linux-kernel - Re: Major KVM issues with kernel 4.5 on the host

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Message-ID: <20160421123711.GD28821@pd.tnic>
Date:	Thu, 21 Apr 2016 14:37:11 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Marc Haber <mh+linux-kernel@...schlus.de>
Cc:	Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org,
	kvm ML <kvm@...r.kernel.org>
Subject: Re: Major KVM issues with kernel 4.5 on the host

On Thu, Apr 21, 2016 at 10:39:48AM +0200, Marc Haber wrote:
> Currently, I cannot explain how this has happened, I must have flagged
> an actually good kernel as bad from my understanding of git bisect.
> 
> Can you give advice how to continue here?

Yap, sounds like you marked a bisection step incorrectly, which lead
into the wrong direction. How reliable is your reproducer?

Also, do the bisection as Paolo suggested:

* try 45bdbcfdf241.

* then do

$ git bisect start v4.5-rc1 v4.4

which marks -rc1 as bad and 4.4 as good.

While you're doing that bisect, do what Paolo said by applying the diff
here

  https://lkml.kernel.org/r/570EADD2.8030300@redhat.com

when the bisection point you're at at each step contains

  46896c73c1a4 ("KVM: svm: add support for RDTSCP")

You should apply the above hunk by doing

$ patch -p1 --dry-run -i /tmp/hunk

If it applies fine, you then apply it

$ patch -p1 -i /tmp/hunk

All clear?

If not, do not hesitate to ask.

Thanks

-- 
Regards/Gruss,
    Boris.

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