From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752669AbcFVNlv (ORCPT ); Wed, 22 Jun 2016 09:41:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50205 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950AbcFVNlt (ORCPT ); Wed, 22 Jun 2016 09:41:49 -0400 Subject: Re: [PATCH] kvm, x86: Properly check whether a pfn is an MMIO or not To: KarimAllah Ahmed , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org References: <1466562866-31524-1-git-send-email-karahmed@amazon.de> Cc: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Borislav Petkov , Denys Vlasenko , Andrew Morton , Toshi Kani , Tony Luck From: Paolo Bonzini Message-ID: <6b30fd96-dc04-13a2-aa8b-7760a85337c6@redhat.com> Date: Wed, 22 Jun 2016 15:41:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <1466562866-31524-1-git-send-email-karahmed@amazon.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 22 Jun 2016 13:41:49 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22/06/2016 04:34, KarimAllah Ahmed wrote: > pfn_valid check is not sufficient because it only checks if a page has a struct > page or not, if for example "mem=" was passed to the kernel some valid pages > won't have a struct page. This means that if guests were assigned valid memory > that lies after the mem= boundary it will be passed uncached to the guest no > matter what the guest caching attributes are for this memory. How can you pass memory after the mem= boundary to the guest? Paolo