From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [PATCH v1] xen/arm: Do not allocate pte entries for
 MAP_SMALL_PAGES
Date: Tue, 3 Mar 2015 11:57:01 +0000
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To: Julien Grall <julien.grall@linaro.org>
Cc: Vijay Kilari <vijay.kilari@gmail.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Prasun Kapoor <Prasun.Kapoor@caviumnetworks.com>, Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>, Tim Deegan <tim@xen.org>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Stefano Stabellini <stefano.stabellini@citrix.com>, manish.jaggi@caviumnetworks.com
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On Tue, 2015-03-03 at 11:51 +0000, Julien Grall wrote:
> 
> On 03/03/2015 11:47, Ian Campbell wrote:
> >> I'm not sure to follow here. Do you think MAP_SMALL_PAGES should be
> >> defined as WRITE_ALLOC?
> >
> > Sorry I just meant that:
> >          +#define PAGE_HYPERVISOR_WC      ((DEV_WC) | PTE_PRESENT )
> > should be just:
> >          +#define PAGE_HYPERVISOR_WC      (DEV_WC | PTE_PRESENT )
> > etc, no need for the inner-()s.
> >
> > MAP_SMALL_PAGES was correct as
> >          +#define MAP_SMALL_PAGES         (WRITEALLOC)
> 
> I wanted to check the definition of MAP_SMALL_PAGES you were agreed.
> 
> I think using WRITEALLOC here is confusing. There is no resulting PTE 
> and therefore WRITEALLOC will never be set.
> 
> I think it would be better to have a separate helper (as you suggested 
> on a previous mail).

Ah yes, I'd forgotten I'd thought of that. A separate helper to
provision an empty PT range would indeed be the best thing here.


> 
> Regards,
>