[libvirt] [PATCH 3/4] conf: introduce sev element in domain

[Brijesh Singh]

On 02/27/2018 05:10 AM, Daniel P. Berrangé wrote:
> On Mon, Feb 26, 2018 at 11:53:35AM -0600, Brijesh Singh wrote:
>> Secure Encrypted Virtualization (sev) element is used to provide the guest
>> owners input parameters used for creating an encrypted VM using AMD SEV
>> feature. SEV feature supports running encrypted VM under the control of
>> KVM. Encrypted VMs have their pages (code and data) secured such that only
>> the guest itself has access to the unencrypted version. Each encrypted VM
>> is associated with a unique encryption key; if its data is accessed to a
>> different entity using a different key the encrypted guests data will be
>> incorrectly decrypted, leading to unintelligible data.
>>
>> QEMU >= 2.12 provides 'sev-guest' object which supports launching encrypted
>> VMs. A typical command line
>>
>> # $QEMU ... \
>>     -machine memory-encryption=sev0 \
>>     -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \
>>     ...
>>
>> Signed-off-by: Brijesh Singh <brijesh.singh at amd.com>
>> ---
>>   docs/formatdomain.html.in | 71 +++++++++++++++++++++++++++++++++++++++++++
>>   src/conf/domain_conf.c    | 64 +++++++++++++++++++++++++++++++++++++++
>>   src/conf/domain_conf.h    | 18 +++++++++++
>>   src/qemu/qemu_command.c   | 77 +++++++++++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 230 insertions(+)
> 
> In general we'd expect to see additions to the test suite for any XML
> changes. eg a qemuxml2xmltest and qemuxml2argvtest addition.
> 


Sure, this is my first stab at libvirt and will look into getting 
familiar with test and add them in next round.


>>
>> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
>> index 6fd2189cd2f4..d18e3fb1d976 100644
>> --- a/docs/formatdomain.html.in
>> +++ b/docs/formatdomain.html.in
>> @@ -8195,6 +8195,77 @@ qemu-kvm -net nic,model=? /dev/null
>>   
>>       <p>Note: DEA/TDEA is synonymous with DES/TDES.</p>
>>   
>> +    <h3><a id="sev">Secure Encrypted Virtualization (SEV)</a></h3>
>> +
>> +    <p>
>> +       The contents of the <code>sev</code> element is used to provide the
>> +       guest owners input used for creating an encrypted VM using the AMD
>> +       Secure Encrypted Virtualization (SEV) feature.
>> +
>> +       SEV is an extension to the AMD-V architecture which supports running
>> +       encrypted virtual machine (VMs) under the control of KVM. Encrypted
>> +       VMs have their pages (code and data) secured such that only the guest
>> +       itself has access to the unencrypted version. Each encrypted VM is
>> +       associated with a unique encryption key; if its data is accessed to a
>> +       different entity using a different key the encrypted guests data will
>> +       be incorrectly decrypted, leading to unintelligible data.
>> +       </p>
>> +    <pre>
>> +<domain>
>> +  ...
>> +  <sev>
>> +    <policy> 1 </policy>
>> +    <cbitpos> 47 </cbitpos>
>> +    <reduced-phys-bits> 5 </reduced-phys-bits>
>> +    <session> ... </session>
>> +    <dh-cert> ... </dh>
>> +  </sev>
> 
> Minor nitpick - since this inheranted SEV specific, I think we could do
> with having a generic top level element with a type=sev. eg
> 
>    <launch-security type="sev">
>         <policy>...</policy>
>         <cbitpos>..</cbitpos>
>         ...etc...
>    </launch>
> 
> then we can plug in custom data if other vendors invent competing
> solutions to AMD's SEV.
> 

I am okay with this, how about <memory-encryption> instead of 
<launch-security>, are you okay with it ?