KVM: Remove memory alias support

As advertised in feature-removal-schedule.txt.  Equivalent support is provided
by overlapping memory regions.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 6fd40f5..636fc38 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -619,6 +619,7 @@
  */
 #define KVM_CREATE_VCPU           _IO(KVMIO,   0x41)
 #define KVM_GET_DIRTY_LOG         _IOW(KVMIO,  0x42, struct kvm_dirty_log)
+/* KVM_SET_MEMORY_ALIAS is obsolete: */
 #define KVM_SET_MEMORY_ALIAS      _IOW(KVMIO,  0x43, struct kvm_memory_alias)
 #define KVM_SET_NR_MMU_PAGES      _IO(KVMIO,   0x44)
 #define KVM_GET_NR_MMU_PAGES      _IO(KVMIO,   0x45)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 2d96555..240e460 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -286,8 +286,6 @@
 				int user_alloc);
 void kvm_disable_largepages(void);
 void kvm_arch_flush_shadow(struct kvm *kvm);
-gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);
-gfn_t unalias_gfn_instantiation(struct kvm *kvm, gfn_t gfn);
 
 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
 unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
@@ -564,10 +562,6 @@
 }
 #endif
 
-#ifndef KVM_ARCH_HAS_UNALIAS_INSTANTIATION
-#define unalias_gfn_instantiation unalias_gfn
-#endif
-
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
 
 #define KVM_MAX_IRQ_ROUTES 1024