Kernel: Pull apart CPU.h

This does not add any functional changes

Kernel/Arch/x86/MSR.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+#include <Kernel/Arch/x86/CPUID.h>
+
+namespace Kernel {
+
+class MSR {
+    uint32_t m_msr;
+
+public:
+    static bool have()
+    {
+        CPUID id(1);
+        return (id.edx() & (1 << 5)) != 0;
+    }
+
+    MSR(const MSR&) = delete;
+    MSR& operator=(const MSR&) = delete;
+
+    MSR(uint32_t msr)
+        : m_msr(msr)
+    {
+    }
+
+    void get(u32& low, u32& high)
+    {
+        asm volatile("rdmsr"
+                     : "=a"(low), "=d"(high)
+                     : "c"(m_msr));
+    }
+
+    void set(u32 low, u32 high)
+    {
+        asm volatile("wrmsr" ::"a"(low), "d"(high), "c"(m_msr));
+    }
+};
+
+}