Re: [PATCH] xen/arm: introduce XENFEAT_direct_mapped and XENFEAT_not_direct_mapped

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 19 Mar 2021, Boris Ostrovsky wrote:
> On 3/18/21 7:28 PM, Stefano Stabellini wrote:
> >
> > So, I'll follow you suggestion, keep the x86 side named as it is today,
> > and provide a tiny wrapper so that we can still have an arch-neutral
> > xen_swiotlb_detect function (on x86 just calls pci_xen_swiotlb_detect.)
> 
> 
> But now on x86 side we end up with a routine that noone calls. And 
> pci_xen_swiotlb_detect() becomes not __init and so it will have to stick 
> around after boot for no good reason. (You could have made it __ref btw).
> 
> 
> I think we should leave x86 alone. And if there is a declaration in 
> include/xen/swiotlb-xen.h that's only relevant to ARM --- well, so be it. Or 
> perhaps you can create arch/arm/include/asm/xen/swiotlb-xen.h

Yeah I wanted to avoid creating arch/arm/include/asm/xen/swiotlb-xen.h
because I would have to do one of the following:

1) add one more #include <asm/xen/swiotlb-xen.h> to arch/arm64/mm/dma-mapping.c
   (#include <xen/swiotlb-xen.h> is there already)
2) add #include <asm/xen/swiotlb-xen.h> to include/xen/swiotlb-xen.h

What's your preference? If I have to create
arch/arm/include/asm/xen/swiotlb-xen.h, I would go with 2).