Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754107AbbGXKex (ORCPT ); Fri, 24 Jul 2015 06:34:53 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:1926 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751794AbbGXKev (ORCPT ); Fri, 24 Jul 2015 06:34:51 -0400 X-IronPort-AV: E=Sophos;i="5.15,537,1432598400"; d="scan'208";a="287214572" Message-ID: <55B214C5.3020501@citrix.com> Date: Fri, 24 Jul 2015 11:34:45 +0100 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: Julien Grall , CC: , Boris Ostrovsky , , , Subject: Re: [Xen-devel] [PATCH v2 01/20] xen: Add Xen specific page definition References: <1436474552-31789-1-git-send-email-julien.grall@citrix.com> <1436474552-31789-2-git-send-email-julien.grall@citrix.com> <55B20540.3020000@citrix.com> <55B207C6.4020300@citrix.com> <55B209D9.1080602@citrix.com> <55B20ABE.7000609@citrix.com> In-Reply-To: <55B20ABE.7000609@citrix.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1956 Lines: 51 On 24/07/15 10:51, Julien Grall wrote: > On 24/07/15 10:48, David Vrabel wrote: >> On 24/07/15 10:39, Julien Grall wrote: >>> Hi David, >>> >>> On 24/07/15 10:28, David Vrabel wrote: >>>> On 09/07/15 21:42, Julien Grall wrote: >>>>> The Xen hypercall interface is always using 4K page granularity on ARM >>>>> and x86 architecture. >>>>> >>>>> With the incoming support of 64K page granularity for ARM64 guest, it >>>>> won't be possible to re-use the Linux page definition in Xen drivers. >>>>> >>>>> Introduce Xen page definition helpers based on the Linux page >>>>> definition. They have exactly the same name but prefixed with >>>>> XEN_/xen_ prefix. >>>>> >>>>> Also modify page_to_pfn to use new Xen page definition. >>>>> >>>>> Signed-off-by: Julien Grall >>>>> Cc: Konrad Rzeszutek Wilk >>>>> Cc: Boris Ostrovsky >>>>> Cc: David Vrabel >>>>> --- >>>>> I'm wondering if we should drop page_to_pfn has the macro will likely >>>>> misuse when Linux is using 64KB page granularity. >>>> >>>> I think we want xen_gfn_to_page() and xen_page_to_gfn() and Xen >>>> front/back drivers never deal with PFNs only GFNs. >>> >>> What is xen_gfn_to_page and xen_page_to_gfn? Neither Linux, nor my >>> series have them. >> >> I suggesting that you introduce these. > > It's still not clear to me what you are suggesting here... Do you > suggest to rename xen_pfn_to_page and xen_page_to_pfn by xen_gfn_to_page > and xen_page_to_gfn? Effectively, yes but it would be better to think that: PFNs index guest-sized pages (which may be 64 KiB). GFNs index Xen-sized pages (which is always 4 KiB). David -- 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/