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From: Anthony Liguori <anthony@codemonkey.ws>
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Date: Tue, 18 Sep 2012 16:13:30 -0500
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Subject: Re: [Qemu-devel] qmp: dump-guest-memory: -p option has issues,
	fix it or drop it?
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To: Markus Armbruster <armbru@redhat.com>, Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, Eric Blake <eblake@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Luiz Capitulino <lcapitulino@redhat.com>

Markus Armbruster <armbru@redhat.com> writes:

> Jan Kiszka <jan.kiszka@siemens.com> writes:
>
>>>>>>  * The issues discussed in this email plus the fact that the guest
>>>>>>    memory may be corrupted, and the guest may be in real-mode even
>>>>>>    when paging is enabled
>>>>>>
>>>>>
>>>>> Yes, there are some limitations with this option. Jan said that he
>>>>> always use gdb to deal with vmcore, so he needs such information.
>>>>
>>>> The point is to overcome the focus on Linux-only dump processing tools.
>>> 
>>> While I don't care for supporting alternate dump processing tools
>>> myself, I certainly don't mind supporting them, as long as the code
>>> satisfies basic safety and reliability requirements.
>>> 
>>> This code doesn't, as far as I can tell.
>>
>> It works, thought not under all circumstances.
>
> I don't doubt it works often enough to be useful to somebody.  But basic
> safety and reliability requirements are a bit more than that.  They
> include "don't explode in ways a reasonable user can't be expected to
> foresee".  I don't think a reasonable user can be expected to see that
> -p is safe only for trusted guests.

We shipped the API, we're not removing it.  Our compatibility isn't
"whatever libvirt is currently using".

It's perfectly reasonable to ask to document the behavior of the
method.  It's also a trivial patch to qapi-schema.json.

It's unreasonable to ask for an interface to be removed just because it
could be misused when it has a legimitate use-case.

Regards,

Anthony Liguori