From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 275461DFE3; Tue, 2 Jul 2024 18:40:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719945622; cv=none; b=YD7+m27XCmcpJW9tpbLdOsPFYUPb5iGR2pTdiduBvZLdQZAKBzS5YSD+YW/Or3546tZdqZE4qed6TFsXed+KKKUj/AYK3/Cm6lmppAWlHQ8XoweOW4ihc0TzCHLzMH6ox70Mx03qpyfcFmtlAfH87bzIebtxPfjh9mAlFPlaFuk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719945622; c=relaxed/simple; bh=XlhLqAUMcg+sJf064MDVicDasZ/lcOHYbpSPJSTSDvI=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=G9X0vP6+SfjLScSMv20+d0ZNZH7p72a/pipKdLYaPYQhj/axp/yJbUiKmgxrDUpnI1PnszMCtgZPEIzkRqkYoGnN5EZQll28/oyOtw0zzycWGey8f7TGY37NFPdIZNj6e6eWWDm/8+saAMWp1+kAWwuUPspDi2Xk6q0RGWJ7xRk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=desiato.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=W8u3i889; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=desiato.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="W8u3i889" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:Content-Type :MIME-Version:Message-ID:References:In-Reply-To:Subject:CC:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=RJSqylBZlzW9UDCHCqo3Xfdt29Ffczco70FXx734zXo=; b=W8u3i889blo/jC1uilhFu/Yv9K DQ9k2/5RYKE9bFhzWgXt+qmRVEYimUpcIzTQorHpZTs0sI+Wuw9P7Y9PKvMWZy7Hyt+1ku1VT3L4j zigvimNVllEcFg+TAavc51UyH6hvMn5lWe7yyv/WCORZItTjkvmM+ible75PooH827bgjsC3/HBzY DxFtxU+Nl4iICPDA/17ID9pxbpRhuTxgAZjT7ZiSwSySjsRuQMugzG6eSy/oUKFrjqf3pXeBiJsGR ywLBRO+CmelMGec+Q/a6G+Lp5eow6Xtl6Ei4AfGmU79ts4I4BYyE0s0VInEBotHZ770lYW+Q+HD8l EGHkoTbQ==; Received: from [2a00:23ee:2318:7901:3188:7b97:6ee:f783] (helo=[IPv6:::1]) by desiato.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1sOiQ9-00000009rA4-2tiF; Tue, 02 Jul 2024 18:40:06 +0000 Date: Tue, 02 Jul 2024 19:40:04 +0100 From: David Woodhouse To: Peter Hilber , linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-rtc@vger.kernel.org, "Ridoux, Julien" , virtio-dev@lists.linux.dev, "Luu, Ryan" CC: "Christopher S. Hall" , Jason Wang , John Stultz , "Michael S. Tsirkin" , netdev@vger.kernel.org, Richard Cochran , Stephen Boyd , Thomas Gleixner , Xuan Zhuo , Marc Zyngier , Mark Rutland , Daniel Lezcano , Alessandro Zummo , Alexandre Belloni Subject: Re: [RFC PATCH v2] ptp: Add vDSO-style vmclock support User-Agent: K-9 Mail for Android In-Reply-To: <19c75212-bcb6-49e3-964d-ed727da2ba54@opensynergy.com> References: <20231218073849.35294-1-peter.hilber@opensynergy.com> <684eac07834699889fdb67be4cee09319c994a42.camel@infradead.org> <671a784b-234f-4be6-80bf-5135e257ed40@opensynergy.com> <4a0a240dffc21dde4d69179288547b945142259f.camel@infradead.org> <8d9d7ce2-4dd1-4f54-a468-79ef5970a708@opensynergy.com> <2de9275f-b344-4a76-897b-52d5f4bdca59@opensynergy.com> <51087cd7149ce576aa166d32d051592b146ce2c4.camel@infradead.org> <3707d99d0dfea45d05fd65f669132c2e546f35c6.camel@infradead.org> <19c75212-bcb6-49e3-964d-ed727da2ba54@opensynergy.com> Message-ID: <02E9F187-A38C-4D14-A287-AFD7503B6B0F@infradead.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-SRS-Rewrite: SMTP reverse-path rewritten from by desiato.infradead.org. See http://www.infradead.org/rpr.html On 2 July 2024 19:12:00 BST, Peter Hilber wrote: >On 02=2E07=2E24 18:39, David Woodhouse wrote: >> To clarify then, the main types are >>=20 >> VIRTIO_RTC_CLOCK_UTC =3D=3D 0 >> VIRTIO_RTC_CLOCK_TAI =3D=3D 1 >> VIRTIO_RTC_CLOCK_MONOTONIC =3D=3D 2 >> VIRTIO_RTC_CLOCK_SMEARED_UTC =3D=3D 3 >>=20 >> And the subtypes are *only* for the case of >> VIRTIO_RTC_CLOCK_SMEARED_UTC=2E They include >>=20 >> VIRTIO_RTC_SUBTYPE_STRICT >> VIRTIO_RTC_SUBTYPE_UNDEFINED /* or whatever you want to call it */ >> VIRTIO_RTC_SUBTYPE_SMEAR_NOON_LINEAR=20 >> VIRTIO_RTC_SUBTYPE_UTC_SLS /* if it's worth doing this one */ >>=20 >> Is that what we just agreed on? >>=20 >>=20 > >This is a misunderstanding=2E My idea was that the main types are > >> VIRTIO_RTC_CLOCK_UTC =3D=3D 0 >> VIRTIO_RTC_CLOCK_TAI =3D=3D 1 >> VIRTIO_RTC_CLOCK_MONOTONIC =3D=3D 2 >> VIRTIO_RTC_CLOCK_SMEARED_UTC =3D=3D 3 > >VIRTIO_RTC_CLOCK_MAYBE_SMEARED_UTC =3D=3D 4 > >The subtypes would be (1st for clocks other than >VIRTIO_RTC_CLOCK_SMEARED_UTC, 2nd to last for >VIRTIO_RTC_CLOCK_SMEARED_UTC): > >#define VIRTIO_RTC_SUBTYPE_STRICT 0 >#define VIRTIO_RTC_SUBTYPE_SMEAR_NOON_LINEAR 1 >#define VIRTIO_RTC_SUBTYPE_SMEAR_UTC_SLS 2 > Thanks=2E I really do think that from the guest point of view there's real= ly no distinction between "maybe smeared" and "undefined smearing", and hav= e a preference for using the latter form, which is the key difference there= ? Again though, not a hill for me to die on=2E