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An exporter on drm_gem_prime_dmabuf_ops has >>>> no .pin, and drm_gem_ttm_vmap() answers iomem for a VRAM resident >>>> object, so an NPU paired with nouveau or radeon does. >>>> >>>> Refuse the mapping. vmw_gem_vmap() does the same; unlike that one this >>>> path is reachable from an unprivileged ioctl, so it does not warn. >>>> >>>> Signed-off-by: Taimuraz Kaitmazov >>>> --- >>>>    drivers/accel/amdxdna/amdxdna_gem.c | 10 ++++++++-- >>>>    1 file changed, 8 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/accel/amdxdna/amdxdna_gem.c b/drivers/accel/amdxdna/amdxdna_gem.c >>>> index 1f190b319bb..b66ec9e4828 100644 >>>> --- a/drivers/accel/amdxdna/amdxdna_gem.c >>>> +++ b/drivers/accel/amdxdna/amdxdna_gem.c >>>> @@ -683,10 +683,16 @@ static int amdxdna_gem_obj_vmap(struct drm_gem_object *obj, struct iosys_map *ma >>>>          dma_resv_assert_held(obj->resv); >>>>    -    if (is_import_bo(abo)) >>>> +    if (is_import_bo(abo)) { >>>>            ret = dma_buf_vmap(abo->dma_buf, map); >> Mhm, why does amdxdna a vmap in the first place? For some workaround? > > This is used for flushing the imported BO before. Based on our discussion before, the driver should not flush imported BO, so this becomes a invalid case. > > On the other hand, vmap on a io_mem should not happen. So I suggested to move the check to amdxdna_gem_vmap() for an extra check. Oh my, you should not use a vmap to flush CPU caches even if you own that GEM buffer! That is as buggy as it can be and most likely doesn't work 100% reliable. What is the complete command submission flow here? Regards, Christian. > > > Thanks, > > Lizhi > >> >> Usually DMA-buf only provides that framebuffer emulation scanout inside the kernel. >> >> On the other hand as far as I can see that here should work correctly. >> >> Regards, >> Christian. >> >>>> -    else >>>> +        /* Callers use mem.kva as an ordinary kernel address. */ >>>> +        if (!ret && map->is_iomem) { >>>> +            dma_buf_vunmap(abo->dma_buf, map); >>>> +            return -EOPNOTSUPP; >>>> +        } >>> Thanks for the fix. The 'is_iomem' check should be moved to amdxdna_gem_vmap() to cover all the cases. >>> >>> Lizhi >>> >>>> +    } else { >>>>            ret = drm_gem_shmem_object_vmap(obj, map); >>>> +    } >>>>        if (ret) >>>>            return ret; >>>>        if (!map->vaddr)