From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 620DB6B0260 for ; Mon, 16 Nov 2015 13:55:38 -0500 (EST) Received: by wmvv187 with SMTP id v187so192183489wmv.1 for ; Mon, 16 Nov 2015 10:55:38 -0800 (PST) Received: from pandora.arm.linux.org.uk (pandora.arm.linux.org.uk. [2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by mx.google.com with ESMTPS id w15si27554304wme.61.2015.11.16.10.55.37 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 16 Nov 2015 10:55:37 -0800 (PST) Date: Mon, 16 Nov 2015 18:55:19 +0000 From: Russell King - ARM Linux Subject: Re: [PATCH v2 07/12] ARM: split off core mapping logic from create_mapping Message-ID: <20151116185519.GE8644@n2100.arm.linux.org.uk> References: <1447698757-8762-1-git-send-email-ard.biesheuvel@linaro.org> <1447698757-8762-8-git-send-email-ard.biesheuvel@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1447698757-8762-8-git-send-email-ard.biesheuvel@linaro.org> Sender: owner-linux-mm@kvack.org List-ID: To: Ard Biesheuvel Cc: linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, matt.fleming@intel.com, will.deacon@arm.com, grant.likely@linaro.org, catalin.marinas@arm.com, mark.rutland@arm.com, leif.lindholm@linaro.org, roy.franz@linaro.org, msalter@redhat.com, ryan.harkin@linaro.org, akpm@linux-foundation.org, linux-mm@kvack.org On Mon, Nov 16, 2015 at 07:32:32PM +0100, Ard Biesheuvel wrote: > In order to be able to reuse the core mapping logic of create_mapping > for mapping the UEFI Runtime Services into a private set of page tables, > split it off from create_mapping() into a separate function > __create_mapping which we will wire up in a subsequent patch. I'm slightly worried about this. Generally, these functions setup global mappings. If you're wanting to have a private set of page tables for UEFI, and those private page tables contain global mappings which are different from the mappings in the kernel's page tables, then you need careful break-TLBflush-make handling when switching from the kernel's page tables to the private UEFI ones, and vice versa. Has this aspect been considered? -- FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org