scripts/vmstate-static-checker.py

   1 #!/usr/bin/python
   2 #
   3 # Compares vmstate information stored in JSON format, obtained from
   4 # the -dump-vmstate QEMU command.
   5 #
   6 # Copyright 2014 Amit Shah <amit.shah@redhat.com>
   7 # Copyright 2014 Red Hat, Inc.
   8 #
   9 # This program is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 2 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # This program is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License along
  20 # with this program; if not, see <http://www.gnu.org/licenses/>.
  21
  22 import argparse
  23 import json
  24 import sys
  25
  26 # Count the number of errors found
  27 taint = 0
  28
  29 def bump_taint():
  30     global taint
  31
  32     # Ensure we don't wrap around or reset to 0 -- the shell only has
  33     # an 8-bit return value.
  34     if taint < 255:
  35         taint = taint + 1
  36
  37
  38 def check_fields_match(name, s_field, d_field):
  39     if s_field == d_field:
  40         return True
  41
  42     # Some fields changed names between qemu versions.  This list
  43     # is used to whitelist such changes in each section / description.
  44     changed_names = {
  45         'apic': ['timer', 'timer_expiry'],
  46         'e1000': ['dev', 'parent_obj'],
  47         'ehci': ['dev', 'pcidev'],
  48         'I440FX': ['dev', 'parent_obj'],
  49         'ich9_ahci': ['card', 'parent_obj'],
  50         'ich9-ahci': ['ahci', 'ich9_ahci'],
  51         'ioh3420': ['PCIDevice', 'PCIEDevice'],
  52         'ioh-3240-express-root-port': ['port.br.dev',
  53                                        'parent_obj.parent_obj.parent_obj',
  54                                        'port.br.dev.exp.aer_log',
  55                                 'parent_obj.parent_obj.parent_obj.exp.aer_log'],
  56         'cirrus_vga': ['hw_cursor_x', 'vga.hw_cursor_x',
  57                        'hw_cursor_y', 'vga.hw_cursor_y'],
  58         'lsiscsi': ['dev', 'parent_obj'],
  59         'mch': ['d', 'parent_obj'],
  60         'pci_bridge': ['bridge.dev', 'parent_obj', 'bridge.dev.shpc', 'shpc'],
  61         'pcnet': ['pci_dev', 'parent_obj'],
  62         'PIIX3': ['pci_irq_levels', 'pci_irq_levels_vmstate'],
  63         'piix4_pm': ['dev', 'parent_obj', 'pci0_status',
  64                      'acpi_pci_hotplug.acpi_pcihp_pci_status[0x0]',
  65                      'pm1a.sts', 'ar.pm1.evt.sts', 'pm1a.en', 'ar.pm1.evt.en',
  66                      'pm1_cnt.cnt', 'ar.pm1.cnt.cnt',
  67                      'tmr.timer', 'ar.tmr.timer',
  68                      'tmr.overflow_time', 'ar.tmr.overflow_time',
  69                      'gpe', 'ar.gpe'],
  70         'rtl8139': ['dev', 'parent_obj'],
  71         'qxl': ['num_surfaces', 'ssd.num_surfaces'],
  72         'usb-ccid': ['abProtocolDataStructure', 'abProtocolDataStructure.data'],
  73         'usb-host': ['dev', 'parent_obj'],
  74         'usb-mouse': ['usb-ptr-queue', 'HIDPointerEventQueue'],
  75         'usb-tablet': ['usb-ptr-queue', 'HIDPointerEventQueue'],
  76         'vmware_vga': ['card', 'parent_obj'],
  77         'vmware_vga_internal': ['depth', 'new_depth'],
  78         'xhci': ['pci_dev', 'parent_obj'],
  79         'x3130-upstream': ['PCIDevice', 'PCIEDevice'],
  80         'xio3130-express-downstream-port': ['port.br.dev',
  81                                             'parent_obj.parent_obj.parent_obj',
  82                                             'port.br.dev.exp.aer_log',
  83                                 'parent_obj.parent_obj.parent_obj.exp.aer_log'],
  84         'xio3130-downstream': ['PCIDevice', 'PCIEDevice'],
  85         'xio3130-express-upstream-port': ['br.dev', 'parent_obj.parent_obj',
  86                                           'br.dev.exp.aer_log',
  87                                           'parent_obj.parent_obj.exp.aer_log'],
  88     }
  89
  90     if not name in changed_names:
  91         return False
  92
  93     if s_field in changed_names[name] and d_field in changed_names[name]:
  94         return True
  95
  96     return False
  97
  98 def get_changed_sec_name(sec):
  99     # Section names can change -- see commit 292b1634 for an example.
