KVM: Move gfn_to_memslot() to kvm_host.h

This moves __gfn_to_memslot() and search_memslots() from kvm_main.c to
kvm_host.h to reduce the code duplication caused by the need for
non-modular code in arch/powerpc/kvm/book3s_hv_rm_mmu.c to call
gfn_to_memslot() in real mode.

Rather than putting gfn_to_memslot() itself in a header, which would
lead to increased code size, this puts __gfn_to_memslot() in a header.
Then, the non-modular uses of gfn_to_memslot() are changed to call
__gfn_to_memslot() instead.  This way there is only one place in the
source code that needs to be changed should the gfn_to_memslot()
implementation need to be modified.

On powerpc, the Book3S HV style of KVM has code that is called from
real mode which needs to call gfn_to_memslot() and thus needs this.
(Module code is allocated in the vmalloc region, which can't be
accessed in real mode.)

With this, we can remove builtin_gfn_to_memslot() from book3s_hv_rm_mmu.c.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 5f3c60b..def880a 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -21,25 +21,6 @@
 #include <asm/synch.h>
 #include <asm/ppc-opcode.h>
 
-/*
- * Since this file is built in even if KVM is a module, we need
- * a local copy of this function for the case where kvm_main.c is
- * modular.
- */
-static struct kvm_memory_slot *builtin_gfn_to_memslot(struct kvm *kvm,
-						gfn_t gfn)
-{
-	struct kvm_memslots *slots;
-	struct kvm_memory_slot *memslot;
-
-	slots = kvm_memslots(kvm);
-	kvm_for_each_memslot(memslot, slots)
-		if (gfn >= memslot->base_gfn &&
-		      gfn < memslot->base_gfn + memslot->npages)
-			return memslot;
-	return NULL;
-}
-
 /* Translate address of a vmalloc'd thing to a linear map address */
 static void *real_vmalloc_addr(void *x)
 {
@@ -99,7 +80,7 @@
 	rcbits = hpte_r & (HPTE_R_R | HPTE_R_C);
 	ptel = rev->guest_rpte |= rcbits;
 	gfn = hpte_rpn(ptel, hpte_page_size(hpte_v, ptel));
-	memslot = builtin_gfn_to_memslot(kvm, gfn);
+	memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
 	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
 		return;
 
@@ -181,7 +162,7 @@
 	/* Find the memslot (if any) for this address */
 	gpa = (ptel & HPTE_R_RPN) & ~(psize - 1);
 	gfn = gpa >> PAGE_SHIFT;
-	memslot = builtin_gfn_to_memslot(kvm, gfn);
+	memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
 	pa = 0;
 	is_io = ~0ul;
 	rmap = NULL;