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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69EF0C433F5 for ; Tue, 1 Mar 2022 17:47:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232512AbiCARsM (ORCPT ); Tue, 1 Mar 2022 12:48:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41516 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231362AbiCARsL (ORCPT ); Tue, 1 Mar 2022 12:48:11 -0500 Received: from mail-ed1-x529.google.com (mail-ed1-x529.google.com [IPv6:2a00:1450:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9D37E0E2 for ; Tue, 1 Mar 2022 09:47:28 -0800 (PST) Received: by mail-ed1-x529.google.com with SMTP id cm8so23049535edb.3 for ; Tue, 01 Mar 2022 09:47:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=references:user-agent:from:to:cc:subject:date:in-reply-to :message-id:mime-version:content-transfer-encoding; bh=46fkMdfnhldasufV90xDHsl7VVgwtq23xkVkYCN993Y=; b=Zcw8gkvqyRpCx7TkAb7ewvbX3ESrUtgZgz1+tqTmW+xfrv5qEHo+dTIACLBazRzkG6 LktcxuvBgvMZi0TZ74HzsvWWJay97EtiiFgRLFL9bp80cUfVY1uAZGb/+0m0jFsksuje 90j8REdw5T6TL/AIXOknC2I+//tzpCsKVEo+PLqkICMQV0GfzbP5LoUg371e2jjJU9Iz Yf67/Wg4GLhEFpb9tLBN1c8Y1INP0rx3+Mw7EmaGBNXrlnMCN8FgGB4eC+XeItvmMXw6 oa/AfNwD6Jc7Iegt1QGO4vopaei9rJVDBtZ7PGso32bY9D3lc6WhsVcMIRGBQ+Fdfu6p f+kg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:references:user-agent:from:to:cc:subject:date :in-reply-to:message-id:mime-version:content-transfer-encoding; bh=46fkMdfnhldasufV90xDHsl7VVgwtq23xkVkYCN993Y=; b=vlgD09sNmFeexu4cgQz6P+PyiK+Ksp1Bfl/WVH5KjxoDMjNZzg5DONIEA+WVgCZVRe vuOEvxhtUziQbV4p2jJPIK5GvBvvSx421fjoZPkZaZfJ8PbQr3znyJho7DUJSYJg/5YJ pvt9Jl4MzDTf45SH5AJzAiL9ORQ4ESMdHUvzQs53+4xxTSZ5XSoo3NrGzJ3r88fVXnj4 AlORQ0grYuUskWVlSrBAkiMFq3zl0rzpy73tpPhRswAMP0soXrg6hu1rGF+lg7pVbod0 mTjlV9j15dNZyf2JcJuVKOibzkz4P5VXS7GAyEBMXoqgBqdSU/WD+lHntFmfG+llDl1Y xD3A== X-Gm-Message-State: AOAM531lWXRgAEHxFuMi/xL7ZFEsAAVuF7INv7r8ft2PR1VN7p7P5XiR qGbaB+t0mOsF4SHLnZM8FBVy7g== X-Google-Smtp-Source: ABdhPJzGDqFNhnBcVeqndQdVVn1EIsHMjA0aFlvtBsu5SAJrnUqV36pcueRAofN9M+9pIUz3iChE5g== X-Received: by 2002:a05:6402:34c5:b0:411:f082:d69 with SMTP id w5-20020a05640234c500b00411f0820d69mr25570682edc.65.1646156847271; Tue, 01 Mar 2022 09:47:27 -0800 (PST) Received: from zen.linaroharston ([51.148.130.216]) by smtp.gmail.com with ESMTPSA id n25-20020aa7db59000000b00415965e9727sm704812edt.18.2022.03.01.09.47.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Mar 2022 09:47:26 -0800 (PST) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id B534F1FFB7; Tue, 1 Mar 2022 17:47:25 +0000 (GMT) References: <20220211120747.3074-1-Jonathan.Cameron@huawei.com> <20220211120747.3074-15-Jonathan.Cameron@huawei.com> User-agent: mu4e 1.7.9; emacs 28.0.91 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Jonathan Cameron Cc: qemu-devel@nongnu.org, Marcel Apfelbaum , "Michael S . Tsirkin" , Igor Mammedov , linux-cxl@vger.kernel.org, Ben Widawsky , Peter Maydell , linuxarm@huawei.com, Shameerali Kolothum Thodi , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Saransh Gupta1 , Shreyas Shah , Chris Browy , Samarth Saxena , Dan Williams Subject: Re: [PATCH v6 14/43] hw/pxb: Allow creation of a CXL PXB (host bridge) Date: Tue, 01 Mar 2022 17:47:20 +0000 In-reply-to: <20220211120747.3074-15-Jonathan.Cameron@huawei.com> Message-ID: <87tuchlg42.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Jonathan Cameron writes: > From: Ben Widawsky > > This works like adding a typical pxb device, except the name is > 'pxb-cxl' instead of 'pxb-pcie'. An example command line would be as > follows: > -device pxb-cxl,id=3Dcxl.0,bus=3D"pcie.0",bus_nr=3D1 > > A CXL PXB is backward compatible with PCIe. What this means in practice > is that an operating system that is unaware of CXL should still be able > to enumerate this topology as if it were PCIe. > > One can create multiple CXL PXB host bridges, but a host bridge can only > be connected to the main root bus. Host bridges cannot appear elsewhere > in the topology. > > Note that as of this patch, the ACPI tables needed for the host bridge > (specifically, an ACPI object in _SB named ACPI0016 and the CEDT) aren't > created. So while this patch internally creates it, it cannot be > properly used by an operating system or other system software. > > Also necessary is to add an exception to scripts/device-crash-test > similar to that for exiting pxb as both must created on a PCIexpress > host bus. > > Signed-off-by: Ben Widawsky > Signed-off-by: Jonathan.Cameron Reviewed-by: Alex Benn=C3=A9e --=20 Alex Benn=C3=A9e