From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AECBEC433E1 for ; Thu, 13 Aug 2020 10:02:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 818DC20781 for ; Thu, 13 Aug 2020 10:02:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="PUtHyuV+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726600AbgHMKCf (ORCPT ); Thu, 13 Aug 2020 06:02:35 -0400 Received: from esa5.hc3370-68.iphmx.com ([216.71.155.168]:2786 "EHLO esa5.hc3370-68.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726174AbgHMKCf (ORCPT ); Thu, 13 Aug 2020 06:02:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1597312953; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=kkFMyNBbOdtaKP3s0IKVuqUHyo7Vk4EymQC6D+Rwakc=; b=PUtHyuV+1nFCJVxLFo0saWWoqxCPE6AHBTl6JUr6fRLbJXRwswEl3yVs v8rDA+0QtH+53JiY72lkWmHtgcR/oxS0Re3xWe/8+zfkblGw3tuegmndO VrcIX3/TmVxH44dqUX2jIFF+dHoHR2Q4N4nOOJy8WfmUYy1a3LSCZ+58O M=; Authentication-Results: esa5.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: wDtbUOGkC+v+QIiO9GW5InSj95+N5bZvHh0cz2sCfx8x8/0y/wKXIBeFTsdWA5IVAl9fHYeLN9 bkgatnmpc6dbgREHUynY40qpDjj/p707iFysIZlm+vriXLDuiKG2hWjEZM5lJMCBJKbBHnmRzT Ek4wVev1cfJou5ZUSJS2/wZJUJSBFN8IxZXcndS/Kdi0ZOoHWEwqy1VaqoDA1I5FfmKdrqia00 lv846+KFNsoIoemtWsa3un39WI8J3cPm1e5CBVfxjR5zuJsQM3Dozc/9+9CouCiP2ZBQIjfCnw Sa8= X-SBRS: 2.7 X-MesageID: 24601489 X-Ironport-Server: esa5.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.76,307,1592884800"; d="scan'208";a="24601489" Date: Thu, 13 Aug 2020 12:02:26 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Daniel Vetter CC: Christoph Hellwig , , Oleksandr Andrushchenko , David Airlie , Boris Ostrovsky , "Juergen Gross" , Stefano Stabellini , "Dan Carpenter" , Wei Liu , Yan Yankovskyi , , , , David Hildenbrand , Michal Hocko , Dan Williams Subject: Re: [PATCH v4 2/2] xen: add helpers to allocate unpopulated memory Message-ID: <20200813100226.GG975@Air-de-Roger> References: <20200811094447.31208-1-roger.pau@citrix.com> <20200811094447.31208-3-roger.pau@citrix.com> <20200813073337.GA16160@infradead.org> <20200813075420.GC975@Air-de-Roger> <20200813094946.GJ2352366@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200813094946.GJ2352366@phenom.ffwll.local> X-ClientProxiedBy: AMSPEX02CAS02.citrite.net (10.69.22.113) To AMSPEX02CL02.citrite.net (10.69.22.126) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Your email client seems to set 'Reply-to:' to point to everyone on the 'Cc:' field, but not yourself, which is kind of weird. I've manually fixed it on this reply by moving everyone to the 'Cc:' field and setting you on 'To:'. On Thu, Aug 13, 2020 at 11:49:46AM +0200, Daniel Vetter wrote: > On Thu, Aug 13, 2020 at 09:54:20AM +0200, Roger Pau Monné wrote: > > On Thu, Aug 13, 2020 at 08:33:37AM +0100, Christoph Hellwig wrote: > > > On Tue, Aug 11, 2020 at 11:44:47AM +0200, Roger Pau Monne wrote: > > > > If enabled (because ZONE_DEVICE is supported) the usage of the new > > > > functionality untangles Xen balloon and RAM hotplug from the usage of > > > > unpopulated physical memory ranges to map foreign pages, which is the > > > > correct thing to do in order to avoid mappings of foreign pages depend > > > > on memory hotplug. > > > > > > So please just select ZONE_DEVICE if this is so much better rather > > > than maintaining two variants. > > > > We still need to other variant for Arm at least, so both need to be > > maintained anyway, even if we force ZONE_DEVICE on x86. > > Why does arm not have ZONE_DEVICE? It's not that Arm doesn't have ZONE_DEVICE, it's just that the approach used here won't work correctly on an Arm Xen dom0 as-is. This is due to the usage of an identity second stage translation in order to workaround the lack of an IOMMU in some Arm boards. It can be made to work on Arm, but will likely require someone from the Arm side doing that. Roger.