From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] KVM: MMU: Disassociate direct maps from guest levels Date: Wed, 17 Mar 2010 15:16:25 -0300 Message-ID: <20100317181625.GA10372@amt.cnet> References: <1268554972-9827-1-git-send-email-avi@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:59945 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755335Ab0CQSYM (ORCPT ); Wed, 17 Mar 2010 14:24:12 -0400 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o2HIOCIp020302 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 17 Mar 2010 14:24:12 -0400 Content-Disposition: inline In-Reply-To: <1268554972-9827-1-git-send-email-avi@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Sun, Mar 14, 2010 at 10:22:52AM +0200, Avi Kivity wrote: > Direct maps are linear translations for a section of memory, used for > real mode or with large pages. As such, they are independent of the guest > levels. > > Teach the mmu about this by making page->role.glevels = 0 for direct maps. > This allows direct maps to be shared among real mode and the various paging > modes. > > Signed-off-by: Avi Kivity > --- > arch/x86/kvm/mmu.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index b137515..a984bc1 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -1328,6 +1328,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, > role = vcpu->arch.mmu.base_role; > role.level = level; > role.direct = direct; > + if (role.direct) > + role.glevels = 0; > role.access = access; > if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) { > quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level)); > -- > 1.7.0.2 Isnt this what happens already, since for tdp base_role.glevels is not initialized?