Re: [kvm-devel] [Qemu-devel] [PATCH 2 of 3] Optionally link against libuuid if present

["Filip Navara" <xnavara@volny.cz>]

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On Jan 20, 2008 5:53 PM, Alexander Graf <alex@csgraf.de> wrote:

>
> On Jan 20, 2008, at 5:37 PM, Filip Navara wrote:
>
> The specific VMware backdoor call isn't implemented, but the framework is
> there and it wouldn't be hard to add support for it. The BIOS can fallback
> to some "reasonable" value if the backdoor isn't available.
>
>
> +        memset(bios_uuid, 0, 16);
>
> This value? Why not put something more "reasonable" in there? Does a uuid
> have to meet specific criteria (checksums)? If not, why not simply put
> something like "QEMU" in here? If I remember correctly OSX needs a value in
> the uuid or it fails to boot, so it might be a good idea to give it
> something better than an empty string.
>

Yes, this value. All zeroes means that UUID is not present in the system.
The value has to follow the criteria of SMBIOS specification, section
3.3.2.1, namely it has to be formatted like this:

DWORD time_low;
WORD time_mid;
WORD time_high_and_version;
BYTE clock_seq_hi_and_reserved;
BYTE clock_seq_low;
BYTE node_number[6];

I doubt any driver really checks the value, except maybe for the all-0xFF or
all-0x00 case.

- Filip

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