From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934272AbdDFQW4 (ORCPT ); Thu, 6 Apr 2017 12:22:56 -0400 Received: from mx2.suse.de ([195.135.220.15]:35590 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751972AbdDFQWr (ORCPT ); Thu, 6 Apr 2017 12:22:47 -0400 Subject: Re: [PATCH] arm64: xen: Implement EFI reset_system callback To: Daniel Kiper , Julien Grall 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> Cc: Boris Ostrovsky , xen-devel@lists.xen.org, sstabellini@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org From: Juergen Gross Message-ID: Date: Thu, 6 Apr 2017 18:22:44 +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: <20170406160653.GJ4372@olila.local.net-space.pl> 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 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. Juergen From mboxrd@z Thu Jan 1 00:00:00 1970 From: jgross@suse.com (Juergen Gross) Date: Thu, 6 Apr 2017 18:22:44 +0200 Subject: [PATCH] arm64: xen: Implement EFI reset_system callback In-Reply-To: <20170406160653.GJ4372@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> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. Juergen