARGET_PAGE_SIZE = 0x1000
27 TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
28
29 # Special value for e_phnum. This indicates that the real number of
30 # program headers is too large to fit into e_phnum. Instead the real
31 # value is in the field sh_info of section 0.
32 PN_XNUM = 0xFFFF
33
34 EV_CURRENT = 1
35
36 ELFCLASS32 = 1
37 ELFCLASS64 = 2
38
39 ELFDATA2LSB = 1
40 ELFDATA2MSB = 2
41
42 ET_CORE = 4
43
44 PT_LOAD = 1
45 PT_NOTE = 4
46
47 EM_386 = 3
48 EM_PPC = 20
49 EM_PPC64 = 21
50 EM_S390 = 22
51 EM_AARCH = 183
52 EM_X86_64 = 62
53
54 VMCOREINFO_FORMAT_ELF = 1
55
56 def le16_to_cpu(val):
57 return struct.unpack("<H", struct.pack("=H", val))[0]
58
59 def le32_to_cpu(val):
60 return struct.unpack("<I", struct.pack("=I", val))[0]
61
62 def le64_to_cpu(val):
63 return struct.unpack("<Q", struct.pack("=Q", val))[0]
64
65 class ELF(object):
66 """Representation of a ELF file."""
67
68 def __init__(self, arch):
69 self.ehdr = None
70 self.notes = []
71 self.segments = []
72 self.notes_size = 0
73 self.endianness = None
74 self.elfclass = ELFCLASS64
75
76 if arch == 'aarch64-le':
77 self.endianness = ELFDATA2LSB
78 self.elfclass = ELFCLASS64
79 self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
80 self.ehdr.e_machine = EM_AARCH
81
82 elif arch == 'aarch64-be':
83 self.endianness = ELFDATA2MSB
84 self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
85 self.ehdr.e_machine = EM_AARCH
86
87 elif arch == 'X86_64':
88 self.endianness = ELFDATA2LSB
89 self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
90 self.ehdr.e_machine = EM_X86_64
91
92 elif arch == '386':
93 self.endianness = ELFDATA2LSB
94 self.elfclass = ELFCLASS32
95 self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
96 self.ehdr.e_machine = EM_386
97
98 elif arch == 's390':
99 self.endianness = ELFDATA2MSB
100 self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
101 self.ehdr.e_machine = EM_S390
102
103 elif arch == 'ppc64-le':
104 self.endianness = ELFDATA2LSB
105 self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
106 self.ehdr.e_machine = EM_PPC64
107
108 elif arch == 'ppc64-be':
109 self.endianness = ELFDATA2MSB
110 self.ehdr = get_arch_ehdr(self.endianness, self.elfclass)
111 self.ehdr.e_machine = EM_PPC64
112
113 else:
114 raise gdb.GdbError("No valid arch type specified.\n"
115 "Currently supported types:\n"
116 "aarch64-be, aarch64-le, X86_64, 386, s390, "
117 "ppc64-be, ppc64-le")
118
119 self.add_segment(PT_NOTE, 0, 0)
120
121 def add_note(self, n_name, n_desc, n_type):
122 """Adds a note to the ELF."""
123
124 note = get_arch_note(self.endianness, len(n_name), len(n_desc))
125 note.n_namesz = len(n_name) + 1
126 note.n_descsz = len(n_desc)
127 note.n_name = n_name.encode()
128 note.n_type = n_type
129
130 # Desc needs to be 4 byte aligned (although the 64bit spec
131 # specifies 8 byte). When defining n_desc as uint32 it will be
132 # automatically aligned but we need the memmove to copy the
133 # string into it.
134 ctypes.memmove(note.n_desc, n_desc.encode(), len(n_desc))
135
136 self.notes.append(note)
137 self.segments[0].p_filesz += ctypes.sizeof(note)
138 self.segments[0].p_memsz += ctypes.sizeof(note)
139
140
141 def add_vmcoreinfo_note(self, vmcoreinfo):
142 """Adds a vmcoreinfo note to the ELF dump."""
