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=-5.5 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, 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 39F73C43381 for ; Tue, 26 Jan 2021 15:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 010C32311B for ; Tue, 26 Jan 2021 15:21:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406265AbhAZPUq (ORCPT ); Tue, 26 Jan 2021 10:20:46 -0500 Received: from mail-wr1-f49.google.com ([209.85.221.49]:42809 "EHLO mail-wr1-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391796AbhAZPUl (ORCPT ); Tue, 26 Jan 2021 10:20:41 -0500 Received: by mail-wr1-f49.google.com with SMTP id h9so6634379wrr.9; Tue, 26 Jan 2021 07:20:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=460NPPZwyIUmxq4OnFGdo8FcYglMWQ0+AliFnnOiLnM=; b=iti1bZz1pOUuri9X1BYmMUlf3aj/FKBo2G1LohP9q3Etw5cQihAsRlFChpPIecVPQ3 PJIzkoQ9LzXHnwhZOXiknxwBja43wd3TK+84FskTJvewsKqNuEvbnP3tTEdwimQ+lIzo jbKW+y3PD2sj/n6w/WigRUgxMf3EzgAPGcwv40tOLsc52MI4U7N8NJEcEQIehlNaXBCn ED5yS294B6+HYj1xGJkeQi1lWXA2wZ05eKWV6GJOaSVMd7bEdYHFD4Y88diNCEWpAaRj czlN+95J4lJXi5q2e851mD69coD7kOnBcOIbLxrClCHm1ZcqiFqc7GBBzn4ffphG//2P dk6g== X-Gm-Message-State: AOAM53175XcP3lkLmnbq+uIbral2oFwoSPWF94zRfvt29+wEXosExtkg loHgNI8pyN8U5mRwY/iOA5E= X-Google-Smtp-Source: ABdhPJzrWkjBXfd9WHDyZ5AWbLFubFbKr07XM5tjuvAetHbQYWycZU4X02gmBbQwXJsnH6LfA/pBRg== X-Received: by 2002:adf:d206:: with SMTP id j6mr6474841wrh.427.1611674399762; Tue, 26 Jan 2021 07:19:59 -0800 (PST) Received: from liuwe-devbox-debian-v2 ([51.145.34.42]) by smtp.gmail.com with ESMTPSA id c20sm3552041wmb.38.2021.01.26.07.19.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Jan 2021 07:19:59 -0800 (PST) Date: Tue, 26 Jan 2021 15:19:58 +0000 From: Wei Liu To: Pavel Tatashin Cc: Wei Liu , Linux on Hyper-V List , virtualization@lists.linux-foundation.org, Linux Kernel List , Michael Kelley , Vineeth Pillai , Sunil Muthuswamy , Nuno Das Neves , Daniel Lezcano , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Thomas Gleixner Subject: Re: [PATCH v5 05/16] clocksource/hyperv: use MSR-based access if running as root Message-ID: <20210126151958.anyp2ncjykivsfvn@liuwe-devbox-debian-v2> References: <20210120120058.29138-1-wei.liu@kernel.org> <20210120120058.29138-6-wei.liu@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Wed, Jan 20, 2021 at 11:13:28AM -0500, Pavel Tatashin wrote: > On Wed, Jan 20, 2021 at 7:01 AM Wei Liu wrote: > > > > When Linux runs as the root partition, the setup required for TSC page > > is different. > > Why would we need a TSC page as a clock source for root partition at > all? I think the above can be removed. > The TSC page is considered superior to MSR-based clock. In the future we may want to switch back to that TSC page instead. I think it provides more context than without. Wei. > Luckily Linux also has access to the MSR based > > clocksource. We can just disable the TSC page clocksource if Linux is > > the root partition. > >