On Fri, 15 Sep 2017, Greg KH wrote: > 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 > rules?
It implements a previously unimplemented function (mmap), although it calls the generic functions to do it. Yes, I agree with you that it can be classified as a new feature. If that is against the stable kernel rules, then please discard this request. FYI the reason why it didn't raise a flag in my mind is that users reported something like "unhandled alignment fault (11) at 0xffffa6048080, esr 0x92000061", which really looks more like a bug. > > Could you please backport the following commit: > > > > commit 7e91c7df29b5e196de3dc6f086c8937973bd0b88 > > Author: Stefano Stabellini <stefano.stabell...@eu.citrix.com> > > 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? That would be the Xen maintainers right? In that case, Boris, Juergen, please let us know what you think.
