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Re: [Xen-devel] 32-on-64 support in xen-unstable?

To: "Chris Lalancette" <clalance@xxxxxxxxxx>
Subject: Re: [Xen-devel] 32-on-64 support in xen-unstable?
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Mon, 06 Jul 2009 15:37:52 +0100
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>>> Chris Lalancette <clalance@xxxxxxxxxx> 06.07.09 16:18 >>>
>     I've been browsing through the preemptible pagetable stuff, and ran across
>a piece of code that I don't understand or is buggy.  Looking at
>arch/x86/mm.c:new_guest_cr3(), we have this code for 32-on-64 support:

You probably overlooked the == 0 et the end of the expression:

>    if ( is_pv_32on64_domain(d) )
>    {
>        okay = paging_mode_refcounts(d)
>            ? 0 /* Old code was broken, but what should it be? */
>            : mod_l4_entry(
>                    __va(pagetable_get_paddr(curr->arch.guest_table)),
>                    l4e_from_pfn(
>                        mfn,
>                        (_PAGE_PRESENT|_PAGE_RW|_PAGE_USER|_PAGE_ACCESSED)),
>                    pagetable_get_pfn(curr->arch.guest_table), 0, 0, curr) == 
> 0;

Which basically is equivalent to what you were trying to suggest.


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