Re: [Xen-devel] [PATCH v5 12/15] x86: add iommu_op to enable modification of IOMMU mappings

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Paul Durrant [mailto:Paul.Durrant@xxxxxxxxxx]
> Sent: Tuesday, August 7, 2018 5:12 PM
> 
> 
> > So here current version pvIOMMU only provides global address space,
> > though unlike any existing IOMMU. maybe we should explicitly call out
> > this fact in some capability field for future extension.
> >
> 
> Does Linux expose such a thing through the dma_ops? I didn't see one, but
> if there is one then we can of course set it correctly according to the
> limitations of the underying hypervisor. Thus, if Xen is modified in future to
> support per-device mappings, this could be exposed through to the drivers
> using DMA.
> 

not about Linux internal exposing. it's about hypervisor exposing
the capability to pvIOMMU driver, so the latter knows whether to
enable per-device mapping. But as you commented in another
mail, it could be achieved through enabling sequence.

btw could you put clarification according to our discussions in your 
next version coverletter to set the tone clear from start? I don't
think I'll be the only one interpreting wrong goal for this work. :-)

Thanks
Kevin
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel