ANDROID: KVM: arm64: FAR_EL2 mask as a define

Create a macro definition for the FAR_EL2 mask and use it instead
of a hard-coded value, and put it in a share header to be used by
hyp.

No functional change intended.

Bug: 357781595
Change-Id: Ib83932d670cba6bf8f1ed45d2c0e1ed34331d98d
Signed-off-by: Fuad Tabba <tabba@google.com>

arch/arm64/include/asm/kvm_arm.h

@@ -406,6 +406,8 @@
 #define PAR_TO_HPFAR(par)		\
 	(((par) & GENMASK_ULL(52 - 1, 12)) >> 8)
 
+#define FAR_MASK GENMASK_ULL(11, 0)
+
 #define ECN(x) { ESR_ELx_EC_##x, #x }
 
 #define kvm_arm_exception_class \

arch/arm64/kvm/mmu.c

@@ -1999,7 +1999,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		 * faulting VA. This is always 12 bits, irrespective
 		 * of the page size.
 		 */
-		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
+		ipa |= kvm_vcpu_get_hfar(vcpu) & FAR_MASK;
 		ret = io_mem_abort(vcpu, ipa);
 		goto out_unlock;
 	}