 100     changes = {
 101         "ICH9 LPC": "ICH9-LPC",
 102         "e1000-82540em": "e1000",
 103     }
 104
 105     for item in changes:
 106         if item == sec:
 107             return changes[item]
 108         if changes[item] == sec:
 109             return item
 110     return ""
 111
 112 def exists_in_substruct(fields, item):
 113     # Some QEMU versions moved a few fields inside a substruct.  This
 114     # kept the on-wire format the same.  This function checks if
 115     # something got shifted inside a substruct.  For example, the
 116     # change in commit 1f42d22233b4f3d1a2933ff30e8d6a6d9ee2d08f
 117
 118     if not "Description" in fields:
 119         return False
 120
 121     if not "Fields" in fields["Description"]:
 122         return False
 123
 124     substruct_fields = fields["Description"]["Fields"]
 125
 126     if substruct_fields == []:
 127         return False
 128
 129     return check_fields_match(fields["Description"]["name"],
 130                               substruct_fields[0]["field"], item)
 131
 132
 133 def check_fields(src_fields, dest_fields, desc, sec):
 134     # This function checks for all the fields in a section.  If some
 135     # fields got embedded into a substruct, this function will also
 136     # attempt to check inside the substruct.
 137
 138     d_iter = iter(dest_fields)
 139     s_iter = iter(src_fields)
 140
 141     # Using these lists as stacks to store previous value of s_iter
 142     # and d_iter, so that when time comes to exit out of a substruct,
 143     # we can go back one level up and continue from where we left off.
 144
 145     s_iter_list = []
 146     d_iter_list = []
 147
 148     advance_src = True
 149     advance_dest = True
 150     unused_count = 0
 151
 152     while True:
 153         if advance_src:
 154             try:
 155                 s_item = s_iter.next()
 156             except StopIteration:
 157                 if s_iter_list == []:
 158                     break
 159
 160                 s_iter = s_iter_list.pop()
 161                 continue
 162         else:
 163             if unused_count == 0:
 164                 # We want to avoid advancing just once -- when entering a
 165                 # dest substruct, or when exiting one.
 166                 advance_src = True
 167
 168         if advance_dest:
 169             try:
 170                 d_item = d_iter.next()
 171             except StopIteration:
 172                 if d_iter_list == []:
 173                     # We were not in a substruct
 174                     print "Section \"" + sec + "\",",
 175                     print "Description " + "\"" + desc + "\":",
 176                     print "expected field \"" + s_item["field"] + "\",",
 177                     print "while dest has no further fields"
 178                     bump_taint()
 179                     break
 180
 181                 d_iter = d_iter_list.pop()
 182                 advance_src = False
 183                 continue
 184         else:
 185             if unused_count == 0:
 186                 advance_dest = True
 187
 188         if unused_count != 0:
 189             if advance_dest == False:
 190                 unused_count = unused_count - s_item["size"]
 191                 if unused_count == 0:
 192                     advance_dest = True
 193                     continue
 194                 if unused_count < 0:
 195                     print "Section \"" + sec + "\",",
 196                     print "Description \"" + desc + "\":",
 197                     print "unused size mismatch near \"",
 198                     print s_item["field"] + "\""
 199                     bump_taint()
 200                     break
 201                 continue
 202
 203             if advance_src == False:
 204                 unused_count = unused_count - d_item["size"]
 205                 if unused_count == 0:
 206                     advance_src = True
 207                     continue
 208                 if unused_count < 0:
 209                     print "Section \"" + sec + "\",",
 210                     print "Description \"" + desc + "\":",
 211                     print "unused size mismatch near \"",
 212                     print d_item["field"] + "\""
 213                     bump_taint()
 214                     break
 215                 continue
 216
 217         if not check_fields_match(desc, s_item["field"], d_item["field"]):
 218             # Some fields were put in substructs, keeping the
 219             # on-wire format the same, but breaking static tools
 220             # like this one.
