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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98056C88CB2 for ; Mon, 12 Jun 2023 17:16:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234579AbjFLRQp (ORCPT ); Mon, 12 Jun 2023 13:16:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233361AbjFLRQj (ORCPT ); Mon, 12 Jun 2023 13:16:39 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98CAA1727 for ; Mon, 12 Jun 2023 10:16:23 -0700 (PDT) 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 2F86862087 for ; Mon, 12 Jun 2023 17:16:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6DA5C433D2; Mon, 12 Jun 2023 17:16:20 +0000 (UTC) Date: Mon, 12 Jun 2023 18:16:18 +0100 From: Catalin Marinas To: Marc Zyngier Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Quentin Perret , Will Deacon , Fuad Tabba Subject: Re: [PATCH v3 03/17] arm64: Turn kaslr_feature_override into a generic SW feature override Message-ID: References: <20230609162200.2024064-1-maz@kernel.org> <20230609162200.2024064-4-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230609162200.2024064-4-maz@kernel.org> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Jun 09, 2023 at 05:21:46PM +0100, Marc Zyngier wrote: > diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c > index 370ab84fd06e..8c93b6198bf5 100644 > --- a/arch/arm64/kernel/idreg-override.c > +++ b/arch/arm64/kernel/idreg-override.c > @@ -138,15 +138,11 @@ static const struct ftr_set_desc smfr0 __initconst = { > }, > }; > > -extern struct arm64_ftr_override kaslr_feature_override; > - > -static const struct ftr_set_desc kaslr __initconst = { > - .name = "kaslr", > -#ifdef CONFIG_RANDOMIZE_BASE > - .override = &kaslr_feature_override, > -#endif > +static const struct ftr_set_desc sw_features __initconst = { > + .name = "arm64_sw", > + .override = &arm64_sw_feature_override, > .fields = { > - FIELD("disabled", 0, NULL), > + FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL), > {} > }, > }; > @@ -158,7 +154,7 @@ static const struct ftr_set_desc * const regs[] __initconst = { > &isar1, > &isar2, > &smfr0, > - &kaslr, > + &sw_features, > }; > > static const struct { > @@ -175,7 +171,7 @@ static const struct { > "id_aa64isar1.api=0 id_aa64isar1.apa=0 " > "id_aa64isar2.gpa3=0 id_aa64isar2.apa3=0" }, > { "arm64.nomte", "id_aa64pfr1.mte=0" }, > - { "nokaslr", "kaslr.disabled=1" }, > + { "nokaslr", "arm64_sw.nokaslr=1" }, > }; I think structuring it as a sw feature makes more sense and I don't think it breaks anything (as long as people only used "nokaslr"). Reviewed-by: Catalin Marinas As a side note, I was wondering if we should add a SW_FIELD macro to define width of 1 for such fields (and probably the field extraction functions need some tweaking) so that we define ARM64_SW_FEATURE_OVERRIDE_* in increments of 1 rather than 4. Anyway, that's something to worry if we get too many such software features. -- Catalin