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Date: Thu, 3 Aug 2017 12:19:49 -0700
From: Greg KH <gregkh@linuxfoundation.org>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: stable@vger.kernel.org
Subject: Re: [PATCH 2/4 v4.4.y] KVM: PPC: Book3S HV: Restore critical SPRs to
 host values on guest exit
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 <20170731004241.mxqatl5fwhh5wgfr@oak.ozlabs.ibm.com>
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On Mon, Jul 31, 2017 at 10:42:41AM +1000, Paul Mackerras wrote:
> commit 4c3bb4ccd074e1a0552078c0bf94c662367a1658 upstream.
> 
> This restores several special-purpose registers (SPRs) to sane values
> on guest exit that were missed before.
> 
> TAR and VRSAVE are readable and writable by userspace, and we need to
> save and restore them to prevent the guest from potentially affecting
> userspace execution (not that TAR or VRSAVE are used by any known
> program that run uses the KVM_RUN ioctl).  We save/restore these
> in kvmppc_vcpu_run_hv() rather than on every guest entry/exit.

I also already have this one, right?