 221
 222             # First, check if dest has a new substruct.
 223             if exists_in_substruct(d_item, s_item["field"]):
 224                 # listiterators don't have a prev() function, so we
 225                 # have to store our current location, descend into the
 226                 # substruct, and ensure we come out as if nothing
 227                 # happened when the substruct is over.
 228                 #
 229                 # Essentially we're opening the substructs that got
 230                 # added which didn't change the wire format.
 231                 d_iter_list.append(d_iter)
 232                 substruct_fields = d_item["Description"]["Fields"]
 233                 d_iter = iter(substruct_fields)
 234                 advance_src = False
 235                 continue
 236
 237             # Next, check if src has substruct that dest removed
 238             # (can happen in backward migration: 2.0 -> 1.5)
 239             if exists_in_substruct(s_item, d_item["field"]):
 240                 s_iter_list.append(s_iter)
 241                 substruct_fields = s_item["Description"]["Fields"]
 242                 s_iter = iter(substruct_fields)
 243                 advance_dest = False
 244                 continue
 245
 246             if s_item["field"] == "unused" or d_item["field"] == "unused":
 247                 if s_item["size"] == d_item["size"]:
 248                     continue
 249
 250                 if d_item["field"] == "unused":
 251                     advance_dest = False
 252                     unused_count = d_item["size"] - s_item["size"]
 253                     continue
 254
 255                 if s_item["field"] == "unused":
 256                     advance_src = False
 257                     unused_count = s_item["size"] - d_item["size"]
 258                     continue
 259
 260             print "Section \"" + sec + "\",",
 261             print "Description \"" + desc + "\":",
 262             print "expected field \"" + s_item["field"] + "\",",
 263             print "got \"" + d_item["field"] + "\"; skipping rest"
 264             bump_taint()
 265             break
 266
 267         check_version(s_item, d_item, sec, desc)
 268
 269         if not "Description" in s_item:
 270             # Check size of this field only if it's not a VMSTRUCT entry
 271             check_size(s_item, d_item, sec, desc, s_item["field"])
 272
 273         check_description_in_list(s_item, d_item, sec, desc)
 274
 275
 276 def check_subsections(src_sub, dest_sub, desc, sec):
 277     for s_item in src_sub:
 278         found = False
 279         for d_item in dest_sub:
 280             if s_item["name"] != d_item["name"]:
 281                 continue
 282
 283             found = True
 284             check_descriptions(s_item, d_item, sec)
 285
 286         if not found:
 287             print "Section \"" + sec + "\", Description \"" + desc + "\":",
 288             print "Subsection \"" + s_item["name"] + "\" not found"
 289             bump_taint()
 290
 291
 292 def check_description_in_list(s_item, d_item, sec, desc):
 293     if not "Description" in s_item:
 294         return
 295
 296     if not "Description" in d_item:
 297         print "Section \"" + sec + "\", Description \"" + desc + "\",",
 298         print "Field \"" + s_item["field"] + "\": missing description"
 299         bump_taint()
 300         return
 301
 302     check_descriptions(s_item["Description"], d_item["Description"], sec)
 303
 304
 305 def check_descriptions(src_desc, dest_desc, sec):
 306     check_version(src_desc, dest_desc, sec, src_desc["name"])
 307
 308     if not check_fields_match(sec, src_desc["name"], dest_desc["name"]):
 309         print "Section \"" + sec + "\":",
 310         print "Description \"" + src_desc["name"] + "\"",
 311         print "missing, got \"" + dest_desc["name"] + "\" instead; skipping"
 312         bump_taint()
 313         return
 314
 315     for f in src_desc:
 316         if not f in dest_desc:
 317             print "Section \"" + sec + "\"",
 318             print "Description \"" + src_desc["name"] + "\":",
