Enhance comment informative

Author: ranvd

main.c

@@ -286,7 +286,7 @@ static inline sbi_ret_t handle_sbi_ecall_IPI(hart_t *hart, int32_t fid)
 
 static inline sbi_ret_t handle_sbi_ecall_RFENCE(hart_t *hart, int32_t fid)
 {
-    /* TODO */
+    /* TODO: RFENCE SBI extension */
     uint64_t hart_mask, hart_mask_base;
     switch (fid) {
     case 0:

minimal.dts

@@ -1,5 +1,8 @@
 /dts-v1/;
 
+/*
+ * RISC-V harts descriptions
+ */ 
 #include "riscv-harts.dtsi"
 
 / {

riscv.h

@@ -123,7 +123,10 @@ struct __hart_internal {
      */
     uint32_t *(*mem_page_table)(const hart_t *vm, uint32_t ppn);
 
-    /* Point to the belonged vm_t */
+    /* Point to the associated vm_t for better access to other harts. For
+     * example, if hart 0 needs to send an IPI to hart 1, the IPI signal can be
+     * sent to hart 1 through the *vm pointer.
+     */
     vm_t *vm;
     int32_t hsm_status;
     bool hsm_resume_is_ret;