Subject: [PATCH v3] KVM: Move gfn_to_memslot() to kvm_host.h

From: Paul Mackerras <[email-masked]>
Date: Fri, 13 Jan 2012 17:09:51 +1100

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 <[email-masked]>
---
v3: Add comment, change kvm_gfn_to_hva_cache_init as requested.

 arch/powerpc/kvm/book3s_hv_rm_mmu.c |   23 ++---------------------
 include/linux/kvm_host.h            |   25 +++++++++++++++++++++++++
 virt/kvm/kvm_main.c                 |   21 +--------------------
 3 files changed, 28 insertions(+), 41 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index d3e36fc..9055cd2 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)
 {
@@ -97,7 +78,7 @@ static void remove_revmap_chain(struct kvm *kvm, long pte_index,
 	rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
 	ptel = rev->guest_rpte;
 	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;
 
@@ -171,7 +152,7 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
 	/* 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;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ec79a45..688f37b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -649,6 +649,31 @@ static inline void kvm_guest_exit(void)
 	current->flags &= ~PF_VCPU;
 }
 
+/*
+ * search_memslots() and __gfn_to_memslot() are here because they are
+ * used in non-modular code in arch/powerpc/kvm/book3s_hv_rm_mmu.c.
+ * gfn_to_memslot() itself isn't here as an inline because that would
+ * bloat other code too much.
+ */
+static inline struct kvm_memory_slot *
+search_memslots(struct kvm_memslots *slots, gfn_t gfn)
+{
+	struct kvm_memory_slot *memslot;
+
+	kvm_for_each_memslot(memslot, slots)
+		if (gfn >= memslot->base_gfn &&
+		      gfn < memslot->base_gfn + memslot->npages)
+			return memslot;
+
+	return NULL;
+}
+
+static inline struct kvm_memory_slot *
+__gfn_to_memslot(struct kvm_memslots *slots, gfn_t gfn)
+{
+	return search_memslots(slots, gfn);
+}
+
 static inline int memslot_id(struct kvm *kvm, gfn_t gfn)
 {
 	return gfn_to_memslot(kvm, gfn)->id;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c144132..8ae6b76 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -640,19 +640,6 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
 }
 #endif /* !CONFIG_S390 */
 
-static struct kvm_memory_slot *
-search_memslots(struct kvm_memslots *slots, gfn_t gfn)
-{
-	struct kvm_memory_slot *memslot;
-
-	kvm_for_each_memslot(memslot, slots)
-		if (gfn >= memslot->base_gfn &&
-		      gfn < memslot->base_gfn + memslot->npages)
-			return memslot;
-
-	return NULL;
-}
-
 static int cmp_memslot(const void *slot1, const void *slot2)
 {
 	struct kvm_memory_slot *s1, *s2;
@@ -1031,12 +1018,6 @@ int kvm_is_error_hva(unsigned long addr)
 }
 EXPORT_SYMBOL_GPL(kvm_is_error_hva);
 
-static struct kvm_memory_slot *__gfn_to_memslot(struct kvm_memslots *slots,
-						gfn_t gfn)
-{
-	return search_memslots(slots, gfn);
-}
-
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
 {
 	return __gfn_to_memslot(kvm_memslots(kvm), gfn);
@@ -1459,7 +1440,7 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
 
 	ghc->gpa = gpa;
 	ghc->generation = slots->generation;
-	ghc->memslot = __gfn_to_memslot(slots, gfn);
+	ghc->memslot = gfn_to_memslot(kvm, gfn);
 	ghc->hva = gfn_to_hva_many(ghc->memslot, gfn, NULL);
 	if (!kvm_is_error_hva(ghc->hva))
 		ghc->hva += offset;
-- 
1.7.5.4