diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 682583d1d1..25b1e6d6b0 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -2102,6 +2102,7 @@ void ppc_compat_add_property(Object *obj, const char *name,
 #define SPR_PMCR              (0x374)
 #define SPR_440_ITV0          (0x374)
 #define SPR_440_ITV1          (0x375)
+#define SPR_RWMR              (0x375)
 #define SPR_440_ITV2          (0x376)
 #define SPR_440_ITV3          (0x377)
 #define SPR_440_CCR1          (0x378)
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 54035c7bbb..8d73e11540 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -5773,6 +5773,11 @@ static void register_power9_book4_sprs(CPUPPCState *env)
                      SPR_NOACCESS, SPR_NOACCESS,
                      &spr_read_generic, &spr_write_generic,
                      KVM_REG_PPC_WORT, 0);
+    spr_register_hv(env, SPR_RWMR, "RWMR",
+                 SPR_NOACCESS, SPR_NOACCESS,
+                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, &spr_write_generic,
+                 0x00000000);
 #endif
 }