linux-kernel - Re: [PATCH 2/6] KVM: VMX: cleanup check for invalid EPT violation

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Message-ID: <52507881-6444-8704-7c3a-a9c87f8e0a9b@redhat.com>
Date:   Thu, 9 Mar 2017 11:50:56 +0100
From:   David Hildenbrand <david@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     bdas@...hat.com, dmatlack@...gle.com
Subject: Re: [PATCH 2/6] KVM: VMX: cleanup check for invalid EPT violation

Am 09.03.2017 um 11:43 schrieb David Hildenbrand:
> Am 08.03.2017 um 19:03 schrieb Paolo Bonzini:
>> handle_ept_violation is checking for "guest-linear-address invalid" +
>> "paging-structure walk", which is a sign of a bug in KVM.  However,
>> _all_ EPT violations without a valid guest linear address are paging
>> structure walks, because those EPT violations happen when loading the
>> guest PDPTEs.  So simplify the check to only look at bit 7 of the
>> exit qualification.
> 
> Do we have any define for this magic bit 7?
> 
> #EPT_EXITQ_GLA_VALID 0x80
> 

Introducing

#define EPT_VIOLATION_GLA_VALID_BIT
#define EPT_VIOLATION_GLA_VALID

would make sense.

-- 
Thanks,

David