Reserve physical page

Hello everyone, I am wondering whether it is possible to reserve a particular physical page in the kernel. The GFP pages can start from _any_ location, and i cannot find a way to specify a starting pfn. I need a few dozen pages to store a bitmap starting at a particular physical page frame number. Perhaps i am trying to do this wrong? I am trying to establish a (one-way) communication between KVM and a guest VM, by assuming that if KVM knows the physical address in the VM , it can access that bitmap. Thanks !