Messages in this thread | | | Date | Wed, 8 Sep 2021 08:14:19 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH 12/12] swiotlb-xen: this is PV-only on x86 |
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On Tue, Sep 07, 2021 at 02:13:21PM +0200, Jan Beulich wrote: > The code is unreachable for HVM or PVH, and it also makes little sense > in auto-translated environments. On Arm, with > xen_{create,destroy}_contiguous_region() both being stubs, I have a hard > time seeing what good the Xen specific variant does - the generic one > ought to be fine for all purposes there. Still Arm code explicitly > references symbols here, so the code will continue to be included there.
Can the Xen/arm folks look into that? Getting ARM out of using swiotlb-xen would be a huge step forward cleaning up some DMA APIs.
> > Instead of making PCI_XEN's "select" conditional, simply drop it - > SWIOTLB_XEN will be available unconditionally in the PV case anyway, and > is - as explained above - dead code in non-PV environments. > > This in turn allows dropping the stubs for > xen_{create,destroy}_contiguous_region(), the former of which was broken > anyway - it failed to set the DMA handle output.
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
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