From: Mark Rutland <mark.rutland@arm.com>
To: Julien Grall <julien.grall@arm.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>,
Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
sstabellini@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, xen-devel@lists.xen.org,
Matt Fleming <matt@codeblueprint.co.uk>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
linux-efi@vger.kernel.org
Subject: Re: [PATCH] arm64: xen: Implement EFI reset_system callback
Date: Thu, 6 Apr 2017 16:55:11 +0100 [thread overview]
Message-ID: <20170406155453.GA3966@leverpostej> (raw)
In-Reply-To: <e449f220-8db7-d58c-bdbf-47ccd6dd014b@arm.com>
[Adding the EFI maintainers]
Tl;DR: Xen's EFI wrappery doesn't implement reset_system, so when
invoked on arm64 we get a NULL dereference.
On Thu, Apr 06, 2017 at 04:39:13PM +0100, Julien Grall wrote:
> 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).
Please, let's keep the Xen knowledge constrained to the Xen EFI wrapper,
rather than spreading it further.
IMO, given reset_system is a *mandatory* function, the Xen wrapper
should provide an implementation.
I don't see why you can't implement a wrapper that calls the usual Xen
poweroff/reset functions.
Thanks,
Mark.
next prev parent reply other threads:[~2017-04-06 15:55 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 18:14 [PATCH] arm64: xen: Implement EFI reset_system callback Julien Grall
2017-04-05 19:49 ` Boris Ostrovsky
2017-04-06 6:23 ` Juergen Gross
2017-04-06 8:32 ` Julien Grall
2017-04-06 8:37 ` Juergen Gross
2017-04-06 14:27 ` Daniel Kiper
2017-04-06 14:32 ` Julien Grall
2017-04-06 14:37 ` Boris Ostrovsky
2017-04-06 14:38 ` Juergen Gross
2017-04-06 15:20 ` Daniel Kiper
2017-04-06 15:39 ` Julien Grall
2017-04-06 15:55 ` Mark Rutland [this message]
2017-04-18 13:46 ` Matt Fleming
2017-04-19 19:29 ` Daniel Kiper
2017-04-19 19:37 ` Matt Fleming
2017-04-19 19:43 ` Daniel Kiper
2017-04-06 16:06 ` Daniel Kiper
2017-04-06 16:22 ` Juergen Gross
2017-04-06 16:43 ` Daniel Kiper
2017-04-06 17:39 ` Juergen Gross
2017-04-18 18:37 ` Stefano Stabellini
2017-04-18 18:43 ` Juergen Gross
2017-04-18 18:46 ` Stefano Stabellini
2017-04-18 18:51 ` Juergen Gross
2017-04-20 18:09 ` Julien Grall
2017-04-05 21:26 ` Stefano Stabellini
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