Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755181AbdDRSqz (ORCPT ); Tue, 18 Apr 2017 14:46:55 -0400 Received: from mail.kernel.org ([198.145.29.136]:35000 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750975AbdDRSqx (ORCPT ); Tue, 18 Apr 2017 14:46:53 -0400 Date: Tue, 18 Apr 2017 11:46:27 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-X260 To: Juergen Gross cc: Stefano Stabellini , Daniel Kiper , Julien Grall , Boris Ostrovsky , xen-devel@lists.xen.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: xen: Implement EFI reset_system callback In-Reply-To: Message-ID: References: <20170405181417.15985-1-julien.grall@arm.com> <3f6f5853-cd08-8afc-f71a-b0c1545c7564@arm.com> <20170406142710.GE4372@olila.local.net-space.pl> <20170406152040.GH4372@olila.local.net-space.pl> <20170406160653.GJ4372@olila.local.net-space.pl> <20170406164309.GM4372@olila.local.net-space.pl> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4188 Lines: 94 On Tue, 18 Apr 2017, Juergen Gross wrote: > On 18/04/17 20:37, Stefano Stabellini wrote: > > On Thu, 6 Apr 2017, Juergen Gross wrote: > >> On 06/04/17 18:43, Daniel Kiper wrote: > >>> On Thu, Apr 06, 2017 at 06:22:44PM +0200, Juergen Gross wrote: > >>>> On 06/04/17 18:06, Daniel Kiper wrote: > >>>>> Hi Julien, > >>>>> > >>>>> On Thu, Apr 06, 2017 at 04:39:13PM +0100, Julien Grall wrote: > >>>>>> Hi Daniel, > >>>>>> > >>>>>> On 06/04/17 16:20, Daniel Kiper wrote: > >>>>>>> On Thu, Apr 06, 2017 at 04:38:24PM +0200, Juergen Gross wrote: > >>>>>>>> On 06/04/17 16:27, Daniel Kiper wrote: > >>>>>>>>> On Thu, Apr 06, 2017 at 09:32:32AM +0100, Julien Grall wrote: > >>>>>>>>>> Hi Juergen, > >>>>>>>>>> > >>>>>>>>>> On 06/04/17 07:23, Juergen Gross wrote: > >>>>>>>>>>> On 05/04/17 21:49, Boris Ostrovsky wrote: > >>>>>>>>>>>> On 04/05/2017 02:14 PM, Julien Grall wrote: > >>>>>>>>>>>>> The x86 code has theoritically a similar issue, altought EFI does not > >>>>>>>>>>>>> seem to be the preferred method. I have left it unimplemented on x86 and > >>>>>>>>>>>>> CCed Linux Xen x86 maintainers to know their view here. > >>>>>>>>>>>> > >>>>>>>>>>>> (+Daniel) > >>>>>>>>>>>> > >>>>>>>>>>>> This could be a problem for x86 as well, at least theoretically. > >>>>>>>>>>>> xen_machine_power_off() may call pm_power_off(), which is efi.reset_system. > >>>>>>>>>>>> > >>>>>>>>>>>> So I think we should have a similar routine there. > >>>>>>>>>>> > >>>>>>>>>>> +1 > >>>>>>>>>>> > >>>>>>>>>>> I don't see any problem with such a routine added, in contrast to > >>>>>>>>>>> potential "reboots" instead of power off without it. > >>>>>>>>>>> > >>>>>>>>>>> So I think this dummy xen_efi_reset_system() should be added to > >>>>>>>>>>> drivers/xen/efi.c instead. > >>>>>>>>>> > >>>>>>>>>> I will resend the patch during day with xen_efi_reset_system moved > >>>>>>>>>> to common code and implement the x86 counterpart (thought, I will > >>>>>>>>>> not be able to test it). > >>>>>>>>> > >>>>>>>>> I think that this is ARM specific issue. On x86 machine_restart() calls > >>>>>>>>> xen_restart(). Hence, everything works. So, I think that it should be > >>>>>>>>> fixed only for ARM. Anyway, please CC me when you send a patch. > >>>>>>>> > >>>>>>>> What about xen_machine_power_off() (as stated in Boris' mail)? > >>>>>>> > >>>>>>> Guys what do you think about that: > >>>>>>> > >>>>>>> --- a/drivers/firmware/efi/reboot.c > >>>>>>> +++ b/drivers/firmware/efi/reboot.c > >>>>>>> @@ -55,7 +55,7 @@ static void efi_power_off(void) > >>>>>>> > >>>>>>> static int __init efi_shutdown_init(void) > >>>>>>> { > >>>>>>> - if (!efi_enabled(EFI_RUNTIME_SERVICES)) > >>>>>>> + if (!efi_enabled(EFI_RUNTIME_SERVICES) || efi_enabled(EFI_PARAVIRT)) > >>>>>>> return -ENODEV; > >>>>>>> > >>>>>>> if (efi_poweroff_required()) > >>>>>>> > >>>>>>> > >>>>>>> Julien, for ARM64 please take a look at arch/arm64/kernel/efi.c:efi_poweroff_required(void). > >>>>>>> > >>>>>>> I hope that tweaks for both files should solve our problem. > >>>>>> > >>>>>> This sounds good for power off (I haven't tried to power off DOM0 > >>>>>> yet). But this will not solve the restart problem (see > >>>>>> machine_restart in arch/arm64/kernel/process.c) which call directly > >>>>>> efi_reboot. > >>>>> > >>>>> Hmmm... It seems to me that efi.reset_system override with empty function > >>>>> in arch/arm/xen/efi.c is the best solution. So, I see three patches here. > >>>>> One for drivers/firmware/efi/reboot.c, one for arch/arm/xen/efi.c and one > >>>>> for arch/arm64/kernel/efi.c. Does it make sense? > >>>> > >>>> I still think the empty function should be in drivers/xen/efi.c and we > >>>> should use it in arch/x86/xen/efi.c, too. > >>> > >>> If you wish we can go that way too. Though I thing that we should fix > >>> drivers/firmware/efi/reboot.c:efi_shutdown_init() too. Just in case. > >> > >> Sure, go ahead. I won't object. > > > > For the Xen on ARM side, the original patch that started this thread > > (20170405181417.15985-1-julien.grall@arm.com) is good to go, right? > > > > As I said: the dummy xen_efi_reset_system() should be in > drivers/xen/efi.c OK. Who is working on it?