feat(inc/hypercall): add generic hypercall get/set argument methods

This commit introduces two methods for setting and retrieving hypercall
arguments, allowing each hypercall implementation to flexibly manage its
specific arguments as needed.

Signed-off-by: João Peixoto <[email protected]>

Author: joaopeixoto13

src/core/hypercall.c

@@ -4,21 +4,14 @@
  */
 
 #include <hypercall.h>
-#include <cpu.h>
-#include <vm.h>
-#include <ipc.h>
 
 long int hypercall(unsigned long id)
 {
     long int ret = -HC_E_INVAL_ID;
 
-    unsigned long arg0 = vcpu_readreg(cpu()->vcpu, HYPCALL_IN_ARG_REG(0));
-    unsigned long arg1 = vcpu_readreg(cpu()->vcpu, HYPCALL_IN_ARG_REG(1));
-    unsigned long arg2 = vcpu_readreg(cpu()->vcpu, HYPCALL_IN_ARG_REG(2));
-
     switch (id) {
         case HC_IPC:
-            ret = ipc_hypercall(arg0, arg1, arg2);
+            ret = ipc_hypercall();
             break;
         default:
             WARNING("Unknown hypercall id %d", id);

src/core/inc/hypercall.h

@@ -8,14 +8,24 @@
 
 #include <bao.h>
 #include <arch/hypercall.h>
+#include <vm.h>
 
 enum { HC_INVAL = 0, HC_IPC = 1 };
 
 enum { HC_E_SUCCESS = 0, HC_E_FAILURE = 1, HC_E_INVAL_ID = 2, HC_E_INVAL_ARGS = 3 };
 
-typedef unsigned long (*hypercall_handler)(unsigned long arg0, unsigned long arg1,
-    unsigned long arg2);
+typedef unsigned long (*hypercall_handler)(void);
 
 long int hypercall(unsigned long id);
 
+static inline unsigned long hypercall_get_arg(struct vcpu* vcpu, size_t arg_index)
+{
+    return vcpu_readreg(vcpu, HYPCALL_IN_ARG_REG(arg_index));
+}
+
+static inline void hypercall_set_ret(struct vcpu* vcpu, size_t arg_index, unsigned long arg_val)
+{
+    vcpu_writereg(vcpu, HYPCALL_OUT_ARG_REG(arg_index), arg_val);
+}
+
 #endif /* HYPERCALL_H */

src/core/inc/ipc.h

@@ -19,7 +19,7 @@ struct ipc {
 
 struct vm_config;
 
-long int ipc_hypercall(unsigned long arg0, unsigned long arg1, unsigned long arg2);
+long int ipc_hypercall(void);
 void ipc_init(void);
 
 #endif /* IPC_H */

src/core/ipc.c

@@ -58,9 +58,10 @@ static void ipc_handler(uint32_t event, uint64_t data)
 }
 CPU_MSG_HANDLER(ipc_handler, IPC_CPUMSG_ID)
 
-long int ipc_hypercall(unsigned long ipc_id, unsigned long ipc_event, unsigned long arg2)
+long int ipc_hypercall(void)
 {
-    UNUSED_ARG(arg2);
+    unsigned long ipc_id = hypercall_get_arg(cpu()->vcpu, 0);
+    unsigned long ipc_event = hypercall_get_arg(cpu()->vcpu, 1);
 
     long int ret = -HC_E_SUCCESS;