xen/riscv: implement sync_vcpu_execstate()

The scheduler may call this function to force synchronization of given
vCPU's state. RISC-V does not support lazy context switching, so nothing
is done in sync_vcpu_execstate() and sync_local_execstate().

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/riscv/domain.c

@@ -278,6 +278,16 @@ void vcpu_kick(struct vcpu *v)
     }
 }
 
+void sync_local_execstate(void)
+{
+    /* Nothing to do -- no lazy switching */
+}
+
+void sync_vcpu_execstate(struct vcpu *v)
+{
+    /* Nothing to do -- no lazy switching */
+}
+
 static void __init __maybe_unused build_assertions(void)
 {
     /*

xen/arch/riscv/stubs.c

@@ -91,16 +91,6 @@ void continue_running(struct vcpu *same)
     BUG_ON("unimplemented");
 }
 
-void sync_local_execstate(void)
-{
-    BUG_ON("unimplemented");
-}
-
-void sync_vcpu_execstate(struct vcpu *v)
-{
-    BUG_ON("unimplemented");
-}
-
 void startup_cpu_idle_loop(void)
 {
     BUG_ON("unimplemented");