From mboxrd@z Thu Jan  1 00:00:00 1970
From: Brijesh Singh <brijesh.singh@amd.com>
Subject: Re: [PATCH] x86: kvm: Avoid guest page table walk when gpa_available
 is set
Date: Tue, 2 May 2017 16:44:19 -0500
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Cc: <brijesh.singh@amd.com>, <joro@8bytes.org>, <kvm@vger.kernel.org>,
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To: Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>
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Hi Paolo,

>>
>> I've tried the below patch and it seems to work fine. This does not
>> consider
>> PIO case and as you rightly pointed PIO should trigger #NPF relatively
>> rarely.
>> At least so far in my runs I have not seen PIO causing #NPF. If this sounds
>> acceptable approach then I can submit v2 with these changes and remove
>> gpa_val
>> additional.
>
> PIO can certainly cause #NPF, albeit rarely, so this is not a viable one.
>

For SEV guest cases, we anyway want to avoid any guest page table walks
(even if it happens rarely). Sounds like we have to depend on gpa_val variable.
I will refresh the patch to address one of Ramdim's feedback
(move vcpu->arch.gpa_val assignment from handle_exit to pf_interception).

Brijesh