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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 8F003C636D3 for ; Tue, 7 Feb 2023 20:40:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=c2E4RbBugk+6x1p9jwK9omM5yC5q9Q4eC8wh8lov1NU=; b=s+MXXDvKprzchzB/fA6w8GEj77 Tb/T4/RAOiKCVdBQ23FqhVqa/PvHss0x962ljoXP38FhqoANLFx+7b3S7a+j50YSimbjJNGVS5mvb UCkTXeJrJsDbH+F+J7BE4roMn5XNnrzRzp6X9EZJqLyhm8yEdZWGZIyJCGXKoXmAa6JBGv2X0trBg ms/khuB1VL9VzNbf+t5cxXQKpu06FEG1QQ35LWg/vh7imEMxtrjjqIRBR2YEzXwk+6n7NyvBnMczF eocQZjUJ4Q2u3Pg+9EMtFkS7+jOoZ1ZYuE7ZWnOmx4v9TY9UVzkaDhRaHzNb1W+72Bi4sNd2hILKZ k5qWJNgA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pPUl7-00DLuo-V4; Tue, 07 Feb 2023 20:40:09 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pPUkw-00DLrD-Am; Tue, 07 Feb 2023 20:40:00 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 092F461181; Tue, 7 Feb 2023 20:39:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC9A6C433EF; Tue, 7 Feb 2023 20:39:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675802396; bh=w+rrQhOyjX+xSn+lkCQA/ZfXpy18C9NT1orJsYu8WrQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jh1hM7/xhNsp/euzJURNrI+OgX9NYfI06u2yZss0I6KDbq+5mrqpNKv8MsLvkwADB lQVMSiYfmlhEGfJ8RT7Wyx1XMNSSU3n1K3AA0HyOQ/e2OrqIZTTuBA6xNg2Iy+tF+p 8YA7hGhyU2ppwZAdeqqXhoKcCS4xLok2D12P55uEl+xu/KT5UiW880XEbUwHpOQgG7 rFApPUaz18FwXMUy1KfE7zc4IygGCc3fjLTJVvn3M7OlqpfY8jiVToMNaa7ldr6YsP kW6BoUPcRZb7OoxuxQGq/t6TsGqZ5s0MfMGNZVDKOqKHUv8+qM3erYHWl0G4oaO9FJ YSP3OLGluXDHg== Date: Tue, 7 Feb 2023 20:39:51 +0000 From: Conor Dooley To: Atish Patra Cc: Stephano Cetola , Jeff Scheel , Anup Patel , Palmer Dabbelt , pbonzini@redhat.com, Paul Walmsley , ajones@ventanamicro.com, anup@brainfault.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/7] RISC-V: Detect AIA CSRs from ISA string Message-ID: References: <20230128072737.2995881-3-apatel@ventanamicro.com> MIME-Version: 1.0 In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230207_123959_046425_941E7419 X-CRM114-Status: GOOD ( 38.98 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============9045515870965239635==" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org --===============9045515870965239635== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="zu6F9f3ZsZxSjFKz" Content-Disposition: inline --zu6F9f3ZsZxSjFKz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 07, 2023 at 10:15:22AM -0800, Atish Patra wrote: > On Tue, Feb 7, 2023 at 10:05 AM Conor Dooley wrote: > > On Fri, Feb 03, 2023 at 05:31:01PM +0530, Anup Patel wrote: > > > On Fri, Feb 3, 2023 at 5:54 AM Palmer Dabbelt wr= ote: > > > > > > > > On Fri, 27 Jan 2023 23:27:32 PST (-0800), apatel@ventanamicro.com w= rote: > > > > > We have two extension names for AIA ISA support: Smaia (M-mode AI= A CSRs) > > > > > and Ssaia (S-mode AIA CSRs). > > > > > > > > This has pretty much the same problem that we had with the other > > > > AIA-related ISA string patches, where there's that ambiguity with t= he > > > > non-ratified chapters. IIRC when this came up in GCC the rough ide= a was > > > > to try and document that we're going to interpret the standard ISA > > > > strings that way, but now that we're doing custom ISA extensions it > > > > seems saner to just define on here that removes the ambiguity. > > > > > > > > I just sent > > > > > > > > which documents that. > > > > > > I am not sure why you say that these are custom extensions. > > > > > > Multiple folks have clarified that both Smaia and Ssaia are frozen > > > ISA extensions as-per RVI process. The individual chapters which > > > are in the draft state have nothing to do with Smaia and Ssaia CSRs. > > > > > > Please refer: > > > https://github.com/riscv/riscv-aia/pull/36 > > > https://lists.riscv.org/g/tech-aia/message/336 > > > https://lists.riscv.org/g/tech-aia/message/337 > > > > All of these links seem to discuss the draft chapters somehow being > > incompatible with the non-draft ones. I would very expect that that, > > as pointed out in several places there, that the draft chapters > > finalisation would not lead to meaningful (and incompatible!) changes > > being made to the non-draft chapters. > > >=20 > Here is the status of all RVI specs. It states that the Smaia, Ssaia > extensions are frozen (i.e. public review complete). > https://wiki.riscv.org/display/HOME/Specification+Status >=20 > I have added stephano/Jeff to confirm the same. >=20 > AFAIK, IOMMU spec is close to the public review phase and should be > frozen in this or next quarter. > IIRC, this chapter in AIA will be frozen along with IOMMU spec. >=20 > Anup: Please correct me if that's not correct. >=20 > > Maybe yourself and Palmer are looking at this from different > > perspectives? Looking at his patch from Friday: > > https://lore.kernel.org/linux-riscv/20230203001201.14770-1-palmer@rivos= inc.com/ > > He specifically mentioned this aspect, as opposed to the aspect that > > your links refer to. > > > > Surely a duo-plic, if that ever comes to be, could be detected from > > compatible strings in DT or w/e - but how do you intend differentiating > > between an implementation of S*aia that contains the IOMMU support in > > Chapter 9 in a finalised form, versus an implementation that may make > > "different decisions" when it comes to that chapter of the spec? >=20 > We will most likely have an extension specific to iommu spec as well. Right, but unless I am misunderstanding you, that is an extension for the IOMMU spec, not for Chapter 9 of the AIA spec? I would say that it is likely that if you have AIA and IOMMU that you'd want to be implementing Chapter 9, but that would not appear sufficient to draw a conclusion from. Maybe the RVI lads that you've added (or Anup for that matter!) can clarify if there is a requirement that if you do AIA and IOMMU that you must do Chapter 9. If not, my prior question about a differentiation mechanism still applies I think! > > I thought that would be handled by extension versions, but I am told > > that those are not a thing any more. > > If that's not true, and there'll be a version number that we can pull in > > from a DT and parse which will distinguish between the two, then please > > correct my misunderstanding here! --zu6F9f3ZsZxSjFKz Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCY+K3FwAKCRB4tDGHoIJi 0nRUAQCzGk/oJbWN9mf9OIFLN+uyotpOGeyxY90lVVK4R5DBpgD/SR9y2qhD9PD/ NukTfTz4ynWyNGYdGD5ZL6W7V2x9DAg= =ZDei -----END PGP SIGNATURE----- --zu6F9f3ZsZxSjFKz-- --===============9045515870965239635== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv --===============9045515870965239635==--