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=-8.0 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 9C24BC4320A for ; Thu, 12 Aug 2021 15:53:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C12960FD7 for ; Thu, 12 Aug 2021 15:53:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238421AbhHLPxv (ORCPT ); Thu, 12 Aug 2021 11:53:51 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:26124 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238195AbhHLPxs (ORCPT ); Thu, 12 Aug 2021 11:53:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628783602; 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=dHPw1bhKl19tpaWZWxIqL1UIJ8eN+9Q1TmLAPmpMLXc=; b=diI3w0Fg1ancmdWWLeAMr4G92L/XajtbciMHRdwvI3Hq0jIaI/NKmW5qGsDHT0TZ81VNSP HlVmdvlGWza0+cVDtd8kL0OZedodaPr1EYUPHkd83kEO0t5RCV7Ot5KllLWKcA3vVKLCYv bZltZr2CXyja8tfkbmYBTk3dlg1GpYE= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-442-xgxI_37jN_SNh0IBJU3yJA-1; Thu, 12 Aug 2021 11:53:21 -0400 X-MC-Unique: xgxI_37jN_SNh0IBJU3yJA-1 Received: by mail-ej1-f71.google.com with SMTP id ja25-20020a1709079899b02905b2a2bf1a62so1996868ejc.4 for ; Thu, 12 Aug 2021 08:53:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=dHPw1bhKl19tpaWZWxIqL1UIJ8eN+9Q1TmLAPmpMLXc=; b=KA7zCYUGypeZ4qnqJO6p4rbzSJ5Q+NgXjDT5sjmIKSWU8q+RuPOPljNV+odtfXuZNH UkCbz/6aGOhLOW161A9FvWAflQmORks6r9o7oLeLEXOVF3mxvptYq+J5yUXaztEB+ej3 w9C8fSXpNNasTbwexRRAC97MJ191qdGUf8V7pzvz6jDg+88nAPwHV9H1BIEfm0sDn+MR CTRmjH9jVkUo2GpiKIu77R6DaYwdGMBpHHzR2ecv8LKJ6ieAZKM4fU6ChtSkChGV+4qR K30PQhr9wxznvurKWs0MhQoOMeefg+ljtv5vmsUdep+2pEVdV5bxsQgbnsNFEArYEkf9 7CUQ== X-Gm-Message-State: AOAM530YIE61v/uQVhXqUh89EPp4+SuKmU34kvGNkZavBFnpqIKxrDd2 XRA0qzKE3SN4v26gTbzENXO99qBFy/e19wWT/8mx/GmJiLKN1M4b8syTAnaCQntlU2/pGFeW10D Iam5yemarRQ4KETCWY3q7FCdH X-Received: by 2002:aa7:c345:: with SMTP id j5mr2694260edr.331.1628783599819; Thu, 12 Aug 2021 08:53:19 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyA2o0pTKirLj0DNfQbHbvFJAFWpUMp09yyngCH8w5NoiU/HesRnlmz+BQfPLisSylJ4MIxPw== X-Received: by 2002:aa7:c345:: with SMTP id j5mr2694241edr.331.1628783599604; Thu, 12 Aug 2021 08:53:19 -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 m25sm1293859edv.81.2021.08.12.08.53.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Aug 2021 08:53:18 -0700 (PDT) To: Marcelo Tosatti Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, vkuznets@redhat.com References: <20210811102356.3406687-1-pbonzini@redhat.com> <20210811102356.3406687-2-pbonzini@redhat.com> <20210811180322.GA178399@fuller.cnet> From: Paolo Bonzini Subject: Re: [PATCH 1/2] KVM: KVM-on-hyperv: shorten no-entry section on reenlightenment Message-ID: <5e3ddaea-c0f4-f207-de54-5702c970079b@redhat.com> Date: Thu, 12 Aug 2021 17:53:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210811180322.GA178399@fuller.cnet> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/08/21 20:03, Marcelo Tosatti wrote: > hyperv_stop_tsc_emulation(); > > /* TSC frequency always matches when on Hyper-V */ > for_each_present_cpu(cpu) > per_cpu(cpu_tsc_khz, cpu) = tsc_khz; > kvm_max_guest_tsc_khz = tsc_khz; Yeah, it's more complicated than this. The right sequence is: - update the master clock - update the TSC page parameters - stop TSC emulation There is no need to invalidate the TSC page. Related to this, after kvm_hv_invalidate_tsc_page the sequence value in the Hyper-V TSC page will always be 1, which is wrong. I'll take a look at that too. Paolo