linux-kernel - Re: [PATCH v3 2/5] KVM: MMU: check guest CR3 reserved bits based on its physical address width.

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Message-ID: <f199b361-e4ac-74f4-c039-185e19418a15@redhat.com>
Date:   Thu, 24 Aug 2017 18:27:41 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Yu Zhang <yu.c.zhang@...ux.intel.com>, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, rkrcmar@...hat.com,
        tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        xiaoguangrong@...cent.com, joro@...tes.org
Subject: Re: [PATCH v3 2/5] KVM: MMU: check guest CR3 reserved bits based on
 its physical address width.

On 24/08/2017 17:38, Yu Zhang wrote:
>>
>>
>> In practice, MAXPHYADDR will never be 59 even because the PKRU bits are
>> at bits 59..62.
> 
> Thanks, Paolo.
> I see. I had made an assumption that MAXPHYADDR shall not exceed the
> physical one,
> which is 52 I believe. But I'm not sure there's any place to check this.
> Maybe we should make sure the vcpu->arch.maxphyaddr will not be greater
> than the value of the host?

That's a separate change anyway.  In any case, since currently the
MAXPHYADDR is not validated, your change to rsvd_bits makes sense.

Paolo