Re: scrubbing pages on vm pause

[Joanna Rutkowska <joanna@invisiblethingslab.com>]

[-- Attachment #1.1: Type: text/plain, Size: 932 bytes --]

On 05/25/2010 04:13 PM, Keir Fraser wrote:
> On 25/05/2010 15:12, "Joanna Rutkowska" <joanna@invisiblethingslab.com>
> wrote:
> 
>>> 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
> pages.
> 

Let's consider this scenario:

xm save domain1

xm create domain2

Can the domain2 get *unscrubbed* pages that were previously used by
domain1, but were not scrubbed properly by domain1?

j.


[-- Attachment #1.2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 226 bytes --]

[-- Attachment #2: Type: text/plain, Size: 138 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel