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/gfp.h | 2 ++
arch/arm64/kvm/hyp/include/nvhe/memory.h | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/gfp.h b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
index d420e5c0845f..a82f73faf41e 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/gfp.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
@@ -24,6 +24,8 @@ struct hyp_pool {
static inline void hyp_page_ref_inc(struct hyp_page *p)
{
+ if (p->refcount == USHRT_MAX)
+ BUG();
p->refcount++;
}
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;
};
--
2.31.1.818.g46aad6cb9e-goog
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