This script compares the vmstate dumps in JSON format as output by QEMU with the -dump-vmstate option.
It flags various errors, like version mismatch, sections going away, size mismatches, etc. This script is tolerant of a few changes that do not change the on-wire format, like embedding a few fields within substructs. The script takes -s/--src and -d/--dest parameters, to which filenames are given as arguments. Signed-off-by: Amit Shah <amit.s...@redhat.com> --- scripts/vmstate-static-checker.py | 304 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 304 insertions(+) create mode 100755 scripts/vmstate-static-checker.py diff --git a/scripts/vmstate-static-checker.py b/scripts/vmstate-static-checker.py new file mode 100755 index 0000000..c24e8bb --- /dev/null +++ b/scripts/vmstate-static-checker.py @@ -0,0 +1,304 @@ +#!/usr/bin/python +# +# Compares vmstate information stored in JSON format, obtained from +# the -dump-vmstate QEMU command. +# +# Copyright 2014 Amit Shah <amit.s...@redhat.com> +# Copyright 2014 Red Hat, Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, see <http://www.gnu.org/licenses/>. + +import json +import argparse + +def check_fields_match(s_field, d_field): + if s_field == d_field: + return True + + # Some fields changed names between qemu versions. This list + # is used to whitelist such changes. + changed_names = [ + ['d', 'dev', 'pcidev', 'pci_dev', 'parent_obj'], + ['card', 'parent_obj'], + ['bridge.dev', 'parent_obj'], + ['br.dev', 'parent_obj.parent_obj'], + ['port.br.dev', 'parent_obj.parent_obj.parent_obj'], + ['port.br.dev.exp.aer_log', + 'parent_obj.parent_obj.parent_obj.exp.aer_log'], + ['br.dev.exp.aer_log', + 'parent_obj.parent_obj.exp.aer_log'], + ['shpc', 'bridge.dev.shpc'], + ['pci0_status', + 'acpi_pci_hotplug.acpi_pcihp_pci_status[0x0]'], + ['pci_irq_levels', 'pci_irq_levels_vmstate'], + ['usb-ptr-queue', 'HIDPointerEventQueue'], + ['num_surfaces', 'ssd.num_surfaces'], + ['timer', 'timer_expiry'], + ] + + for grp in changed_names: + if s_field in grp and d_field in grp: + return True + + return False + + +def exists_in_substruct(fields, item): + # Some QEMU versions moved a few fields inside a substruct. This + # kept the on-wire format the same. This function checks if + # something got shifted inside a substruct. For example, the + # change in commit 1f42d22233b4f3d1a2933ff30e8d6a6d9ee2d08f + + if not "Description" in fields: + return False + + if not "Fields" in fields["Description"]: + return False + + substruct_fields = fields["Description"]["Fields"] + + if substruct_fields == []: + return False + + return check_fields_match(substruct_fields[0]["field"], item) + + +def check_fields(src_fields, dest_fields, desc, sec): + # This function checks for all the fields in a section. If some + # fields got embedded into a substruct, this function will also + # attempt to check inside the substruct. + + d_iter = iter(dest_fields) + s_iter = iter(src_fields) + + # Using these lists as stacks to store previous value of s_iter + # and d_iter, so that when time comes to exit out of a substruct, + # we can go back one level up and continue from where we left off. + + s_iter_list = [] + d_iter_list = [] + + advance_src = True + advance_dest = True + + while True: + if advance_src: + try: + s_item = s_iter.next() + except StopIteration: + if s_iter_list == []: + break + + s_iter = s_iter_list.pop() + continue + else: + # We want to avoid advancing just once -- when entering a + # substruct, or when exiting one. + advance_src = True + + if advance_dest: + try: + d_item = d_iter.next() + except StopIteration: + if d_iter_list == []: + # We were not in a substruct + print "Section \"" + sec + "\",", + print "Description " + "\"" + desc + "\":", + print "expected field \"" + s_item["field"] + "\",", + print "while dest has no further fields" + break + + d_iter = d_iter_list.pop() + advance_src = False + continue + else: + advance_dest = True + + if not check_fields_match(s_item["field"], d_item["field"]): + # Some fields were put in substructs, keeping the + # on-wire format the same, but breaking static tools + # like this one. + + # First, check if dest has a new substruct. + if exists_in_substruct(d_item, s_item["field"]): + # listiterators don't have a prev() function, so we + # have to store our current location, descend into the + # substruct, and ensure we come out as if nothing + # happened when the substruct is over. + # + # Essentially we're opening the substructs that got + # added which didn't