Re: [PATCH 1/2] VMware guest detection for x86 and x86-64

H. Peter Anvin
2008-09-25T04:55:08Z

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.

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.)

-hpa