From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH 1/4] kvm-s390: add capability indicating COW support
Date: Tue, 15 May 2012 15:33:17 +0300
Message-ID: <4FB24D0D.7090707@redhat.com>
References: <1337084128-38219-1-git-send-email-borntraeger@de.ibm.com> <1337084128-38219-2-git-send-email-borntraeger@de.ibm.com> <4FB24B11.1050607@redhat.com> <4FB24CB5.3070606@de.ibm.com>
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Cc: Marcelo Tossati <mtosatti@redhat.com>,
	Carsten Otte <cotte@de.ibm.com>,
	Alexander Graf <agraf@suse.de>,
	Jens Freimann <jfrei@linux.vnet.ibm.com>,
	Cornelia Huck <cornelia.huck@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Heinz Graalfs <graalfs@linux.vnet.ibm.com>,
	KVM <kvm@vger.kernel.org>
To: Christian Borntraeger <borntraeger@de.ibm.com>
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On 05/15/2012 03:31 PM, Christian Borntraeger wrote:
> On 15/05/12 14:24, Avi Kivity wrote:
> >> Newer systems allow to write-protect the guest backing memory
> >> and let the fault be delivered to the host, thus allowing COW.
> >>
> >> Use a capability bit to tell qemu if that is possible.
> >>
> > 
> > Asking out of ignorance: who is doing the write protection here? The
> > guest?  If so, why is qemu involved?
>
> It is about the host doing write protection of guest/user memory (e.g. for 
> dirty pages tracking or KSM)

Ok, so why does qemu^Wuserspace need to know about it?

-- 
error compiling committee.c: too many arguments to function