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

From	Bandan Das <bsd@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry
Date	2016-07-22 18:00 +0200
Message-ID	<rXL1M-7Ib-17@gated-at.bofh.it> (permalink)
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Paolo Bonzini <pbonzini@redhat.com> writes:

>> Paolo Bonzini <pbonzini@redhat.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.
>
> Do you mean that this could happen if the VMCS is modified by L1
> after VMPTRLD?  That makes sense, but with David Matlack's change

Yeah that's the only way I can see it happen. If there's a separate path
that takes care of this, should I drop this one ?

> to cache the VMCS it wouldn't be possible to trigger it anymore.
>
> Paolo
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[PATCH 4/4] nvmx: check for shadow vmcs check on entry Bandan Das <bsd@redhat.com> - 2016-07-21 00:30 +0200
  Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry Paolo Bonzini <pbonzini@redhat.com> - 2016-07-21 11:20 +0200
    Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry Bandan Das <bsd@redhat.com> - 2016-07-21 21:30 +0200
      Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry Paolo Bonzini <pbonzini@redhat.com> - 2016-07-22 10:50 +0200
        Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry Bandan Das <bsd@redhat.com> - 2016-07-22 18:00 +0200

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