diff --git a/target/ppc/power8-pmu.c b/target/ppc/power8-pmu.c
index 1381072..64a6486 100644
--- a/target/ppc/power8-pmu.c
+++ b/target/ppc/power8-pmu.c
@@ -272,7 +272,7 @@
 {
     pmu_update_cycles(env);
 
-    env->spr[sprn] = value;
+    env->spr[sprn] = (uint32_t)value;
 
     pmc_update_overflow_timer(env, sprn);
 }