Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754658Ab0DZHjc (ORCPT ); Mon, 26 Apr 2010 03:39:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61917 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754591Ab0DZHja (ORCPT ); Mon, 26 Apr 2010 03:39:30 -0400 Message-ID: <4BD5432C.20409@redhat.com> Date: Mon, 26 Apr 2010 10:39:24 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Xiao Guangrong CC: Marcelo Tosatti , KVM list , LKML Subject: Re: [PATCH v2 1/10] KVM MMU: fix for calculating gpa in invlpg code References: <4BD3E306.4020202@cn.fujitsu.com> <4BD3E870.60000@cn.fujitsu.com> <4BD40F6D.3090002@redhat.com> <4BD50417.6090409@cn.fujitsu.com> In-Reply-To: <4BD50417.6090409@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2220 Lines: 69 On 04/26/2010 06:10 AM, Xiao Guangrong wrote: > > Avi Kivity wrote: > >> On 04/25/2010 10:00 AM, Xiao Guangrong wrote: >> >>> If the guest is 32-bit, we should use 'quadrant' to adjust gpa >>> offset >>> >>> Changlog v2: >>> - when level is PT_DIRECTORY_LEVEL, the 'offset' should be >>> 'role.quadrant<< 8', thanks Avi for point it out >>> >>> Signed-off-by: Xiao Guangrong >>> --- >>> arch/x86/kvm/paging_tmpl.h | 13 +++++++++++-- >>> 1 files changed, 11 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h >>> index d0cc07e..83cc72f 100644 >>> --- a/arch/x86/kvm/paging_tmpl.h >>> +++ b/arch/x86/kvm/paging_tmpl.h >>> @@ -478,9 +478,18 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, >>> gva_t gva) >>> ((level == PT_DIRECTORY_LEVEL&& is_large_pte(*sptep))) || >>> ((level == PT_PDPE_LEVEL&& is_large_pte(*sptep)))) { >>> struct kvm_mmu_page *sp = page_header(__pa(sptep)); >>> - >>> + int offset = 0; >>> + >>> + if (PTTYPE == 32) { >>> + if (level == PT_DIRECTORY_LEVEL) >>> + offset = PAGE_SHIFT - 4; >>> + else >>> + offset = PT64_LEVEL_BITS; >>> + offset = sp->role.quadrant<< offset; >>> + } >>> >>> >> The calculation is really >> >> shift = (PT32_LEVEL_BITS - PT64_LEVEL_BITS) * level; >> >> > So, the offset is q<< (PAGE_SHIFT - (PT32_LEVEL_BITS - PT64_LEVEL_BITS) * level - 2)? > Ugh, what I meant was shift = PAGE_SHIFT - (PT_LEVEL_BITS - PT64_LEVEL_BITS) * level; offset = q << shift so, pte_gpa = (sp->gfn << PAGE_SHIFT) + offset + (spte - sp->spt) * sizeof(pt_element_t) No magic numbers please. Note it could work without the 'if (PTTYPE == 32)'. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/