From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] QEMU support for virtio balloon driver Date: Sat, 8 Mar 2008 17:51:15 -0300 Message-ID: <20080308205115.GA20105@dmt> References: <1201209786831-git-send-email-aliguori@us.ibm.com> <4799115F.8010506@us.ibm.com> <20080125160857.GA17437@dmt> <479A162C.1060209@us.ibm.com> <479B8040.1000901@qumranet.com> <20080308192713.GA19321@dmt> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Andrea Arcangeli To: Avi Kivity Return-path: Content-Disposition: inline In-Reply-To: <20080308192713.GA19321@dmt> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org On Sat, Mar 08, 2008 at 04:27:13PM -0300, Marcelo Tosatti wrote: > On Sat, Jan 26, 2008 at 08:47:28PM +0200, Avi Kivity wrote: > > Anthony Liguori wrote: > > >Do others expect KVM to just cope with the virtual mapping being changed > > >out from underneath of it? > > > > > > > kvm should cope with both malicious guests and malicious (or buggy) host > > userspace. It's difficuly to analyze, but mmu notifiers might be > > necessary for the latter. > > The reason for the host crash with madvise is that the rmap code relies > on the guest process virtual mappings from not disappearing while there > are active shadow mappings. > > How to proceed now? Do we want to efficiently support ballooning without > mmu notifiers? If so, an ioctl to zap the mmu is necessary as discussed > before. Err, actually zapping the mmu is necessary to guarantee guest will not use stale shadow entries vs entries pointing to old unreacheable pages. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/