From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kiszka <jan.kiszka@web.de>
Subject: Re: [PATCH] kvm: Fix overlapping check for memory slots
Date: Mon, 13 Apr 2009 11:42:35 +0200
Message-ID: <49E3090B.2090200@web.de>
References: <49E06754.8050906@web.de> <49E306C0.1050505@redhat.com>
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Cc: kvm-devel <kvm@vger.kernel.org>,
	Glauber Costa <glommer@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>
To: Avi Kivity <avi@redhat.com>
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Avi Kivity wrote:
> Jan Kiszka wrote:
>> This nice little buglet complicates a smarter slot management in qemu
>> user space just "slightly". Sigh...
>>
>> -------->
>>
>> When checking for overlapping slots on registration of a new one, kvm
>> currently also considers zero-length (ie. deleted) slots and rejects
>> requests incorrectly. This finally denies user space from joining slot=
s.
>> Fix the check by skipping deleted slots.
>>  =20
>=20
> Can userspace fail gracefully when the bug is present?  If not, the you=

> should add a KVM_CAP_ to advertise the fix; without the capability don'=
t
> attempt the smarter slot management.

I already thought about adding some
KVM_CAP_DESTROY_MEMORY_REGION_NOW_REALLY_WORKS and skip the workaround
in [1]. Maybe a good idea, comments welcome.

Jan

[1] http://permalink.gmane.org/gmane.comp.emulators.qemu/41326


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