diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index f71d7dec90..25ca87f244 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -412,6 +412,19 @@ static inline void rtas_st(target_ulong phys, int n, uint32_t val)
     stl_be_phys(&address_space_memory, ppc64_phys_to_real(phys + 4*n), val);
 }
 
+
+static inline void rtas_st_buffer(target_ulong phys, target_ulong phys_len,
+                                  uint8_t *buffer, uint16_t buffer_len)
+{
+    if (phys_len < 2) {
+        return;
+    }
+    stw_be_phys(&address_space_memory,
+                ppc64_phys_to_real(phys), buffer_len);
+    cpu_physical_memory_write(ppc64_phys_to_real(phys + 2),
+                              buffer, MIN(buffer_len, phys_len - 2));
+}
+
 typedef void (*spapr_rtas_fn)(PowerPCCPU *cpu, sPAPREnvironment *spapr,
                               uint32_t token,
                               uint32_t nargs, target_ulong args,