[RFC PATCH 1/9] target/arm: Add API for dynamic exception injection

[Ruslan Ruslichenko <ruslichenko.r@gmail.com>]

From: Ruslan Ruslichenko <Ruslan_Ruslichenko@epam.com>

Implement arm_cpu_inject_exception() to allow external clients,
such as QEMU plugins or asynchronous timers, to inject exceptions
into the ARM guest.

Signed-off-by: Ruslan Ruslichenko <Ruslan_Ruslichenko@epam.com>
---
 target/arm/cpu.h    |  4 ++++
 target/arm/helper.c | 55 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 657ff4ab20..f1d2d6e240 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -2680,4 +2680,8 @@ extern const uint64_t pred_esz_masks[5];
 #define LOG2_TAG_GRANULE 4
 #define TAG_GRANULE      (1 << LOG2_TAG_GRANULE)
 
+#ifndef CONFIG_USER_ONLY
+void arm_cpu_inject_exception(int excp_index, uint32_t syndrome);
+#endif
+
 #endif
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 8c5769477c..73df3a9e6e 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -10241,4 +10241,59 @@ ARMSecuritySpace arm_security_space_below_el3(CPUARMState *env)
         return ARMSS_NonSecure;
     }
 }
+
+typedef struct {
+    int excp_index;
+    uint32_t syndrome;
+}  FIExcpAsync;
+
+static void fi_setup_exception(CPUState *cs, int excp_index, uint32_t syndrome)
+{
+    CPUARMState *env = cpu_env(cs);
+
+    cs->exception_index = excp_index;
+    env->exception.syndrome = syndrome;
+    env->exception.vaddress = env->pc;
+
+    if (excp_index == EXCP_VSERR) {
+        /* Serror syndrome constructed from vsesr_el2 */
+        env->cp15.vsesr_el2 = syndrome;
+    }
+
+    env->exception.target_el = arm_current_el(env);
+}
+
+static void arm_cpu_inject_exception_async(CPUState *cs, run_on_cpu_data data)
+{
+    FIExcpAsync *excp_data = (FIExcpAsync *)data.host_ptr;
+
+    fi_setup_exception(cs, excp_data->excp_index, excp_data->syndrome);
+
+    g_free(excp_data);
+}
+
+void arm_cpu_inject_exception(int excp_index, uint32_t syndrome)
+{
+    CPUState *cs = current_cpu;
+
+    if (!cs) {
+        /* If we called outside CPU thread (timer callback, etc) schedule async */
+        run_on_cpu_data async_data;
+        CPUState *cs0 = qemu_get_cpu(0);
+
+        FIExcpAsync *excp_data = g_new0(FIExcpAsync, 1);
+
+        excp_data->excp_index = excp_index;
+        excp_data->syndrome = syndrome;
+
+        async_data.host_ptr = excp_data;
+
+        async_run_on_cpu(cs0, arm_cpu_inject_exception_async, async_data);
+        return;
+    }
+
+    fi_setup_exception(cs, excp_index, syndrome);
+
+    cpu_loop_exit(cs);
+}
 #endif /* !CONFIG_USER_ONLY */
-- 
2.43.0