Re: [Xen-devel] Superpages for VT-D

["Nakajima, Jun" <jun.nakajima@xxxxxxxxx>]

On Thu, Jul 19, 2012 at 7:53 AM, Tim Deegan <tim@xxxxxxx> wrote:

At 07:01 -0700 on 19 Jul (1342681270), Santosh Jodh wrote:
> I understand the value of using superpages for IOMMU. What are the
> other advantages of sharing the table between the MMU and IOMMU (other
> than saving table memory)?

It's mostly the memory, but also it's faster to update one table than
two, and we don't have to worry about them getting out of sync with each
other.  I don't think there are any deeper reasons.

Cheers,

Tim.

- The code can be simpler because you don't need to maintain the same info "guest physical -> host physical" in two different places.

- Maybe cache utilization can be better

--

Jun

Intel Open Source Technology Center

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