From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933452AbdDFQoC (ORCPT ); Thu, 6 Apr 2017 12:44:02 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:38148 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753698AbdDFQnx (ORCPT ); Thu, 6 Apr 2017 12:43:53 -0400 Date: Thu, 6 Apr 2017 18:43:09 +0200 From: Daniel Kiper To: Juergen Gross Cc: Julien Grall , Boris Ostrovsky , xen-devel@lists.xen.org, sstabellini@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: xen: Implement EFI reset_system callback Message-ID: <20170406164309.GM4372@olila.local.net-space.pl> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Daniel