From: Scott Wood <scottwood@freescale.com>
To: McClintock Matthew-B29882 <B29882@freescale.com>
Cc: Wood Scott-B07421 <B07421@freescale.com>,
Alexander Graf <agraf@suse.de>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
kvm list <kvm@vger.kernel.org>,
"<kvm-ppc@vger.kernel.org>" <kvm-ppc@vger.kernel.org>
Subject: Re: [PATCH] PPC: Don't sync timebase when inside VM
Date: Thu, 08 Mar 2012 18:20:15 +0000 [thread overview]
Message-ID: <4F58F85F.8090604@freescale.com> (raw)
In-Reply-To: <CAEsOVNczPUdfUK6oZ7WOTGUQbA135HgrntwvnydbYd-Eo4joLg@mail.gmail.com>
On 03/08/2012 11:31 AM, McClintock Matthew-B29882 wrote:
> On Fri, Mar 2, 2012 at 11:17 AM, Scott Wood <scottwood@freescale.com> wrote:
>> On 03/02/2012 10:30 AM, Alexander Graf wrote:
>>>
>>> On 02.03.2012, at 17:20, Scott Wood wrote:
>>>> Again, for 85xx we should *never* sync the timebase in the kernel,
>>>> hypervisor or no.
>>>
>>> The code says "if the kexec config option is enabled, do the sync". I'm fairly sure it's there for a reason.
>>
>> Sigh. I forgot about that. It's because instead of doing kexec the
>> simple way, we actually physically reset the core. We really shouldn't
>> do that. And we *really* shouldn't do it just because CONFIG_KEXEC is
>> defined, regardless of whether we're actually booting from kexec.
>
> How would one rocver a core that's off in the weeds?
System reset?
I thought kexec was for upgrading your kernel, not recovering from crashes.
> We need to at least stop it somehow before we restart into the kdump kernel. kexec
> seems feasible since we have all the cores in a known state...
Stop, yes. Reset, no.
-Scott
WARNING: multiple messages have this Message-ID (diff)
From: Scott Wood <scottwood@freescale.com>
To: McClintock Matthew-B29882 <B29882@freescale.com>
Cc: "<kvm-ppc@vger.kernel.org>" <kvm-ppc@vger.kernel.org>,
Wood Scott-B07421 <B07421@freescale.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Alexander Graf <agraf@suse.de>, kvm list <kvm@vger.kernel.org>
Subject: Re: [PATCH] PPC: Don't sync timebase when inside VM
Date: Thu, 8 Mar 2012 12:20:15 -0600 [thread overview]
Message-ID: <4F58F85F.8090604@freescale.com> (raw)
In-Reply-To: <CAEsOVNczPUdfUK6oZ7WOTGUQbA135HgrntwvnydbYd-Eo4joLg@mail.gmail.com>
On 03/08/2012 11:31 AM, McClintock Matthew-B29882 wrote:
> On Fri, Mar 2, 2012 at 11:17 AM, Scott Wood <scottwood@freescale.com> wrote:
>> On 03/02/2012 10:30 AM, Alexander Graf wrote:
>>>
>>> On 02.03.2012, at 17:20, Scott Wood wrote:
>>>> Again, for 85xx we should *never* sync the timebase in the kernel,
>>>> hypervisor or no.
>>>
>>> The code says "if the kexec config option is enabled, do the sync". I'm fairly sure it's there for a reason.
>>
>> Sigh. I forgot about that. It's because instead of doing kexec the
>> simple way, we actually physically reset the core. We really shouldn't
>> do that. And we *really* shouldn't do it just because CONFIG_KEXEC is
>> defined, regardless of whether we're actually booting from kexec.
>
> How would one rocver a core that's off in the weeds?
System reset?
I thought kexec was for upgrading your kernel, not recovering from crashes.
> We need to at least stop it somehow before we restart into the kdump kernel. kexec
> seems feasible since we have all the cores in a known state...
