From 666e7252a15b7fc4a116e65deaf6da5e4ce660e3 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Thu, 29 Jul 2010 14:47:43 +0200 Subject: KVM: PPC: Convert MSR to shared page One of the most obvious registers to share with the guest directly is the MSR. The MSR contains the "interrupts enabled" flag which the guest has to toggle in critical sections. So in order to bring the overhead of interrupt en- and disabling down, let's put msr into the shared page. Keep in mind that even though you can fully read its contents, writing to it doesn't always update all state. There are a few safe fields that don't require hypervisor interaction. See the documentation for a list of MSR bits that are safe to be set from inside the guest. Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/powerpc/kvm/booke_interrupts.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kvm/booke_interrupts.S') diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S index 380a78cf484..049846911ce 100644 --- a/arch/powerpc/kvm/booke_interrupts.S +++ b/arch/powerpc/kvm/booke_interrupts.S @@ -415,7 +415,8 @@ lightweight_exit: lwz r8, VCPU_GPR(r8)(r4) lwz r3, VCPU_PC(r4) mtsrr0 r3 - lwz r3, VCPU_MSR(r4) + lwz r3, VCPU_SHARED(r4) + lwz r3, VCPU_SHARED_MSR(r3) oris r3, r3, KVMPPC_MSR_MASK@h ori r3, r3, KVMPPC_MSR_MASK@l mtsrr1 r3 -- cgit v1.2.3-18-g5258