Re: [BACKPORT] swiotlb-xen: implement xen_swiotlb_dma_mmap callback

From: Greg KH
Date: Fri Sep 15 2017 - 21:23:58 EST

On Thu, Sep 14, 2017 at 04:23:05PM -0700, Stefano Stabellini wrote:
> Hi all,
> We are getting reports from Xen on ARM users about DMA issues. The
> problem is that the commit below
> (7e91c7df29b5e196de3dc6f086c8937973bd0b88) is necessary to support mmap
> on Xen on ARM. It is self-contained and doesn't affect anything outside
> of Xen on ARM, so I think is a good candidate for backporting. It went
> upstream in 4.11.

But it's a new feature, right? How does that fit the stable kernel

> Could you please backport the following commit:
> commit 7e91c7df29b5e196de3dc6f086c8937973bd0b88
> Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Date: Tue Feb 7 19:58:02 2017 +0200
> swiotlb-xen: implement xen_swiotlb_dma_mmap callback
> This function creates userspace mapping for the DMA-coherent memory.
> to the stable trees up until 3.14?
> Because of 00085f1efa387a8ce100e3734920f7639c80caa3 "dma-mapping: use
> unsigned long for dma_attrs", the appended patch (to be applied on top)
> is required for trees older than 4.8.

What does the kvm maintainers think about this?


greg k-h