143 # compute the header size, and copy that many bytes from the note
144 header = get_arch_note(self.endianness, 0, 0)
145 ctypes.memmove(ctypes.pointer(header),
146 vmcoreinfo, ctypes.sizeof(header))
147 if header.n_descsz > 1 << 20:
148 print('warning: invalid vmcoreinfo size')
149 return
150 # now get the full note
151 note = get_arch_note(self.endianness,
152 header.n_namesz - 1, header.n_descsz)
153 ctypes.memmove(ctypes.pointer(note), vmcoreinfo, ctypes.sizeof(note))
154
155 self.notes.append(note)
156 self.segments[0].p_filesz += ctypes.sizeof(note)
157 self.segments[0].p_memsz += ctypes.sizeof(note)
158
159 def add_segment(self, p_type, p_paddr, p_size):
160 """Adds a segment to the elf."""
161
162 phdr = get_arch_phdr(self.endianness, self.elfclass)
163 phdr.p_type = p_type
164 phdr.p_paddr = p_paddr
165 phdr.p_vaddr = p_paddr
166 phdr.p_filesz = p_size
167 phdr.p_memsz = p_size
168 self.segments.append(phdr)
169 self.ehdr.e_phnum += 1
170
171 def to_file(self, elf_file):
172 """Writes all ELF structures to the passed file.
173
174 Structure:
175 Ehdr
176 Segment 0:PT_NOTE
177 Segment 1:PT_LOAD
178 Segment N:PT_LOAD
179 Note 0..N
180 Dump contents
181 """
182 elf_file.write(self.ehdr)
183 off = ctypes.sizeof(self.ehdr) + \
184 len(self.segments) * ctypes.sizeof(self.segments[0])
185
186 for phdr in self.segments:
187 phdr.p_offset = off
188 elf_file.write(phdr)
189 off += phdr.p_filesz
190
191 for note in self.notes:
192 elf_file.write(note)
193
194
195 def get_arch_note(endianness, len_name, len_desc):
196 """Returns a Note class with the specified endianness."""
197
198 if endianness == ELFDATA2LSB:
199 superclass = ctypes.LittleEndianStructure
200 else:
201 superclass = ctypes.BigEndianStructure
202
203 len_name = len_name + 1
204
205 class Note(superclass):
206 """Represents an ELF note, includes the content."""
207
208 _fields_ = [("n_namesz", ctypes.c_uint32),
209 ("n_descsz", ctypes.c_uint32),
210 ("n_type", ctypes.c_uint32),
211 ("n_name", ctypes.c_char * len_name),
212 ("n_desc", ctypes.c_uint32 * ((len_desc + 3) // 4))]
213 return Note()
214
215
216 class Ident(ctypes.Structure):
217 """Represents the ELF ident array in the ehdr structure."""
218
219 _fields_ = [('ei_mag0', ctypes.c_ubyte),
220 ('ei_mag1', ctypes.c_ubyte),
221 ('ei_mag2', ctypes.c_ubyte),
222 ('ei_mag3', ctypes.c_ubyte),
223 ('ei_class', ctypes.c_ubyte),
224 ('ei_data', ctypes.c_ubyte),
225 ('ei_version', ctypes.c_ubyte),
226 ('ei_osabi', ctypes.c_ubyte),
227 ('ei_abiversion', ctypes.c_ubyte),
228 ('ei_pad', ctypes.c_ubyte * 7)]
229
230 def __init__(self, endianness, elfclass):
231 self.ei_mag0 = 0x7F
232 self.ei_mag1 = ord('E')
233 self.ei_mag2 = ord('L')
234 self.ei_mag3 = ord('F')
235 self.ei_class = elfclass
236 self.ei_data = endianness
237 self.ei_version = EV_CURRENT
238
239
240 def get_arch_ehdr(endianness, elfclass):
241 """Returns a EHDR64 class with the specified endianness."""
242
243 if endianness == ELFDATA2LSB:
244 superclass = ctypes.LittleEndianStructure
245 else:
246 superclass = ctypes.BigEndianStructure
247
248 class EHDR64(superclass):
249 """Represents the 64 bit ELF header struct."""
