linux-kernel - Re: [PATCH v2] KVM: x86: Avoid guest page table walk when gpa

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Message-ID: <20170720074316.GA30718@potion>
Date:   Thu, 20 Jul 2017 09:43:16 +0200
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     Brijesh Singh <brijesh.singh@....com>
Cc:     pbonzini@...hat.com, joro@...tes.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
        hpa@...or.com, x86@...nel.org, Thomas.Lendacky@....com
Subject: Re: [PATCH v2] KVM: x86: Avoid guest page table walk when
 gpa_available is set

2017-07-19 08:35-0500, Brijesh Singh:
> On 07/19/2017 06:19 AM, Radim Krčmář wrote:
> > 2017-07-17 16:32-0500, Brijesh Singh:
> > > Hi Paolo and Radim
> > > 
> > > Any comments on this patch, I could not find it in 4.13-2 branch.
> > > 
> > > Please let me know if you want to fix something, or want me to
> > > refresh and resend the patch.
> > 
> > Sorry, I tried it during the merge window, but it didn't pass tests on
> > VMX and I got distracted by other bugs before looking into the cause.
> > 
> > Can you reproduce the fail?
> > 
> 
> No worries, thanks.
> 
> I can try to reproduce it, are you running kvm-unittest or something different?

I noticed that a linux guest hung in early boot, but at least (io)apic
kvm-unit-tests failed as well, IIRC.

> IIRC, VMX does not set the gpa_available flag hence I am wondering what did I miss
> in the patch to trigger the failure. I will debug it and let you know.

It does now, in ept_violation and ept_misconfig,

thanks.