Re: [PATCH 2/4 v4.4.y] KVM: PPC: Book3S HV: Restore critical SPRs to host values on guest exit

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?