KVM/MIPS32: KVM Guest kernel support.

Both Guest kernel and Guest Userspace execute in UM. The memory map is as follows:
Guest User address space:   0x00000000 -> 0x40000000
Guest Kernel Unmapped:      0x40000000 -> 0x60000000
Guest Kernel Mapped:        0x60000000 -> 0x80000000
- Guest Usermode virtual memory is limited to 1GB.

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/cevt-r4k.c

@@ -118,6 +118,10 @@ int c0_compare_int_usable(void)
 	unsigned int delta;
 	unsigned int cnt;
 
+#ifdef CONFIG_KVM_GUEST
+    return 1;
+#endif
+
 	/*
 	 * IP7 already pending?	 Try to clear it by acking the timer.
 	 */