We want to remove AArch32 DBGDTRTX which was erroneously exposed.
This was attempted by 655659a74a36b ("target/arm: Correct encoding
of Debug Communications Channel registers") but it was discovered
that the removal of this debug register broke forward migration on
TCG. Now we have the cpreg migration tolerance infrastructure, we
can declare one for the DBGDTRTX. This allow to revert the reinstate
patch.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Sebastian Ott <sebott@redhat.com>
---
 target/arm/helper.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 7389f2988c4..3cba62705dc 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6426,9 +6426,14 @@ void register_cp_regs_for_features(ARMCPU *cpu)
             .fgt = FGT_CLIDR_EL1,
             .resetvalue = GET_IDREG(isar, CLIDR)
         };
+        uint64_t dbgtr_el0_kvmidx =
+            cpreg_to_kvm_id(ENCODE_CP_REG(14, 0, 1, 0, 5, 3, 0));
+
         define_one_arm_cp_reg(cpu, &clidr);
         define_arm_cp_regs(cpu, v7_cp_reginfo);
         define_debug_regs(cpu);
+        arm_register_cpreg_mig_tolerance(cpu, dbgtr_el0_kvmidx,
+                                         0, 0, ToleranceNotOnBothEnds);
     } else {
         define_arm_cp_regs(cpu, not_v7_cp_reginfo);
     }
-- 
2.53.0