Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934946AbbEOPyc (ORCPT ); Fri, 15 May 2015 11:54:32 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:26066 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934533AbbEOPya (ORCPT ); Fri, 15 May 2015 11:54:30 -0400 Message-ID: <55561605.4020805@oracle.com> Date: Fri, 15 May 2015 11:51:33 -0400 From: Boris Ostrovsky User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: David Vrabel , Julien Grall , xen-devel@lists.xenproject.org CC: wei.liu2@citrix.com, ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, tim@xen.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, roger.pau@citrix.com Subject: Re: [Xen-devel] [RFC 00/23] arm64: Add support for 64KB page granularity in Xen guest References: <1431622863-28575-1-git-send-email-julien.grall@citrix.com> <555614AB.9000006@citrix.com> In-Reply-To: <555614AB.9000006@citrix.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 31 On 05/15/2015 11:45 AM, David Vrabel wrote: > On 14/05/15 18:00, Julien Grall wrote: >> Hi all, >> >> ARM64 Linux is supporting both 4KB and 64KB page granularity. Although, Xen >> hypercall interface and PV protocol are always based on 4KB page granularity. >> >> Any attempt to boot a Linux guest with 64KB pages enabled will result to a >> guest crash. >> >> This series is a first attempt to allow those Linux running with the current >> hypercall interface and PV protocol. >> >> This solution has been chosen because we want to run Linux 64KB in released >> Xen ARM version or/and platform using an old version of Linux DOM0. > The key problem I see with this approach is the confusion between guest > page size and Xen page size. This is going to be particularly > problematic since the majority of development/usage will remain on x86 > where PAGE_SIZE == XEN_PAGE_SIZE. > > I think it would be nice to keep XEN_PAGE_SIZE etc out of front and > backend drivers. Perhaps with a suitable set of helper functions? I am thinking exactly the same thing as I am going over these patches. -boris -- 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/