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 90E1BEEAA69 for ; Thu, 14 Sep 2023 19:35:23 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qgs6s-00073r-QN; Thu, 14 Sep 2023 15:34:42 -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 1qgs6r-00073V-7Y for qemu-devel@nongnu.org; Thu, 14 Sep 2023 15:34:41 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgs6p-0001OV-IP for qemu-devel@nongnu.org; Thu, 14 Sep 2023 15:34:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694720077; 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=dyQgtSS2sDlsPzeXyPR/i4txkO22/a60POyvmeZdcs8=; b=CTetHf27oxIEp7nTsA2BT2iY3IICREGAvAMyv22xBWRQXvFO0kTA3e4VS0Ar46yU5PEs84 O9O6dYn3XqbmyIiw13dkeoz0noH3QtQX5+jpy9124G2AUGZkGahk+3i797dTuXFaBY+xAj Q9ZtEpO8HjfJwBWt/iC3R2GzKnrVmx4= 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-458-tTnpCYSYN3miy1tNbokf7Q-1; Thu, 14 Sep 2023 15:34:32 -0400 X-MC-Unique: tTnpCYSYN3miy1tNbokf7Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (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 4C06C101B456; Thu, 14 Sep 2023 19:34:32 +0000 (UTC) Received: from localhost (unknown [10.39.194.105]) by smtp.corp.redhat.com (Postfix) with ESMTP id B9A191054FC0; Thu, 14 Sep 2023 19:34:31 +0000 (UTC) Date: Thu, 14 Sep 2023 15:34:30 -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: <20230914193430.GD1066211@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="MXBt3DPGoq7m1tgY" Content-Disposition: inline In-Reply-To: <20230907130410.498935-6-mnissler@rivosinc.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; 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_H3=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 --MXBt3DPGoq7m1tgY 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. Byteswapping only works when registers are accessed with their natural size, even with this patch. If there is something like a PCI Capability structure, then it needs to be read one register at a time to get back valid data. It cannot simply be copied in a single multi-DWORD access. I'm not sure if this fix is sufficient. Maybe pci_host_*() needs to be extended to support little-endian accesses instead? >=20 > Signed-off-by: Mattias Nissler > --- > hw/remote/vfio-user-obj.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) >=20 > diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c > index cee5e615a9..d38b4700f3 100644 > --- a/hw/remote/vfio-user-obj.c > +++ b/hw/remote/vfio-user-obj.c > @@ -281,7 +281,7 @@ static ssize_t vfu_object_cfg_access(vfu_ctx_t *vfu_c= tx, char * const buf, > while (bytes > 0) { > len =3D (bytes > pci_access_width) ? pci_access_width : bytes; > if (is_write) { > - memcpy(&val, ptr, len); > + val =3D ldn_le_p(ptr, len); > pci_host_config_write_common(o->pci_dev, offset, > pci_config_size(o->pci_dev), > val, len); > @@ -289,7 +289,7 @@ static ssize_t vfu_object_cfg_access(vfu_ctx_t *vfu_c= tx, char * const buf, > } else { > val =3D pci_host_config_read_common(o->pci_dev, offset, > pci_config_size(o->pci_dev= ), len); > - memcpy(ptr, &val, len); > + stn_le_p(ptr, len, val); > trace_vfu_cfg_read(offset, val); > } > offset +=3D len; > --=20 > 2.34.1 >=20 --MXBt3DPGoq7m1tgY Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmUDYEYACgkQnKSrs4Gr c8jNEggAgjVfyDQ5d5bmRSdvdX5oUNXPFyDpLesIy2n5lb9N6TbyJ5so+OTYYWqO 1DQCsgzLQbrSUIQgqFuUs5v12wRuvRWgHqGbuWCg2dSLtmv7sQsehPsg6GgxRJNP la2O78M18dA38Paps0FwwihQgQ1DDmgozM/3VBOhOcOQOUEZ3PZFUPyf2VL6L8DZ 203+Y5oRQKYTPCqexiW05nIQuTUMMoL8gOpSDRZdviYyEMeSW+hRk/BrumAO0M8d 2br0FSS20dK7ysFTY73jiYscCrv2FG0/UG1i6OYK8eFFQfrh7PFl1kECJTDxMQdG ejaAdcDdwmENjX8FC4om5NKS1SU75A== =pTCm -----END PGP SIGNATURE----- --MXBt3DPGoq7m1tgY--