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=-2.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 F0082C43387 for ; Mon, 14 Jan 2019 16:14:01 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 B044520873 for ; Mon, 14 Jan 2019 16:14:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="eLv4R/dO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B044520873 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.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:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+kwqwDqQ+f1KA1gHTknxrglXS/Mbyq2DyclRTGo0pGk=; b=eLv4R/dO7tjFHw ROIApdR0cqbWQ8k/cx0mV+IwqkAh0uQ/0+GMgZE/HEElrAogdSkR7VnvtyRwUk2wZgX24zy7k78gH Pc31y+mMI3oRYJMKf/Byl2vwnSUfSoQDauqnVrJ9k7IfGFasPGoPmtJKh9Hf90XIgvXeG3Bd/ntvf P6Bo1d1JeLrMG5xCJvdc4QQSVx1TGK7TnNXYTYro/15EsPYRt/KNJguT3njcu9hAD76dwe82CltpO 3HSG3f5wA9JcVEV7XrJE+DcjuRRH4LohFQBi1x/h5tgDfZWZvt7LXEm5qGK2iKknyiSn7+DctXXg0 Oo/Hw9Ivoc8eWzyXLdyA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gj4sC-00005V-G5; Mon, 14 Jan 2019 16:14:00 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gj4qz-0007Rc-16 for linux-arm-kernel@lists.infradead.org; Mon, 14 Jan 2019 16:13:23 +0000 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 1F84C15AB; Mon, 14 Jan 2019 08:12:43 -0800 (PST) Received: from [10.1.197.45] (e112298-lin.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 089CA3F5BD; Mon, 14 Jan 2019 08:12:40 -0800 (PST) Subject: Re: [PATCH v8 01/26] arm64: Fix HCR.TGE status for NMI contexts To: Catalin Marinas References: <1546956464-48825-1-git-send-email-julien.thierry@arm.com> <1546956464-48825-2-git-send-email-julien.thierry@arm.com> <20190114155634.GB84430@arrakis.emea.arm.com> From: Julien Thierry Message-ID: <229aade3-5bb3-aad4-bd9a-d6220db836c0@arm.com> Date: Mon, 14 Jan 2019 16:12:39 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190114155634.GB84430@arrakis.emea.arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190114_081245_334276_FFA355B1 X-CRM114-Status: GOOD ( 12.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: 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, 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+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 14/01/2019 15:56, Catalin Marinas wrote: > 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) If I remember correctly, the SDEI interrupt might perform cache maintenance with EL2&0 translation regime, but James can probably give more detail (or correct me if I'm wrong). Otherwise, if we decide to use the pseudo NMI for profiling with perf, I believe the perf interrupt can access user space (although I'm not completely sure whether that might be to record profiling data in buffers shared with user space or something else). Thanks, -- Julien Thierry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel