KVM: PPC: Preload magic page when in kernel mode

When the guest jumps into kernel mode and has the magic page mapped, theres a
very high chance that it will also use it. So let's detect that scenario and
map the segment accordingly.

Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index 37db61d37041..54ca578239db 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -145,6 +145,16 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u64 msr)
                    (old_msr & (MSR_PR|MSR_IR|MSR_DR))) {
                 kvmppc_mmu_flush_segments(vcpu);
                 kvmppc_mmu_map_segment(vcpu, kvmppc_get_pc(vcpu));
+
+                /* Preload magic page segment when in kernel mode */
+                if (!(msr & MSR_PR) && vcpu->arch.magic_page_pa) {
+                        struct kvm_vcpu_arch *a = &vcpu->arch;
+
+                        if (msr & MSR_DR)
+                                kvmppc_mmu_map_segment(vcpu, a->magic_page_ea);
+                        else
+                                kvmppc_mmu_map_segment(vcpu, a->magic_page_pa);
+                }
         }
 
         /* Preload FPU if it's enabled */