KVM: arm/arm64: vgic: Defer touching GICH_VMCR to vcpu_load/put
We don't have to save/restore the VMCR on every entry to/from the guest,
since on GICv2 we can access the control interface from EL1 and on VHE
systems with GICv3 we can access the control interface from KVM running
in EL2.
GICv3 systems without VHE becomes the rare case, which has to
save/restore the register on each round trip.
Note that userspace accesses may see out-of-date values if the VCPU is
running while accessing the VGIC state via the KVM device API, but this
is already the case and it is up to userspace to quiesce the CPUs before
reading the CPU registers from the GIC for an up-to-date view.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index b72dd2a..f7a2e31 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -306,6 +306,9 @@
int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
+void kvm_vgic_load(struct kvm_vcpu *vcpu);
+void kvm_vgic_put(struct kvm_vcpu *vcpu);
+
#define irqchip_in_kernel(k) (!!((k)->arch.vgic.in_kernel))
#define vgic_initialized(k) ((k)->arch.vgic.initialized)
#define vgic_ready(k) ((k)->arch.vgic.ready)