KVM: arm64: Rewrite sysreg alternatives to static keys

As we are about to move calls around in the sysreg save/restore logic,
let's first rewrite the alternative function callers, because it is
going to make the next patches much easier to read.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm64/kvm/hyp/sysreg-sr.c

@@ -22,9 +22,6 @@
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 
-/* Yes, this does nothing, on purpose */
-static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { }
-
 /*
  * Non-VHE: Both host and guest must save everything.
  *
@@ -81,13 +78,10 @@ static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
 		ctxt->sys_regs[DISR_EL1] = read_sysreg_s(SYS_VDISR_EL2);
 }
 
-static hyp_alternate_select(__sysreg_call_save_host_state,
-			    __sysreg_save_el1_state, __sysreg_do_nothing,
-			    ARM64_HAS_VIRT_HOST_EXTN);
-
 void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
 {
-	__sysreg_call_save_host_state()(ctxt);
+	if (!has_vhe())
+		__sysreg_save_el1_state(ctxt);
 	__sysreg_save_common_state(ctxt);
 	__sysreg_save_user_state(ctxt);
 }
@@ -148,13 +142,10 @@ static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
 		write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);
 }
 
-static hyp_alternate_select(__sysreg_call_restore_host_state,
-			    __sysreg_restore_el1_state, __sysreg_do_nothing,
-			    ARM64_HAS_VIRT_HOST_EXTN);
-
 void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
 {
-	__sysreg_call_restore_host_state()(ctxt);
+	if (!has_vhe())
+		__sysreg_restore_el1_state(ctxt);
 	__sysreg_restore_common_state(ctxt);
 	__sysreg_restore_user_state(ctxt);
 }