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: <5239a3ba-f324-3362-f257-f6c655c50f2a@redhat.com>
Date:   Thu, 24 Aug 2017 18:51:41 +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 18:21, Yu Zhang wrote:
> 
> 
> On 8/25/2017 12:27 AM, Paolo Bonzini wrote:
>> 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.
> 
> Thanks, Paolo.
> As to this patch series, any change I need do?

No, it's fine.

> BTW,  I have written a patch for kvm-unit-test access test, but the test
> failed.
> Not sure if my patch is erroneous or due to a simulator error. I'll send
> out the
> test patch after it works.:-)

Try to send it.  I can also test it with QEMU TCG.

Paolo