On 2025-10-03 14:15, Philip Yang wrote:
svm_range_unmap_from_gpus uses page aligned start, end address, the end
address is inclusive.
Fixes: 38c55f6719f7 ("drm/amdkfd: Handle lack of READ permissions in SVM
mapping")
Signed-off-by: Philip Yang <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index e8a15751c125..0aadd20be56a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1723,10 +1723,9 @@ static int svm_range_validate_and_map(struct mm_struct
*mm,
svm_range_lock(prange);
if (vma->vm_flags & VM_WRITE)
pr_debug("VM_WRITE without VM_READ is not
supported");
- s = max(start, prange->start);
- e = min(end, prange->last);
- if (e >= s)
- r = svm_range_unmap_from_gpus(prange,
s, e,
+ s = max(addr >> PAGE_SHIFT, prange->start);
+ e = s + npages - 1;
This is confusing. The old code was clamping prange->start/last with
start/end. start/end are based on map_start/map_end. Your updated code
uses npages, which comes from the VMA, which may not start at the same
address as the prange or the map_start. So I think just using npages
here is incorrect.
You also completely removed the condition that s >= e. I think that's
OK, since all callers make sure that map_start/map_end fall inside
prange->start/last.
What are you actually trying to unmap here? Do you want to unmap the
entire prange, the part of prange inside map_start..map_end, or the part
of prange that overlaps with the VMA, or something else?
Regards,
Felix
+ r = svm_range_unmap_from_gpus(prange, s, e,
KFD_SVM_UNMAP_TRIGGER_UNMAP_FROM_CPU);
svm_range_unlock(prange);
/* If unmap returns non-zero, we'll bail on the
next for loop
