Hi Marc,
On 3/15/21 7:52 PM, Marc Zyngier wrote:
On Mon, 15 Mar 2021 04:18:42 +0000,
Gavin Shan <gshan@xxxxxxxxxx> wrote:
find_vma_intersection() has been existing to search the intersected
vma. This uses the function where it's applicable, to simplify the
code.
Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
---
arch/arm64/kvm/mmu.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 84e70f953de6..286b603ed0d3 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -421,10 +421,11 @@ static void stage2_unmap_memslot(struct kvm *kvm,
* +--------------------------------------------+
*/
do {
- struct vm_area_struct *vma = find_vma(current->mm, hva);
+ struct vm_area_struct *vma;
hva_t vm_start, vm_end;
- if (!vma || vma->vm_start >= reg_end)
+ vma = find_vma_intersection(current->mm, hva, reg_end);
For context, here's the definition of find_vma_intersection():
<quote>
static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
{
struct vm_area_struct * vma = find_vma(mm,start_addr);
if (vma && end_addr <= vma->vm_start)
vma = NULL;
return vma;
}
</quote>
It seems that there is a boundary issue in either the old code or the
new one in the case where (reg_end == vma->start).
Which one is which?
The old and new code is interchangeable, meaning "reg_end == vma->start"
is invalid in both cases. So if there is a boundary issue, the old and new
code should have same issue.
According to the code, "reg_end == vma->start" is invalid. So I don't see
there is a boundary issue. Hopefully, I don't miss anything :)
Thanks,
Gavin
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