Add with_value_of and with_value to MSR

kernel/include/misc/MSR.h

@@ -13,6 +13,9 @@ struct MSR
     static void write_to(uint32_t msr_num, uint64_t value);
     static uint64_t read_from(uint32_t msr_num);
 
+    static void with_value_of(uint32_t msr_num, void (*callback)(uint64_t&));
+    void with_value(void (*callback)(uint64_t&));
+
   private:
     uint32_t m_msr_num;
 };

kernel/src/misc/MSR.cpp

@@ -28,3 +28,18 @@ uint64_t MSR::read()
 MSR::MSR(uint32_t msr_num) : m_msr_num(msr_num)
 {
 }
+
+void MSR::with_value_of(uint32_t msr_num, void (*callback)(uint64_t&))
+{
+    MSR msr(msr_num);
+    uint64_t value = msr.read();
+    callback(value);
+    msr.write(value);
+}
+
+void MSR::with_value(void (*callback)(uint64_t&))
+{
+    uint64_t value = read();
+    callback(value);
+    write(value);
+}