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=-7.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 81198C433ED for ; Thu, 20 May 2021 16:18:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5950460FE5 for ; Thu, 20 May 2021 16:18:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233846AbhETQUM (ORCPT ); Thu, 20 May 2021 12:20:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:37624 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233840AbhETQUK (ORCPT ); Thu, 20 May 2021 12:20:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621527528; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6OgNPYxA7i+etU7xLj3nrXr95skp7dY81DNzdhoz9rg=; b=MbsdO9p21Pkqs8IQ0urYaiImkcuy7g1gNMWLTZMZGpJLqdv4uo2/3EqOymTAztfVA54BjK cFxtdpy2XXa5ppZXxRWb+jXjxuQZb8c7sL5CPCqc4UCg18euIXBxMzzyZ9EDWIeuSBzWmc GB3PTWHbmRXEvLVVXAaYOBRSknnOAvg= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-510-cQVypByEO0-L9DU84zn2RQ-1; Thu, 20 May 2021 12:18:43 -0400 X-MC-Unique: cQVypByEO0-L9DU84zn2RQ-1 Received: by mail-wr1-f69.google.com with SMTP id i15-20020a5d558f0000b029011215b1cf5cso2424190wrv.22 for ; Thu, 20 May 2021 09:18:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=6OgNPYxA7i+etU7xLj3nrXr95skp7dY81DNzdhoz9rg=; b=oD72nqRMnmLeUxd8QeJ4IK43QZGMDjzmFgfV5YprhTJ4xE7GUHF2X9+Kk97i3I1g8t pr43mmu6IyH+HtHrReDo6mb+Mj126ZdMffLoJSGQhk5Zeyvf6D6fQzbK8joorr3gZMsk 4XBC8gHCkNdaT6wXk9FlU4Q8JCfnXfae5ZmQs0QhYTX27ysGgty5lwsv1tDBBNwm6Y7p 6733Osl/Giz99gX/XB3HooegTrv5QPdZwiLWBn+yu4Zyz+sZgpIMr3Qtl71aj4L6S9mX RndWmHNt42hJHhlhWstlkAKXFG1MyN74Z0BgT/2CqxQTib75+Pe+3n0IxkvrMcVGG3wa JiZg== X-Gm-Message-State: AOAM533WzKWJTvjqbVNJ+L7T4VdsnpaWge64uRk1LrLGG8dNlvf6MAVw 7cHxzEcPSmIDsYlWMjLKrIMbJLHLZ9c7QspkQoXqXlTSLpOi3ql9s6J2LFseF5z9qa7m1Q0M5BW s60BSGof7T6AfVBhoa1qc/Zjs X-Received: by 2002:a5d:59a4:: with SMTP id p4mr5320581wrr.248.1621527522005; Thu, 20 May 2021 09:18:42 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyHdHvZnHkFtg16t/tFIWUALZddO72xh0A6mKZ4eMSItEm7NWMHJO7CM8CAVLCm09/8wvuHlw== X-Received: by 2002:a5d:59a4:: with SMTP id p4mr5320562wrr.248.1621527521813; Thu, 20 May 2021 09:18:41 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id b8sm3978942wrx.15.2021.05.20.09.18.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 20 May 2021 09:18:40 -0700 (PDT) Subject: Re: [PATCH] Move VMEnter and VMExit tracepoints closer to the actual event To: Sean Christopherson , Stefano De Venuto Cc: linux-kernel@vger.kernel.org, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, x86@kernel.org, hpa@zytor.com, kvm@vger.kernel.org, rostedt@goodmis.org, y.karadz@gmail.com, Dario Faggioli References: <20210519182303.2790-1-stefano.devenuto99@gmail.com> From: Paolo Bonzini Message-ID: Date: Thu, 20 May 2021 18:18:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/05/21 17:32, Sean Christopherson wrote: > On VMX, I think the tracepoint can be moved below the VMWRITEs without much > contention (though doing so is likely a nop), but moving it below > kvm_load_guest_xsave_state() requires a bit more discussion. Indeed; as a rule of thumb, the tracepoint on SVM could match the clgi/stgi region, and on VMX it could be placed in a similar location. Paolo > I 100% agree that the current behavior can be a bit confusing, but I wonder if > we'd be better off "solving" that problem through documentation.