Re: [Qemu-devel] [PATCH 1/2] pc-dimm: No numa option shouldn't break hotplug memory feature

[Hu Tao]

On Wed, Sep 17, 2014 at 02:19:05PM +0400, Andrey Korolyov wrote:
> On Wed, Sep 17, 2014 at 2:00 PM, Tang Chen <address@hidden> wrote:
> > Add Andrey Korolyov <address@hidden>
> >
> > On 09/17/2014 04:32 PM, Hu Tao wrote:
> >>
> >> On Tue, Sep 16, 2014 at 06:39:15PM +0800, zhanghailiang wrote:
> >>>
> >>> If we do not configure numa option, memory hotplug should work as well.
> >>> It should not depend on numa option.
> >>>
> >>> Steps to reproduce:
> >>> (1) Start VM: qemu-kvm -m 1024,slots=4,maxmem=8G
> >>> (2) Hotplug memory
> >>> It will fail and reports:
> >>> "'DIMM property node has value 0' which exceeds the number of numa nodes:
> >>> 0"
> >>>
> >> I rememberd Tang Chen had a patch for this bug, this is what Andrey
> >> suggested:
> >>
> >>    I thnk that there should be no
> >>    cases when dimm is plugged (and check from patch is fired up) without
> >>    actually populated NUMA, because not every OS will workaround this by
> >>    faking the node.
> >
> >
> > According to Andrey Korolyov <address@hidden>, memory hotplug should not
> > work without SRAT. So maybe forcing to create a NUMA node and SRAT will be
> > better idea.
> >
> > I'm have been working on it.
> >
> > Thanks.
> >
> >
> >>
> >> https://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg04587.html
> >>
> >> Have you tested this patch with Windows guest?
> >>
> >> Regards,
> >> Hu
> >>
> >>
> >
> 
> Thanks, is there will be a place to guard against misconfiguration in
> the dimm properties for NUMA too? For example, right now I may specify
> just one node for a topo and assign dimms to more than one node, which
> will pass argument checks and will result in memory allocation errors
> in guest.

Yes, there is, in function pc_dimm_realize().

Regards,
Hu