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=-9.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 25015C433FE for ; Wed, 8 Sep 2021 14:47:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03AE760724 for ; Wed, 8 Sep 2021 14:47:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349395AbhIHOst (ORCPT ); Wed, 8 Sep 2021 10:48:49 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:46858 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349052AbhIHOss (ORCPT ); Wed, 8 Sep 2021 10:48:48 -0400 Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 52D7022256; Wed, 8 Sep 2021 14:47:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1631112459; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jEFNWRIePbeIPt9GmDov9/wA6u8O4zqeE8y8N3lFb/0=; b=R7t45CL/vN0fqwIkKaTAptvlWWf5gcWvgVuoFeE8stPitbx+wMt2erghnki2rfI1oLiRal wySquU2/gkjDEWjjC/y+en3qzsYcI3d8UpNpxOHZ8/P2XcT+jtCtj+m9xtfmFOMJM65BAm 5nu0K6rkLjboJJnJRO4INfze4CY3N6A= Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id E608C13A96; Wed, 8 Sep 2021 14:47:38 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id Kxm0NgrNOGFWNwAAGKfGzw (envelope-from ); Wed, 08 Sep 2021 14:47:38 +0000 To: Jan Beulich Cc: Boris Ostrovsky , Stefano Stabellini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , stable@vger.kernel.org, Sander Eikelenboom , xen-devel@lists.xenproject.org, x86@kernel.org, linux-kernel@vger.kernel.org References: <20210908073640.11299-1-jgross@suse.com> <5a4859db-d173-88dd-5ea9-dd5fd893d934@suse.com> <34afed98-5072-c563-5d29-97e09a0b4ebd@suse.com> <6862566d-4d55-dc5c-082a-da4fbcafcfce@suse.com> From: Juergen Gross Subject: Re: [PATCH] xen: fix usage of pmd/pud_poplulate in mremap for pv guests Message-ID: <21bad77f-90fb-1288-be52-291b56ccdd40@suse.com> Date: Wed, 8 Sep 2021 16:47:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <6862566d-4d55-dc5c-082a-da4fbcafcfce@suse.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="3GzrgL9tJGXXoMnm3mnp4eEQIR0B4Ilr6" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --3GzrgL9tJGXXoMnm3mnp4eEQIR0B4Ilr6 Content-Type: multipart/mixed; boundary="BAS2MNyQNemPES6JplNDoPiAx8GLYmZex"; protected-headers="v1" From: Juergen Gross To: Jan Beulich Cc: Boris Ostrovsky , Stefano Stabellini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , stable@vger.kernel.org, Sander Eikelenboom , xen-devel@lists.xenproject.org, x86@kernel.org, linux-kernel@vger.kernel.org Message-ID: <21bad77f-90fb-1288-be52-291b56ccdd40@suse.com> Subject: Re: [PATCH] xen: fix usage of pmd/pud_poplulate in mremap for pv guests References: <20210908073640.11299-1-jgross@suse.com> <5a4859db-d173-88dd-5ea9-dd5fd893d934@suse.com> <34afed98-5072-c563-5d29-97e09a0b4ebd@suse.com> <6862566d-4d55-dc5c-082a-da4fbcafcfce@suse.com> In-Reply-To: <6862566d-4d55-dc5c-082a-da4fbcafcfce@suse.com> --BAS2MNyQNemPES6JplNDoPiAx8GLYmZex Content-Type: multipart/mixed; boundary="------------57ADF394A2EC90BAF7B799FF" Content-Language: en-US This is a multi-part message in MIME format. --------------57ADF394A2EC90BAF7B799FF Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 08.09.21 16:28, Jan Beulich wrote: > On 08.09.2021 15:32, Juergen Gross wrote: >> On 08.09.21 13:07, Jan Beulich wrote: >>> On 08.09.2021 09:36, Juergen Gross wrote: >>>> Commit 0881ace292b662 ("mm/mremap: use pmd/pud_poplulate to update p= age >>>> table entries") introduced a regression when running as Xen PV guest= =2E >>> >>> The description of that change starts with "pmd/pud_populate is the >>> right interface to be used to set the respective page table entries."= >>> If this is deemed true, I don't think pmd_populate() should call >>> paravirt_alloc_pte(): The latter function, as its name says, is >>> supposed to be called for newly allocated page tables only (aiui). >> >> In theory you are correct, but my experience with reality tells me tha= t >> another set of macros for this case will not be appreciated. >=20 > Perhaps a new parameter to the macros / inlines identifying fresh > vs moved? Or perhaps the offending change wasn't really correct in > what its description said? The problem is that those macros are spread over all architectures with each architecture defining them separately. Changing all those will not be really welcomed. And the change was correct IMO, as the replaced pmd_set() should be used for leaf entries only (at least in arch independent code). pmd_populate() is the correct one for non-leaf entries. 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