KVM: Portability: Move memslot aliases to new struct kvm_arch

This patches create kvm_arch to hold arch-specific kvm fileds
and moves fields naliases and aliases to kvm_arch.

Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/x86.h b/drivers/kvm/x86.h
index 4ca8485..be84f2b 100644
--- a/drivers/kvm/x86.h
+++ b/drivers/kvm/x86.h
@@ -54,6 +54,8 @@
 
 #define IOPL_SHIFT 12
 
+#define KVM_ALIAS_SLOTS 4
+
 #define KVM_PERMILLE_MMU_PAGES 20
 #define KVM_MIN_ALLOC_MMU_PAGES 64
 #define KVM_NUM_MMU_PAGES 1024
@@ -255,6 +257,17 @@
 	struct x86_emulate_ctxt emulate_ctxt;
 };
 
+struct kvm_mem_alias {
+	gfn_t base_gfn;
+	unsigned long npages;
+	gfn_t target_gfn;
+};
+
+struct kvm_arch{
+	int naliases;
+	struct kvm_mem_alias aliases[KVM_ALIAS_SLOTS];
+};
+
 struct kvm_vcpu_stat {
 	u32 pf_fixed;
 	u32 pf_guest;