linux-kernel - Re: [PATCH v7 3/7] set_memory: allow set_direct_map_*

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Message-ID: <9202c4c1-9f1f-175f-0a85-fc8c30bc5e3b@redhat.com>
Date:   Tue, 27 Oct 2020 09:12:23 +0100
From:   David Hildenbrand <david@...hat.com>
To:     "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
        "rppt@...nel.org" <rppt@...nel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
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Subject: Re: [PATCH v7 3/7] set_memory: allow set_direct_map_*_noflush() for
 multiple pages

On 26.10.20 20:01, Edgecombe, Rick P wrote:
> On Mon, 2020-10-26 at 10:37 +0200, Mike Rapoport wrote:
>> +++ b/arch/x86/mm/pat/set_memory.c
>> @@ -2184,14 +2184,14 @@ static int __set_pages_np(struct page *page,
>> int numpages)
>>         return __change_page_attr_set_clr(&cpa, 0);
>>  }
>>  
>> -int set_direct_map_invalid_noflush(struct page *page)
>> +int set_direct_map_invalid_noflush(struct page *page, int numpages)
>>  {
>> -       return __set_pages_np(page, 1);
>> +       return __set_pages_np(page, numpages);
>>  }
>>  
>> -int set_direct_map_default_noflush(struct page *page)
>> +int set_direct_map_default_noflush(struct page *page, int numpages)
>>  {
>> -       return __set_pages_p(page, 1);
>> +       return __set_pages_p(page, numpages);
>>  }
> 
> Somewhat related to your other series, this could result in large NP
> pages and trip up hibernate.
> 

It feels somewhat desirable to disable hibernation once secretmem is
enabled, right? Otherwise you'll be writing out your secrets to swap,
where they will remain even after booting up again ...

Skipping secretmem pages when hibernating is the wrong approach I guess ...

-- 
Thanks,

David / dhildenb