linux-kernel - Re: [PATCH] X86: don't print a warning when MTRR are blank and running in KVM

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Date:	Thu, 21 Feb 2008 21:37:48 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Joerg Roedel <joerg.roedel@....com>
Cc:	tglx@...utronix.de, mingo@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] X86: don't print a warning when MTRR are blank and
	running in KVM


* Joerg Roedel <joerg.roedel@....com> wrote:

> -	if (!highest_pfn) {
> +	if (!highest_pfn && !kvm_para_available()) {
>  		printk(KERN_WARNING "WARNING: strange, CPU MTRRs all blank?\n");
>  		WARN_ON(1);
> -		return 0;
>  	}
>  
> +	if (!highest_pfn)
> +		return 0;

hm, why not have a single test for !highest_pfn:

	if (!highest_pfn) {
		if (!kvm_para_available()) {
  			printk(KERN_WARNING
			       "WARNING: strange, CPU MTRRs all blank?\n");
	  		WARN_ON(1);
		}
		return 0;
	}

? But yeah, your patch looks good otherwise.

I'm not sure how we could detect pure Qemu instances - perhaps it should 
define some special MSR or something?

	Ingo
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