Re: [Qemu-devel] [Bug 1297651] [NEW] KVM create a win7 guest with Qemu, it boots up fail

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Mar 26, 2014 at 12:06:38PM -0300, Eduardo Habkost wrote:
> On Wed, Mar 26, 2014 at 04:54:31PM +0200, Michael S. Tsirkin wrote:
> > On Wed, Mar 26, 2014 at 02:48:29PM +0100, Igor Mammedov wrote:
> [...]
> > > more clean would be to abort if CPON index (i.e. APIC ID)
> > > is more than 255. That would affect small number of weird
> > > topologies but sould be fine for most usecases.
> > 
> > Any idea how to trigger this behaviour?
> 
> Set sockets and/or cores to a 2^n+1 value. It will use n+1 bits for the
> socket ID and core ID, making APIC ID larger than CPU index. You can get
> a very large APIC ID if you use, for example:
> 
>   -smp 1,cores=17,threads=17,maxcpus=200
> 
> There's code to limit the maximum APIC ID and abort if it is too large,
> already (so the above command-line will make QEMU abort).

Okay so how do you make this package size exactly 256?

> If we want to
> limit APIC IDs to <255 instead of <256, we just need to change
> ACPI_CPU_HOTPLUG_ID_LIMIT.
> 
> -- 
> Eduardo