On Wed, Sep 24, 2008 at 09:54:36PM -0700, H. Peter Anvin wrote:
quoted text
> Greg KH wrote:
>> Well, having a config option like this isn't the way to go as it will be
>> forced on for all distros and users anyway.
>> A simple cpuid test is the easier way to do this, that's what the
>> userspace tools do, if it's really needed in the kernel.  But hopefully,
>> such things shouldn't be needed within the kernel as it's not Linux's
>> fault that the hypervisor has bugs in it :)
>> We wouldn't be wanting to work around bugs in Microsoft's hypervisor,
>> would we?
>
> We pretty much have to, just as we have to work around bugs in, say, AMD's 
> microcode.  We have avoided it so far, but it's gotten to a breaking point, 
> and rather than having ad hoc hacks scattered all over the place I want a 
> centralized test site setting a single global variable.

Ok, fair enough.

quoted text
> Unfortunately, hypervisor vendors haven't adopted a uniform detection 
> scheme (CPUID level 0x40000000 is sometimes mentioned as a pseudo-standard, 
> but it's not universal, and not all virtualization solutions even can 
> override CPUID.)

Ah, I was hoping they were all doing this, as it seems the most "sane"
manner.  Good luck :)

greg k-h
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