From: Charlie Jenkins <charlie@rivosinc.com>
To: Conor Dooley <conor@kernel.org>
Cc: Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Jisheng Zhang <jszhang@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Samuel Holland <samuel@sholland.org>,
Samuel Holland <samuel.holland@sifive.com>,
Jonathan Corbet <corbet@lwn.net>, Shuah Khan <shuah@kernel.org>,
Guo Ren <guoren@kernel.org>, Evan Green <evan@rivosinc.com>,
Andy Chiu <andy.chiu@sifive.com>,
Jessica Clarke <jrtc27@jrtc27.com>,
Andrew Jones <ajones@ventanamicro.com>,
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 <conor.dooley@microchip.com>,
Heiko Stuebner <heiko@sntech.de>
Subject: Re: [PATCH v9 00/13] riscv: Add support for xtheadvector
Date: Mon, 12 Aug 2024 17:45:30 -0700 [thread overview]
Message-ID: <ZrqsqsCtKwfG4Q5B@ghost> (raw)
In-Reply-To: <20240809-slapping-graph-461287bac506@spud>
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 xtheadvector
> > was determined to be supported at boot.
> >
> > vlenb is not supported on the existing xtheadvector hardware, so a
> > devicetree property thead,vlenb is added to provide the vlenb to Linux.
> >
> > 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.
> >
> > Support for xtheadvector is also added to the vector kselftests.
>
> So uh, since noone seems to have brought it up, in the light of the issues
> with thead's vector implementation, (https://ghostwriteattack.com/) do we
> want to enable it at all?
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.
- Charlie
next prev parent reply other threads:[~2024-08-13 0:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-07 0:31 [PATCH v9 00/13] riscv: Add support for xtheadvector Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 01/13] dt-bindings: riscv: Add xtheadvector ISA extension description Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 02/13] dt-bindings: cpus: add a thead vlen register length property Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 03/13] riscv: dts: allwinner: Add xtheadvector to the D1/D1s devicetree Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 04/13] riscv: Add thead and xtheadvector as a vendor extension Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 05/13] riscv: vector: Use vlenb from DT for thead Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 06/13] RISC-V: define the elements of the VCSR vector CSR Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 07/13] riscv: csr: Add CSR encodings for CSR_VXRM/CSR_VXSAT Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 08/13] riscv: Add xtheadvector instruction definitions Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 09/13] riscv: vector: Support xtheadvector save/restore Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 10/13] riscv: hwprobe: Add thead vendor extension probing Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 11/13] riscv: hwprobe: Document thead vendor extensions and xtheadvector extension Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 12/13] selftests: riscv: Fix vector tests Charlie Jenkins
2024-08-07 0:31 ` [PATCH v9 13/13] selftests: riscv: Support xtheadvector in " Charlie Jenkins
2024-08-09 22:31 ` [PATCH v9 00/13] riscv: Add support for xtheadvector Conor Dooley
2024-08-13 0:45 ` Charlie Jenkins [this message]
2024-08-13 15:55 ` Conor Dooley
2024-08-19 23:06 ` Charlie Jenkins
2024-08-20 16:42 ` Conor Dooley
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