Re: [libvirt] [PATCH] 0/4 Add SMBIOS settings to domain definition
On Fri, Oct 22, 2010 at 09:28:48AM +0100, Daniel P. Berrange wrote:
On Thu, Oct 21, 2010 at 09:52:51PM +0200, Daniel Veillard wrote:
> The SMBIOS data are a standardized set of data structures available
> in the BIOS area of PCs. Those blocks of data describe things like
> BIOS version informations, machine vendor, model and identifiers,
> as well as various parts of the machine capability. On a linux
> machine running dmidecode allows to dump those informations.
>
> Spec available at the DMTF: http://dmtf.org/standards/smbios
>
> From a virtualization POV, it's mostly the first block describing
> the BIOS named "type 0" and the second block describing the machine
> named "type 1" which are of interest. Those data are usually accessed
> either from the OS or from management application, and being able to
> override the default setings may be needed for such management.
>
> The suggested XML description follows the logical structure of the
> data, one top smbios description, with one or more blocks, each
> containing the entries, the example below gives an idea:
>
> <smbios>
> <table type="0">
> <entry name="Vendor">QEmu/KVM</entry>
> <entry name="Version">0.13</entry>
> </table>
> <table type="1">
> <entry name="Manufacturer">Fedora</entry>
> <entry name="Product">Virt-Manager</entry>
> <entry name="Version">0.8.2-3.fc14</entry>
> <entry
name="UUID">c7a5fdbdedaf9455926ad65c16db1809</entry>
> </table>
> </smbios>
I've never really been a fan of the idea of including SMBios
data in the XML because it is an x86 specific concept, which
only works with HVM guests & the type=1/2/3 is rather opaque
in meaning.
The semantic is well defined it's information available
from the BIOS, c.f. the DMTF spec. The we know how to get it
from a guest, and it's not dependant on the virtualization
layer used, it may or may not support it, but at least
the expectation are clear.
I can't help thinking that we should define a set of general
metadata tags, and then have a internal mapping of those to
SMBIOS fields, in the same way that the <uuid> is automatically
mapped to SMBIOS.
eg, define a set of metadata like this:
<metadata>
<bios-vendor>SeaBIOS</bios-vendor>
<bios-version>0.13</bios-version>
<system-manufacturer>Fedora</system-manufacturer>
<system-product>KVM</system-product>
<system-version>0.8.2</system-version>
<system-uuid>c7a5fdbdedaf9455926ad65c16db1809</system-uuid>
</metadata>
Okay, but what is the semantic of <system-product> for example ?
Does that mean SMBIOS type 1 Product Name or something else left
to the appreciation of the driver or of the user ?
And for smbios just indicate what the source of the data is:
<smbios mode="host|emulate"/>
host - copy from host SMBIOS
emulate - generic emulator settings + metadata overrides
This would map better to what VMWare is letting you do, and let us expose
the metadata through other non-SMBIOS data channels
Your suggestion is far more flexible, but that comes with the
trouble that we have to define those metadata semantic, or we don't
define their semantic, and it may get messy in the long term.
Daniel
--
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