From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E019D1A073C; Tue, 13 Aug 2024 15:55:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723564535; cv=none; b=FEDzJLoLl5J4UaTWQ6lo4XJI0+ig5QZMZhmbEPlWbCV+frhla7s3FiJHY99nOFazJcVxvyszMy3ESDMNa0NCimQwhcubeKp/ZeEQZyU4fqraMVt1zUCxRvS52N5ODcSV37QWCjcaWBKlZhaV+5558hes0e/+iipYJnBmZANPmlc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723564535; c=relaxed/simple; bh=2qbznLVAWa/HOCkibpwEKuFx9BRG0jfLiyGPm/O5D0U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DrysTMLe8/lW4Ac9VRJvwngkcSIWbSRXJGhNcYxhEy9FCfbpQhDsehFYZW9P19vR8u/vCZWaDb7HQJ6WUf4mU2LtpUmB4R8laEoloNWTQL2ST8KIm+sSd2ev+NNZSZLf9f/TpYmSZXRIGiQxMrDllAsS5F5JHlv0Cok5LgPjG48= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TdDaa/og; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TdDaa/og" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B120C4AF09; Tue, 13 Aug 2024 15:55:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723564534; bh=2qbznLVAWa/HOCkibpwEKuFx9BRG0jfLiyGPm/O5D0U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TdDaa/og08j0LYWxMjIfmT62Kse6nlmDNAqFUWXRmeAOd4L8HUcdtoNGpFIKZ2ovK Wo8eroMPA7ljNcvycCtAJoCPSOW0sL4ez8CU0njPbAl5s4w3e1pL1xt0z/5bkAsd3W AyI8VSs3BZHOYosptDMzpeCBZYGxHn2H8y8LbYAnhcsMLr91GM20TL0ixceE9tPfzb Vx1zlFj6nEUair4k8rdOYdoG4DTk8CIJwZHafLxB8o8P/RrW8+9bZFSBxfXNpqDFNr VwMB5tfnO4Fx23eAhjULiqlqOWHy4r2C5DEKNZSBu0vrreLkayROtBxCfuvWvflTI4 xxXxYgEv0gapw== Date: Tue, 13 Aug 2024 16:55:27 +0100 From: Conor Dooley To: Charlie Jenkins Cc: Rob Herring , Krzysztof Kozlowski , Paul Walmsley , Palmer Dabbelt , Albert Ou , Jisheng Zhang , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Samuel Holland , Jonathan Corbet , Shuah Khan , Guo Ren , Evan Green , Andy Chiu , Jessica Clarke , Andrew Jones , linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Conor Dooley , Heiko Stuebner Subject: Re: [PATCH v9 00/13] riscv: Add support for xtheadvector Message-ID: <20240813-strode-revival-07b8556a8bfe@spud> References: <20240806-xtheadvector-v9-0-62a56d2da5d0@rivosinc.com> <20240809-slapping-graph-461287bac506@spud> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="wVALGEdsN5/GZu0E" Content-Disposition: inline In-Reply-To: --wVALGEdsN5/GZu0E Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Aug 12, 2024 at 05:45:30PM -0700, Charlie Jenkins wrote: > On Fri, Aug 09, 2024 at 11:31:15PM +0100, Conor Dooley wrote: > > On Tue, Aug 06, 2024 at 05:31:36PM -0700, Charlie Jenkins wrote: > > > xtheadvector is a custom extension that is based upon riscv vector > > > version 0.7.1 [1]. All of the vector routines have been modified to > > > support this alternative vector version based upon whether xtheadvect= or > > > was determined to be supported at boot. > > >=20 > > > vlenb is not supported on the existing xtheadvector hardware, so a > > > devicetree property thead,vlenb is added to provide the vlenb to Linu= x. > > >=20 > > > There is a new hwprobe key RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 that = is > > > used to request which thead vendor extensions are supported on the > > > current platform. This allows future vendors to allocate hwprobe keys > > > for their vendor. > > >=20 > > > Support for xtheadvector is also added to the vector kselftests. > >=20 > > So uh, since noone seems to have brought it up, in the light of the iss= ues > > with thead's vector implementation, (https://ghostwriteattack.com/) do = we > > want to enable it at all? >=20 > I can make it clear in the kconfig that xtheadvector is succeptible to > this attack and that it should be enabled with caution. I think we > should let people that understand the risk to enable it. I think the clearest way might be "depends on BROKEN"? --wVALGEdsN5/GZu0E Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZruB7wAKCRB4tDGHoIJi 0tDJAQCrAAwyJAAGcGaB0lSjHQowc1+M+60A33xWLVpFubDEggD+PdA/5VviAMYd FtjIx2BGIAbBB5DLVfsxw4duVA3eAQc= =/cR1 -----END PGP SIGNATURE----- --wVALGEdsN5/GZu0E--