Re: [Qemu-discuss] Guests don't start with qemu 2.1.0: smbios_get_tables: Assertion `smbios_smp_sockets >= 1' failed

[Jakob Bohm]

On 8/12/2014 8:40 PM, Brian Rak wrote:
> I've been testing 2.1.0, and qemu will no longer start up with our CPU
> configuration.  I get the error:
>
> qemu-kvm: /root/qemu/src/hw/i386/smbios.c:825: smbios_get_tables:
> Assertion `smbios_smp_sockets >= 1' failed.
>
> The relevant parts of my command line:
>
> -smp 4,sockets=2,cores=12,threads=2
>
> This is ultimately coming from my libvirt config of:
>
>    <vcpu placement='static'>4</vcpu>
>    <cpu mode='custom' match='exact'>
>      <topology sockets='2' cores='12' threads='2'/>
>    </cpu>
>
>
> Is this configuration no longer supported?  Up until 2.1.0, this was
> handled well.. for any CPU count < 12, I got one socket with the correct
> number of cores.  For anything over 12 vcpus, I got two sockets.  This
> makes Windows licensing happy.
>
> I took a look at the code, and it seems like it should just cap the
> minimum number of sockets at 1, rather then this assert.
>
> --- ../src_clean/hw/i386/smbios.c       2014-08-01 10:12:17.000000000 -0400
> +++ hw/i386/smbios.c    2014-08-12 14:39:40.560485901 -0400
> @@ -822,7 +822,7 @@
>           smbios_build_type_3_table();
>
>           smbios_smp_sockets = smp_cpus / (smp_cores * smp_threads);
> -        assert(smbios_smp_sockets >= 1);
> +       if (smbios_smp_sockets < 1) smbios_smp_sockets = 1;
>
>           for (i = 0; i < smbios_smp_sockets; i++) {
>               smbios_build_type_4_table(i);
>
> Is there a downside to this patch?

Have you checked why the variable is 0 and not 1 (or 2), maybe there is
a deeper bug which leaves it at 0, even when it should be 2 (or more).

Remember, the place that reports an error is rarely the cause of the
problem.

Enjoy

Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S.  http://www.wisemo.com
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