Re: [PATCH] x86: make clflush a required feature on x86_64

From: H. Peter Anvin
Date: Fri Jan 18 2008 - 01:34:56 EST


Kyle McMartin wrote:
On Fri, Jan 18, 2008 at 06:53:53AM +0100, Andi Kleen wrote:
One problem that we had in the past is that some simulators
only implement the absolutely minimum feature set and you
might have well broken one of these with this.

Yeah, true. Please ignore the patch folks.

cheers, Kyle

Simulators can be fixed, even if it takes time; for something like clflush this is easier since clflush can be implemented as a simple noop for most of them.

I just verified that Bochs 2.3.0 lacks this CPUID bit whereas the current version, 2.3.6, enables CLFLUSH iff SSE2 is enabled. Qemu 0.9.0 has CLFLUSH. Andi, do you happen to know of any specific simulators which are problematic? I would assume any recent version of SimNow is up to date.

-hpa
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