From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [RFC PATCH] xen_cpufreq implementation in kernel Date: Tue, 07 Oct 2014 16:44:40 +0100 Message-ID: <54340A68.5030002@linaro.org> References: <1412691618-7408-1-git-send-email-oleksandr.dmytryshyn@globallogic.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1412691618-7408-1-git-send-email-oleksandr.dmytryshyn@globallogic.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: Oleksandr Dmytryshyn , Ian Campbell , Stefano Stabellini , Tim Deegan , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 10/07/2014 03:20 PM, Oleksandr Dmytryshyn wrote: > Hi to all. Hi Oleksandr, > Next series of patches implements xen-cpufreq driver in kernel. > > Cpufreq core and registered cpufreq governors are located in xen. Dom0 has CPU > driver which can only change frequency of the physical CPUs. In addition this > driver can change CPUs regulator voltage. At start time xen-cpufreq driver > in kernel uploads to Xen information about physical cpus. > Xen notifies Dom0 kernel using VIRQ_CPUFREQ interrupt. Then xen-cpufreq driver > in kernel uses XEN_SYSCTL_cpufreq_op operation from HYPERVISOR_sysctl hypercall > to get some parameters from Xen (frequency, relation and cpu number). > Then xen-cpufreq changes frequency on physical cpu and uses the same > XEN_SYSCTL_cpufreq_op operation ti give the result to Xen. > > Next configs should be enabled to use xen-cpufreq driver: > CONFIG_GENERIC_CPUFREQ_CPU0 > CONFIG_XEN_CPUFREQ It's common to CC maintainers of the specific code in each patch. You only CC Xen folks, but some parts of the code touch the cpufreq subsystem. I believe that those guys will have the last word on those changes. Regards, -- Julien Grall