SSID and CPU pool parsing in xl / libxl

SSID and CPU pool parsing in xl / libxl

[Wei Liu]

Hi Daniel, Dario, Juergen and others

I'm trying to overhaul some libxl infrastructure at the moment, so that
we can preserve domain configurations across save and restore. The first
step is libxl needs to be able to serialize / deserialize
configurations.

When I went through the list of xl config file options, most of the
options can be easily serialized and sent over the wire to the other
end. But SSID parsing and CPU pool ID parsing look exceptional -- they
happen in xl (toolstack) level, not libxl (library) level.

Take "init_seclabel" as an example, xl calls libxl_flask_context_to_sid
to translate a string to an SSID (which is local to host) then passes it
to libxl. If libxl serialize its data, then the receiving end only sees
the translated SSID, not the "init_seclabel". The string is actually the
relavent bit to rebuild a domain, not the SSID (because it's local to
host). The same situation applies to CPU pool ID parsing.

I plan to push the parsing down to libxl level, but I'm not sure if
there's any reason it's done in xl in the first place. Please let me
know if you have any concern.

Thanks
Wei.

Re: SSID and CPU pool parsing in xl / libxl

[Ian Campbell]

On Fri, 2014-04-25 at 11:20 +0100, Wei Liu wrote:
> Hi Daniel, Dario, Juergen and others
> 
> I'm trying to overhaul some libxl infrastructure at the moment, so that
> we can preserve domain configurations across save and restore. The first
> step is libxl needs to be able to serialize / deserialize
> configurations.
> 
> When I went through the list of xl config file options, most of the
> options can be easily serialized and sent over the wire to the other
> end. But SSID parsing and CPU pool ID parsing look exceptional -- they
> happen in xl (toolstack) level, not libxl (library) level.
> 
> Take "init_seclabel" as an example, xl calls libxl_flask_context_to_sid
> to translate a string to an SSID (which is local to host) then passes it
> to libxl. If libxl serialize its data, then the receiving end only sees
> the translated SSID, not the "init_seclabel". The string is actually the
> relavent bit to rebuild a domain, not the SSID (because it's local to
> host). The same situation applies to CPU pool ID parsing.
> 
> I plan to push the parsing down to libxl level, but I'm not sure if
> there's any reason it's done in xl in the first place. Please let me
> know if you have any concern.

FWIW when I spoke to Wei about this IRL I couldn't think of/remember any
reason why this parsing was done in xl not libxl.

Ian.

Re: SSID and CPU pool parsing in xl / libxl

[Daniel De Graaf]

On 04/25/2014 06:20 AM, Wei Liu wrote:
> Hi Daniel, Dario, Juergen and others
>
> I'm trying to overhaul some libxl infrastructure at the moment, so that
> we can preserve domain configurations across save and restore. The first
> step is libxl needs to be able to serialize / deserialize
> configurations.
>
> When I went through the list of xl config file options, most of the
> options can be easily serialized and sent over the wire to the other
> end. But SSID parsing and CPU pool ID parsing look exceptional -- they
> happen in xl (toolstack) level, not libxl (library) level.
>
> Take "init_seclabel" as an example, xl calls libxl_flask_context_to_sid
> to translate a string to an SSID (which is local to host) then passes it
> to libxl. If libxl serialize its data, then the receiving end only sees
> the translated SSID, not the "init_seclabel". The string is actually the
> relavent bit to rebuild a domain, not the SSID (because it's local to
> host). The same situation applies to CPU pool ID parsing.
>
> I plan to push the parsing down to libxl level, but I'm not sure if
> there's any reason it's done in xl in the first place. Please let me
> know if you have any concern.
>
> Thanks
> Wei.

I agree, the label-to-sid conversion should be pushed down to the libxl
level.

-- 
Daniel De Graaf
National Security Agency

Re: SSID and CPU pool parsing in xl / libxl

[Juergen Gross]

On 25.04.2014 12:20, Wei Liu wrote:
> Hi Daniel, Dario, Juergen and others
>
> I'm trying to overhaul some libxl infrastructure at the moment, so that
> we can preserve domain configurations across save and restore. The first
> step is libxl needs to be able to serialize / deserialize
> configurations.
>
> When I went through the list of xl config file options, most of the
> options can be easily serialized and sent over the wire to the other
> end. But SSID parsing and CPU pool ID parsing look exceptional -- they
> happen in xl (toolstack) level, not libxl (library) level.
>
> Take "init_seclabel" as an example, xl calls libxl_flask_context_to_sid
> to translate a string to an SSID (which is local to host) then passes it
> to libxl. If libxl serialize its data, then the receiving end only sees
> the translated SSID, not the "init_seclabel". The string is actually the
> relavent bit to rebuild a domain, not the SSID (because it's local to
> host). The same situation applies to CPU pool ID parsing.
>
> I plan to push the parsing down to libxl level, but I'm not sure if
> there's any reason it's done in xl in the first place. Please let me
> know if you have any concern.

Just go ahead. CPU pool ID parsing was only used in xl, so I put it there.


Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
PSO PM&D ES&S SWE OS6                  Telephone: +49 (0) 89 62060 2932
Fujitsu                                   e-mail: juergen.gross@ts.fujitsu.com
Mies-van-der-Rohe-Str. 8                Internet: ts.fujitsu.com
D-80807 Muenchen                 Company details: ts.fujitsu.com/imprint.html