Wrote some simple MSR code

src/x86/msr.c

@@ -0,0 +1,17 @@
+#include "msr.h"
+
+void read_msr(enum msr_id_t msr_addr, uint64_t *value)
+{
+    uint64_t v;
+    asm volatile("rdmsr"
+        : "=edx:eax" (v)
+        : "ecx" (msr_addr));
+    *value = v;
+}
+
+void write_msr(enum msr_id_t msr_addr, uint64_t *value)
+{
+    uint64_t v = *value;
+    asm volatile("wrmsr"
+        :: "ecx"(msr_addr), "A"(v));
+}