From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] KVM: x86: Fix page-tables reserved bits
Date: Wed, 16 Apr 2014 14:17:08 -0700
Message-ID: <534EF354.3090204@zytor.com>
References: <1396582264-9864-1-git-send-email-namit@cs.technion.ac.il> <20140416190329.GB8773@amt.cnet>
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Cc: gleb@kernel.org, pbonzini@redhat.com, tglx@linutronix.de,
	mingo@redhat.com, x86@kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Marcelo Tosatti <mtosatti@redhat.com>,
	Nadav Amit <namit@cs.technion.ac.il>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20140416190329.GB8773@amt.cnet>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On 04/16/2014 12:03 PM, Marcelo Tosatti wrote:
>> @@ -3550,9 +3550,9 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
>>  		break;
>>  	case PT64_ROOT_LEVEL:
>>  		context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
>> -			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
>> +			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 7);
>>  		context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
>> -			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
>> +			rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 7);
> 
> Bit 7 is not reserved either, for the PDPTE (its PageSize bit).
> 

In long mode (IA-32e), bit 7 is definitely reserved.

	-hpa