Re: [Xen-devel] AES Encryption information

[Joanna Rutkowska <joanna@xxxxxxxxxxxxxxxxxxxxxx>]

On 07/06/10 20:52, Jeremy Fitzhardinge wrote:
> On 07/06/2010 11:13 AM, ReehanAhmedKhan I L wrote:
>> On creating a fully encrypted para-virtualised Xen guest system, is
>> all the data stored on the hard-disk fully encrypted?  If so when is
>> the encryption done.
>> The shared memory is used to communicate between dom0 and domU.  Is
>> the encryption done before data is put in the shared memory?
>> Does not the whole encryption procedure slow down the system?
> 
> Xen has no specific support for encrypting disk data.  You can use
> whatever mechanisms the dom0 and/or domU kernels support.  If you're
> using Linux, for example, you can configure your setup to encrypt within
> the domU so that the dom0 domain only ever sees encrypted data, or you
> can encrypt in dom0.
> 
> The performance effects really depend on your workload and system, but
> my laptop with an encrypted ssd has used 19min 35s for disk encryption
> over the last 13 days of uptime.
> 

I know this is really off-topic, but I'm curious whether you have a Core
i5/i7 processor with an AESNI instruction, and if you have, if you got
the aesni-intel module to work properly with your kernel?

I noticed that using LUKS with a very fast SSD, that normally could have
a read throughput of around 200MB/s, significantly limits the
performance down to around 80-100 MB/s, with the bottleneck being the
kcryptd process easting 100% CPU (core).

joanna.

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