[Xen-devel] swiotlb and Xen query?

["pradeep singh rautela" <rautelap@xxxxxxxxx>]

Hi All,

dom0 and domU uses swiotlb mechanism to emulate hardware IOMMU, right? 
And that so because the whole memory is visible to hypervisor only and not to other domains, am i right? 

My doubt is once the translation table between virtual and physical addresses is set by the 
swiotlb.How does device becomes aware of this table which is emulated in hardware as a matter of fact using swiotlb.the device does not knows about this table when accessing physical memory, isnt it? 

Another question is - 
dom0 and domU they both have their swiotlb mappings.This means Xen also keeps record of a mapping between these two tables in dom0 and domU? Am i right? Doesnt this means wasting a lot of memory in allocating bounce buffers for swiotlb during booting of dom0 and then during booting of domUs? 

Please bear as i am just starting with the Xen code .
Any pointers or links will be really helpful.

Thank you
~psr


-- 
---
pradeep singh rautela

"Genius is 1% inspiration, and 99% perspiration" - not me :)
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