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.c b/drivers/kvm/x86.c
index 60f9722..7e1bd52 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -1191,8 +1191,8 @@
 	int i;
 	struct kvm_mem_alias *alias;
 
-	for (i = 0; i < kvm->naliases; ++i) {
-		alias = &kvm->aliases[i];
+	for (i = 0; i < kvm->arch.naliases; ++i) {
+		alias = &kvm->arch.aliases[i];
 		if (gfn >= alias->base_gfn
 		    && gfn < alias->base_gfn + alias->npages)
 			return alias->target_gfn + gfn - alias->base_gfn;
@@ -1228,15 +1228,15 @@
 
 	mutex_lock(&kvm->lock);
 
-	p = &kvm->aliases[alias->slot];
+	p = &kvm->arch.aliases[alias->slot];
 	p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
 	p->npages = alias->memory_size >> PAGE_SHIFT;
 	p->target_gfn = alias->target_phys_addr >> PAGE_SHIFT;
 
 	for (n = KVM_ALIAS_SLOTS; n > 0; --n)
-		if (kvm->aliases[n - 1].npages)
+		if (kvm->arch.aliases[n - 1].npages)
 			break;
-	kvm->naliases = n;
+	kvm->arch.naliases = n;
 
 	kvm_mmu_zap_all(kvm);