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Re: [Xen-devel] frame_table initialisation

  • To: PUCCETTI Armand <armand.puccetti@xxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: Keir Fraser <keir@xxxxxxxxxxxxx>
  • Date: Mon, 26 Feb 2007 16:02:12 +0000
  • Delivery-date: Mon, 26 Feb 2007 08:01:41 -0800
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-index: AcdZv3nGuJnKksWyEdu1UwAX8io7RQ==
  • Thread-topic: [Xen-devel] frame_table initialisation

On 26/2/07 14:45, "PUCCETTI Armand" <armand.puccetti@xxxxxx> wrote:

> 2. some lines before in __start_xen, this variable is referenced by
> function map_pages_to_xen -> virt_to_xen_l2 -> alloc_xen_pagetable ->
> mfn_to_page.
> What should the value of frame_table be there?
> Do I miss some pre-initialisation(s)?

The fact that frame_table is not initialised here (and hence will be NULL)
doesn't actually matter, since the result of mfn_to_page() is only actually
used as a value to page_to_mfn(). And page_to_mfn(mfn_to_page(m))==m for any
(constant) value of frame_table.

This code could be clearer I'll admit. It probably makes sense for
alloc_xen_pagetable to return an MFN rather than a page_info pointer.

 -- Keir

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