Re: [PATCH] xen/arm: Scrub heap pages during boot

[Julien Grall <julien.grall@linaro.org>]

On 01/10/2014 09:52 AM, Ian Campbell wrote:
> On Fri, 2014-01-10 at 03:27 +0000, Julien Grall wrote:
>> Scrub heap pages was disabled because it was slow on the models. Now that Xen
>> supports real hardware, it's possible to enable by default scrubbing.
>>
>> Signed-off-by: Julien Grall <julien.grall@linaro.org>
>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>

Thanks.


>> ---
>>      This patch should go to Xen 4.4. It avoid to give non-cleared page to
>>      a domain.
>>
>>      The downside is it's now slow on models.
>
> There is a no-bootscrub command-line option which can be used in that
> case. Could you update the relevant model wiki pages to mention it
> please?

I have updated the wiki page.

>
>>      The current implementation of scrub_heap_pages loop on every page in the
>>      frametable. On ARM, there is only which can contains MMIO. We are safe
>>      because when frametable is initialized, page are marked inuse. So the
>>      function won't clear theses pages.
>
> I don't think this behaviour is specific to ARM, x86 has MMIO regions
> mixed in with RAM as well.

I was not sure, so I prefered to explain why it's ok.

-- 
Julien Grall