linux-kernel - Re: [PATCH 4/5] KVM: x86: fix check legal type of Variable Range MTRRs

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Message-ID: <53F1D543.4060700@redhat.com>
Date:	Mon, 18 Aug 2014 12:28:19 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Wanpeng Li <wanpeng.li@...ux.intel.com>
CC:	Gleb Natapov <gleb@...nel.org>, hpa@...or.com, x86@...nel.org,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] KVM: x86: fix check legal type of Variable Range
 MTRRs

Il 18/08/2014 11:50, Wanpeng Li ha scritto:
> +	if (msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR) {

This should be a WARN_ON, and the base/mask can be separated just with
an "&".

	WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR));

	if ((msr & 1) == 0)
		/* MTRR base */
		return valid_mtrr_type(data & 0xff);

	/* MTRR mask */
	return true;

Please provide a unit test for this patch and for patch 1.

Paolo

> +		int idx, is_mtrr_mask;
> +
> +		idx = (msr - 0x200) / 2;
> +		is_mtrr_mask = msr - 0x200 - 2 * idx;
> +		if (!is_mtrr_mask)
> +			return valid_mtrr_type(data & 0xff);
> +	}
> +	return true;
>  }

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