Re: [Xen-devel] [patch] nx bit shouldn't get set when disabled

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 8 Jun 2005, at 22:56, Nakajima, Jun wrote:

> These should not be necessary if pte is created correctly (w/ or w/o NX
> bit depending on __supported_pte_mask) in the first place, as Keir
> pointed out. That's what I meant by "We should fix the creator of the
> pte (by __supported_pte_mask), not the consumer of it." And you always
> cut off the NX bit in your patch.
>
> So remove the changes to pci-dma.c and init.c. If that does not work,
> move check_efer to right before pda_init(0) in x86_64_start_kernel() in
> head64.c.
I think the changes in pci-dma.c *are* required: that code currently 
just does pte->pte >> PAGE_SHIFT, which certainly isn't right. That's 
code that doesn't exist in native Linux so it probably does need fixing 
up for PAE/NX.
But 'fixes' to simple native functions like set_pud, set_pmd, etc. 
ought not to be necessary. We shouldn't have to fix ubiquitous 
functions like that to support nx bit on xenlinux. If we do, it's a 
sign that something is very wrong! :-)
 -- Keir


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