From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH v3] xen/acpi: upload _PSD info for non Dom0 CPUs too Date: Wed, 21 Mar 2018 17:15:06 -0400 Message-ID: <4b9b40ce-a19c-758f-9a0b-451fadecf347@oracle.com> References: <20180315142205.15839-1-joao.m.martins@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180315142205.15839-1-joao.m.martins@oracle.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Joao Martins , linux-kernel@vger.kernel.org Cc: Juergen Gross , "Rafael J. Wysocki" , Len Brown , Robert Moore , Erik Schmauss , xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, devel@acpica.org List-Id: linux-acpi@vger.kernel.org On 03/15/2018 10:22 AM, Joao Martins wrote: > All uploaded PM data from non-dom0 CPUs takes the info from vCPU 0 and > changing only the acpi_id. For processors which P-state coordination type > is HW_ALL (0xFD) it is OK to upload bogus P-state dependency information > (_PSD), because Xen will ignore any cpufreq domains created for past CPUs. > > Albeit for platforms which expose coordination types as SW_ANY or SW_ALL, > this will have some unintended side effects. Effectively, it will look at > the P-state domain existence and *if it already exists* it will skip the > acpi-cpufreq initialization and thus inherit the policy from the first CPU > in the cpufreq domain. This will finally lead to the original cpu not > changing target freq to P0 other than the first in the domain. Which will > make turbo boost not getting enabled (e.g. for 'performance' governor) for > all cpus. > > This patch fixes that, by also evaluating _PSD when we enumerate all ACPI > processors and thus always uploading the correct info to Xen. We export > acpi_processor_get_psd() for that this purpose, but change signature > to not assume an existent of acpi_processor given that ACPI isn't creating > an acpi_processor for non-dom0 CPUs. > > Signed-off-by: Joao Martins Applied to for-linus-4.17 -boris