Re: [PATCH] PPC: Don't sync timebase when inside VM

On Thu, Mar 8, 2012 at 12:20 PM, Scott Wood [off-list ref] wrote=
:

On 03/08/2012 11:31 AM, McClintock Matthew-B29882 wrote:

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On Fri, Mar 2, 2012 at 11:17 AM, Scott Wood [off-list ref] wr=

ote:

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On 03/02/2012 10:30 AM, Alexander Graf wrote:

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On 02.03.2012, at 17:20, Scott Wood wrote:

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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.

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Sigh. =A0I forgot about that. =A0It's because instead of doing kexec th=

e

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simple way, we actually physically reset the core. =A0We really shouldn=

't

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do that. =A0And we *really* shouldn't do it just because CONFIG_KEXEC i=

s

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defined, regardless of whether we're actually booting from kexec.

How would one rocver a core that's off in the weeds?

System reset?

kdump restarts a kernel using a reserved memory region to inspect the
memory of the crashed kernel. Wouldn't system reset cause issues here?

I thought kexec was for upgrading your kernel, not recovering from crashe=

s.

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We need to at least stop it somehow before we restart into the kdump ker=

nel. kexec

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seems feasible since we have all the cores in a known state...

Stop, yes. =A0Reset, no.

How would we stop the remaining cores assuming they could be in any state?

-M=