Stop, yes. Reset, no.
-Scott
WARNING: multiple messages have this Message-ID (diff)
From: Scott Wood <scottwood@freescale.com>
To: McClintock Matthew-B29882 <B29882@freescale.com>
Cc: Wood Scott-B07421 <B07421@freescale.com>,
Alexander Graf <agraf@suse.de>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
kvm list <kvm@vger.kernel.org>,
"<kvm-ppc@vger.kernel.org>" <kvm-ppc@vger.kernel.org>
Subject: Re: [PATCH] PPC: Don't sync timebase when inside VM
Date: Thu, 8 Mar 2012 12:20:15 -0600 [thread overview]
Message-ID: <4F58F85F.8090604@freescale.com> (raw)
In-Reply-To: <CAEsOVNczPUdfUK6oZ7WOTGUQbA135HgrntwvnydbYd-Eo4joLg@mail.gmail.com>
On 03/08/2012 11:31 AM, McClintock Matthew-B29882 wrote:
> On Fri, Mar 2, 2012 at 11:17 AM, Scott Wood <scottwood@freescale.com> wrote:
>> On 03/02/2012 10:30 AM, Alexander Graf wrote:
>>>
>>> On 02.03.2012, at 17:20, Scott Wood wrote:
>>>> Again, for 85xx we should *never* sync the timebase in the kernel,
>>>> hypervisor or no.
>>>
>>> The code says "if the kexec config option is enabled, do the sync". I'm fairly sure it's there for a reason.
>>
>> Sigh. I forgot about that. It's because instead of doing kexec the
>> simple way, we actually physically reset the core. We really shouldn't
>> do that. And we *really* shouldn't do it just because CONFIG_KEXEC is
>> defined, regardless of whether we're actually booting from kexec.
>
> How would one rocver a core that's off in the weeds?
System reset?
I thought kexec was for upgrading your kernel, not recovering from crashes.
> We need to at least stop it somehow before we restart into the kdump kernel. kexec
> seems feasible since we have all the cores in a known state...
Stop, yes. Reset, no.
-Scott
next prev parent reply other threads:[~2012-03-08 18:20 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-02 14:12 [PATCH] PPC: Don't sync timebase when inside VM Alexander Graf
2012-03-02 14:12 ` Alexander Graf
2012-03-02 14:12 ` Alexander Graf
2012-03-02 16:20 ` Scott Wood
2012-03-02 16:20 ` Scott Wood
2012-03-02 16:20 ` Scott Wood
2012-03-02 16:30 ` Alexander Graf
2012-03-02 16:30 ` Alexander Graf
2012-03-02 16:30 ` Alexander Graf
2012-03-02 17:17 ` Scott Wood
2012-03-02 17:17 ` Scott Wood
2012-03-02 17:17 ` Scott Wood
2012-03-08 17:31 ` McClintock Matthew-B29882
2012-03-08 17:31 ` McClintock Matthew-B29882
2012-03-08 17:31 ` McClintock Matthew-B29882
2012-03-08 18:20 ` Scott Wood [this message]
2012-03-08 18:20 ` Scott Wood
2012-03-08 18:20 ` Scott Wood
2012-03-08 18:24 ` McClintock Matthew-B29882
2012-03-08 18:24 ` McClintock Matthew-B29882
2012-03-08 18:24 ` McClintock Matthew-B29882
2012-03-08 18:43 ` Scott Wood
2012-03-08 18:43 ` Scott Wood
2012-03-08 18:43 ` Scott Wood
2012-03-08 18:46 ` McClintock Matthew-B29882
2012-03-08 18:46 ` McClintock Matthew-B29882
2012-03-08 18:46 ` McClintock Matthew-B29882
2013-07-22 22:19 ` Scott Wood
2013-07-22 22:19 ` Scott Wood
2013-07-22 22:19 ` Scott Wood
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