x86: KVM guest: add basic paravirt support

Add basic KVM paravirt support. Avoid vm-exits on IO delays.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 483047a..fa19c38 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -80,6 +80,7 @@
 obj-$(CONFIG_DEBUG_NX_TEST)	+= test_nx.o
 
 obj-$(CONFIG_VMI)		+= vmi_32.o vmiclock_32.o
+obj-$(CONFIG_KVM_GUEST)		+= kvm.o
 obj-$(CONFIG_KVM_CLOCK)		+= kvmclock.o
 obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt_patch_$(BITS).o