hypervisor: x86: Add an InstructionHandler interface

And an InstructionMap helper structure to map x86 mnemonic codes
to instruction handlers.

Any instruction emulation implementation should then boil down with
implementing InstructionHandler for any supported mnemonic.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

hypervisor/src/arch/x86/mod.rs

@@ -38,3 +38,28 @@ pub const MTRR_MEM_TYPE_WB: u64 = 0x6;
 
 // IOAPIC pins
 pub const NUM_IOAPIC_PINS: usize = 24;
+
+// X86 Exceptions
+#[allow(dead_code)]
+#[derive(Clone, Debug)]
+pub enum Exception {
+    DE = 1,  // Divide Error
+    DB = 2,  // Debug Exception
+    BP = 3,  // Breakpoint
+    OF = 4,  // Overflow
+    BR = 5,  // BOUND Range Exceeded
+    UD = 6,  // Invalid/Undefined Opcode
+    NM = 7,  // No Math Coprocessor
+    DF = 8,  // Double Fault
+    TS = 10, // Invalid TSS
+    NP = 11, // Segment Not Present
+    SS = 12, // Stack Segment Fault
+    GP = 13, // General Protection
+    PF = 14, // Page Fault
+    MF = 16, // Math Fault
+    AC = 17, // Alignment Check
+    MC = 18, // Machine Check
+    XM = 19, // SIMD Floating-Point Exception
+    VE = 20, // Virtualization Exception
+    CP = 21, // Control Protection Exception
+}