Re: [PATCH 6/7] x86, mm: setup page table from top-down

[H. Peter Anvin]

On 10/10/2012 10:38 AM, Yinghai Lu wrote:
> On Wed, Oct 10, 2012 at 10:26 AM, Stefano Stabellini
> <stefano.stabellini@xxxxxxxxxxxxx> wrote:
> > On Wed, 10 Oct 2012, Yinghai Lu wrote:
> >
> > It doesn't matter whether they come from BRK or other memory: Xen
> > assumes that all the pagetable pages come from
> > pgt_buf_start-pgt_buf_top, so if you are going to use another range you
> > need to tell Xen about it.
> >
> > Alternatively, you can follow Peter's suggestion and replace the current
> > hooks with a new one with a more precise and well defined semantic.
> > Something along the lines of "this pagetable page is about to be hooked
> > into the live pagetable". Xen would use the hook to mark it RO.
>
> attached patch on top of this patch will fix the problem?

 	.mapping = {
-		.pagetable_reserve		= native_pagetable_reserve,
+		.mark_page_ro			= mark_page_ro_noop;
 	},

I have already objected to this naming in the past, because it describes 
an implementation ("hypervisor make readonly") as opposed to a semantic 
function "make this page permissible to use as a page table".  I would 
call it pagetable_prepare or something like that.

	-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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