diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 3968369554..11d4b5cd0c 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -127,7 +127,8 @@ struct SysemuCPUOps;
  * @gdb_adjust_breakpoint: Callback for adjusting the address of a
  *       breakpoint.  Used by AVR to handle a gdb mis-feature with
  *       its Harvard architecture split code and data.
- * @gdb_num_core_regs: Number of core registers accessible to GDB.
+ * @gdb_num_core_regs: Number of core registers accessible to GDB or 0 to infer
+ *                     from @gdb_core_xml_file.
  * @gdb_core_xml_file: File name for core registers GDB XML description.
  * @gdb_stop_before_watchpoint: Indicates whether GDB expects the CPU to stop
  *           before the insn which triggers a watchpoint rather than after it.
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 7bea7075e1..83eafbe4b1 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -452,8 +452,6 @@ static inline void cpu_get_tb_cpu_state(CPUS390XState *env, vaddr *pc,
 #define S390_R13_REGNUM 15
 #define S390_R14_REGNUM 16
 #define S390_R15_REGNUM 17
-/* Total Core Registers. */
-#define S390_NUM_CORE_REGS 18
 
 static inline void setcc(S390CPU *cpu, uint64_t cc)
 {
diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index 5ecd1f23e6..af63b5d159 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -546,9 +546,12 @@ void gdb_init_cpu(CPUState *cpu)
         gdb_register_feature(cpu, 0,
                              cc->gdb_read_register, cc->gdb_write_register,
                              feature);
+        cpu->gdb_num_regs = cpu->gdb_num_g_regs = feature->num_regs;
     }
 
-    cpu->gdb_num_regs = cpu->gdb_num_g_regs = cc->gdb_num_core_regs;
+    if (cc->gdb_num_core_regs) {
+        cpu->gdb_num_regs = cpu->gdb_num_g_regs = cc->gdb_num_core_regs;
+    }
 }
 
 void gdb_register_coprocessor(CPUState *cpu,
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 6c6c551573..6d9bf6a14e 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -2391,7 +2391,6 @@ static void arm_cpu_class_init(ObjectClass *oc, void *data)
 #ifndef CONFIG_USER_ONLY
     cc->sysemu_ops = &arm_sysemu_ops;
 #endif
-    cc->gdb_num_core_regs = 26;
     cc->gdb_arch_name = arm_gdb_arch_name;
     cc->gdb_get_dynamic_xml = arm_gdb_get_dynamic_xml;
     cc->gdb_stop_before_watchpoint = true;
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 1cb9d5b81a..5c7a4a0bf7 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -792,7 +792,6 @@ static void aarch64_cpu_class_init(ObjectClass *oc, void *data)
 
     cc->gdb_read_register = aarch64_cpu_gdb_read_register;
     cc->gdb_write_register = aarch64_cpu_gdb_write_register;
-    cc->gdb_num_core_regs = 34;
     cc->gdb_core_xml_file = "aarch64-core.xml";
     cc->gdb_arch_name = aarch64_gdb_arch_name;
 
diff --git a/target/avr/cpu.c b/target/avr/cpu.c
index 14d8b9d1f0..01adfb5089 100644
--- a/target/avr/cpu.c
+++ b/target/avr/cpu.c
@@ -244,7 +244,6 @@ static void avr_cpu_class_init(ObjectClass *oc, void *data)
     cc->gdb_read_register = avr_cpu_gdb_read_register;
     cc->gdb_write_register = avr_cpu_gdb_write_register;
     cc->gdb_adjust_breakpoint = avr_cpu_gdb_adjust_breakpoint;
-    cc->gdb_num_core_regs = 35;
     cc->gdb_core_xml_file = "avr-cpu.xml";
     cc->tcg_ops = &avr_tcg_ops;
 }
diff --git a/target/hexagon/cpu.c b/target/hexagon/cpu.c
index 60d52e1e9d..7c1426f70c 100644
--- a/target/hexagon/cpu.c
+++ b/target/hexagon/cpu.c
@@ -385,7 +385,6 @@ static void hexagon_cpu_class_init(ObjectClass *c, void *data)
     cc->get_pc = hexagon_cpu_get_pc;
     cc->gdb_read_register = hexagon_gdb_read_register;
     cc->gdb_write_register = hexagon_gdb_write_register;
-    cc->gdb_num_core_regs = TOTAL_PER_THREAD_REGS;
     cc->gdb_stop_before_watchpoint = true;
     cc->gdb_core_xml_file = "hexagon-core.xml";
     cc->disas_set_info = hexagon_cpu_disas_set_info;
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 3aab05ddad..fa63ce9311 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -7968,10 +7968,8 @@ static void x86_cpu_common_class_init(ObjectClass *oc, void *data)
     cc->gdb_arch_name = x86_gdb_arch_name;
 #ifdef TARGET_X86_64
     cc->gdb_core_xml_file = "i386-64bit.xml";
-    cc->gdb_num_core_regs = 66;
 #else
     cc->gdb_core_xml_file = "i386-32bit.xml";
-    cc->gdb_num_core_regs = 50;
 #endif
     cc->disas_set_info = x86_disas_set_info;
 
diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index ef1bf89dac..1b25920895 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -775,7 +775,6 @@ static void loongarch32_cpu_class_init(ObjectClass *c, void *data)
 {
     CPUClass *cc = CPU_CLASS(c);
 
-    cc->gdb_num_core_regs = 35;
     cc->gdb_core_xml_file = "loongarch-base32.xml";
     cc->gdb_arch_name = loongarch32_gdb_arch_name;
 }
@@ -789,7 +788,6 @@ static void loongarch64_cpu_class_init(ObjectClass *c, void *data)
 {
     CPUClass *cc = CPU_CLASS(c);
 
-    cc->gdb_num_core_regs = 35;
     cc->gdb_core_xml_file = "loongarch-base64.xml";
     cc->gdb_arch_name = loongarch64_gdb_arch_name;
 }
diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
index 538d9473c2..5fdbe5602b 100644
--- a/target/m68k/cpu.c
+++ b/target/m68k/cpu.c
@@ -565,7 +565,6 @@ static void m68k_cpu_class_init(ObjectClass *c, void *data)
 #endif
     cc->disas_set_info = m68k_cpu_disas_set_info;
 
-    cc->gdb_num_core_regs = 18;
     cc->tcg_ops = &m68k_tcg_ops;
 }
 
diff --git a/target/microblaze/cpu.c b/target/microblaze/cpu.c
index 1998f69828..9d3fbfe159 100644
--- a/target/microblaze/cpu.c
+++ b/target/microblaze/cpu.c
@@ -428,7 +428,6 @@ static void mb_cpu_class_init(ObjectClass *oc, void *data)
     cc->sysemu_ops = &mb_sysemu_ops;
 #endif
     device_class_set_props(dc, mb_properties);
-    cc->gdb_num_core_regs = 32 + 25;
     cc->gdb_core_xml_file = "microblaze-core.xml";
 
     cc->disas_set_info = mb_disas_set_info;
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 5e083b5798..3ee1e6ae03 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -1586,7 +1586,6 @@ static void riscv_cpu_common_class_init(ObjectClass *c, void *data)
     cc->get_pc = riscv_cpu_get_pc;
     cc->gdb_read_register = riscv_cpu_gdb_read_register;
     cc->gdb_write_register = riscv_cpu_gdb_write_register;
-    cc->gdb_num_core_regs = 33;
     cc->gdb_stop_before_watchpoint = true;
     cc->disas_set_info = riscv_cpu_disas_set_info;
 #ifndef CONFIG_USER_ONLY
diff --git a/target/rx/cpu.c b/target/rx/cpu.c
index 4d0d3a0c8c..7b9e46d1bc 100644
--- a/target/rx/cpu.c
+++ b/target/rx/cpu.c
@@ -235,7 +235,6 @@ static void rx_cpu_class_init(ObjectClass *klass, void *data)
     cc->gdb_write_register = rx_cpu_gdb_write_register;
     cc->disas_set_info = rx_cpu_disas_set_info;
 
-    cc->gdb_num_core_regs = 26;
     cc->gdb_core_xml_file = "rx-core.xml";
     cc->tcg_ops = &rx_tcg_ops;
 }
diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index 6093ab0a12..f49ee0bb46 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -346,7 +346,6 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     s390_cpu_class_init_sysemu(cc);
 #endif
     cc->disas_set_info = s390_cpu_disas_set_info;
-    cc->gdb_num_core_regs = S390_NUM_CORE_REGS;
     cc->gdb_core_xml_file = "s390x-core64.xml";
     cc->gdb_arch_name = s390_gdb_arch_name;
 
