Re: [Xen-devel] Pinning a DomU Guest data page from Hypervisor

[Tim Deegan <tim@xxxxxxx>]

Hi, 

At 23:20 +0530 on 03 Aug (1312413612), veerasena reddy wrote:
> By pinning, I mean to keep the data page always in main memory for the
> device to access. Once the device processes the page, i can unpin.
> Please correct me, if i understood page pinning concept wrongly.
> But, my goal is to keep the page in main memory until the device processes
> it.

If you want to stop _xen_ reassigning this frame (including any
hypervisor-level paging) you can just take a reference count (probably
you want a writeable-tyrp typecount using get_page_and_type()).  But Xen
can't stop the guest OS from reusing the frame (including paging its
contents out), so you will need to address that inside the guest OS.

Tim.

-- 
Tim Deegan <tim@xxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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