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* [PATCH v3] KVM: arm64: Use consistent type for pool size
@ 2026-11-06 17:27 Mostafa Saleh
  2026-11-06 21:26 ` Oliver Upton
  0 siblings, 1 reply; 2+ messages in thread
From: Mostafa Saleh @ 2026-11-06 17:27 UTC (permalink / raw)
  To: linux-kernel, kvmarm, linux-arm-kernel
  Cc: maz, oupton, seiden, joey.gouly, suzuki.poulose, yuzenghui,
	catalin.marinas, will, vdonnefort, tabba, xuheng, Mostafa Saleh,
	Fuad Tabba

All the pool sizes in the hypervisor are "unsigned long" but when
they get passed to hyp_early_alloc_contig() or hyp_pool_init() they get
truncated to 32-bits.

That is not a big problem at the moment as to overflow this we need
4G bytes of carveout (2 TB of host or guest system memory).

However when new users are added (as IOMMU) it is hard to reason
about the carveout size anymore.

Fixes: e75960408723 ("KVM: arm64: Introduce an early Hyp page allocator")
Fixes: 8e17c66249e9 ("KVM: arm64: Introduce a Hyp buddy page allocator")
Reviewed-by: Fuad Tabba <fuad.tabba@linux.dev>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/early_alloc.h | 2 +-
 arch/arm64/kvm/hyp/include/nvhe/gfp.h         | 4 ++--
 arch/arm64/kvm/hyp/nvhe/early_alloc.c         | 2 +-
 arch/arm64/kvm/hyp/nvhe/page_alloc.c          | 6 +++---
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/early_alloc.h b/arch/arm64/kvm/hyp/include/nvhe/early_alloc.h
index dc61aaa56f31..462883c4e325 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/early_alloc.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/early_alloc.h
@@ -7,7 +7,7 @@
 void hyp_early_alloc_init(void *virt, unsigned long size);
 unsigned long hyp_early_alloc_nr_used_pages(void);
 void *hyp_early_alloc_page(void *arg);
-void *hyp_early_alloc_contig(unsigned int nr_pages);
+void *hyp_early_alloc_contig(unsigned long nr_pages);
 
 extern struct kvm_pgtable_mm_ops hyp_early_alloc_mm_ops;
 
diff --git a/arch/arm64/kvm/hyp/include/nvhe/gfp.h b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
index 3766333bace9..3a428dc40b14 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/gfp.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
@@ -29,6 +29,6 @@ void hyp_get_page(struct hyp_pool *pool, void *addr);
 void hyp_put_page(struct hyp_pool *pool, void *addr);
 
 /* Used pages cannot be freed */
-int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned int nr_pages,
-		  unsigned int reserved_pages);
+int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned long nr_pages,
+		  unsigned long reserved_pages);
 #endif /* __KVM_HYP_GFP_H */
diff --git a/arch/arm64/kvm/hyp/nvhe/early_alloc.c b/arch/arm64/kvm/hyp/nvhe/early_alloc.c
index 00de04153cc6..9fef0c7d2185 100644
--- a/arch/arm64/kvm/hyp/nvhe/early_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/early_alloc.c
@@ -21,7 +21,7 @@ unsigned long hyp_early_alloc_nr_used_pages(void)
 	return (cur - base) >> PAGE_SHIFT;
 }
 
-void *hyp_early_alloc_contig(unsigned int nr_pages)
+void *hyp_early_alloc_contig(unsigned long nr_pages)
 {
 	unsigned long size = (nr_pages << PAGE_SHIFT);
 	void *ret = (void *)cur;
diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
index 57f86aa0f82f..51460d420c94 100644
--- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
@@ -229,12 +229,12 @@ void *hyp_alloc_pages(struct hyp_pool *pool, u8 order)
 	return hyp_page_to_virt(p);
 }
 
-int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned int nr_pages,
-		  unsigned int reserved_pages)
+int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned long nr_pages,
+		  unsigned long reserved_pages)
 {
 	phys_addr_t phys = hyp_pfn_to_phys(pfn);
 	struct hyp_page *p;
-	int i;
+	unsigned long i;
 
 	hyp_spin_lock_init(&pool->lock);
 	pool->max_order = min(MAX_PAGE_ORDER,
-- 
2.56.0.455.g6c5a503b38-goog


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2026-11-06 17:27 [PATCH v3] KVM: arm64: Use consistent type for pool size Mostafa Saleh
2026-11-06 21:26 ` Oliver Upton

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