Add rdmsr/wrmsr to io.cpp

src/kernel/io.h

@@ -14,6 +14,16 @@ uint8_t inb(uint16_t port);
 /// \arg val   The byte to write
 void outb(uint16_t port, uint8_t val);
 
+/// Read the value of a MSR
+/// \arg addr   The MSR address
+/// \returns    The current value of the MSR
+uint64_t rdmsr(uint64_t addr);
+
+/// Write to a MSR
+/// \arg addr   The MSR address
+/// \arg value  The value to write
+void wrmsr(uint64_t addr, uint64_t value);
+
 }
 
 const uint16_t COM1 = 0x03f8;