> -----Original Message----- > From: Alexander Graf [mailto:agraf@xxxxxxx] > Sent: Thursday, July 17, 2014 9:41 PM > To: Bhushan Bharat-R65777; kvm-ppc@xxxxxxxxxxxxxxx > Cc: kvm@xxxxxxxxxxxxxxx; Wood Scott-B07421; Yoder Stuart-B08248 > Subject: Re: [PATCH] kvm: ppc: booke: Restore SPRG3 when entering guest > > > On 16.07.14 08:02, Bharat Bhushan wrote: > > SPRG3 is guest accessible and SPRG3 can be clobbered by host or > > another guest, So this need to be restored when loading guest state. > > > > Signed-off-by: Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx> > > --- > > arch/powerpc/kvm/booke_interrupts.S | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/arch/powerpc/kvm/booke_interrupts.S > > b/arch/powerpc/kvm/booke_interrupts.S > > index 2c6deb5ef..0d3403f 100644 > > --- a/arch/powerpc/kvm/booke_interrupts.S > > +++ b/arch/powerpc/kvm/booke_interrupts.S > > @@ -459,6 +459,8 @@ lightweight_exit: > > * written directly to the shared area, so we > > * need to reload them here with the guest's values. > > */ > > + PPC_LD(r3, VCPU_SHARED_SPRG3, r5) > > + mtspr SPRN_SPRG3, r3 > > We also need to restore it when resuming the host, no? I do not think host expect some meaningful value when returning from guest, same true for SPRG4-7. So there seems no reason to save host values and restore them. Thanks -Bharat > > > Alex > > > PPC_LD(r3, VCPU_SHARED_SPRG4, r5) > > mtspr SPRN_SPRG4W, r3 > > PPC_LD(r3, VCPU_SHARED_SPRG5, r5) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
