| Subject | Re: [RFC PATCH 18/33] Subarch support for CPUID instruction | From | Arjan van de Ven <> | Date | Tue, 18 Jul 2006 12:14:46 +0200 |
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On Tue, 2006-07-18 at 00:00 -0700, Chris Wright wrote: > plain text document attachment (i386-cpuid) > Allow subarchitectures to modify the CPUID instruction. This allows > the subarch to provide a limited set of CPUID feature flags during CPU > identification. Add a subarch implementation for Xen that traps to the > hypervisor where unsupported feature flags can be hidden from guests.
Hi,
I'm wondering if this is entirely the wrong level of abstraction; to me it feels the subarch shouldn't override the actual cpuid, but the cpu feature flags that linux uses. That's a lot less messy: cpuid has many many pieces of information which are near impossible to filter in practice, however filtering the USAGE of it is trivial; linux basically flattens the cpuid namespace into a simple bitmap of "what the kernel can use". That is really what the subarch should filter/fixup, just like we do for cpu quirks etc etc.
Greetings, Arjan van de Ven
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