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 X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D34BBC433DF for ; Sat, 11 Jul 2020 00:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB035207BB for ; Sat, 11 Jul 2020 00:28:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594427284; bh=BRp8sZxnMGB3vpZ0E+ioDMibR1SlBT/gKwtr/pLNEYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=I1iTpBcRHLkcqhW6M6ExAv2Qg8OW2mu13rDskhTE1B8OhlSyrOlYkblDfK9m4QxBY fQXCF1dVyxQYU7qHDsqeJbu5qDV4GxPJ/Iq3Dc7pgKzv7Q42TzE7hWvahYbSeh7oHX Fmv8w0tJkbXFrV2yFXwREKIJ6+Rohx6/9rc58Kp4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726851AbgGKA2D (ORCPT ); Fri, 10 Jul 2020 20:28:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:55838 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726581AbgGKA2D (ORCPT ); Fri, 10 Jul 2020 20:28:03 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 928E32078B; Sat, 11 Jul 2020 00:28:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594427282; bh=BRp8sZxnMGB3vpZ0E+ioDMibR1SlBT/gKwtr/pLNEYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rcoEfIMjSYOscAN4dOPiRCIwgHLNfsr7WG33Xmy4XgKSPX9fNs3pkh0AaMgqZdLtc LssjVDTYv0uJJtzW6DQThgD3hoW9QztI7ZtFZvf178SFjx1tBiMW5qHGFPnzn80fn4 gl3ywItY31zXbbTGkHz3MQJEXwCvCnACTvLT8/rI= Date: Fri, 10 Jul 2020 20:28:01 -0400 From: Sasha Levin To: Florian Fainelli Cc: linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org, Will Deacon , Catalin Marinas , Will Deacon , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Mark Rutland , Mark Brown , Kristina Martsenko , Sami Tolvanen , Andrew Jones , Ard Biesheuvel , Nick Desaulniers , Fangrui Song , open list , "open list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" Subject: Re: [PATCH stable v4.9 v2] arm64: entry: Place an SB sequence following an ERET instruction Message-ID: <20200711002801.GE2722994@sasha-vm> References: <20200709195034.15185-1-f.fainelli@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200709195034.15185-1-f.fainelli@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 09, 2020 at 12:50:23PM -0700, Florian Fainelli wrote: >From: Will Deacon > >commit 679db70801da9fda91d26caf13bf5b5ccc74e8e8 upstream > >Some CPUs can speculate past an ERET instruction and potentially perform >speculative accesses to memory before processing the exception return. >Since the register state is often controlled by a lower privilege level >at the point of an ERET, this could potentially be used as part of a >side-channel attack. > >This patch emits an SB sequence after each ERET so that speculation is >held up on exception return. > >Signed-off-by: Will Deacon >[florian: Adjust hyp-entry.S to account for the label > added change to hyp/entry.S] >Signed-off-by: Florian Fainelli I've queued it up, thanks! -- Thanks, Sasha