diff --git a/target-arm/helper.c b/target-arm/helper.c
index f981569ae2ce17565be43b7cafa18ca42ed1ac12..2a77c97c7bf192b2d2e9f33db2175b5dc0c0d908 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2204,7 +2204,9 @@ static const ARMCPRegInfo debug_cp_reginfo[] = {
      */
     { .name = "MDSCR_EL1", .state = ARM_CP_STATE_BOTH,
       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 2,
-      .access = PL1_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
+      .access = PL1_RW,
+      .fieldoffset = offsetof(CPUARMState, cp15.mdscr_el1),
+      .resetvalue = 0 },
     /* We define a dummy WI OSLAR_EL1, because Linux writes to it. */
     { .name = "OSLAR_EL1", .state = ARM_CP_STATE_BOTH,
       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,