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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3FC90EEAA71 for ; Thu, 14 Sep 2023 20:34:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qgt1O-0005RR-8V; Thu, 14 Sep 2023 16:33:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgt1M-0005Qk-5V for qemu-devel@nongnu.org; Thu, 14 Sep 2023 16:33:04 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgt1K-0003a0-P6 for qemu-devel@nongnu.org; Thu, 14 Sep 2023 16:33:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694723581; h=from:from:reply-to:subject:subject: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=QbcHbohncSUgHsfr8JHw3fe0I9frPbrX/z7vDcww3y4=; b=MMN2svQXTLFe4xm1EQY7Q4rKx5iEaoZvUUvB/quJkNM0e1iy+ggWP97vGM9mZVdxVNuiuv sT9R56QCxalNIifVDUtS1aUfIC2wazZXIvFdkVXwQgkK4uwZB4bgQueIQe+E+Xr85t1HtQ zrG3RVIgquMiZjtYPr1NfAZ8H3zNHDk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-235-puQc1DvmMSaXMvKv_eG7JA-1; Thu, 14 Sep 2023 16:32:55 -0400 X-MC-Unique: puQc1DvmMSaXMvKv_eG7JA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 07302857A9C; Thu, 14 Sep 2023 20:32:55 +0000 (UTC) Received: from localhost (unknown [10.39.194.105]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7402940C2070; Thu, 14 Sep 2023 20:32:54 +0000 (UTC) Date: Thu, 14 Sep 2023 16:32:52 -0400 From: Stefan Hajnoczi To: Mattias Nissler Cc: qemu-devel@nongnu.org, john.levon@nutanix.com, Elena Ufimtseva , "Michael S. Tsirkin" , David Hildenbrand , Marcel Apfelbaum , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Richard Henderson , Jagannathan Raman , Peter Xu , Paolo Bonzini Subject: Re: [PATCH v3 5/5] vfio-user: Fix config space access byte order Message-ID: <20230914203252.GA1098343@fedora> References: <20230907130410.498935-1-mnissler@rivosinc.com> <20230907130410.498935-6-mnissler@rivosinc.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="1SskSS2+6QHN77oN" Content-Disposition: inline In-Reply-To: <20230907130410.498935-6-mnissler@rivosinc.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --1SskSS2+6QHN77oN Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Sep 07, 2023 at 06:04:10AM -0700, Mattias Nissler wrote: > PCI config space is little-endian, so on a big-endian host we need to > perform byte swaps for values as they are passed to and received from > the generic PCI config space access machinery. >=20 > Signed-off-by: Mattias Nissler > --- > hw/remote/vfio-user-obj.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) After some discussion about PCI Configuration Space endianness on IRC with aw, mcayland, and f4bug I am now happy with this patch: 1. Configuration space can only be accessed in 1-, 2-, or 4-byte accesses. 2. If it's a 2- or 4-byte access then your patch adds the missing little-endian conversion. 3. If it's a 1-byte access then there is (effectively) no byteswap in the code path and the pci_dev->config[] array is already little-endian. Reviewed-by: Stefan Hajnoczi --1SskSS2+6QHN77oN Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmUDbfQACgkQnKSrs4Gr c8jlrwf9E+Pz4mEmDNHccAjkq5Dxocs/4ErHaKJrZHLA+VGhqdzoK49fPV8CKheZ XvAP15UolRWt0zw3fAbFBzxbKddVW0t20mszmjqqo9KD7viKBEN6r8+HFGpuBcIB Dfr5XiTyK0ALC1Bsq1BW/fxP+SJvxkRE3HXqJiiERb29MKDFT0Ctj2jm+1eVukOG Wuor343YDSQ5QD8crp0IFepTVTIvumGkezKTIOovCFkp4mT5BydLEjFQ2dAEF4bl KsteT3W6XxnSq1pdgErY7CnviI5++ts+1rCd2g0QjdC08bbaA/RVPvXalZx/X2uT BeZ/T+9dZvrGQbaiJ+ogCszHCcJRUw== =bfXD -----END PGP SIGNATURE----- --1SskSS2+6QHN77oN--