Re: [Xen-devel] [PATCH] Disable Xen PowerNow! support on Opteron 2nd gen and earlier processors

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 29/1/08 10:32, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx> wrote:

> On 29/1/08 09:53, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx> wrote:
> 
>> As promised I've instrumented and kicked that code path, and I execute it
>> with no problems, with the VCPU concerned being correctly migrated before
>> and after the continue_hypercall_on_cpu() is executed. I've tried it with
>> 'dom0_vcpus_pin' and also I've tried making fairly extreme calls to
>> cpu_frequency_change() inside the hypercall-continuation 'helper' function.
>> None of this causes my dom0 boot to hang. So it looks like something a bit
>> subtle must be going wrong on your test system.
> 
> Actually I've now eyeballed the problem. We access a stack variable after
> the stack frame is gone away. Probably we therefore end up setting a CPU's
> frequency to zero, which is not good at all. I'll work up a fix.

Changeset 16927 should fix the problem for you.

 -- Keir



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