[Xen-devel] Re: [PATCHEs]: support more than 32 VCPUs in guests

[Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>]

On Mon, 14 Jun 2010 10:37:30 +0100
Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

> On 06/10/2010 03:13 AM, Mukesh Rathor wrote:
> > Well, BUG_ON is only triggered if booting more than 32 VCPUs on a
> > *very old* xen (pre xen 3.1.0). 
> >
> > Looking at code closely, we could just set setup_max_cpus to 32 some
> > where in xen function, perhaps even in xen_vcpu_setup(). That way
> > later in smp_init() it would just be ok. 
> >   
> 
> Yes.
> 
> > One thing tho, the per cpus areas are already setup at that point,
> > so that would need to be cleaned. BTW, I don't understand why 
> > have_vcpu_info_placement is set to 0 in xen_guest_init()? 
> >   
> 
> xen_guest_init is used by the pvhvm path, and hvm domains don't have a
> notion of vcpu info placement.
> 
> > What minimum version of xen is required to run pvops kernel?
> >   
> 
> In theory it should be back-compatible for all Xen 3, but in practice
> it tweaks lots of bugs in older Xens (particularly 32-on-64).  I
> don't know that anyone has definitively established an earliest
> version.  I implemented vcpu info placement for use in pvops kernels,
> but it was never my intention that it be an absolute requirement.
> 
>     J

Ok, attached  patch without BUG_ON. Please feel free to modify
to your liking also.

Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>


thanks,
Mukesh

Attachment: pvops.diff
Description: Text Data

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