RE: [Xen-devel] Re: [Xen-users] rebased openSUSE Xen dom0 Patches

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> "Simon Graham" <simon.graham@xxxxxxxxxxxxxxxxxxx> 19.04.10 16:52 >>>
>Now, the first of these hypercalls creates a pte with PAGE_KERNEL as the
>opts and
>I think this includes read-write access whereas the second one
>completely deletes
>the pte for the alternate mapping -- the combined affect should leave
>the page type 
>ref count as one shouldn't it? (for the read-write kernel mapping)
>
>That being the case, I'm not sure how the page type ref count is
>supposed to get to
>zero when reusing one of these pages as a page table page later on.

Such pages get converted to read-only when they get allocated for
the purpose of being a page table. Hence there being a type refcount
of 1 at the point of the insertion means that there's a second mapping
to the page somewhere else. That's what you want to find.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel