The hyp_page refcount is currently encoded on 4 bytes even though we
never need to count that many objects in a page. Make it 2 bytes to save
some space in the vmemmap.
As overflows are more likely to happen as well, make sure to catch those
with a BUG in the increment function.
Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
---
arch/arm64/kvm/hyp/include/nvhe/memory.h | 2 +-
arch/arm64/kvm/hyp/nvhe/page_alloc.c | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h
index 3fe34fa30ea4..592b7edb3edb 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/memory.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h
@@ -8,7 +8,7 @@
#include <linux/types.h>
struct hyp_page {
- unsigned int refcount;
+ unsigned short refcount;
unsigned short order;
};
diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
index be07055bbc10..41fc25bdfb34 100644
--- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
@@ -146,6 +146,7 @@ static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool,
static inline void hyp_page_ref_inc(struct hyp_page *p)
{
+ BUG_ON(p->refcount == USHRT_MAX);
p->refcount++;
}
--
2.32.0.rc0.204.g9fa02ecfa5-goog
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