arm: KVM: Allow an exit code to be tagged with a Virtual Abort

An asynchronous abort can also be triggered whilst running at EL2.
But instead of making that a new error code, we need to communicate
it to the rest of KVM together with the exit reason.
So let's hijack a single bit that allows the exception code to be
tagged with a "pending Abort" information.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NChristoffer Dall <christoffer.dall@linaro.org>

arch/arm/include/asm/kvm_asm.h

@@ -21,6 +21,10 @@
 
 #include <asm/virt.h>
 
+#define ARM_EXIT_WITH_ABORT_BIT  31
+#define ARM_EXCEPTION_CODE(x)	  ((x) & ~(1U << ARM_EXIT_WITH_ABORT_BIT))
+#define ARM_ABORT_PENDING(x)	  !!((x) & (1U << ARM_EXIT_WITH_ABORT_BIT))
+
 #define ARM_EXCEPTION_RESET	  0
 #define ARM_EXCEPTION_UNDEFINED   1
 #define ARM_EXCEPTION_SOFTWARE    2