250
251 _fields_ = [('e_ident', Ident),
252 ('e_type', ctypes.c_uint16),
253 ('e_machine', ctypes.c_uint16),
254 ('e_version', ctypes.c_uint32),
255 ('e_entry', ctypes.c_uint64),
256 ('e_phoff', ctypes.c_uint64),
257 ('e_shoff', ctypes.c_uint64),
258 ('e_flags', ctypes.c_uint32),
259 ('e_ehsize', ctypes.c_uint16),
260 ('e_phentsize', ctypes.c_uint16),
261 ('e_phnum', ctypes.c_uint16),
262 ('e_shentsize', ctypes.c_uint16),
263 ('e_shnum', ctypes.c_uint16),
264 ('e_shstrndx', ctypes.c_uint16)]
265
266 def __init__(self):
267 super(superclass, self).__init__()
268 self.e_ident = Ident(endianness, elfclass)
269 self.e_type = ET_CORE
270 self.e_version = EV_CURRENT
271 self.e_ehsize = ctypes.sizeof(self)
272 self.e_phoff = ctypes.sizeof(self)
273 self.e_phentsize = ctypes.sizeof(get_arch_phdr(endianness, elfclass))
274 self.e_phnum = 0
275
276
277 class EHDR32(superclass):
278 """Represents the 32 bit ELF header struct."""
279
280 _fields_ = [('e_ident', Ident),
281 ('e_type', ctypes.c_uint16),
282 ('e_machine', ctypes.c_uint16),
283 ('e_version', ctypes.c_uint32),
284 ('e_entry', ctypes.c_uint32),
285 ('e_phoff', ctypes.c_uint32),
286 ('e_shoff', ctypes.c_uint32),
287 ('e_flags', ctypes.c_uint32),
288 ('e_ehsize', ctypes.c_uint16),
289 ('e_phentsize', ctypes.c_uint16),
290 ('e_phnum', ctypes.c_uint16),
291 ('e_shentsize', ctypes.c_uint16),
292 ('e_shnum', ctypes.c_uint16),
293 ('e_shstrndx', ctypes.c_uint16)]
294
295 def __init__(self):
296 super(superclass, self).__init__()
297 self.e_ident = Ident(endianness, elfclass)
298 self.e_type = ET_CORE
299 self.e_version = EV_CURRENT
300 self.e_ehsize = ctypes.sizeof(self)
301 self.e_phoff = ctypes.sizeof(self)
302 self.e_phentsize = ctypes.sizeof(get_arch_phdr(endianness, elfclass))
303 self.e_phnum = 0
304
305 # End get_arch_ehdr
306 if elfclass == ELFCLASS64:
307 return EHDR64()
308 else:
309 return EHDR32()
310
311
312 def get_arch_phdr(endianness, elfclass):
313 """Returns a 32 or 64 bit PHDR class with the specified endianness."""
314
315 if endianness == ELFDATA2LSB:
316 superclass = ctypes.LittleEndianStructure
317 else:
318 superclass = ctypes.BigEndianStructure
319
320 class PHDR64(superclass):
321 """Represents the 64 bit ELF program header struct."""
322
323 _fields_ = [('p_type', ctypes.c_uint32),
324 ('p_flags', ctypes.c_uint32),
325 ('p_offset', ctypes.c_uint64),
326 ('p_vaddr', ctypes.c_uint64),
327 ('p_paddr', ctypes.c_uint64),
328 ('p_filesz', ctypes.c_uint64),
329 ('p_memsz', ctypes.c_uint64),
330 ('p_align', ctypes.c_uint64)]
331
332 class PHDR32(superclass):
333 """Represents the 32 bit ELF program header struct."""
334
335 _fields_ = [('p_type', ctypes.c_uint32),
336 ('p_offset', ctypes.c_uint32),
337 ('p_vaddr', ctypes.c_uint32),
338 ('p_paddr', ctypes.c_uint32),
339 ('p_filesz', ctypes.c_uint32),
340 ('p_memsz', ctypes.c_uint32),
341 ('p_flags', ctypes.c_uint32),
342 ('p_align', ctypes.c_uint32)]
343
344 # End get_arch_phdr
345 if elfclass == ELFCLASS64:
346 return PHDR64()
347 else:
348 return PHDR32()
349
350
351 def int128_get64(val):
352 """Returns low 64bit part of Int128 struct."""
353
354 try:
355 assert val["hi"] == 0
356 return val["lo"]
357 except gdb.error:
358 u64t = gdb.lookup_type('uint64_t').array(2)
359 u64 = val.cast(u64t)
360 if sys.byteorder == 'little':
361 assert u64[1] == 0
362 return u64[0]
363 else:
364 assert u64[0] == 0
365 return u64[1]
366
367
368 def qlist_foreach(head, field_str):
369 """Generator for qlists."""
