On 5/7/19 1:11 PM, Jan Beulich wrote:
>>>> On 07.05.19 at 13:34, <elnik...@amazon.com> wrote:
>> --- a/xen/common/page_alloc.c
>> +++ b/xen/common/page_alloc.c
>> @@ -214,6 +214,10 @@ custom_param("bootscrub", parse_bootscrub_param);
>> static unsigned long __initdata opt_bootscrub_chunk = MB(128);
>> size_param("bootscrub_chunk", opt_bootscrub_chunk);
>>
>> + /* scrub-domheap -> Domheap pages are scrubbed when freed */
>> +static bool __read_mostly opt_scrub_domheap;
>> +boolean_param("scrub-domheap", opt_scrub_domheap);
>
> Upon 2nd thought this, btw, would seem to be an excellent candidate
> for becoming a runtime parameter.
>
>> @@ -2378,9 +2382,10 @@ void free_domheap_pages(struct page_info *pg,
>> unsigned int order)
>> /*
>> * Normally we expect a domain to clear pages before freeing
>> them,
>> * if it cares about the secrecy of their contents. However,
>> after
>> - * a domain has died we assume responsibility for erasure.
>> + * a domain has died we assume responsibility for erasure. We do
>> + * scrub regardless if option scrub_domheap is set.
>> */
>> - scrub = d->is_dying || scrub_debug;
>> + scrub = d->is_dying || scrub_debug || opt_scrub_domheap;
>
> Did you consider setting opt_scrub_domheap when scrub_debug is
> set? This would shorten the (runtime) calculation here by a tiny bit,
> at the price of doing one more thing once while booting.
Just for clarification Jan -- did you mean, "I'm happy for this to go in
as it is, but if you feel like it, here are two improvements"?
-George
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