Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753056AbbG2Ozy (ORCPT ); Wed, 29 Jul 2015 10:55:54 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:18486 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752331AbbG2Ozw (ORCPT ); Wed, 29 Jul 2015 10:55:52 -0400 Message-ID: <55B8E866.60308@oracle.com> Date: Wed, 29 Jul 2015 10:51:18 -0400 From: Boris Ostrovsky User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Julien Grall , xen-devel@lists.xenproject.org CC: linux-fbdev@vger.kernel.org, "H. Peter Anvin" , Jiri Slaby , stefano.stabellini@eu.citrix.com, Russell King , linux-scsi@vger.kernel.org, x86@kernel.org, Tomi Valkeinen , linux-input@vger.kernel.org, Jean-Christophe Plagniol-Villard , ian.campbell@citrix.com, Konrad Rzeszutek Wilk , "James E.J. Bottomley" , Thomas Gleixner , Ingo Molnar , linux-arm-kernel@lists.infradead.org, Juergen Gross , Wei Liu , Greg Kroah-Hartman , Dmitry Torokhov , linux-kernel@vger.kernel.org, David Vrabel , netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, =?windows-1252?Q?Roger_Pau_Monn=E9?= Subject: Re: [PATCH 4/8] xen: Use the correctly the Xen memory terminologies References: <1438095769-2560-1-git-send-email-julien.grall@citrix.com> <1438095769-2560-5-git-send-email-julien.grall@citrix.com> <55B7D40B.5080903@oracle.com> <55B8B846.2060103@citrix.com> <55B8DFD7.6070107@oracle.com> <55B8E1C7.6070608@citrix.com> In-Reply-To: <55B8E1C7.6070608@citrix.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1727 Lines: 42 On 07/29/2015 10:23 AM, Julien Grall wrote: > On 29/07/15 15:14, Boris Ostrovsky wrote: >>> static inline unsigned long pfn_to_gfn(unsigned long pfn) >>> { >>> if (xen_feature(XENFEAT_autotranslated_physmap)) >>> return pfn; >>> else >>> return pfn_to_mfn(pfn); >>> } >> >> But you'd still say 'op.arg1.mfn = pfn_to_gfn(pfn);' in xen_do_pin() >> i.e. assign GFN to MFN, right? That's what I was referring to. > Well no. I would use op.arg1.mfn = pfn_to_mfn(pfn) given that the code, > if I'm right, is only executed for PV. > > mfn = pfn_to_gfn(...) was valid too because on PV is always an MFN. The > suggestion of pfn_to_mfn was just for more readability, Right, and my comments were also not about correctness. > >> (In general, I am not sure a guest should ever use 'mfn' as it is purely >> a hypervisor construct. Including p2m, which I think should really be >> p2g as this is what we use to figure out what to stick into page tables) > I think avoid to use mfn in the hypervisor interface is out-of-scope for > this series. If we ever want to modify the Xen API in Linux, we should > do in sync with Xen to avoid inconsistency on naming. > > Anyway, the oddity of mfn = pfn_to_gfn(...) is mostly contained in the > x86 specific code. I don't mind to either add pfn_to_mfn and use it or > add a comment /* PV-specific so mfn == gfn */ for every use of mfn = > pfn_to_gfn(...). I think the former is better (even thought it adds a test) -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/