From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 2/2] KVM: MMU: Use base_role.nxe for mmu.nx Date: Thu, 16 Sep 2010 16:00:34 +0200 Message-ID: <4C922302.20900@redhat.com> References: <1284479173-4515-1-git-send-email-joerg.roedel@amd.com> <1284479173-4515-3-git-send-email-joerg.roedel@amd.com> <20100914220836.GA3553@amt.cnet> <20100915084833.GH17759@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" To: "Roedel, Joerg" Return-path: In-Reply-To: <20100915084833.GH17759@amd.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 09/15/2010 10:48 AM, Roedel, Joerg wrote: > On Tue, Sep 14, 2010 at 06:08:37PM -0400, Marcelo Tosatti wrote: > > > > For tdp better set base_role.nxe to zero, otherwise duplicate tdp > > pagetables can be created if the guest switches between nx/non-nx. > > > > This does not work because bit 63 is marked as reserved if base_role.nxe > is 0. If the walk_addr_generic function then runs with tdp enabled it > would report a set nx bit as a rsvd fault. > We also can't use is_nx() in those path because it does not distinguish > between l1 and l2 nx. Are there guests that switch the efer.nx bit > regularly enough so that it matters? If so I would suggest to drop this > patch and keep mmu.nx. > > I'll do that then. I'm still unhappy about the duplication. -- error compiling committee.c: too many arguments to function