From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] kvm: Fix overlapping check for memory slots Date: Mon, 13 Apr 2009 12:49:28 +0300 Message-ID: <49E30AA8.1040709@redhat.com> References: <49E06754.8050906@web.de> <49E306C0.1050505@redhat.com> <49E3090B.2090200@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm-devel , Glauber Costa , qemu-devel To: Jan Kiszka Return-path: Received: from mx2.redhat.com ([66.187.237.31]:48216 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754259AbZDMJtd (ORCPT ); Mon, 13 Apr 2009 05:49:33 -0400 In-Reply-To: <49E3090B.2090200@web.de> Sender: kvm-owner@vger.kernel.org List-ID: Jan Kiszka wrote: > 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 slots. >>> Fix the check by skipping deleted slots. >>> >>> >> 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. > > It's a good idea regardless of how qemu handles it. There can be other users. -- error compiling committee.c: too many arguments to function