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 8164EC47DB3 for ; Wed, 31 Jan 2024 18:53:45 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rVFhK-0002kb-4y; Wed, 31 Jan 2024 13:52:34 -0500 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 1rVFhI-0002jk-5l; Wed, 31 Jan 2024 13:52:32 -0500 Received: from sin.source.kernel.org ([2604:1380:40e1:4800::1]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rVFhF-0007G9-OG; Wed, 31 Jan 2024 13:52:31 -0500 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 2AE22CE218B; Wed, 31 Jan 2024 18:52:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28416C433F1; Wed, 31 Jan 2024 18:52:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706727137; bh=czBRZcYgNVSyZkkOYTT2dhNf10PuR0vW9rEahq38vEE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dkNDmVNJ0eqMU5SErP0KRoykAPVw26WJ2dckkZuZmblk6yist+NB/Lbed6tnTxcjf qB5+6Zh8zG9BFoT+uetSTiDYL4xNbMEgSWEdFd8L1+l53Md2T+FuwhAySZLoh4LUj/ JTGamt0gt9H+Mje1zMNqBY6iQ6K8Xbt1WMizPxqjg8wZX5JBAViONte0YwaIMhXvYp vVF4P7oyQcRLnpNrdfYS+PFo8H437QXS4zoV4iYhFmdHLbCFV6JnPCFnhl8fptTVTb t2I2X5eh/16amEdUu5GVvSWHcDJdrpLSj2wGy8i5Sc7HUO6pZBFKmH2R/4x5GcsiQ2 JEsvzRf6PswbA== Date: Wed, 31 Jan 2024 18:52:12 +0000 From: Conor Dooley To: Christoph =?iso-8859-1?Q?M=FCllner?= Cc: LIU Zhiwei , qemu-devel@nongnu.org, Alistair.Francis@wdc.com, palmer@dabbelt.com, bin.meng@windriver.com, liwei1518@gmail.com, dbarboza@ventanamicro.com, qemu-riscv@nongnu.org, bjorn@kernel.org, Philipp Tomsich Subject: Re: [PATCH 2/2] target/riscv: Support xtheadmaee for thead-c906 Message-ID: <20240131-groove-preamble-a2334b869f4e@spud> References: <20240130111159.532-1-zhiwei_liu@linux.alibaba.com> <20240130111159.532-3-zhiwei_liu@linux.alibaba.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Y5kulPWHU31cP58D" Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=2604:1380:40e1:4800::1; envelope-from=conor@kernel.org; helo=sin.source.kernel.org X-Spam_score_int: -56 X-Spam_score: -5.7 X-Spam_bar: ----- X-Spam_report: (-5.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.292, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 --Y5kulPWHU31cP58D Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 30, 2024 at 12:43:25PM +0100, Christoph M=C3=BCllner wrote: > On Tue, Jan 30, 2024 at 12:12=E2=80=AFPM LIU Zhiwei > wrote: > > > > thead-c906 uses some flags in pte [60-63] bits. It has history reasons = that > > SVPBMT didn't exist when thead-c906 came to world. > > > > We named this feature as xtheadmaee. this feature is controlled by an c= ustom > > CSR named mxstatus, whose maee field encodes whether enable the pte [60= -63] bits. > > > > The sections "5.2.2.1 Page table structure" and "15.1.7.1 M-mode extens= ion > > status register (MXSTATUS)" in document[1] give the detailed information > > about its design. >=20 > I would prefer if we would not define an extension like XTheadMaee > without a specification. > The linked document defines the bit MAEE in a custom CSR, but the > scope of XTheadMaee > is not clearly defined (the term XTheadMaee is not even part of the PDF). >=20 > We have all the XThead* extensions well described here: > https://github.com/T-head-Semi/thead-extension-spec/tree/master > And it would not be much effort to add XTheadMaee there as well. Yeah, I was gonna request exactly this, so glad to see you beat me to the punch. It would be really great if this was done, particularly if this xmaee is going to appear in devicetrees and sooner or later is gonna want to be documented in a binding. Cheers, Conor. > For those who don't know the context of this patch, here is the c906 > boot regression report from Bj=C3=B6rn: > https://lists.gnu.org/archive/html/qemu-devel/2024-01/msg04766.html --Y5kulPWHU31cP58D Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZbqW3AAKCRB4tDGHoIJi 0hVWAQCCqKZ6/90laeEqKGvCIrydZllOe1Kpyz/pyNmmVZU0ywD/YDxhjADP0PR9 d9Ae4Pv71r+42PEEUQDaw4ca4xvCVg0= =bchw -----END PGP SIGNATURE----- --Y5kulPWHU31cP58D--