370
371 var_p = head["lh_first"]
372 while var_p != 0:
373 var = var_p.dereference()
374 var_p = var[field_str]["le_next"]
375 yield var
376
377
378 def qemu_map_ram_ptr(block, offset):
379 """Returns qemu vaddr for given guest physical address."""
380
381 return block["host"] + offset
382
383
384 def memory_region_get_ram_ptr(memory_region):
385 if memory_region["alias"] != 0:
386 return (memory_region_get_ram_ptr(memory_region["alias"].dereference())
387 + memory_region["alias_offset"])
388
389 return qemu_map_ram_ptr(memory_region["ram_block"], 0)
390
391
392 def get_guest_phys_blocks():
393 """Returns a list of ram blocks.
394
395 Each block entry contains:
396 'target_start': guest block phys start address
397 'target_end': guest block phys end address
398 'host_addr': qemu vaddr of the block's start
399 """
400
401 guest_phys_blocks = []
402
403 print("guest RAM blocks:")
404 print("target_start target_end host_addr message "
405 "count")
406 print("---------------- ---------------- ---------------- ------- "
407 "-----")
408
409 current_map_p = gdb.parse_and_eval("address_space_memory.current_map")
410 current_map = current_map_p.dereference()
411
412 # Conversion to int is needed for python 3
413 # compatibility. Otherwise range doesn't cast the value itself and
414 # breaks.
415 for cur in range(int(current_map["nr"])):
416 flat_range = (current_map["ranges"] + cur).dereference()
417 memory_region = flat_range["mr"].dereference()
418
419 # we only care about RAM
420 if (not memory_region["ram"] or
421 memory_region["ram_device"] or
422 memory_region["nonvolatile"]):
423 continue
424
425 section_size = int128_get64(flat_range["addr"]["size"])
426 target_start = int128_get64(flat_range["addr"]["start"])
427 target_end = target_start + section_size
428 host_addr = (memory_region_get_ram_ptr(memory_region)
429 + flat_range["offset_in_region"])
430 predecessor = None
431
432 # find continuity in guest physical address space
433 if len(guest_phys_blocks) > 0:
434 predecessor = guest_phys_blocks[-1]
435 predecessor_size = (predecessor["target_end"] -
436 predecessor["target_start"])
437
438 # the memory API guarantees monotonically increasing
439 # traversal
440 assert predecessor["target_end"] <= target_start
441
442 # we want continuity in both guest-physical and
443 # host-virtual memory
444 if (predecessor["target_end"] < target_start or
445 predecessor["host_addr"] + predecessor_size != host_addr):
446 predecessor = None
447
448 if predecessor is None:
449 # isolated mapping, add it to the list
450 guest_phys_blocks.append({"target_start": target_start,
451 "target_end": target_end,
452 "host_addr": host_addr})
453 message = "added"
454 else:
455 # expand predecessor until @target_end; predecessor's
456 # start doesn't change
457 predecessor["target_end"] = target_end
458 message = "joined"
459
460 print("%016x %016x %016x %-7s %5u" %
461 (target_start, target_end, host_addr.cast(UINTPTR_T),
462 message, len(guest_phys_blocks)))
463
464 return guest_phys_blocks
465
466
467 # The leading docstring doesn't have idiomatic Python formatting. It is
468 # printed by gdb's "help" command (the first line is printed in the
469 # "help data" summary), and it should match how other help texts look in
470 # gdb.
471 class DumpGuestMemory(gdb.Command):
472 """Extract guest vmcore from qemu process coredump.
473
474 The two required arguments are FILE and ARCH:
475 FILE identifies the target file to write the guest vmcore to.
476 ARCH specifies the architecture for which the core will be generated.
477
478 This GDB command reimplements the dump-guest-memory QMP command in
479 python, using the representation of guest memory as captured in the qemu
480 coredump. The qemu process that has been dumped must have had the
481 command line option "-machine dump-guest-core=on" which is the default.
482
483 For simplicity, the "paging", "begin" and "end" parameters of the QMP
484 command are not supported -- no attempt is made to get the guest's
485 internal paging structures (ie. paging=false is hard-wired), and guest
486 memory is always fully dumped.
487
488 Currently aarch64-be, aarch64-le, X86_64, 386, s390, ppc64-be,
489 ppc64-le guests are supported.
