From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Roedel, Joerg" Subject: Re: question about nested ntp Date: Wed, 13 Oct 2010 10:57:55 +0200 Message-ID: <20101013085755.GK1983@amd.com> References: <20101012132611.GA28070@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: "kvm@vger.kernel.org" To: Gleb Natapov Return-path: Received: from tx2ehsobe005.messaging.microsoft.com ([65.55.88.15]:33488 "EHLO TX2EHSOBE009.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753050Ab0JMI5X (ORCPT ); Wed, 13 Oct 2010 04:57:23 -0400 Content-Disposition: inline In-Reply-To: <20101012132611.GA28070@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Hi Gleb, On Tue, Oct 12, 2010 at 09:26:11AM -0400, Gleb Natapov wrote: > I have a question about nested ntp code. Comment in init_kvm_nested_mmu() > function says "arch.mmu.gva_to_gpa translates l2_gva to l1_gpa". If > I read the code correctly at the time of nested guest execution > arch.mmu.gva_to_gpa() points to one of paging*_gva_to_gpa() variants. The > function calls walk_addr() with provided address which should be > l2_gva according to the comment. Now when NPF happens while nested > guest runs arch.mmu.page_fault() is called which translates to call > to one of paging*_page_fault() variants. paging*_page_fault() calls > walk_addr() too, but now it gets l2_gpa as a parameter since during > NPF svm->vmcb->control.exit_info_2 will not point to l2_gva, but l2_gpa > instead. Do I miss something here? No, the comment is wrong. The comment actually was right in -v1 of the patch-series. But I changed that in -v2 and forgot the update/remove the comment. Thanks for mentioning that :-) Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632