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authorQuentin Perret2021-06-08 11:45:18 +0000
committerMarc Zyngier2021-06-11 13:24:12 +0100
commit6929586d8eddad184f43526efe7bf0a8be4f18b2 (patch)
tree285136df8a757c3ade2eaa347c1386c0a5fa9009 /arch/arm64/kvm
parent87ec0606733e1aa9568f54ddb41f03aa6b5687f2 (diff)
KVM: arm64: Use less bits for hyp_page refcount
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@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210608114518.748712-8-qperret@google.com
Diffstat (limited to 'arch/arm64/kvm')
-rw-r--r--arch/arm64/kvm/hyp/include/nvhe/memory.h2
-rw-r--r--arch/arm64/kvm/hyp/nvhe/page_alloc.c1
2 files changed, 2 insertions, 1 deletions
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++;
}