KVM: introduce gfn_to_pfn_memslot

Which takes a memslot pointer instead of using kvm->memslots.

To be used by SRCU convertion later.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

include/linux/kvm_host.h

@@ -273,6 +273,8 @@ void kvm_set_page_dirty(struct page *page);
 void kvm_set_page_accessed(struct page *page);
 
 pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);
+pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
+			 struct kvm_memory_slot *slot, gfn_t gfn);
 void kvm_release_pfn_dirty(pfn_t);
 void kvm_release_pfn_clean(pfn_t pfn);
 void kvm_set_pfn_dirty(pfn_t pfn);