[PATCH v4 01/25] KVM: arm64: Move hyp refcount manipulation helpers to common header file

[Will Deacon <will@kernel.org>]

From: Quentin Perret <qperret@google.com>

We will soon need to manipulate 'struct hyp_page' refcounts from outside
page_alloc.c, so move the helpers to a common header file to allow them
to be reused easily.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kvm/hyp/include/nvhe/memory.h | 22 ++++++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/page_alloc.c     | 19 -------------------
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h
index 592b7edb3edb..9422900e5c6a 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/memory.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h
@@ -38,6 +38,10 @@ static inline phys_addr_t hyp_virt_to_phys(void *addr)
 #define hyp_page_to_virt(page)	__hyp_va(hyp_page_to_phys(page))
 #define hyp_page_to_pool(page)	(((struct hyp_page *)page)->pool)
 
+/*
+ * Refcounting for 'struct hyp_page'.
+ * hyp_pool::lock must be held if atomic access to the refcount is required.
+ */
 static inline int hyp_page_count(void *addr)
 {
 	struct hyp_page *p = hyp_virt_to_page(addr);
@@ -45,4 +49,22 @@ static inline int hyp_page_count(void *addr)
 	return p->refcount;
 }
 
+static inline void hyp_page_ref_inc(struct hyp_page *p)
+{
+	BUG_ON(p->refcount == USHRT_MAX);
+	p->refcount++;
+}
+
+static inline int hyp_page_ref_dec_and_test(struct hyp_page *p)
+{
+	BUG_ON(!p->refcount);
+	p->refcount--;
+	return (p->refcount == 0);
+}
+
+static inline void hyp_set_page_refcounted(struct hyp_page *p)
+{
+	BUG_ON(p->refcount);
+	p->refcount = 1;
+}
 #endif /* __KVM_HYP_MEMORY_H */
diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
index d40f0b30b534..1ded09fc9b10 100644
--- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
@@ -144,25 +144,6 @@ static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool,
 	return p;
 }
 
-static inline void hyp_page_ref_inc(struct hyp_page *p)
-{
-	BUG_ON(p->refcount == USHRT_MAX);
-	p->refcount++;
-}
-
-static inline int hyp_page_ref_dec_and_test(struct hyp_page *p)
-{
-	BUG_ON(!p->refcount);
-	p->refcount--;
-	return (p->refcount == 0);
-}
-
-static inline void hyp_set_page_refcounted(struct hyp_page *p)
-{
-	BUG_ON(p->refcount);
-	p->refcount = 1;
-}
-
 static void __hyp_put_page(struct hyp_pool *pool, struct hyp_page *p)
 {
 	if (hyp_page_ref_dec_and_test(p))
-- 
2.38.0.413.g74048e4d9e-goog