From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755476AbbI3LrG (ORCPT ); Wed, 30 Sep 2015 07:47:06 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:24020 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754148AbbI3LrE (ORCPT ); Wed, 30 Sep 2015 07:47:04 -0400 X-IronPort-AV: E=Sophos;i="5.17,612,1437436800"; d="scan'208";a="307071785" Message-ID: <560BCB67.1060100@citrix.com> Date: Wed, 30 Sep 2015 12:45:43 +0100 From: Julien Grall User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.8.0 MIME-Version: 1.0 To: Mark Rutland CC: "xen-devel@lists.xenproject.org" , "wei.liu2@citrix.com" , "Ian.Campbell@citrix.com" , "stefano.stabellini@eu.citrix.com" , "konrad.wilk@oracle.com" , "linux-kernel@vger.kernel.org" , "david.vrabel@citrix.com" , "boris.ostrovsky@oracle.com" , "linux-arm-kernel@lists.infradead.org" , "roger.pau@citrix.com" , Suzuki Poulose Subject: Re: [PATCH v5 00/22] xen/arm64: Add support for 64KB page in Linux References: <1443609937-25278-1-git-send-email-julien.grall@citrix.com> <20150930113214.GA10997@leverpostej> In-Reply-To: <20150930113214.GA10997@leverpostej> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/09/15 12:32, Mark Rutland wrote: > On Wed, Sep 30, 2015 at 11:45:15AM +0100, Julien Grall wrote: >> Hi all, > > Hi, > >> 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. > > Just to check, would this be expected to work with a 16K DomU (e.g. > [2])? > > From a quick scan it looks like the relaxations provided by this series > should work so long as PAGE_SIZE % XEN_PAGE_SIZE == 0, assuming I > haven't missed something. Correct, this series is able to cope with any PAGE_SIZE as long as it's a multiple of the granularity used by Xen (i.e 4KB on ARM). >> There is room for improvement, such as support of 64KB grant, modification >> of PV protocol to support different page size... They will be explored in a >> separate patch series later. >> >> TODO list: >> - Convert xenfb to 64KB >> - Support for multiple page ring support >> - Support for 64KB in gnttdev >> - Support of non-indirect grant with 64KB frontend (patch sent [1]) >> - It may be possible to move some common define between >> netback/netfront and blkfront/blkback in an header > > Would any of these require more work to also handle 16K? No. It should just boot on Xen as long as the CPU is support 16K granularity. Regards, -- Julien Grall