From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH RFC] x86: Limit MSR_IA32_THERM_CONTROL and MSR_IA32_ENERGY_PERF_BIAS Date: Fri, 18 Dec 2015 21:31:38 +0000 Message-ID: <56747B3A.1050707@citrix.com> References: <1450471606-19129-1-git-send-email-konrad.wilk@oracle.com> <1450471606-19129-2-git-send-email-konrad.wilk@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aA2cm-0005wY-UA for xen-devel@lists.xenproject.org; Fri, 18 Dec 2015 21:31:41 +0000 In-Reply-To: <1450471606-19129-2-git-send-email-konrad.wilk@oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk , gang.wei@intel.com, JBeulich@suse.com, xen-devel@lists.xenproject.org, ian.campbell@citrix.com, keir@xen.org, tim@xen.org List-Id: xen-devel@lists.xenproject.org On 18/12/2015 20:46, Konrad Rzeszutek Wilk wrote: > Those two allow the OS pinned dom0 to change the T-state > (throttling) behind the Xen cpufreq code. > > The patch that introduced this: f78e2193b6409577314167ed9e077de7ac3e652f > > x86: Enable THERM_CONTROL_MSR write for dom0 even when cpufreq=xen > > Signed-off-by: Wei Gang > Signed-off-by: Keir Fraser > > is very lacking on details. > > Anyhow this patch in effect reverts the above commit. It is also > lacking in details :-) > > Signed-off-by: Konrad Rzeszutek Wilk We absolutely shouldn't let dom0 play with controls behind the back of a driver in Xen. It would be nice if we can find out some of the reasoning behind this change, but I am in principle for it. ~Andrew