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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 5D730ECE58C for ; Wed, 9 Oct 2019 18:51:08 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 35AAB20679 for ; Wed, 9 Oct 2019 18:51:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35AAB20679 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:54174 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIH3C-0004u7-Hd for qemu-devel@archiver.kernel.org; Wed, 09 Oct 2019 14:51:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46311) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIBvq-0002nN-PE for qemu-devel@nongnu.org; Wed, 09 Oct 2019 09:23:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIBvp-0001LB-MZ for qemu-devel@nongnu.org; Wed, 09 Oct 2019 09:23:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45390) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIBvp-0001L3-HU for qemu-devel@nongnu.org; Wed, 09 Oct 2019 09:23:09 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AFD789B299; Wed, 9 Oct 2019 13:23:08 +0000 (UTC) Received: from dell-r430-03.lab.eng.brq.redhat.com (dell-r430-03.lab.eng.brq.redhat.com [10.37.153.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1503B5C1D6; Wed, 9 Oct 2019 13:23:06 +0000 (UTC) From: Igor Mammedov To: qemu-devel@nongnu.org Subject: [RFC 2/3] acpi: cpuhp: add typical usecases into spec Date: Wed, 9 Oct 2019 09:22:51 -0400 Message-Id: <20191009132252.17860-3-imammedo@redhat.com> In-Reply-To: <20191009132252.17860-1-imammedo@redhat.com> References: <20191009132252.17860-1-imammedo@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Wed, 09 Oct 2019 13:23:08 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , "Michael S. Tsirkin" , Laszlo Ersek , Gerd Hoffmann , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Clarify values of "CPU selector' register and add workflows for * finding CPU with pending 'insert/remove' event * enumerating present/non present CPUs Signed-off-by: Igor Mammedov --- docs/specs/acpi_cpu_hotplug.txt | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt index ac5903b2b1..43c5a193f0 100644 --- a/docs/specs/acpi_cpu_hotplug.txt +++ b/docs/specs/acpi_cpu_hotplug.txt @@ -54,6 +54,7 @@ write access: [0x0-0x3] CPU selector: (DWORD access) selects active CPU device. All following accesses to other registers will read/store data from/to selected CPU. + Valid values: [0 .. max_cpus) [0x4] CPU device control fields: (1 byte access) bits: 0: reserved, OSPM must clear it before writing to register. @@ -93,3 +94,24 @@ Selecting CPU device beyond possible range has no effect on platform: ignored - read accesses to CPU hot-plug registers not documented above return all bits set to 0. + +Typical usecases: + - Get a cpu with pending event + 1. write 0x0 into 'Command field' register + 2. read from 'Command data' register, CPU selector value (CPU's UID in ACPI + tables) and event for selected CPU from 'CPU device status fields' + register. If there aren't pending events, CPU selector value doesn't + change and 'insert' and 'remove' bits are not set. + - Enumerate CPUs present/non present CPUs. + 1. set iterator to 0x0 + 2. write 0x0 into 'Command field' register and then iterator + into 'CPU selector' register. + 3. read 'enabled' flag for selected CPU from 'CPU device status fields' + register + 4. to continue to the next CPU, increment iterator and repeat step 2 + 5. read 'Command data' register + 5.1 if 'Command data' register matches iterator continue to step 3. + (read presence bit for the next CPU) + 5.2 if 'Command data' register has not changed, there is not CPU + corresponding to iterator value and the last valid iterator value + equals to 'max_cpus' + 1 -- 2.18.1