[Qemu-arm] [PATCH v1 2/2] target/arm: defer setting up of aarch64 gdb until arm_cpu_realize

[Alex Bennée]

If we setup earlier we miss the parsing of the aarch64 state of the
CPU. If the user has booted up with:

  qemu-system-aarch64 -cpu host,aarch64=off -enable-kvm

we end up presenting an aarch64 view of the world via the gdbstub and
hilarity ensues.

Reported-by: Ard Biesheuvel <address@hidden>
Signed-off-by: Alex Bennée <address@hidden>
Cc: Omair Javaid <address@hidden>
---
 include/hw/arm/arm.h |  2 ++
 target/arm/cpu.c     |  4 ++++
 target/arm/cpu64.c   | 20 +++++++++++++++-----
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/include/hw/arm/arm.h b/include/hw/arm/arm.h
index ffed39252d..f9a7a6e2fb 100644
--- a/include/hw/arm/arm.h
+++ b/include/hw/arm/arm.h
@@ -171,4 +171,6 @@ void arm_write_secure_board_setup_dummy_smc(ARMCPU *cpu,
    ticks.  */
 extern int system_clock_scale;
 
+void arm_cpu_enable_aarch64_gdbstub(CPUClass *cc);
+
 #endif /* HW_ARM_H */
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 60411f6bfe..100a72ff81 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -890,9 +890,13 @@ static void arm_cpu_realizefn(DeviceState *dev, Error 
**errp)
      * queries ID_ISAR0_EL1 on such a host, the value is UNKNOWN.
      * Similarly, we cannot check ID_AA64PFR0 without AArch64 support.
      */
+#ifdef TARGET_AARCH64
     if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
+        CPUClass *cc = CPU_GET_CLASS(cs);
         no_aa32 = !cpu_isar_feature(aa64_aa32, cpu);
+        arm_cpu_enable_aarch64_gdbstub(cc);
     }
+#endif
 
     if (arm_feature(env, ARM_FEATURE_V7VE)) {
         /* v7 Virtualization Extensions. In real hardware this implies
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 873f059bf2..53cde60557 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -434,12 +434,14 @@ static gchar *aarch64_gdb_arch_name(CPUState *cs)
     return g_strdup("aarch64");
 }
 
-static void aarch64_cpu_class_init(ObjectClass *oc, void *data)
-{
-    CPUClass *cc = CPU_CLASS(oc);
+/*
+ * We can only setup aarch64 gdb support once we realize the CPU
+ * object and know what mode it has been booted in. This is called
+ * from arm_cpu_realize.
+ */
 
-    cc->cpu_exec_interrupt = arm_cpu_exec_interrupt;
-    cc->set_pc = aarch64_cpu_set_pc;
+void arm_cpu_enable_aarch64_gdbstub(CPUClass *cc)
+{
     cc->gdb_read_register = aarch64_cpu_gdb_read_register;
     cc->gdb_write_register = aarch64_cpu_gdb_write_register;
     cc->gdb_num_core_regs = 34;
@@ -447,6 +449,14 @@ static void aarch64_cpu_class_init(ObjectClass *oc, void 
*data)
     cc->gdb_arch_name = aarch64_gdb_arch_name;
 }
 
+static void aarch64_cpu_class_init(ObjectClass *oc, void *data)
+{
+    CPUClass *cc = CPU_CLASS(oc);
+
+    cc->cpu_exec_interrupt = arm_cpu_exec_interrupt;
+    cc->set_pc = aarch64_cpu_set_pc;
+}
+
 static void aarch64_cpu_register(const ARMCPUInfo *info)
 {
     TypeInfo type_info = {
-- 
2.17.1