KVM: arm64: Re-jig logic when patching hardened hyp vectors

The hardened hyp vectors are not used on systems running with VHE or CPUs
without the ARM64_HARDEN_EL2_VECTORS capability.

Re-jig the checking logic slightly in kvm_patch_vector_branch() so that
it's a bit clearer what we're looking for. This is purely cosmetic.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-7-will@kernel.org

arch/arm64/kvm/va_layout.c

@@ -139,8 +139,8 @@ void kvm_patch_vector_branch(struct alt_instr *alt,
 
 	BUG_ON(nr_inst != 5);
 
-	if (has_vhe() || !cpus_have_const_cap(ARM64_HARDEN_EL2_VECTORS)) {
-		WARN_ON_ONCE(cpus_have_const_cap(ARM64_HARDEN_EL2_VECTORS));
+	if (!cpus_have_const_cap(ARM64_HARDEN_EL2_VECTORS) ||
+	    WARN_ON_ONCE(has_vhe())) {
 		return;
 	}