From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH] arm64: KVM: Obey RES0/1 reserved bits when setting CPTR_EL2 Date: Tue, 19 Jan 2016 16:32:43 +0000 Message-ID: <569E652B.8040202@arm.com> References: <1453220418-24744-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 87517496F5 for ; Tue, 19 Jan 2016 11:28:18 -0500 (EST) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id zX8lHkDF5++3 for ; Tue, 19 Jan 2016 11:28:17 -0500 (EST) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 6496F49680 for ; Tue, 19 Jan 2016 11:28:17 -0500 (EST) In-Reply-To: <1453220418-24744-1-git-send-email-Dave.Martin@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Dave Martin , kvmarm@lists.cs.columbia.edu Cc: Geoff Levand , linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu On 19/01/16 16:20, Dave Martin wrote: > Some bits in CPTR are defined as RES1 in the architecture. Setting > these bits to zero may unintentionally enable future architecture > extensions, allowing guests to use them without supervision by the host. > > This would be bad: for forwards compatibility, this patch makes > sure the affected bits are always written with 1, not 0. > > This patch only addresses CPTR_EL2. Initialisation of other system > registers may still need review. > > Signed-off-by: Dave Martin Thanks for putting this together: Reviewed-by: Marc Zyngier Unless someone has an objection, I plan to queue this post -rc1. M. -- Jazz is not dead. It just smells funny...