On 11/11/2024 09:26, Akash Goel wrote:
> This commit fixes the handling of partial GPU mapping of buffer objects
> in Panthor.
> VM_BIND ioctl allows Userspace to partially map the BOs to GPU.
> To map a BO, Panthor walks through the sg_table to retrieve the physical
> address of pages. If the mapping is created at an offset into the BO,
> then the scatterlist(s) at the beginning have to be skipped to reach the
> one corresponding to the offset. But the case where the offset didn't
> point to the first page of desired scatterlist wasn't handled correctly.
> The bug caused the partial GPU mapping of BO to go wrong for the said
> case, as the pages didn't get map at the expected virtual address and
> consequently there were kernel warnings on unmap.
>
> Signed-off-by: Akash Goel <akash.g...@arm.com>
Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block")
Reviewed-by: Steven Price <steven.pr...@arm.com>
Thanks,
Steve
> ---
> drivers/gpu/drm/panthor/panthor_mmu.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c
> b/drivers/gpu/drm/panthor/panthor_mmu.c
> index d8cc9e7d064e..6bc188d9a9ad 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -957,6 +957,7 @@ panthor_vm_map_pages(struct panthor_vm *vm, u64 iova, int
> prot,
>
> paddr += offset;
> len -= offset;
> + offset = 0;
> len = min_t(size_t, len, size);
> size -= len;
>
