Re: problems with recursively mapping page directory as a page table

[Christian Limpach <chris@pin.lu>]

> The following code:
>     /* install a pde recursively mapping page directory as a page table */
>     FILLKPT(IdlePTD, PTDPTDI, 1, IdlePTD, L2_PROT_RO);
>
> Which basically sets IdlePTD[PTDPTDI] = IdlePTD | LT_PROT_RO appears to
> be causing the error below. Any thoughts?
>
> (file=/u/kmacy/xen/xeno-unstable.bk.home/xen/include/xeno/mm.h,line=243)
Unexpected type (saw 40000000 != exp 20000000) for pfDOM0:
> (file=memory.c, line=339) Bad page type for pfn 0001228d (40000001)

I think it's not an error:  get_page_from_l2e first tries to validate the PD
entry as a regular PD entry (i.e. the page it points to should be an L1
pagetable page, PGT_l1_page_table type) and if this fails, it tries to
validate it as a linear pagetable mapping (the page it points to should be
an L2 pagetable page, PGT_l2_page_table type).  You could add a test around
the warnings to check for this condition and then not output the warnings.

    christian



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