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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17C99C433F5 for ; Wed, 29 Sep 2021 11:20:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 005EE613D0 for ; Wed, 29 Sep 2021 11:20:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230339AbhI2LWZ (ORCPT ); Wed, 29 Sep 2021 07:22:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:25125 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245694AbhI2LWR (ORCPT ); Wed, 29 Sep 2021 07:22:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632914436; 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=QT1rFRDBhzmSS+/lGbt19+2aAndXLLtwvTkh1G4vaX8=; b=Cswm0QeTk1WyNE2MH8WI8CGhXf65dnA/VfUHKIf2ze+V5LPhmLiXdgR2ruGoAq5US1Kddo qJPXiNc9wzcWTXGBrkl9wce/0sk4BPwxN10ZqX+5sGEUqc39tJ49lULzqjRKqot4v3ilTP OOI+GYCqUQKmmVUsJ8hfRC19DKBvUGI= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-226-z05M6g0aP_6zw1T8pqkdZA-1; Wed, 29 Sep 2021 07:20:34 -0400 X-MC-Unique: z05M6g0aP_6zw1T8pqkdZA-1 Received: by mail-ed1-f70.google.com with SMTP id e21-20020a50a695000000b003daa0f84db2so1986452edc.23 for ; Wed, 29 Sep 2021 04:20:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=QT1rFRDBhzmSS+/lGbt19+2aAndXLLtwvTkh1G4vaX8=; b=KgbaBbriInmIGqfc0tCF5diKk2Tyye74jHXuhUV+Ffy3L/dKb4b/8NUwiV9W4iFTHS YL7qpilk93Po5PUUnhykZLZX7PgS7g9aJHl4HsIZkaRLN4CnPygXSneQpsyeRNbvhxQf 2Tt/hBSlFn/OBZ0eG47Xejy6WROfPkzAO7pWXMA603V/YEskk2bl524gDI9lCOBJHxtS /nWgbWVlkUxvzh4RHaoC37YciMtffEnAcM/7UwIa9xPfsyozc3SK923nqnO130WoxiIG Oe5qnD3L3LYyna52+sPH6cuVgMOeBYCxTXWHo+bp/Ufu3OFBEln4lkl+vGP2peg4qyZE Vp6A== X-Gm-Message-State: AOAM531QBMDxytysR7sDVv5lvsEcInjcPGmWTL/Zxyx5ICeBhEwCmMsY ThmreOZdc8xjWKe/qi1Q4pKXY6Vq3ACDJgIj5YT+hlgAO+PiGaTWiYpimnNiYxUAnJ1Hmw6Ntor cp2c/vpU34F+7 X-Received: by 2002:a50:d9cc:: with SMTP id x12mr14222004edj.44.1632914433624; Wed, 29 Sep 2021 04:20:33 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyGsZ/Prx5O98qPZ8PyofLqYoLSSiZlZikvftKjUT4ZzCknxR+J5Y+KhHMLF54Y/OqTNkUIVA== X-Received: by 2002:a50:d9cc:: with SMTP id x12mr14221990edj.44.1632914433453; Wed, 29 Sep 2021 04:20:33 -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 l16sm1352795eds.46.2021.09.29.04.20.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Sep 2021 04:20:32 -0700 (PDT) Message-ID: Date: Wed, 29 Sep 2021 13:20:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 Subject: Re: [PATCH v8 4/7] KVM: x86: Report host tsc and realtime values in KVM_GET_CLOCK Content-Language: en-US To: Marcelo Tosatti , Oliver Upton Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, Sean Christopherson , Marc Zyngier , Peter Shier , Jim Mattson , David Matlack , Ricardo Koller , Jing Zhang , Raghavendra Rao Anata , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, Andrew Jones , Will Deacon , Catalin Marinas References: <20210916181538.968978-1-oupton@google.com> <20210916181538.968978-5-oupton@google.com> <20210928185343.GA97247@fuller.cnet> From: Paolo Bonzini In-Reply-To: <20210928185343.GA97247@fuller.cnet> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 28/09/21 20:53, Marcelo Tosatti wrote: >> +KVM_CLOCK_HOST_TSC. If set, the `host_tsc` field in the kvm_clock_data >> +structure is populated with the value of the host's timestamp counter (TSC) >> +at the instant when KVM_GET_CLOCK was called. If clear, the `host_tsc` field >> +does not contain a value. > If the host TSCs are not stable, then KVM_CLOCK_HOST_TSC bit (and > host_tsc field) are ambiguous. Shouldnt exposing them be conditional on > stable TSC for the host ? > Yes, good point. Paolo