490
491 The CORE/NT_PRSTATUS and QEMU notes (that is, the VCPUs' statuses) are
492 not written to the vmcore. Preparing these would require context that is
493 only present in the KVM host kernel module when the guest is alive. A
494 fake ELF note is written instead, only to keep the ELF parser of "crash"
495 happy.
496
497 Dependent on how busted the qemu process was at the time of the
498 coredump, this command might produce unpredictable results. If qemu
499 deliberately called abort(), or it was dumped in response to a signal at
500 a halfway fortunate point, then its coredump should be in reasonable
501 shape and this command should mostly work."""
502
503 def __init__(self):
504 super(DumpGuestMemory, self).__init__("dump-guest-memory",
505 gdb.COMMAND_DATA,
506 gdb.COMPLETE_FILENAME)
507 self.elf = None
508 self.guest_phys_blocks = None
509
510 def dump_init(self, vmcore):
511 """Prepares and writes ELF structures to core file."""
512
513 # Needed to make crash happy, data for more useful notes is
514 # not available in a qemu core.
515 self.elf.add_note("NONE", "EMPTY", 0)
516
517 # We should never reach PN_XNUM for paging=false dumps,
518 # there's just a handful of discontiguous ranges after
519 # merging.
520 # The constant is needed to account for the PT_NOTE segment.
521 phdr_num = len(self.guest_phys_blocks) + 1
522 assert phdr_num < PN_XNUM
523
524 for block in self.guest_phys_blocks:
525 block_size = block["target_end"] - block["target_start"]
526 self.elf.add_segment(PT_LOAD, block["target_start"], block_size)
527
528 self.elf.to_file(vmcore)
529
530 def dump_iterate(self, vmcore):
531 """Writes guest core to file."""
532
533 qemu_core = gdb.inferiors()[0]
534 for block in self.guest_phys_blocks:
535 cur = block["host_addr"]
536 left = block["target_end"] - block["target_start"]
537 print("dumping range at %016x for length %016x" %
538 (cur.cast(UINTPTR_T), left))
539
540 while left > 0:
541 chunk_size = min(TARGET_PAGE_SIZE, left)
542 chunk = qemu_core.read_memory(cur, chunk_size)
543 vmcore.write(chunk)
544 cur += chunk_size
545 left -= chunk_size
546
547 def phys_memory_read(self, addr, size):
548 qemu_core = gdb.inferiors()[0]
549 for block in self.guest_phys_blocks:
550 if block["target_start"] <= addr \
551 and addr + size <= block["target_end"]:
552 haddr = block["host_addr"] + (addr - block["target_start"])
553 return qemu_core.read_memory(haddr, size)
554 return None
555
556 def add_vmcoreinfo(self):
557 if gdb.lookup_symbol("vmcoreinfo_realize")[0] is None:
558 return
559 vmci = 'vmcoreinfo_realize::vmcoreinfo_state'
560 if not gdb.parse_and_eval("%s" % vmci) \
561 or not gdb.parse_and_eval("(%s)->has_vmcoreinfo" % vmci):
562 return
563
564 fmt = gdb.parse_and_eval("(%s)->vmcoreinfo.guest_format" % vmci)
565 addr = gdb.parse_and_eval("(%s)->vmcoreinfo.paddr" % vmci)
566 size = gdb.parse_and_eval("(%s)->vmcoreinfo.size" % vmci)
567
568 fmt = le16_to_cpu(fmt)
569 addr = le64_to_cpu(addr)
570 size = le32_to_cpu(size)
571
572 if fmt != VMCOREINFO_FORMAT_ELF:
573 return
574
575 vmcoreinfo = self.phys_memory_read(addr, size)
576 if vmcoreinfo:
577 self.elf.add_vmcoreinfo_note(bytes(vmcoreinfo))
578
579 def invoke(self, args, from_tty):
580 """Handles command invocation from gdb."""
581
582 # Unwittingly pressing the Enter key after the command should
583 # not dump the same multi-gig coredump to the same file.
584 self.dont_repeat()
585
586 argv = gdb.string_to_argv(args)
587 if len(argv) != 2:
588 raise gdb.GdbError("usage: dump-guest-memory FILE ARCH")
589
590 self.elf = ELF(argv[1])
591 self.guest_phys_blocks = get_guest_phys_blocks()
592 self.add_vmcoreinfo()
593
594 with open(argv[0], "wb") as vmcore:
595 self.dump_init(vmcore)
596 self.dump_iterate(vmcore)
597
598 DumpGuestMemory()