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=-8.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 D9AE2C433DB for ; Sat, 23 Jan 2021 14:09:32 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9802522B51 for ; Sat, 23 Jan 2021 14:09:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9802522B51 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XlOzmpBRMAeNn2gHHfTW3sk3yjVWWGhMXCKhLSM/40Y=; b=w/pITn0Th9DGso1ArY3BV+eLn LfU8WB9SSz2wxhtETvvXj2O9tc4ObSuz9IxDzXwrbb72fnE+BiVCLD60u0r9D+Wauf5RKpbqSYgce ps5mMx72tnQjPWTchkXc4O85SEVY8QBz0otx0fg7YK+xQp2wE8B2oY854zN7XhXq4IAE6DdJBNzR2 odM8l3PGLTHkKVyfW6TgbyBnOo20VC6l31JpNGpe7M+72EhdUgWeKEnmnmcgoo/0luB1dwW6BaDrW Rc/1uStRgMfjNTfaRfjtd0G+gxzDx+w5WlLH3TFqGoK+/6WwF015xd7eYok8h17YjjJ0YfTmw+5gd oYvfzkxXA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l3Ja5-0005nu-Pv; Sat, 23 Jan 2021 14:08:01 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l3Ja3-0005nY-OI for linux-arm-kernel@lists.infradead.org; Sat, 23 Jan 2021 14:08:00 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2961022B51; Sat, 23 Jan 2021 14:07:56 +0000 (UTC) Date: Sat, 23 Jan 2021 14:07:53 +0000 From: Catalin Marinas To: Marc Zyngier Subject: Re: [PATCH v4 14/21] arm64: Honor VHE being disabled from the command-line Message-ID: References: <20210118094533.2874082-1-maz@kernel.org> <20210118094533.2874082-15-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210118094533.2874082-15-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210123_090759_856837_1A20D7CE X-CRM114-Status: GOOD ( 12.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Jing Zhang , Prasad Sodagudi , Srinivas Ramana , Suzuki K Poulose , Alexandru Elisei , linux-kernel@vger.kernel.org, Ard Biesheuvel , James Morse , Julien Thierry , Ajay Patil , kernel-team@android.com, David Brazdil , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Jan 18, 2021 at 09:45:26AM +0000, Marc Zyngier wrote: > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S > index 59820f9b8522..bbab2148a2a2 100644 > --- a/arch/arm64/kernel/hyp-stub.S > +++ b/arch/arm64/kernel/hyp-stub.S > @@ -77,13 +77,24 @@ SYM_CODE_END(el1_sync) > SYM_CODE_START_LOCAL(mutate_to_vhe) > // Sanity check: MMU *must* be off > mrs x0, sctlr_el2 > - tbnz x0, #0, 1f > + tbnz x0, #0, 2f > > // Needs to be VHE capable, obviously > mrs x0, id_aa64mmfr1_el1 > ubfx x0, x0, #ID_AA64MMFR1_VHE_SHIFT, #4 > - cbz x0, 1f > + cbz x0, 2f > > + // Check whether VHE is disabled from the command line > + adr_l x1, id_aa64mmfr1_val > + ldr x0, [x1] > + adr_l x1, id_aa64mmfr1_mask > + ldr x1, [x1] > + ubfx x0, x0, #ID_AA64MMFR1_VHE_SHIFT, #4 > + ubfx x1, x1, #ID_AA64MMFR1_VHE_SHIFT, #4 > + cbz x1, 1f > + and x0, x0, x1 > + cbz x0, 2f > +1: I can see the advantage here in separate id_aa64mmfr1_val/mask but we could use some asm offsets here and keep the pointer indirection simpler in C code. You'd just need something like 'adr_l mmfr1_ovrd + VAL_OFFSET'. Anyway, if you have a strong preference for the current approach, leave it as is. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel