Re: [PATCH 09/26] KVM: PPC: Add PV guest scratch registers

Avi Kivity
2010-06-27T09:53:14Z

On 06/27/2010 12:41 PM, Alexander Graf wrote:
>
> Am 27.06.2010 um 10:22 schrieb Avi Kivity <avi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>:
>
>> On 06/26/2010 02:24 AM, Alexander Graf wrote:
>>> While running in hooked code we need to store register contents out
>>> because
>>> we must not clobber any registers.
>>>
>>> So let's add some fields to the shared page we can just happily
>>> write to.
>>>
>>>
>>
>> How are these protected during interrupts?
>
> By the 'critical section' bit. When in a critical section (read: using
> scratch registers), we don't issue interrupts.

Ok. I thought you needed scratch registers to set up the critical
section, but you don't. Neat stuff.

--
error compiling committee.c: too many arguments to function