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=-15.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 6C53CC43460 for ; Wed, 7 Apr 2021 21:18:25 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 083DD6121E for ; Wed, 7 Apr 2021 21:18:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 083DD6121E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc: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=YMk1+H5nV3obs1kNLowpU8X1+Mj4EW93ach62wRJFP4=; b=C4rYwldT1MeIOSO1bjZqEL1mu wvQk/ssSxZrSSFcsqOJ2vys3WhhaKVG4nkl8MlcEj9ONGOjH1eOIHhOoi5ZzCYPm4tlyrNXi7zRWp hU7PWUqdUdwLxInWHaxidkKDcJrZFozlG3BiYM/JehZFOXDEYsKoaDXEcHONm4PJgRoZ31VuyITy/ FME0YeSuN5FDggfY/TWBFVBRVhrksYu1R8kxnLeGkzcd6hkyVG2z9MgpMn8aPG4fI76USVMjzdjBZ MfIe+zo0B20x38raI4GOL0Iy63s2Z0yBSsJoFUR3Bu6soagk2uZ9Hz4N+IiujLTWuy14GNh3K1Jok O2Rad0KfA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lUFXb-0061q0-RC; Wed, 07 Apr 2021 21:16:48 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lUFXY-0061pM-4h for linux-arm-kernel@lists.infradead.org; Wed, 07 Apr 2021 21:16:45 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5867761205; Wed, 7 Apr 2021 21:16:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617830202; bh=N/OTzoI/3EfI/lWNQCtc3Jo5Xx+A9MsFxyUjWWJxzc8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pr8WnHgZGXMsVkglq2irh56qVYoT2l18V1a+d/Y1dBEj9jm1mThNOvV/O9nwlkVoX PSQbHeAN2dBdBLjRoAv4RLhtyFJ/5bum/dOUiRtysDmbBy04na6WkYUg9f9fa/lFyx oQVMFhgYVIcVfOGu/KejovGO2nPkpqEDXM8P1umUsorZrt0ptndww9GBirqnd2KuJY TLvUWeYmkb/+lNp9fxMiHctvRP2f42vZVRVQR5SdJ11HRsm/y8GRVAopyjVYEVhojZ AodRM8voKI+n6uWXx9kqFZfJPXTQN1RDN0vGtYALCIUkTycaUWot62jPp39lg+t0sU lpjvEbTNmOGTw== Date: Wed, 7 Apr 2021 22:16:38 +0100 From: Will Deacon To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, Hector Martin , Arnd Bergmann , Mark Rutland , Catalin Marinas , kernel-team@android.com Subject: Re: [PATCH v2 2/3] arm64: Cope with CPUs stuck in VHE mode Message-ID: <20210407211637.GD16198@willie-the-truck> References: <20210330173947.999859-1-maz@kernel.org> <20210330173947.999859-3-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210330173947.999859-3-maz@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210407_221644_411869_E2FEAFB7 X-CRM114-Status: GOOD ( 14.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Tue, Mar 30, 2021 at 06:39:46PM +0100, Marc Zyngier wrote: > It seems that the CPUs part of the SoC known as Apple M1 have the > terrible habit of being stuck with HCR_EL2.E2H==1, in violation > of the architecture. > > Try and work around this deplorable state of affairs by detecting > the stuck bit early and short-circuit the nVHE dance. Additional > filtering code ensures that attempts at switching to nVHE from > the command-line are also ignored. > > It is still unknown whether there are many more such nuggets > to be found... > > Reported-by: Hector Martin > Signed-off-by: Marc Zyngier > --- > arch/arm64/kernel/head.S | 39 +++++++++++++++++++++++++++--- > arch/arm64/kernel/hyp-stub.S | 8 +++--- > arch/arm64/kernel/idreg-override.c | 13 +++++++++- > 3 files changed, 52 insertions(+), 8 deletions(-) Acked-by: Will Deacon Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel