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=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 35373C47254 for ; Fri, 1 May 2020 08:10:19 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 03403208C3 for ; Fri, 1 May 2020 08:10:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=xen.org header.i=@xen.org header.b="RTrPUJA5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 03403208C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jUQjs-0007kH-I1; Fri, 01 May 2020 08:09:40 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jUQjr-0007kB-3d for xen-devel@lists.xenproject.org; Fri, 01 May 2020 08:09:39 +0000 X-Inumbo-ID: 19eb30a2-8b83-11ea-9887-bc764e2007e4 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 19eb30a2-8b83-11ea-9887-bc764e2007e4; Fri, 01 May 2020 08:09:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=U3K9cTwT20CMFOnPsRqWmK3gfZUiU6P5nia29a8XCgM=; b=RTrPUJA5AM9B3Zu6hjKTrYCdhn wT3djYWuNcSex+tTrw1/f82OM1gorVGVu+1B8Pn34mE7VcvUfSqV/o23hHdthHMdzGqnUilPCig4k xQXbt0oBcFg46TwrkPg3ZXuxatFSuo3KEfD+Y2QPZLMFhLstKAY6OJE86jGp1gsdPQR8=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jUQjo-0004WA-DD; Fri, 01 May 2020 08:09:36 +0000 Received: from [54.239.6.185] (helo=a483e7b01a66.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1jUQjo-0000Em-6O; Fri, 01 May 2020 08:09:36 +0000 Subject: Re: [PATCH 10/12] xen/arm: if is_domain_direct_mapped use native UART address for vPL011 To: Stefano Stabellini References: <20200415010255.10081-10-sstabellini@kernel.org> <05b46414-12c3-5f79-f4b1-46cf8750d28c@xen.org> From: Julien Grall Message-ID: <7176c924-eb16-959e-53cd-c73db88f65db@xen.org> Date: Fri, 1 May 2020 09:09:34 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: xen-devel@lists.xenproject.org, Stefano Stabellini , Volodymyr_Babchuk@epam.com Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 01/05/2020 02:26, Stefano Stabellini wrote: > On Wed, 15 Apr 2020, Julien Grall wrote: >> Hi Stefano, >> >> On 15/04/2020 02:02, Stefano Stabellini wrote: >>> We always use a fix address to map the vPL011 to domains. The address >>> could be a problem for domains that are directly mapped. >>> >>> Instead, for domains that are directly mapped, reuse the address of the >>> physical UART on the platform to avoid potential clashes. >> >> How do you know the physical UART MMIO region is big enough to fit the PL011? > > That cannot be because the vPL011 MMIO size is 1 page, which is the > minimum right? No, there are platforms out with multiple UARTs in the same page (see sunxi for instance). > > >> What if the user want to assign the physical UART to the domain + the vpl011? > > A user can assign a UART to the domain, but it cannot assign the UART > used by Xen (DTUART), which is the one we are using here to get the > physical information. > > > (If there is no UART used by Xen then we'll fall back to the virtual > addresses. If they conflict we return error and let the user fix the > configuration.) If there is no UART in Xen, how the user will know the addresses conflicted? Earlyprintk? Cheers, -- Julien Grall