Re: [PATCH v2 4/6] migration: Fix analyze-migration.py when ignore-shared is used

[Fabiano Rosas <farosas@suse.de>]

Juan Quintela <quintela@redhat.com> writes:

> Fabiano Rosas <farosas@suse.de> wrote:
>> The script is currently broken when the x-ignore-shared capability is
>> used:
>>
>> Traceback (most recent call last):
>>   File "./scripts/analyze-migration.py", line 656, in <module>
>>     dump.read(dump_memory = args.memory)
>>   File "./scripts/analyze-migration.py", line 593, in read
>>     section.read()
>>   File "./scripts/analyze-migration.py", line 163, in read
>>     self.name = self.file.readstr(len = namelen)
>>   File "./scripts/analyze-migration.py", line 53, in readstr
>>     return self.readvar(len).decode('utf-8')
>> UnicodeDecodeError: 'utf-8' codec can't decode byte 0x82 in position 55: invalid start byte
>>
>> We're currently adding data to the middle of the ram section depending
>> on the presence of the capability. As a consequence, any code loading
>> the ram section needs to know about capabilities so it can interpret
>> the stream.
>>
>> Skip the byte that's added when x-ignore-shared is used to fix the
>> script.
>>
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>
> Reviewed-by: Juan Quintela <quintela@redhat.com>
>
>> @@ -582,6 +586,7 @@ def read(self, desc_only = False, dump_memory = False, write_memory = False):
>>                  config_desc = self.vmsd_desc.get('configuration')
>>                  section = ConfigurationSection(file, config_desc)
>>                  section.read()
>> +                ramargs['ignore_shared'] = section.has_capability('x-ignore-shared')
>
> should we consider s/x-ignore-shared/ignore-shared/?
>

We can consider s/ignore-shared/x-ignore-shared/ if that's what you
mean. The way you suggested doesn't work because the cap name comes from
QEMU with the "x-" part in it.

If you meant filtering the x out when parsing the capabilities in this
script, I think that would cause a sort of a UX issue because we need to
use x-ignore-shared to set the cap in QMP/HMP.