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On Fri, Feb 23, 2018 at 12:32 AM, Larrew, Jesse <Jesse.Larrew at amd.com> wrote:
> Ah! Yes, live migration of encrypted guests is supported by the hardware. Qemu support is still being actively developed though. The details of migrating encrypted VMs are discussed in our Secure Encrypted Virtualization API [1]. Basically, the AMD Secure Processor re-encrypts and integrity-protects the guest memory into discrete "packets" that can be sent to the destination machine. The transport/integrity keys used for migration are ephemeral keys negotiated with the receiving machine using a Diffie-Hellman exchange.
>
> Live migration is useful for VMs that need to be stateful. However, my impression of container use cases is that they are encouraged to be stateless. For stateless containers, it would most likely be quicker to simply throw away the container and start a new one on the destination machine. Do you have specific use cases that require the ability to migrate containers?
>
Yes. We have an optimization [1] based on the qemu live migration
feature which let us share the initial part of guest memory among
guests on the same host. It's a quite useful feature for vm-based
container workload because the kernel and initramfs are most likely
the same for all guests on the host.

[1]: https://github.com/hyperhq/qemu/commit/162b05b38ddb8505c209cf3c570d70c76427c8a5

Cheers,
Tao

> [1] Secure Encrypted Virtualization API v0.16:
> https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf
>
> Sincerely,
> Jesse
>
>> -----Original Message-----
>> From: Tao Peng [mailto:bergwolf at hyper.sh]
>> Sent: Thursday, February 22, 2018 5:15 AM
>> To: Larrew, Jesse <Jesse.Larrew at amd.com>
>> Cc: kata-dev at lists.katacontainers.io; Hollingsworth, Brent
>> <brent.hollingsworth at amd.com>; Kaplan, David <David.Kaplan at amd.com>;
>> Woller, Thomas <thomas.woller at amd.com>
>> Subject: Re: [kata-dev] Kata with AMD Secure Encrypted Virtualization (SEV)
>>
>> Hi Larrew,
>>
>> > I’m not familiar with qemu VM clone. Is there any documentation or source
>> files I could browse to learn more?
>> >
>> Sorry I meant to say live migration instead of clone since qemu clone is
>> mostly used to mean guest image cloning. Here is some background I can find
>> online:
>> https://developers.redhat.com/blog/2015/03/24/live-migrating-qemu-kvm-
>> virtual-machines/
>>
>> Cheers,
>> Tao
>> --
>> bergwolf at hyper.sh



-- 
bergwolf at hyper.sh