From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2BD5C433F5 for ; Fri, 29 Oct 2021 20:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A60DF61038 for ; Fri, 29 Oct 2021 20:29:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229897AbhJ2Ub5 (ORCPT ); Fri, 29 Oct 2021 16:31:57 -0400 Received: from mail3-relais-sop.national.inria.fr ([192.134.164.104]:8962 "EHLO mail3-relais-sop.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229441AbhJ2Ub4 (ORCPT ); Fri, 29 Oct 2021 16:31:56 -0400 IronPort-HdrOrdr: =?us-ascii?q?A9a23=3AyjgT4qNwVuGiTMBcTkSjsMiBIKoaSvp037B8?= =?us-ascii?q?7TEVdfUzSL3sqynOpoVo6faaskd2ZJgfo6H1BEDtexzhHXAc2/huAV+NNDOWyF?= =?us-ascii?q?dABrsSkbcL+lXbalzDHgQ079YST0EGMqyOMbEYt7ef3ODHKadG/DDdytHLuQ62?= =?us-ascii?q?9R4EJmsGB52M9z0JczpzPXcGMzWubqBJb6Z0iPAom9JgEU5nFPiTNz0pd8qrnb?= =?us-ascii?q?z2vaOjTBIMBxYhgTPvsRqYrJP3GBiR2VMmWzlMybkvmFK18DAQac2YwoyG4w6Z?= =?us-ascii?q?2mPZ75xQ3NP508BEG8CA4/JlUgnRtg=3D=3D?= X-IronPort-AV: E=Sophos;i="5.84,326,1620684000"; d="scan'208";a="397787168" Received: from 173.121.68.85.rev.sfr.net (HELO hadrien) ([85.68.121.173]) by mail3-relais-sop.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Oct 2021 22:29:25 +0200 Date: Fri, 29 Oct 2021 22:29:25 +0200 (CEST) From: Julia Lawall X-X-Sender: jll@hadrien To: "Rafael J. Wysocki" cc: Doug Smythies , Srinivas Pandruvada , Len Brown , "Rafael J. Wysocki" , Viresh Kumar , Linux PM list , Linux Kernel Mailing List Subject: Re: problem in changing from active to passive mode In-Reply-To: Message-ID: References: User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, 29 Oct 2021, Rafael J. Wysocki wrote: > On Thu, Oct 28, 2021 at 10:18 PM Julia Lawall wrote: > > > > > > > > On Thu, 28 Oct 2021, Rafael J. Wysocki wrote: > > > > > On Thu, Oct 28, 2021 at 9:25 PM Julia Lawall wrote: > > [cut] > > > > Attached is a patch to do that, but please note that the 5.9 will need > > > to be patched too to address this issue. > > > > I'm not completely clear on what the new patch is doing and how I should > > test it. If I stay in 5.15, the original patch worked for clearing des > > when going from passive to active. > > Sorry for the confusion. > > If applied to 5.15-rc alone, the last patch would cause des to be > cleared when switching from passive to active and if applied to both > 5.15-rc and 5.9, it would fix the kexec issue as well. > > Never mind, though. > > The patch attached to this message should cause des to be cleared when > switching from passive to active (because it is based on the previous > patch doing that) and it should prevent nonzero des from being leaked > via the HWP_REQUEST MSR to the new kernel started via kexec. With > this patch applied to 5.15-rc des should be 0 when switching from > passive to active and it should also be 0 after starting another > kernel via kexec while intel_pstate is running in the passive mode. > > Can you please verify that it works as expected? I booted 5.15 rc6 in active then changed to passive making the des field non zero, and then changed back to active, making it 0 again. I them changed again to passive and kexeced 5.9. The des field was again 0. So it looks fine. thanks, julia