[PATCH v2 2/5] KVM: arm64: selftests: Fix incorrect rounding in page_align()

Fuad Tabba
2025-12-15T16:52:08Z

The implementation of `page_align()` in `processor.c` calculates
alignment incorrectly for values that are already aligned. Specifically,
`(v + vm->page_size) & ~(vm->page_size - 1)` aligns to the *next* page
boundary even if `v` is already page-aligned, potentially wasting a page
of memory.

Fix the calculation to use standard alignment logic: `(v + vm->page_size
- 1) & ~(vm->page_size - 1)`.

Fixes: 7a6629ef746d ("kvm: selftests: add virt mem support for aarch64")
Signed-off-by: Fuad Tabba <tabba@google.com>
---
tools/testing/selftests/kvm/lib/arm64/processor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/lib/arm64/processor.c b/tools/testing/selftests/kvm/lib/arm64/processor.c
index 5b379da8cb90..607a4e462984 100644
--- a/tools/testing/selftests/kvm/lib/arm64/processor.c
+++ b/tools/testing/selftests/kvm/lib/arm64/processor.c
@@ -23,7 +23,7 @@ static vm_vaddr_t exception_handlers;

static uint64_t page_align(struct kvm_vm *vm, uint64_t v)
{
- return (v + vm->page_size) & ~(vm->page_size - 1);
+ return (v + vm->page_size - 1) & ~(vm->page_size - 1);
}

static uint64_t pgd_index(struct kvm_vm *vm, vm_vaddr_t gva)
--
2.52.0.239.gd5f0c6e74e-goog