change the wire format. + d_iter_list.append(d_iter) + substruct_fields = d_item["Description"]["Fields"] + d_iter = iter(substruct_fields) + advance_src = False + continue + else: + # Next, check if src has substruct that dest removed + # (can happen in backward migration: 2.0 -> 1.5) + if exists_in_substruct(s_item, d_item["field"]): + s_iter_list.append(s_iter) + substruct_fields = s_item["Description"]["Fields"] + s_iter = iter(substruct_fields) + advance_dest = False + continue + else: + print "Section \"" + sec + "\",", + print "Description \"" + desc + "\":", + print "expected field \"" + s_item["field"] + "\",", + print "got \"" + d_item["field"] + "\"; skipping rest" + break + + check_version(s_item, d_item, sec, desc) + + if not "Description" in s_item: + # Check size of this field only if it's not a VMSTRUCT entry + check_size(s_item, d_item, sec, desc, s_item["field"]) + + check_description_in_list(s_item, d_item, sec, desc) + + +def check_subsections(src_sub, dest_sub, desc, sec): + for s_item in src_sub: + found = False + for d_item in dest_sub: + if s_item["name"] != d_item["name"]: + continue + + found = True + check_descriptions(s_item, d_item, sec) + + if not found: + print "Section \"" + sec + "\", Description \"" + desc + "\":", + print "Subsection \"" + s_item["name"] + "\" not found" + + +def check_description_in_list(s_item, d_item, sec, desc): + if not "Description" in s_item: + return + + if not "Description" in d_item: + print "Section \"" + sec + "\", Description \"" + desc + "\",", + print "Field \"" + s_item["field"] + "\": missing description" + return + + check_descriptions(s_item["Description"], d_item["Description"], sec) + + +def check_descriptions(src_desc, dest_desc, sec): + check_version(src_desc, dest_desc, sec, src_desc["name"]) + + if not check_fields_match(src_desc["name"], dest_desc["name"]): + print "Section \"" + sec + "\":", + print "Description \"" + src_desc["name"] + "\"", + print "missing, got \"" + dest_desc["name"] + "\" instead; skipping" + return + + for f in src_desc: + if not f in dest_desc: + print "Section \"" + sec + "\"", + print "Description \"" + src_desc["name"] + "\":", + print "Entry \"" + f + "\" missing" + continue + + if f == 'Fields': + check_fields(src_desc[f], dest_desc[f], src_desc["name"], sec) + + if f == 'Subsections': + check_subsections(src_desc[f], dest_desc[f], src_desc["name"], sec) + + +def check_version(s, d, sec, desc=None): + if s["version_id"] > d["version_id"]: + print "Section \"" + sec + "\"", + if desc: + print "Description \"" + desc + "\":", + print "version error:", s["version_id"], ">", d["version_id"] + + if not "minimum_version_id" in d: + return + + if s["version_id"] < d["minimum_version_id"]: + print "Section \"" + sec + "\"", + if desc: + print "Description \"" + desc + "\":", + print "minimum version error:", s["version_id"], "<", + print d["minimum_version_id"] + + +def check_size(s, d, sec, desc=None, field=None): + if s["size"] != d["size"]: + print "Section \"" + sec + "\"", + if desc: + print "Description \"" + desc + "\"", + if field: + print "Field \"" + field + "\"", + print "size mismatch:", s["size"], ",", d["size"] + + +def check_machine_type(s, d): + if s["Name"] != d["Name"]: + print "Warning: checking incompatible machine types:", + print "\"" + s["Name"] + "\", \"" + d["Name"] + "\"" + return + + +def main(): + parser = argparse.ArgumentParser(description= + 'Parse vmstate dumps from QEMU.') + parser.add_argument('-s', '--src', type=file, required=True, + help='json dump from src qemu') + parser.add_argument('-d', '--dest', type=file, required=True, + help='json dump from dest qemu') + parser.add_argument('--reverse', required=False, default=False, + action='store_true', + help='reverse the direction') + args = parser.parse_args() + + src_data = json.load(args.src) + dest_data = json.load(args.dest) + args.src.close() + args.dest.close() + + if args.reverse: + temp = src_data + src_data = dest_data + dest_data = temp + + for sec in src_data: + if not sec in dest_data: + print "Section \"" + sec + "\" does not exist in dest" + continue + + s = src_data[sec] + d = dest_data[sec] + + if sec == "vmschkmachine": + check_machine_type(s, d) + continue + + check_version(s, d, sec) + + for entry in s: + if not entry in d: + print "Section \"" + sec + "\": Entry \"" + entry + "\"", + print "missing" + continue + + if entry == "Description": + check_descriptions(s[entry], d[entry], sec) + + +if __name__ == '__main__': + main() -- 1.9.3