Am 2023-02-07 um 15:35 schrieb Xiaogang.Chen:
From: Xiaogang Chen <[email protected]>

When xnack is on user space can use svm page restore to set a vm range without
setup it first, then use regular api to register. Currently kfd api and svm are
not interoperable. We already have check on that, but for user buffer the 
mapping
address is not same as buffer cpu virtual address. Add checking on that to
avoid error propagate to hmm.

Signed-off-by: Xiaogang Chen <[email protected]>
---
  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 17 +++++++++++++++++
  1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index f79b8e964140..cb7acb0b9b52 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -1065,6 +1065,23 @@ static int kfd_ioctl_alloc_memory_of_gpu(struct file 
*filep,
                mutex_unlock(&p->svms.lock);
                return -EADDRINUSE;
        }
+
+       /* When register user buffer check if it has been registered by svm by
+        * buffer cpu virtual address.
+        */
+       if (flags & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
+
+               if (interval_tree_iter_first(&p->svms.objects,
+                               untagged_addr(args->mmap_offset) >> PAGE_SHIFT,
+                               (untagged_addr(args->mmap_offset) + args->size - 1) 
>> PAGE_SHIFT)) {

Instead of nesting two if-blocks, you can write this as a single if-block like

        if ((flags & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) &&
            interval_tree_iter_first(&p->svms.objects,
                                     untagged_addr(args->mmap_offset) >> 
PAGE_SHIFT,
                                     (untagged_addr(args->mmap_offset)  + args->size 
- 1) >> PAGE_SHIFT) {

I'm also not sure untagged_addr is needed here. If it is, we're missing it in a bunch of other places too. Most notably, we don't untag pointers anywhere in the SVM API.

Regards,
  Felix


+
+                       pr_err("User Buffer Address: 0x%llx already allocated by 
SVM\n",
+                               untagged_addr(args->mmap_offset));
+                       mutex_unlock(&p->svms.lock);
+                       return -EADDRINUSE;
+               }
+
+       }
        mutex_unlock(&p->svms.lock);
  #endif
        mutex_lock(&p->mutex);

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