[libvirt] [PATCH 1/5] S390: Documentation for CCW address type

Viktor Mihajlovski mihajlov at linux.vnet.ibm.com
Thu Feb 7 16:16:04 UTC 2013


On 02/07/2013 04:02 PM, Daniel P. Berrange wrote:
>
> Can you explaiin the semantics of the different components
> in this device address ? WIth PCI addresses there are 4
> colon-separated numbers a:b:c:d, which we explicitly
> separate in the XML
>
>    <address type="pci" domain="a" bus="b" device="c" function="d"/>
>
> Unless there's a compelling reason not to, I think CCW
> address XML ought to be similar, and use decimal notication
> for each part, rather than hex, or at least require an
> explicit 0x for hex. eg
>
>    <address type="ccw" xxxx="254" yyyy="0" zzzz="1234" />
>    <address type="ccw" xxxx="0xfe" yyyy="0" zzzz="1234" />
>
> Daniel
>
Thanks for taking a look. To be true my initial version
was following the PCI example with individual attributes.
The s390 folks I've talked to didn't like it too much,
finding it unwieldy.

CCW addresses are much more visible (and relevant) to a Linux
admin on s390 than usually PCI addresses on other systems.
In fact on that platform they are more ubiquitous than
say IPv6 addresses which by power of convention are written
in a compact hex notation.

-- 

Mit freundlichen Grüßen/Kind Regards
    Viktor Mihajlovski

IBM Deutschland Research & Development GmbH
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