arm64: hyp/kvm: Make hyp-stub reject kvm_call_hyp()
A later patch implements kvm_arch_hardware_disable(), to remove kvm
from el2, and re-instate the hyp-stub.
This can happen while guests are running, particularly when kvm_reboot()
calls kvm_arch_hardware_disable() on each cpu. This can interrupt a guest,
remove kvm, then allow the guest to be scheduled again. This causes
kvm_call_hyp() to be run against the hyp-stub.
Change the hyp-stub to return a new exception type when this happens,
and add code to kvm's handle_exit() to tell userspace we failed to
enter the guest.
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index eb7490d..dbfbc5f 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -22,6 +22,8 @@
#define ARM_EXCEPTION_IRQ 0
#define ARM_EXCEPTION_TRAP 1
+/* The hyp-stub will return this for any kvm_call_hyp() call */
+#define ARM_EXCEPTION_HYP_GONE 2
#define KVM_ARM64_DEBUG_DIRTY_SHIFT 0
#define KVM_ARM64_DEBUG_DIRTY (1 << KVM_ARM64_DEBUG_DIRTY_SHIFT)