[Qemu-devel] [PATCH v6 17/19] target-arm: helpers which may affect global state need the BQL

["Alex Bennée" <alex.bennee@linaro.org>]

As the arm_call_el_change_hook may affect global state (for example with
updating the global GIC state) we need to assert/take the BQL.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 target-arm/helper.c    | 6 ++++++
 target-arm/op_helper.c | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/target-arm/helper.c b/target-arm/helper.c
index b5b65ca..3f47fa7 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -6669,6 +6669,12 @@ void arm_cpu_do_interrupt(CPUState *cs)
         arm_cpu_do_interrupt_aarch32(cs);
     }
 
+    /* Hooks may change global state so BQL should be held, also the
+     * BQL needs to be held for any modification of
+     * cs->interrupt_request.
+     */
+    g_assert(qemu_mutex_iothread_locked());
+
     arm_call_el_change_hook(cpu);
 
     if (!kvm_enabled()) {
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index 4f0c754..41beabc 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -487,7 +487,9 @@ void HELPER(cpsr_write_eret)(CPUARMState *env, uint32_t val)
      */
     env->regs[15] &= (env->thumb ? ~1 : ~3);
 
+    qemu_mutex_lock_iothread();
     arm_call_el_change_hook(arm_env_get_cpu(env));
+    qemu_mutex_unlock_iothread();
 }
 
 /* Access to user mode registers from privileged modes.  */
@@ -1013,7 +1015,9 @@ void HELPER(exception_return)(CPUARMState *env)
         env->pc = env->elr_el[cur_el];
     }
 
+    qemu_mutex_lock_iothread();
     arm_call_el_change_hook(arm_env_get_cpu(env));
+    qemu_mutex_unlock_iothread();
 
     return;
 
-- 
2.10.1