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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 A17A9C3F2D3 for ; Fri, 28 Feb 2020 09:55:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77F9C246A2 for ; Fri, 28 Feb 2020 09:55:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=shipmail.org header.i=@shipmail.org header.b="mQelTzZK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726884AbgB1JzE (ORCPT ); Fri, 28 Feb 2020 04:55:04 -0500 Received: from pio-pvt-msa1.bahnhof.se ([79.136.2.40]:45986 "EHLO pio-pvt-msa1.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726838AbgB1JzC (ORCPT ); Fri, 28 Feb 2020 04:55:02 -0500 Received: from localhost (localhost [127.0.0.1]) by pio-pvt-msa1.bahnhof.se (Postfix) with ESMTP id 235CF3F8DF; Fri, 28 Feb 2020 10:54:59 +0100 (CET) Authentication-Results: pio-pvt-msa1.bahnhof.se; dkim=pass (1024-bit key; unprotected) header.d=shipmail.org header.i=@shipmail.org header.b="mQelTzZK"; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from pio-pvt-msa1.bahnhof.se ([127.0.0.1]) by localhost (pio-pvt-msa1.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AnuRIWrZjNLw; Fri, 28 Feb 2020 10:54:58 +0100 (CET) Received: from mail1.shipmail.org (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) (Authenticated sender: mb878879) by pio-pvt-msa1.bahnhof.se (Postfix) with ESMTPA id 97ECF3F447; Fri, 28 Feb 2020 10:54:55 +0100 (CET) Received: from localhost.localdomain (h-205-35.A357.priv.bahnhof.se [155.4.205.35]) by mail1.shipmail.org (Postfix) with ESMTPSA id CF44B3600E5; Fri, 28 Feb 2020 10:54:54 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shipmail.org; s=mail; t=1582883694; bh=tqp6+K9mkAPpbwQi+jsZKLI5SGUmSp5Ve+vQDquuiMU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=mQelTzZKfbo2tgQqhKUHfndb2RD0o2tObYs69vboraOahh7loZU5rJsft3sMv2uEv v/ADgf3PykPJwmoWFpjmKHkmqucFFlF40qIOKBFywOmyZmPZ9J4xAxuADX+zDpKTlQ X7iYWW49jjTk+7fudHxvrkp6HZYEpCvbgP3+k5Ic= Subject: Re: [PATCH v5 1/3] drm/shmem: add support for per object caching flags. To: Gerd Hoffmann Cc: dri-devel@lists.freedesktop.org, Guillaume.Gardet@arm.com, David Airlie , open list , gurchetansingh@chromium.org, tzimmermann@suse.de, yuq825@gmail.com, noralf@tronnes.org, robh@kernel.org References: <20200226154752.24328-1-kraxel@redhat.com> <20200226154752.24328-2-kraxel@redhat.com> <20200227075321.ki74hfjpnsqv2yx2@sirius.home.kraxel.org> <41ca197c-136a-75d8-b269-801db44d4cba@shipmail.org> <20200227105643.h4klc3ybhpwv2l3x@sirius.home.kraxel.org> <68a05ace-40bc-76d6-5464-2c96328874b9@shipmail.org> <20200227132137.irruicvlkxpdo3so@sirius.home.kraxel.org> <78eb099e-020f-91d1-672e-15176bf12cd4@shipmail.org> <20200228094903.g7yf73mtnbjyu4ez@sirius.home.kraxel.org> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m_=28VMware=29?= Organization: VMware Inc. Message-ID: <99eea905-db5c-4e07-7b93-6de3482e02f7@shipmail.org> Date: Fri, 28 Feb 2020 10:54:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20200228094903.g7yf73mtnbjyu4ez@sirius.home.kraxel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/28/20 10:49 AM, Gerd Hoffmann wrote: > Hi, > >>> Not clue about the others (lima, tiny, panfrost, v3d). Maybe they use >>> write-combine just because this is what they got by default from >>> drm_gem_mmap_obj(). Maybe they actually need that. Trying to Cc: >>> maintainters (and drop stable@). >>> virtio-gpu needs it, otherwise the host can't show the virtual display. >>> cirrus bounces everything via blits to vram, so it should be ok without >>> decrypted. I guess that implies we should make decrypted configurable. >> Decrypted here is clearly incorrect and violates the SEV spec, regardless of >> a config option. >> >> The only correct way is currently to use dma_alloc_coherent() and >> mmap_coherent() to allocate decrypted memory and then use the >> pgprot_decrypted flag. > Hmm, virtio-gpu uses the dma api to allow the host access the gem > object. So I think I have to correct the statement above, if I > understands things correctly the dma api will use (properly allocated) > decrypted bounce buffers and the virtio-gpu shmem objects don't need > pgprot_decrypted mappings. Yes, that sounds more correct. I wonder whether the "pgprot_decrypted()" perhaps remains from mapping VRAM gem buffers... /Thomas > > That leaves the question what to do about pgprot_writecombine(). Any > comments from the driver maintainers (see first paragraph)? > > cheers, > Gerd