From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754817Ab0EGIw1 (ORCPT ); Fri, 7 May 2010 04:52:27 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:63860 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754589Ab0EGIwZ (ORCPT ); Fri, 7 May 2010 04:52:25 -0400 Message-ID: <4BE3D4C2.4070906@cn.fujitsu.com> Date: Fri, 07 May 2010 16:52:18 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Lai Jiangshan , Avi Kivity , Marcelo Tosatti CC: Joerg Roedel , LKML , kvm@vger.kernel.org, Gui Jianfeng Subject: Re: [RFC PATCH] kvm: calculate correct gfn for small host pages which emulates large guest pages References: <4BD97AC1.8070704@cn.fujitsu.com> <4BDA4342.9070603@cn.fujitsu.com> In-Reply-To: <4BDA4342.9070603@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Lai Jiangshan wrote: > Lai Jiangshan wrote: >> RFC, because maybe I missing something with the old code. >> >> Frome: Lai Jiangshan >> >> In Document/kvm/mmu.txt: >> gfn: >> Either the guest page table containing the translations shadowed by this >> page, or the base page frame for linear translations. See role.direct. >> >> But in function FNAME(fetch)(), sp->gfn is incorrect when one of following >> situations occurred: >> 1) guest is 32bit paging and guest uses pse-36 and the guest PDE maps >> a 4-MByte page(backed by 4k host pages) and bits 20:13 of the guest PDE >> is not equals to 0. >> 2) guest is long mode paging and the guest PDPTE maps a 1-GByte page >> (backed by 4k or 2M host pages) >> > > Resend this patch with the changelog changed. > > As Marcelo Tosatti and Gui Jianfeng points out, > FNAME(fetch)() miss quadrant on 4mb large page emulation with shadow. > > Subject: [PATCH] kvm: calculate correct gfn for small host pages which emulates large guest pages > > In Document/kvm/mmu.txt: > gfn: > Either the guest page table containing the translations shadowed by this > page, or the base page frame for linear translations. See role.direct. > > But in function FNAME(fetch)(), sp->gfn is incorrect when one of following > situations occurred: > 1) guest is 32bit paging and the guest PDE maps a 4-MByte page > (backed by 4k host pages), FNAME(fetch)() miss handling the quadrant. > > And if guest use pse-36, "table_gfn = gpte_to_gfn(gw->ptes[level - delta]);" > is incorrect. > 2) guest is long mode paging and the guest PDPTE maps a 1-GByte page > (backed by 4k or 2M host pages). > > So we fix it to suit to the document and suit to the code which > requires sp->gfn correct when sp->role.direct=1. > > We use the goal mapping gfn(gw->gfn) to calculate the base page frame > for linear translations, it is simple and easy to be understood. > > Signed-off-by: Lai Jiangshan > --- Could you add these: Reported-by: Marcelo Tosatti Reported-by: Gui Jianfeng Thanks. Lai. PS. The whole patches includes: [PATCH] kvm mmu: reduce 50% memory usage [PATCH] kvm: calculate correct gfn for small host pages which emulates large guest pages [PATCH] kvm, tdp: calculate correct base gfn for non-DIR level [PATCH] kvm: update document of gfns