From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Date: Tue, 28 Jul 2015 17:16:02 +0000 Subject: Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies Message-Id: <55B7B8D2.5060107@citrix.com> List-Id: References: <1438095769-2560-1-git-send-email-julien.grall@citrix.com> <1438095769-2560-5-git-send-email-julien.grall@citrix.com> In-Reply-To: <1438095769-2560-5-git-send-email-julien.grall@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On 28/07/15 16:02, Julien Grall wrote: > Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN > is meant, I suspect this is because the first support for Xen was for > PV. This brough some misimplementation of helpers on ARM and make the > developper confused the expected behavior. For the benefit of other subsystem maintainers, this is a purely mechanical change in Xen-specific terminology. It doesn't need reviews or acks from non-Xen people (IMO). > For instance, with pfn_to_mfn, we expect to get an MFN based on the name. > Although, if we look at the implementation on x86, it's returning a GFN. > > For clarity and avoid new confusion, replace any reference of mfn into > gnf in any helpers used by PV drivers. > > Take also the opportunity to simplify simple construction such > as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up > will come in follow-up patches. > > I think it may be possible to do further clean up in the x86 code to > ensure that helpers returning machine address (such as virt_address) is > not used by no auto-translated guests. I will let x86 xen expert doing > it. Reviewed-by: David Vrabel It looks a bit odd to use GFN in some of the PV code where the hypervisor API uses MFN but overall I think using the correct terminology where possible is best. But I'd like to have Boris's or Konrad's opinion on this. David From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies Date: Tue, 28 Jul 2015 18:16:02 +0100 Message-ID: <55B7B8D2.5060107@citrix.com> References: <1438095769-2560-1-git-send-email-julien.grall@citrix.com> <1438095769-2560-5-git-send-email-julien.grall@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.citrix.com ([66.165.176.89]:25741 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751878AbbG1RQm (ORCPT ); Tue, 28 Jul 2015 13:16:42 -0400 In-Reply-To: <1438095769-2560-5-git-send-email-julien.grall@citrix.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Julien Grall , xen-devel@lists.xenproject.org Cc: linux-fbdev@vger.kernel.org, "H. Peter Anvin" , Jiri Slaby , Thomas Gleixner , 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, "James E.J. Bottomley" , Boris Ostrovsky , 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, =?UT On 28/07/15 16:02, Julien Grall wrote: > Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN > is meant, I suspect this is because the first support for Xen was for > PV. This brough some misimplementation of helpers on ARM and make the > developper confused the expected behavior. For the benefit of other subsystem maintainers, this is a purely mechanical change in Xen-specific terminology. It doesn't need reviews or acks from non-Xen people (IMO). > For instance, with pfn_to_mfn, we expect to get an MFN based on the name. > Although, if we look at the implementation on x86, it's returning a GFN. > > For clarity and avoid new confusion, replace any reference of mfn into > gnf in any helpers used by PV drivers. > > Take also the opportunity to simplify simple construction such > as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up > will come in follow-up patches. > > I think it may be possible to do further clean up in the x86 code to > ensure that helpers returning machine address (such as virt_address) is > not used by no auto-translated guests. I will let x86 xen expert doing > it. Reviewed-by: David Vrabel It looks a bit odd to use GFN in some of the PV code where the hypervisor API uses MFN but overall I think using the correct terminology where possible is best. But I'd like to have Boris's or Konrad's opinion on this. David From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from SMTP.CITRIX.COM (smtp.citrix.com [66.165.176.89]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 9FCAA1A0075 for ; Wed, 29 Jul 2015 03:16:45 +1000 (AEST) Message-ID: <55B7B8D2.5060107@citrix.com> Date: Tue, 28 Jul 2015 18:16:02 +0100 From: David Vrabel MIME-Version: 1.0 To: Julien Grall , CC: , "H. Peter Anvin" , "Jiri Slaby" , Thomas Gleixner , , Russell King , , , Tomi Valkeinen , , "Jean-Christophe Plagniol-Villard" , , "James E.J. Bottomley" , Boris Ostrovsky , Ingo Molnar , , Juergen Gross , "Wei Liu" , Greg Kroah-Hartman , Dmitry Torokhov , , David Vrabel , , , =?UTF-8?B?Um9nZXIg?= =?UTF-8?B?UGF1IE1vbm7DqQ==?