linux-kernel - Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry

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Message-ID: <jpgoa5q94sz.fsf@linux.bootlegged.copy>
Date:	Thu, 21 Jul 2016 15:20:12 -0400
From:	Bandan Das <bsd@...hat.com>
To:	Paolo Bonzini <pbonzini@...hat.com>
Cc:	kvm@...r.kernel.org, rkrcmar@...hat.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry

Paolo Bonzini <pbonzini@...hat.com> writes:

> On 21/07/2016 00:25, Bandan Das wrote:
>> vmentry should check whether the vmcs provided by
>> the guest hypervisor is a shadow vmcs and fail.
>
> How can this happen, since vmptrld checks the revision_id as you said below?

This is more of a change that adheres to the spec
(26.1 Basic VM-Entry Checks); the failure path
is slightly different compared to vmptrld though.
It's small and harmless but I am ok if you prefer dropping it.

Thanks for the review!

> Paolo
>
>> Also, vmptrld should check whether a shadow vmcs
>> is being loaded by the guest without support being present
>> but this check happens as part of checking the revision_id.