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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 7E37FC43387 for ; Mon, 14 Jan 2019 15:56:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 574DE206B7 for ; Mon, 14 Jan 2019 15:56:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726800AbfANP4k (ORCPT ); Mon, 14 Jan 2019 10:56:40 -0500 Received: from foss.arm.com ([217.140.101.70]:36198 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726646AbfANP4k (ORCPT ); Mon, 14 Jan 2019 10:56:40 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 09D1D80D; Mon, 14 Jan 2019 07:56:40 -0800 (PST) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.113]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C85113F70D; Mon, 14 Jan 2019 07:56:37 -0800 (PST) Date: Mon, 14 Jan 2019 15:56:35 +0000 From: Catalin Marinas To: Julien Thierry Cc: linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, linux-arch@vger.kernel.org, daniel.thompson@linaro.org, Arnd Bergmann , marc.zyngier@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org, christoffer.dall@arm.com, james.morse@arm.com, joel@joelfernandes.org Subject: Re: [PATCH v8 01/26] arm64: Fix HCR.TGE status for NMI contexts Message-ID: <20190114155634.GB84430@arrakis.emea.arm.com> References: <1546956464-48825-1-git-send-email-julien.thierry@arm.com> <1546956464-48825-2-git-send-email-julien.thierry@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1546956464-48825-2-git-send-email-julien.thierry@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 08, 2019 at 02:07:19PM +0000, Julien Thierry wrote: > When using VHE, the host needs to clear HCR_EL2.TGE bit in order > to interract with guest TLBs, switching from EL2&0 translation regime > to EL1&0. > > However, some non-maskable asynchronous event could happen while TGE is > cleared like SDEI. Because of this address translation operations > relying on EL2&0 translation regime could fail (tlb invalidation, > userspace access, ...). Why would an NMI context need to access user space? (just curious what breaks exactly without this patch; otherwise it looks fine) -- Catalin