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[Xen-devel] swiotlb and Xen query?

  • To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, xenkernelnewbies@xxxxxxxxxxxxxxxx
  • From: "pradeep singh rautela" <rautelap@xxxxxxxxx>
  • Date: Wed, 2 May 2007 18:19:06 +0530
  • Delivery-date: Wed, 02 May 2007 05:47:50 -0700
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  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>

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

pradeep singh rautela

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