diff --git a/sys/dev/sfxge/common/ef10_mcdi.c b/sys/dev/sfxge/common/ef10_mcdi.c
index 22df04048add..46ea572c0665 100644
--- a/sys/dev/sfxge/common/ef10_mcdi.c
+++ b/sys/dev/sfxge/common/ef10_mcdi.c
@@ -159,6 +159,8 @@ ef10_mcdi_poll_response(
 	efx_dword_t hdr;
 
 	EFSYS_MEM_READD(esmp, 0, &hdr);
+	EFSYS_MEM_READ_BARRIER();
+
 	return (EFX_DWORD_FIELD(hdr, MCDI_HEADER_RESPONSE) ? B_TRUE : B_FALSE);
 }