KVM: PPC: Don't flush PTEs on NX/RO hit

When hitting a no-execute or read-only data/inst storage interrupt we were
flushing the respective PTE so we're sure it gets properly overwritten next.

According to the spec, this is unnecessary though. The guest issues a tlbie
anyways, so we're safe to just keep the PTE around and have it manually removed
from the guest, saving us a flush.
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/kvm/book3s.c

@@ -887,7 +887,6 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			vcpu->arch.shared->msr |=
 				to_svcpu(vcpu)->shadow_srr1 & 0x58000000;
 			kvmppc_book3s_queue_irqprio(vcpu, exit_nr);
-			kvmppc_mmu_pte_flush(vcpu, kvmppc_get_pc(vcpu), ~0xFFFUL);
 			r = RESUME_GUEST;
 		}
 		break;
@@ -913,7 +912,6 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			vcpu->arch.shared->dar = dar;
 			vcpu->arch.shared->dsisr = to_svcpu(vcpu)->fault_dsisr;
 			kvmppc_book3s_queue_irqprio(vcpu, exit_nr);
-			kvmppc_mmu_pte_flush(vcpu, dar, ~0xFFFUL);
 			r = RESUME_GUEST;
 		}
 		break;