target/arm: kvm: Handle misconfigured dabt injection

target/arm: kvm: Handle misconfigured dabt injection

Injecting external data abort through KVM might trigger
an issue on kernels that do not get updated to include the KVM fix.
For those and aarch32 guests, the injected abort gets misconfigured
to be an implementation defined exception. This leads to the guest
repeatedly re-running the faulting instruction.

Add support for handling that case.

[
  Fixed-by: 018f22f95e8a
	('KVM: arm: Fix DFSR setting for non-LPAE aarch32 guests')
  Fixed-by: 21aecdbd7f3a
	('KVM: arm: Make inject_abt32() inject an external abort instead')
]

Signed-off-by: Beata Michalska <beata.michalska@linaro.org>
Acked-by: Andrew Jones <drjones@redhat.com>
Message-id: 20200629114110.30723-3-beata.michalska@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>