Re: [PATCH 3/4] x86, head_32: Remove second CPUID detection fromdefault_entry

From: Borislav Petkov
Date: Mon Feb 11 2013 - 12:15:50 EST

On Mon, Feb 11, 2013 at 07:49:14AM -0800, H. Peter Anvin wrote:
> What about CPUs with inconsistent cpuid levels? Yes, they can and do
> happen, as we discussed on IRC.

Yes, this should still work. We're doing the EFLAGS.ID dance right at
the beginning of default_entry on each cpu and cache cpuld level in
new_cpu_data for the time we're in this code.

What this particular patch removes is the yet-another EFLAGS.ID dance
which we IMHO unnecessarily did after enabling paging.

So basically nothing changes wrt handling inconsistent cpuid levels and
MSR mis-programming - we still should be taking care of those cases.



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