KVM: PPC: Ignore PIR writes
While technically it's legal to write to PIR and have the identifier changed,
we don't implement logic to do so because we simply expose vcpu_id to the guest.
So instead, let's ignore writes to PIR. This ensures that we don't inject faults
into the guest for something the guest is allowed to do. While at it, we cross
our fingers hoping that it also doesn't mind that we broke its PIR read values.
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 631a265..2c52ada 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -169,6 +169,9 @@
vcpu->arch.shared->sprg3 = spr_val;
break;
+ /* PIR can legally be written, but we ignore it */
+ case SPRN_PIR: break;
+
default:
emulated = kvmppc_core_emulate_mtspr(vcpu, sprn,
spr_val);