Fix imported dma-buf mmap EINVAL error in qemu virtio path

[dkotipal-xilinx]

Fixes mmap failure for imported BOs seen in qemu virtio (Failed to mmap dma buf -22).

Root cause: imported dma-buf mmap was using DRM’s fake vm_pgoff instead of a buffer-relative offset.

Fix: set vma->vm_pgoff = 0 before dma_buf_mmap() in the imported mmap path.

Scope: imported dma-buf mapping only; non-imported shmem path is unchanged.

Result: imported mmap succeeds, no -EINVAL in this flow.

[wendyliang25]

when user calls mmap() it will provide the vm_pgoff.
Could you provide details on "imported dma-buf mmap was using DRM’s fake vm_pgoff instead of a buffer-relative offset" ?
drm used the offset passed from userspace to look up the gem object, and then calls the gem object mmap() function.
ret = dma_buf_mmap(abo->dma_buf, vma, 0); does the mmap() from offset 0.

thanks

[wendyliang25]

Hi @dkotipal-xilinx , recently, there is a change in xdna-driver and vxdna to disable mmap() for user pointer backed bo, could you try with latest kernel module in drivers/accel and latest vxdna? thanks