On Tue, Jul 30, 2019 at 11:43:25AM +0100, Robin Murphy wrote:
> > Hmm. I remember proposing this patch and you didn't like it because
> > we could also have msis for a !IOMMU_DMA_IOVA_COOKIE cookie type.
> > Or did we talk past each other?
>
> Do you have a pointer? That sparks the vaguest of memories, but I can't seem
> to turn anything up in my inbox. If that was my objection, though, it sounds
> like your patch was probably trying to go a step or two further than this
> one.
I can't find anything either. This must have been a git tree I passed
around to you before posting it.
> > Note that if this change turns out to be valid we should also
> > clean up the iommu_dma_free_iova() side.
>
> We're not touching the iommu_dma_{alloc,free}_iova() path here; those are
> designed to cope with both types of cookie, and I think that's a reasonable
> abstraction to keep. This is just getting rid of the asymmetry - and now bug
> - caused by trying to keep the MSI page flow going through a special case in
> __iommu_dma_map() despite that having evolved into a more specific DMA
> domain fastpath (there's no corresponding unmap special case since MSI
> mappings just persist and get recycled until the domain is destroyed).
Ok, that might have been the issue with my earlier patch..
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