target/arm: Correctly implement handling of HCR_EL2.{VI, VF}

In commit 8a0fc3a29fc2315325400 we tried to implement HCR_EL2.{VI,VF},
but we got it wrong and had to revert it.

In that commit we implemented them as simply tracking whether there
is a pending virtual IRQ or virtual FIQ. This is not correct -- these
bits cause a software-generated VIRQ/VFIQ, which is distinct from
whether there is a hardware-generated VIRQ/VFIQ caused by the
external interrupt controller. So we need to track separately
the HCR_EL2 bit state and the external virq/vfiq line state, and
OR the two together to get the actual pending VIRQ/VFIQ state.

Fixes: 8a0fc3a29fc2315325400c738f807d0d4ae0ab7f
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20181109134731.11605-4-peter.maydell@linaro.org
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 6c2bb2d..a32d359 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -871,4 +871,22 @@
     return cpu_mode_names[psr & 0xf];
 }
 
+/**
+ * arm_cpu_update_virq: Update CPU_INTERRUPT_VIRQ bit in cs->interrupt_request
+ *
+ * Update the CPU_INTERRUPT_VIRQ bit in cs->interrupt_request, following
+ * a change to either the input VIRQ line from the GIC or the HCR_EL2.VI bit.
+ * Must be called with the iothread lock held.
+ */
+void arm_cpu_update_virq(ARMCPU *cpu);
+
+/**
+ * arm_cpu_update_vfiq: Update CPU_INTERRUPT_VFIQ bit in cs->interrupt_request
+ *
+ * Update the CPU_INTERRUPT_VFIQ bit in cs->interrupt_request, following
+ * a change to either the input VFIQ line from the GIC or the HCR_EL2.VF bit.
+ * Must be called with the iothread lock held.
+ */
+void arm_cpu_update_vfiq(ARMCPU *cpu);
+
 #endif