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.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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4AFCAC6FA82 for ; Fri, 23 Sep 2022 10:51:27 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.410705.653829 (Exim 4.92) (envelope-from ) id 1obgH6-0007Ba-KJ; Fri, 23 Sep 2022 10:51:16 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 410705.653829; Fri, 23 Sep 2022 10:51:16 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1obgH6-0007BT-Gw; Fri, 23 Sep 2022 10:51:16 +0000 Received: by outflank-mailman (input) for mailman id 410705; Fri, 23 Sep 2022 10:51:15 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1obgH5-0007BN-GT for xen-devel@lists.xenproject.org; Fri, 23 Sep 2022 10:51:15 +0000 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [2a00:1450:4864:20::42f]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id a276ed89-3b2d-11ed-9374-c1cf23e5d27e; Fri, 23 Sep 2022 12:51:10 +0200 (CEST) Received: by mail-wr1-x42f.google.com with SMTP id g3so19750383wrq.13 for ; Fri, 23 Sep 2022 03:51:14 -0700 (PDT) Received: from horizon ([2a01:e0a:19f:35f0:dde5:d55a:20f5:7ef5]) by smtp.gmail.com with ESMTPSA id o41-20020a05600c512900b003a5c244fc13sm2284917wms.2.2022.09.23.03.51.12 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Sep 2022 03:51:12 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: a276ed89-3b2d-11ed-9374-c1cf23e5d27e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-disposition:mime-version:message-id:subject:to:from:date :from:to:cc:subject:date; bh=ePAqBWVCbNIh2fW7ZvyICalrFQoKNjGDm/4R3uj8Qbs=; b=IUO3AQRwDtsUYvHOB7m7YWA00NaXtnYRAewsB8wJGFYfCHm9P7GtS9JU7PuRCgQWeC xsj7EFPCUSGvZzl5Y5YgTZUsaaYW5kbDzwSbEZhZDnL589jaih2uhPPIWeYxJFxV4jxu CDOPyD0vBmDUfucYmZH4mMw1uzbk694OEqKTz9ZqlQPQJqsHRQ6GP+4yWxCIghRUfxM3 hFgv890lgo4EYTEK5xvxTaxBRliYZRKV6hmlSkRXl9NKYVhPqwnAWlKpVrpe3HCdhdx5 UEO0LebD15Kyj9714LdwDzZkpG+ZFV8w5+WfVmibOpiuOPsH3JmB3iIRBNsVaC7qWLwr vgFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-disposition:mime-version:message-id:subject:to:from:date :x-gm-message-state:from:to:cc:subject:date; bh=ePAqBWVCbNIh2fW7ZvyICalrFQoKNjGDm/4R3uj8Qbs=; b=7ej8/VgRkLnaaFtlLoHWflY2crHLzq3hHRjr1l/qh2YoqLghC0HqldqCD03XZwSBZz y+VQi3Rj38aLafOJ7jF4nzDJ+qP62aF/ub/BhUCTtY44dZbhx2R0w70+NobDKxGT7Uf1 CsqS9T+5UDrupNxF8EFZ/QzwUFcmmAH3nkTxZxQvZjirCPvMNOSgV7zMhIkQRZYGFLWI klzCILIjYz1b8KjwqJp8Tv7ybiEhIj9HDwd6oFwkiJ/WywiDGYxbBQDhwr7rlKSYS7u0 SSNH3G/K8TdNhAiS0W3dztVDIBMk58hbvhHjUVFg0mrEl/HYRwWVb1qyL8VElU9/CViH 5Trg== X-Gm-Message-State: ACrzQf0mejGpUeMEe9HQXHhKHutQdptJAhJ0CQTva/Z/z3RPwrreoWqJ KPSSXohNH3Yg9unfSidUYckGtyxWiDYGKYML X-Google-Smtp-Source: AMsMyM5hD/vhhdM7DveEBMtckkoBllUgQ4Qpj+hVpK72YTUJl8FcqJi/z8WX+uhqw8RegXRp9UqZZA== X-Received: by 2002:a05:6000:887:b0:21e:24a0:f302 with SMTP id ca7-20020a056000088700b0021e24a0f302mr4622829wrb.466.1663930273445; Fri, 23 Sep 2022 03:51:13 -0700 (PDT) Date: Fri, 23 Sep 2022 12:51:11 +0200 From: Matias Ezequiel Vara Larsen To: xen-devel@lists.xenproject.org Subject: Design session "Using the new VCPU counters in XAPI" Message-ID: <20220923105111.GA647305@horizon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Participants: Pau, Edwin, Matias - the semantics of the new interface for querying registers is now async, this would require a initialization phase in xcp-rrdd before query the counters. - why this https://github.com/xenserver/xen.pg/blob/XS-8.2.x/master/mixed-domain-runstates.patch is not up-streamed? - we need to implement a protocol to ensure consistency between producer(hypervisor) and consumer(user-space) - we can get inspiration from in xen/arch/x86/time.c:__update_vcpu_system_time(). This relies on version_update_begin() and version_update_end() - get inspiration from the comment at public/xen.h in the struct vcpu_time_info{} in which a version number is used - get inspiration from arch/x86/time.c:read_xen_timer() - we need something in user-space that relies on the same mechanism, i.e., get a consistent value if version number is the same before and after reading the structure. - add bindings for acquiere resource see https://github.com/xapi-project/xen-api/blob/master/ocaml/xenopsd/c_stubs/xenctrlext_stubs.c#L460) - also get inspiration from 2529c85 - we cannot find where is the implementation of this protocol in user-space. Xenctrl should implement it somewhere