Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754545AbdDRSnI (ORCPT ); Tue, 18 Apr 2017 14:43:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:54577 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753015AbdDRSnG (ORCPT ); Tue, 18 Apr 2017 14:43:06 -0400 Subject: Re: [PATCH] arm64: xen: Implement EFI reset_system callback To: Stefano Stabellini 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> Cc: Daniel Kiper , Julien Grall , Boris Ostrovsky , xen-devel@lists.xen.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org From: Juergen Gross Message-ID: Date: Tue, 18 Apr 2017 20:43:03 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3947 Lines: 94 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 Juergen