From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 6/13] KVM: memory slot management Date: Sun, 29 Oct 2006 11:10:16 +0200 Message-ID: <45446FF8.50502@qumranet.com> References: <4540EE2B.9020606@qumranet.com> <200610270937.11646.arnd@arndb.de> <454208EB.7080007@qumranet.com> <200610271605.27600.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: To: Arnd Bergmann In-Reply-To: <200610271605.27600.arnd-r2nGTMty4D4@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Arnd Bergmann wrote: >> It can shoot not only its foot, but anything the monitor's uid has >> access to. Host files, the host network, other guests belonging to the >> user, etc. >> > > Yes, that's what I meant. It's obviously nicer if the guest can't do that, > but it's a tradeoff of the potential security impact against on how hard > it is to implement hiding the addresses you don't want your guest to see. > To put it into other words, do you want the optimal performance, or the > optimal security? > > Well, isolation is one of the most significant features of full virtualization, both for security and reliability. I don't think we can compromise that. >> It's worse than I thouht: tlb entries generated by guest accesses are >> tagged with the guest virtual address, to if you remove a guest >> physical/host virtual page you need to invalidate the entire guest tlb. >> > > Ok, so it's the HW's fault. They either copied bad or decided doing the > s390 approach was too expensive. > x86 tradition is to make all possible mistakes before getting a working solution. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642