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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B1F1EC4345F for ; Tue, 30 Apr 2024 06:56:11 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s1hOf-0005EP-Rx; Tue, 30 Apr 2024 02:55:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1s1hOc-0005AU-6k for qemu-devel@nongnu.org; Tue, 30 Apr 2024 02:55:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1s1hOa-0005SO-6F for qemu-devel@nongnu.org; Tue, 30 Apr 2024 02:55:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714460118; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=bubZGyS4WO89HecUmrs6HvGAjmtFDOhiVexXEzIIK8o=; b=hmgosPMXlXIbpsaNFIXO7H/sSY+6Ym09RhHaESGULzq0t5xGG0mR655MmNJvaNMYrTj7Ow MrWrUSCV+2q6Ct/bh063HC77M71EKnR8G2UvSszCaO7Cj6aQiqZX83fpS5KbOQTVySo3wq Wssp76DKxygW/JqXLODTOLdLb7qExNA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-6-UzxNebrdOAKNkPJ4RPikDg-1; Tue, 30 Apr 2024 02:55:14 -0400 X-MC-Unique: UzxNebrdOAKNkPJ4RPikDg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4F6B818065B1; Tue, 30 Apr 2024 06:55:14 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.247]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D51041121306; Tue, 30 Apr 2024 06:55:13 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id F3AA721E66E5; Tue, 30 Apr 2024 08:55:12 +0200 (CEST) From: Markus Armbruster To: Jonathan Cameron Cc: , , , , , Dave Jiang , Huang Ying , Paolo Bonzini , , , , , Michael Roth , Ani Sinha Subject: Re: [PATCH 3/6] hw/acpi: Generic Port Affinity Structure support In-Reply-To: <20240429185046.00002a7c@Huawei.com> (Jonathan Cameron's message of "Mon, 29 Apr 2024 18:50:46 +0100") References: <20240403102927.31263-1-Jonathan.Cameron@huawei.com> <20240403102927.31263-4-Jonathan.Cameron@huawei.com> <87r0ewcppm.fsf@pond.sub.org> <20240429185046.00002a7c@Huawei.com> Date: Tue, 30 Apr 2024 08:55:12 +0200 Message-ID: <87frv3e3vz.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.987, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Jonathan Cameron writes: > On Tue, 23 Apr 2024 12:56:21 +0200 > Markus Armbruster wrote: > >> Jonathan Cameron writes: >> >> > These are very similar to the recently added Generic Initiators >> > but instead of representing an initiator of memory traffic they >> > represent an edge point beyond which may lie either targets or >> > initiators. Here we add these ports such that they may >> > be targets of hmat_lb records to describe the latency and >> > bandwidth from host side initiators to the port. A descoverable >> > mechanism such as UEFI CDAT read from CXL devices and switches >> > is used to discover the remainder fo the path and the OS can build >> > up full latency and bandwidth numbers as need for work and data >> > placement decisions. >> > >> > Signed-off-by: Jonathan Cameron > > Hi Markus, > > I've again managed a bad job of defining an interface - thanks for > your help! Good interfaces are hard! >> > --- >> > qapi/qom.json | 18 +++ >> > include/hw/acpi/acpi_generic_initiator.h | 18 ++- >> > include/hw/pci/pci_bridge.h | 1 + >> > hw/acpi/acpi_generic_initiator.c | 141 +++++++++++++++++------ >> > hw/pci-bridge/pci_expander_bridge.c | 1 - >> > 5 files changed, 141 insertions(+), 38 deletions(-) >> > >> > diff --git a/qapi/qom.json b/qapi/qom.json >> > index 85e6b4f84a..5480d9ca24 100644 >> > --- a/qapi/qom.json >> > +++ b/qapi/qom.json >> > @@ -826,6 +826,22 @@ >> > 'data': { 'pci-dev': 'str', >> > 'node': 'uint32' } } >> > >> > + >> > +## >> > +# @AcpiGenericPortProperties: >> > +# >> > +# Properties for acpi-generic-port objects. >> > +# >> > +# @pci-bus: PCI bus of the hostbridge associated with this SRAT entry >> >> What's this exactly? A QOM path? A qdev ID? Something else? > > QOM path I believe as going to call object_resolve_path_type() on it. QOM path then. > Oddity is it's defined for the bus, not the host bridge that > we care about as the host bridge doesn't have a convenient id to let > us identify it. > > e.g. It is specified via --device pxb-cxl,id=XXXX > of TYPE_PXB_CXL_HOST in the command line but ends up on the > TYPE_PCI_BUS with parent set to the PXB_CXL_HOST. > Normally we just want this bus for hanging root ports of it. > > I can clarify it's the QOM path but I'm struggling a bit to explain > the relationship without resorting to an example. > This should also not mention SRAT as at some stage I'd expect DT > bindings to provide similar functionality. Let's start with an example. Not to put it into the doc comment, only to help me understand what you need. Hopefully I can then assist with improving the interface and/or its documentation. >> > +# >> > +# @node: numa node associated with the PCI device >> >> NUMA >> >> Is this a NUMA node ID? > > Fair question with a non obvious answer. ACPI wise it's a proximity domain. > In every other SRAT entry (which define proximity domains) this does map > to a NUMA node in an operating system as they contain at least either some > form of memory access initiator (CPU, Generic Initiator etc) or a target (memory). > > A Generic Port is subtly different in that it defines a proximity domain > that in of itself is not what we'd think of as a NUMA node but > rather an entity that exists to provide the info to the OS to stitch > together non discoverable and discoverable buses. > > So I should have gone with something more specific. Could add this to > the parameter docs, or is it too much? > > @node: Similar to a NUMA node ID, but instead of providing a reference > point used for defining NUMA distances and access characteristics > to memory or from an initiator (e.g. CPU), this node defines the > boundary point between non discoverable system buses which must be > discovered from firmware, and a discoverable bus. NUMA distances > and access characteristics are defined to and from that point, > but for system software to establish full initiator to target > characteristics this information must be combined with information > retrieved form the discoverable part of the path. An example would > use CDAT information read from devices and switches in conjunction > with link characteristics read from PCIe Configuration space. This is mostly greek to me :) Bit I don't think it's too much. >> > +# >> > +# Since: 9.1 >> > +## >> > +{ 'struct': 'AcpiGenericPortProperties', >> > + 'data': { 'pci-bus': 'str', >> > + 'node': 'uint32' } } >> > + >> > ## >> > # @RngProperties: >> > # >> > @@ -944,6 +960,7 @@ >> > { 'enum': 'ObjectType', >> > 'data': [ >> > 'acpi-generic-initiator', >> > + 'acpi-generic-port', >> > 'authz-list', >> > 'authz-listfile', >> > 'authz-pam', >> > @@ -1016,6 +1033,7 @@ >> > 'discriminator': 'qom-type', >> > 'data': { >> > 'acpi-generic-initiator': 'AcpiGenericInitiatorProperties', >> > + 'acpi-generic-port': 'AcpiGenericPortProperties', >> > 'authz-list': 'AuthZListProperties', >> > 'authz-listfile': 'AuthZListFileProperties', >> > 'authz-pam': 'AuthZPAMProperties', >> >> [...] >> >>