From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f50.google.com (mail-qv1-f50.google.com [209.85.219.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A863722AE7E for ; Mon, 10 Mar 2025 14:19:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741616397; cv=none; b=nU4NltVSX/fRuDx9kATAgcfTnc1tqX0ExK4dKUWeo0mVr6sb3xx8z7UVPO2U9kfDg6V6eHc58Ugc1Vz7sZqaIVvXi7KrhY3vNQ1yMom3KOJoTevDSnXQ9pzTRkvi4Ydn7h7q02aH2KeBM+WDDpuCVuH0fut77Ez64ARWWGCn+yU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741616397; c=relaxed/simple; bh=KWu8zDSYCkOIHDj4bVHZMVBK5paBYHLwqNrwSoppf4Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IdF35jp2C1EyyHr7PQJdWSTUxWZ/JnEJe+ubQ61s4uFMHZQZTHmUuvLLS8OX7doZBWtDXPNs8LQ2HpzXFJrEo6eunQiad5mX/8sWf6U6WFOndVe7UYIySq+vCfbhnTcK1f1zgC/pxLzk0tTu84OdUYAHm/1ZoGfoW3BCE27KChw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=kwgCcwKQ; arc=none smtp.client-ip=209.85.219.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="kwgCcwKQ" Received: by mail-qv1-f50.google.com with SMTP id 6a1803df08f44-6e8f6970326so32612606d6.0 for ; Mon, 10 Mar 2025 07:19:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1741616394; x=1742221194; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=ZFZo8zPwzqdWQJxqcj4qgZS2PvMRMOgjbkxudd5sQoM=; b=kwgCcwKQBSDOOnqPDxaJhqV85i9+y2dtmXgk+H6ogRzo28zdmImbeYfpKYgk1K9jm9 GOuB02jIMQNJZuTeMNvlYpOhZ2poCRQGAqaKOv4CtZCGWia96Y2stKDUuFqes3ajvF2H TU19b48ATv6dAUufi8VvKxySo229qsU/Abd4Tu/wJi7zN+CQfjh7MXuAGcu/yjy0ZdSk CmKVG/bcvbjB38SzQ7d9XKpGmzaFFJ4wvA/tGTAOYsQul8iKCwU74Vat0WejCZPGVcpt j7kwiYKL9sOlqO7l/iCN75E4PRWZJOorKQYM/jfa50aZ53LG0NdJPYJ3hhYYM0IlZEeE Gtnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741616394; x=1742221194; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=ZFZo8zPwzqdWQJxqcj4qgZS2PvMRMOgjbkxudd5sQoM=; b=Ew/6lA3GGil5mI7FdPbWCOBBbK5HoQad1KAIp62xFe50P5ZuLTUh2qERYDrSYSIVPy erGuZwCnnLfIqI1q/xQOTdlJe6U7yJbexsbD7PKUTMyUNWRtBOhYQNoQB1xFLn6vNKxc QHju3wGx1sYvPyiVcaiQmu1QE8iZKYobv6IhQWTGXsC6u+Nc+z0GOTGpiZbTpRTdWjh4 WUkoq/vzdabHXpJ/t7M20y3GoQn0DxyrhwD1ivh6DX4xvAfnYd2Qi3xKySuAJFxj02Xi e7dRq4KjoBa/e8ZqE9LKxS6ZKCsxxOPW9VsfrRBhoUZk3IiTOLJoI8ApMlwlR/yfb3kK coXQ== X-Forwarded-Encrypted: i=1; AJvYcCV3jhJ6z/HZYn9ssdrD9qipBZC2iTY9PIP5FDoxUzBispq84YxsNMfBMk2w5VAqmyz+KFi9v2mW3ZP1ojw=@vger.kernel.org X-Gm-Message-State: AOJu0Yw+5UyP1TrAThdZjhz6QH3oR9pp12h04cUeRFiQHTQenRAYtjZQ Ha/+NqBJ7gvMW4uaG+eaqxrnLF517tmHQPptUMzK/sFBlbx7u9XgVS2KSukDLcI= X-Gm-Gg: ASbGncvVDZec0TKgCf7sUMjuKWgA01FNtBpCiik3WEftiyDH3PxN8vDduQN4FrwHEZb scJvwYSy8iBjLm3u7ciQCgTkL5qHbz6aNlHguB7JGu57UIuktqkLXTGsXsFB6Ta46sCwI65uT5l pAiqg/yk3nplOuMYk7lp+vG4h9jKTw+Lv1hGXTNlE9BLQytjyst0tVlq71PVbkrQ2lr64roxWrk zuCqHtqzUHfQKk6nBNN0EMqiDgXbjDf3MX9Ye13cC7tHfQdPqQN193X6oFC8tPu+gvbyrezpvPc dfKiIUVqR7R9LVRNuulIs6bu13iNr/sHiKNrsoc9XwqadF+6JvVZjdsnY8xLbje2gJhLaZ6SQri IKYQywd/a/VLbsHZMsEH+CgXHzbs= X-Google-Smtp-Source: AGHT+IGMJpR5j6TAtQib68qhOoxtIvV+O/W/i3w2HAax+rxX7rMLW1/8B437NQlpd0ajBQv1DIt3fQ== X-Received: by 2002:ad4:5d49:0:b0:6e8:fbb7:6764 with SMTP id 6a1803df08f44-6e9006ba2fbmr185600916d6.45.1741616393666; Mon, 10 Mar 2025 07:19:53 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F (pool-173-79-56-208.washdc.fios.verizon.net. [173.79.56.208]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e8f707c4cbsm58904436d6.22.2025.03.10.07.19.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Mar 2025 07:19:53 -0700 (PDT) Date: Mon, 10 Mar 2025 10:19:51 -0400 From: Gregory Price To: Yuquan Wang Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [LSF/MM] CXL Boot to Bash - Section 1: BIOS, EFI, and Early Boot Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Mar 10, 2025 at 06:45:12PM +0800, Yuquan Wang wrote: > On Tue, Feb 04, 2025 at 09:17:09PM -0500, Gregory Price wrote: > > > > Platform / BIOS / EFI Configuraiton > > =================================== > > --------------------------------------- > > Step 1: BIOS-time hardware programming. > > --------------------------------------- > > > > I don't want to focus on platform specifics, so really all you need > > to know about this phase for the purpose of MM is that platforms may > > program the CXL device heirarchy and lock the configuration. > > > This question can be very naive, what's the meaning of 'MM' here? > Memory Management - linux/mm > And since I am not familiar with cxl bios configurations, based on my > understanding of its acpi results, there are roughly two configuration > schemes in my analysis: a) users should enter some configuration > information manually (like region base/size). b) bios could provide a > recommendatory configuration by device information. > The BIOS must produce ACPI tables to set aside system physical memory address space. *How* BIOS produces these ACPI tables (CEDT + SRAT vs CEDT only) dictates whether this configuration is static or dynamic. The devices will provide a CDAT (coherent device attribute table) used by BIOS to generate these ACPI tables. All of this dictates how linux configures its NUMA topology, programs CXL HDM decoders, and how it associates device physical memory with numa nodes and such. ~Gregory