Re: [Xen-devel] Related to Xen Terminology

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> Can anyone please tell me what does pinning and unpinning of pages mean
> in XEN?

Pinning is a way for a guest to tell Xen what type a page should have.  It is 
a performance optimisation.

For instance, a guest could pin some pages as containing pagetable entries.  
When they are pinned, Xen can validate that they are valid (and safe) 
entries, then write protect the page to prevent modifications.  The page will 
retain its type and validated status until it's unpinned.

If you couldn't do this, Xen would have to revalidate entire page tables 
whenever a new pagetable tree was loaded.

HTH,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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