 319             print "Entry \"" + f + "\" missing"
 320             bump_taint()
 321             continue
 322
 323         if f == 'Fields':
 324             check_fields(src_desc[f], dest_desc[f], src_desc["name"], sec)
 325
 326         if f == 'Subsections':
 327             check_subsections(src_desc[f], dest_desc[f], src_desc["name"], sec)
 328
 329
 330 def check_version(s, d, sec, desc=None):
 331     if s["version_id"] > d["version_id"]:
 332         print "Section \"" + sec + "\"",
 333         if desc:
 334             print "Description \"" + desc + "\":",
 335         print "version error:", s["version_id"], ">", d["version_id"]
 336         bump_taint()
 337
 338     if not "minimum_version_id" in d:
 339         return
 340
 341     if s["version_id"] < d["minimum_version_id"]:
 342         print "Section \"" + sec + "\"",
 343         if desc:
 344             print "Description \"" + desc + "\":",
 345             print "minimum version error:", s["version_id"], "<",
 346             print d["minimum_version_id"]
 347             bump_taint()
 348
 349
 350 def check_size(s, d, sec, desc=None, field=None):
 351     if s["size"] != d["size"]:
 352         print "Section \"" + sec + "\"",
 353         if desc:
 354             print "Description \"" + desc + "\"",
 355         if field:
 356             print "Field \"" + field + "\"",
 357         print "size mismatch:", s["size"], ",", d["size"]
 358         bump_taint()
 359
 360
 361 def check_machine_type(s, d):
 362     if s["Name"] != d["Name"]:
 363         print "Warning: checking incompatible machine types:",
 364         print "\"" + s["Name"] + "\", \"" + d["Name"] + "\""
 365     return
 366
 367
 368 def main():
 369     help_text = "Parse JSON-formatted vmstate dumps from QEMU in files SRC and DEST.  Checks whether migration from SRC to DEST QEMU versions would break based on the VMSTATE information contained within the JSON outputs.  The JSON output is created from a QEMU invocation with the -dump-vmstate parameter and a filename argument to it.  Other parameters to QEMU do not matter, except the -M (machine type) parameter."
 370
 371     parser = argparse.ArgumentParser(description=help_text)
 372     parser.add_argument('-s', '--src', type=file, required=True,
 373                         help='json dump from src qemu')
 374     parser.add_argument('-d', '--dest', type=file, required=True,
 375                         help='json dump from dest qemu')
 376     parser.add_argument('--reverse', required=False, default=False,
 377                         action='store_true',
 378                         help='reverse the direction')
 379     args = parser.parse_args()
 380
 381     src_data = json.load(args.src)
 382     dest_data = json.load(args.dest)
 383     args.src.close()
 384     args.dest.close()
 385
 386     if args.reverse:
 387         temp = src_data
 388         src_data = dest_data
 389         dest_data = temp
 390
 391     for sec in src_data:
 392         dest_sec = sec
 393         if not dest_sec in dest_data:
 394             # Either the section name got changed, or the section
 395             # doesn't exist in dest.
 396             dest_sec = get_changed_sec_name(sec)
 397             if not dest_sec in dest_data:
 398                 print "Section \"" + sec + "\" does not exist in dest"
 399                 bump_taint()
 400                 continue
 401
 402         s = src_data[sec]
 403         d = dest_data[dest_sec]
 404
 405         if sec == "vmschkmachine":
 406             check_machine_type(s, d)
 407             continue
 408
 409         check_version(s, d, sec)
 410
 411         for entry in s:
 412             if not entry in d:
 413                 print "Section \"" + sec + "\": Entry \"" + entry + "\"",
 414                 print "missing"
 415                 bump_taint()
 416                 continue
 417
 418             if entry == "Description":
 419                 check_descriptions(s[entry], d[entry], sec)
 420
 421     return taint
 422
 423
 424 if __name__ == '__main__':
 425     sys.exit(main())