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,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 0C8AFC07E9B for ; Tue, 6 Jul 2021 17:07:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E59A961C5A for ; Tue, 6 Jul 2021 17:07:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230299AbhGFRJt (ORCPT ); Tue, 6 Jul 2021 13:09:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:48986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229956AbhGFRJs (ORCPT ); Tue, 6 Jul 2021 13:09:48 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D8BEB61C3B; Tue, 6 Jul 2021 17:07:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625591229; bh=VhhzIH6gzRT8gtRsisto5IDFaHK+/13p4/dNI43mqXQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hl0xCyjFbo3wnMVlDA8LcQL8eHToHXmUMr23zuNOTdipVfwNhivzNpi8rpTly6eYi yPd2oC5omfpzshqqnFMLEQGIyy9TAQeSgCgSvFYmHpKLsM30eMNC98TPrdW8hja8Kb 4m1fjoFjCWorTG/lEoPVyDyK3SJHLMjyzybho2CdMauS/azg7sMbNbYLaDlqMOER13 ALFzRBBx8Uq7Drdf4gPPQLMEsDVKJLDGxMmwxLH7I7ZcRSFV8ffeda6f2WQMZefhG6 DGh52bATmGicYuUcNyMSkAeHgzE8e4+s/u25yglW+hkrikwQu6kPAYHnUHYwEX7ru4 L8ww7+blLmJBA== Date: Tue, 6 Jul 2021 18:06:58 +0100 From: Will Deacon To: Robin Murphy Cc: Christoph Hellwig , heikki.krogerus@linux.intel.com, thomas.hellstrom@linux.intel.com, peterz@infradead.org, benh@kernel.crashing.org, joonas.lahtinen@linux.intel.com, dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk, grant.likely@arm.com, paulus@samba.org, Frank Rowand , mingo@kernel.org, Stefano Stabellini , Saravana Kannan , mpe@ellerman.id.au, "Rafael J . Wysocki" , Bartosz Golaszewski , bskeggs@redhat.com, linux-pci@vger.kernel.org, xen-devel@lists.xenproject.org, Thierry Reding , intel-gfx@lists.freedesktop.org, matthew.auld@intel.com, linux-devicetree , Jianxiong Gao , Daniel Vetter , Konrad Rzeszutek Wilk , maarten.lankhorst@linux.intel.com, airlied@linux.ie, Dan Williams , linuxppc-dev@lists.ozlabs.org, jani.nikula@linux.intel.com, Nathan Chancellor , Rob Herring , rodrigo.vivi@intel.com, Bjorn Helgaas , Claire Chang , boris.ostrovsky@oracle.com, Andy Shevchenko , jgross@suse.com, Nicolas Boichat , Greg KH , Randy Dunlap , Qian Cai , lkml , "list@263.net:IOMMU DRIVERS" , Jim Quinlan , xypron.glpk@gmx.de, Tom Lendacky , bauerman@linux.ibm.com Subject: Re: [PATCH v15 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing Message-ID: <20210706170657.GD20750@willie-the-truck> References: <20210702135856.GB11132@willie-the-truck> <0f7bd903-e309-94a0-21d7-f0e8e9546018@arm.com> <20210705190352.GA19461@willie-the-truck> <20210706044848.GA13640@lst.de> <20210706132422.GA20327@willie-the-truck> <20210706140513.GA26498@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 06, 2021 at 04:39:11PM +0100, Robin Murphy wrote: > On 2021-07-06 15:05, Christoph Hellwig wrote: > > On Tue, Jul 06, 2021 at 03:01:04PM +0100, Robin Murphy wrote: > > > FWIW I was pondering the question of whether to do something along those > > > lines or just scrap the default assignment entirely, so since I hadn't got > > > round to saying that I've gone ahead and hacked up the alternative > > > (similarly untested) for comparison :) > > > > > > TBH I'm still not sure which one I prefer... > > > > Claire did implement something like your suggestion originally, but > > I don't really like it as it doesn't scale for adding multiple global > > pools, e.g. for the 64-bit addressable one for the various encrypted > > secure guest schemes. > > Ah yes, that had slipped my mind, and it's a fair point indeed. Since we're > not concerned with a minimal fix for backports anyway I'm more than happy to > focus on Will's approach. Another thing is that that looks to take us a > quiet step closer to the possibility of dynamically resizing a SWIOTLB pool, > which is something that some of the hypervisor protection schemes looking to > build on top of this series may want to explore at some point. Ok, I'll split that nasty diff I posted up into a reviewable series and we can take it from there. Will