On Tue, Apr 30, 2019 at 10:41:23AM +1000, Suraj Jitindar Singh wrote:
> On POWER9 and later processors where the host can schedule vcpus on a
> per thread basis, there is a streamlined entry path used when the guest
> is radix. This entry path saves/restores the fp and vr state in
> kvmhv_p9_guest_entry() by calling store_[fp/vr]_state() and
> load_[fp/vr]_state(). This is the same as the old entry path however the
> old entry path also saved/restored the VRSAVE register, which isn't done
> in the new entry path.
>
> This means that the vrsave register is now volatile across guest exit,
> which is an incorrect change in behaviour.
>
> Fix this by saving/restoring the vrsave register in kvmhv_p9_guest_entry().
> This restores the old, correct, behaviour.
>
> Fixes: 95a6432ce9038 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
>
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
Thanks, patch applied to my kvm-ppc-next tree.
Paul.