= Subject: Re: [Xen-devel] [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> In-Reply-To: <1438095769-2560-5-git-send-email-julien.grall@citrix.com> Content-Type: text/plain; charset="utf-8" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 28/07/15 16:02, Julien Grall wrote: > Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN > is meant, I suspect this is because the first support for Xen was for > PV. This brough some misimplementation of helpers on ARM and make the > developper confused the expected behavior. For the benefit of other subsystem maintainers, this is a purely mechanical change in Xen-specific terminology. It doesn't need reviews or acks from non-Xen people (IMO). > For instance, with pfn_to_mfn, we expect to get an MFN based on the name. > Although, if we look at the implementation on x86, it's returning a GFN. > > For clarity and avoid new confusion, replace any reference of mfn into > gnf in any helpers used by PV drivers. > > Take also the opportunity to simplify simple construction such > as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up > will come in follow-up patches. > > I think it may be possible to do further clean up in the x86 code to > ensure that helpers returning machine address (such as virt_address) is > not used by no auto-translated guests. I will let x86 xen expert doing > it. Reviewed-by: David Vrabel It looks a bit odd to use GFN in some of the PV code where the hypervisor API uses MFN but overall I think using the correct terminology where possible is best. But I'd like to have Boris's or Konrad's opinion on this. David From mboxrd@z Thu Jan 1 00:00:00 1970 From: david.vrabel@citrix.com (David Vrabel) Date: Tue, 28 Jul 2015 18:16:02 +0100 Subject: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies In-Reply-To: <1438095769-2560-5-git-send-email-julien.grall@citrix.com> References: <1438095769-2560-1-git-send-email-julien.grall@citrix.com> <1438095769-2560-5-git-send-email-julien.grall@citrix.com> Message-ID: <55B7B8D2.5060107@citrix.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 28/07/15 16:02, Julien Grall wrote: > Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN > is meant, I suspect this is because the first support for Xen was for > PV. This brough some misimplementation of helpers on ARM and make the > developper confused the expected behavior. For the benefit of other subsystem maintainers, this is a purely mechanical change in Xen-specific terminology. It doesn't need reviews or acks from non-Xen people (IMO). > For instance, with pfn_to_mfn, we expect to get an MFN based on the name. > Although, if we look at the implementation on x86, it's returning a GFN. > > For clarity and avoid new confusion, replace any reference of mfn into > gnf in any helpers used by PV drivers. > > Take also the opportunity to simplify simple construction such > as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up > will come in follow-up patches. > > I think it may be possible to do further clean up in the x86 code to > ensure that helpers returning machine address (such as virt_address) is > not used by no auto-translated guests. I will let x86 xen expert doing > it. Reviewed-by: David Vrabel It looks a bit odd to use GFN in some of the PV code where the hypervisor API uses MFN but overall I think using the correct terminology where possible is best. But I'd like to have Boris's or Konrad's opinion on this. David From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [Xen-devel] [PATCH 4/8] xen: Use the correctly the Xen memory terminologies Date: Tue, 28 Jul 2015 18:16:02 +0100 Message-ID: <55B7B8D2.5060107@citrix.com> References: <1438095769-2560-1-git-send-email-julien.grall@citrix.com> <1438095769-2560-5-git-send-email-julien.grall@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: , "H. Peter Anvin" , "Jiri Slaby" , Thomas Gleixner , , Russell King , , , Tomi Valkeinen , , "Jean-Christophe Plagniol-Villard" , , "James E.J. Bottomley" , Boris Ostrovsky , Ingo Molnar , , Juergen Gross , "Wei Liu" , Greg Kroah-Hartman , Dmitry Torokhov , , David Vrabel , , , =?UT To: Julien Grall , Return-path: In-Reply-To: <1438095769-2560-5-git-send-email-julien.grall@citrix.com> Sender: linux-input-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 28/07/15 16:02, Julien Grall wrote: > Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN > is meant, I suspect this is because the first support for Xen was for > PV. This brough some misimplementation of helpers on ARM and make the > developper confused the expected behavior. For the benefit of other subsystem maintainers, this is a purely mechanical change in Xen-specific terminology. It doesn't need reviews or acks from non-Xen people (IMO). > For instance, with pfn_to_mfn, we expect to get an MFN based on the name. > Although, if we look at the implementation on x86, it's returning a GFN. > > For clarity and avoid new confusion, replace any reference of mfn into > gnf in any helpers used by PV drivers. > > Take also the opportunity to simplify simple construction such > as pfn_to_mfn(page_to_pfn(page)) into page_to_gfn. More complex clean up > will come in follow-up patches. > > I think it may be possible to do further clean up in the x86 code to > ensure that helpers returning machine address (such as virt_address) is > not used by no auto-translated guests. I will let x86 xen expert doing > it. Reviewed-by: David Vrabel It looks a bit odd to use GFN in some of the PV code where the hypervisor API uses MFN but overall I think using the correct terminology where possible is best. But I'd like to have Boris's or Konrad's opinion on this. David