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[Xen-devel] Re: scrubbing pages on vm pause

To: Joanna Rutkowska <joanna@xxxxxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] Re: scrubbing pages on vm pause
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Tue, 25 May 2010 15:13:35 +0100
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Rafal Wojtczuk <rafal@xxxxxxxxxxxxxxxxxxxxxx>
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On 25/05/2010 15:12, "Joanna Rutkowska" <joanna@xxxxxxxxxxxxxxxxxxxxxx>

>> New domains are not guaranteed to receive zeroed memory. The only guarantee
>> Xen provides is that when it frees memory for a *dead* domain, it will scrub
>> the contents before reallocation (it may not write zeroes however, in a
>> debug build of Xen for example!). Other memory pages the domain freeing the
>> pages must scrub them itself before freeing them back to Xen.
> And what happens when we pause and save a domain? Are the pages zero-out
> by xen in that case?

If the original domain is subsequently destroyed then yes, Xen zeroes the

 -- Keir

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