From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 533AA7E for ; Wed, 15 Nov 2023 08:49:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tMzx3Ooe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6A18C433C8; Wed, 15 Nov 2023 08:49:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700038179; bh=OuPjk+emTE9UpaDXpxTR2qXCGW+CArulEmPHaMPj4bA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tMzx3OoeufNFnHcPm2vccBzmaOR9CI/LswpZ1a0O/7q6bd7TmS2suyLznB6y9RrzA oZZDcr7qD6w20IH6UnlQ0TfRwp+5JWKmJ5igrfKzmCcqf/1uzqIqA7wSAC+Q9+03t9 f02TWQ/JBDhBZyh45o/Xp9wU3Yf3fVOWNxP3DmwvsiPOKADgPYGlaA6UAY0gNYc5UO xgBiojyhlHAFXOXoZvW62D+rmWyjfmFBDkHULDADzE1sXZd/f0CwGqP4Ao5DpW2b/M 6ME9+xQ1/grSTFVGKawehQi9twHV0ddRWTYEecJBEt8vGT77DTMOTzg2wXa92HI5D8 MzYB1/83M5Pbw== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1r3Bab-00DFvg-0w; Wed, 15 Nov 2023 08:49:37 +0000 Date: Wed, 15 Nov 2023 08:49:36 +0000 Message-ID: <865y231jvj.wl-maz@kernel.org> From: Marc Zyngier To: David Dai Cc: "Rafael J. Wysocki" , Viresh Kumar , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sudeep Holla , Saravana Kannan , Quentin Perret , Masami Hiramatsu , Will Deacon , Peter Zijlstra , Vincent Guittot , Oliver Upton , Dietmar Eggemann , Pavan Kondeti , Gupta Pankaj , Mel Gorman , kernel-team@android.com, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/2] dt-bindings: cpufreq: add virtual cpufreq device In-Reply-To: <20231111014933.1934562-2-davidai@google.com> References: <20231111014933.1934562-1-davidai@google.com> <20231111014933.1934562-2-davidai@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: davidai@google.com, rafael@kernel.org, viresh.kumar@linaro.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, sudeep.holla@arm.com, saravanak@google.com, qperret@google.com, mhiramat@google.com, will@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, oliver.upton@linux.dev, dietmar.eggemann@arm.com, quic_pkondeti@quicinc.com, pankaj.gupta@amd.com, mgorman@suse.de, kernel-team@android.com, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Sat, 11 Nov 2023 01:49:29 +0000, David Dai wrote: > > Adding bindings to represent a virtual cpufreq device. > > Virtual machines may expose MMIO regions for a virtual cpufreq device > for guests to read frequency information or to request frequency > selection. The virtual cpufreq device has an individual controller for > each frequency domain. I would really refrain form having absolute frequencies here. A virtual machine can be migrated, and there are *zero* guarantees that the target system has the same clock range as the source. This really should be a relative number, much like the capacity. That, at least, can be migrated across systems. Thanks, M. -- Without deviation from the norm, progress is not possible.