Re: [Qemu-ppc] [RFC PATCH v0 2/2] spapr: Abort when HTAB of requested size isn't allocated

[David Gibson]

On Thu, Sep 24, 2015 at 09:13:58AM +0530, Bharata B Rao wrote:
> On Wed, Sep 23, 2015 at 01:29:51PM +1000, David Gibson wrote:
> > On Tue, Sep 22, 2015 at 09:09:49AM +0530, Bharata B Rao wrote:
> > > Terminate the guest when HTAB of requested size isn't allocated by
> > > the host.
> > > 
> > > When memory hotplug is attempted on a guest that has booted with
> > > less than requested HTAB size, the guest kernel will not be able
> > > to gracefully fail the hotplug request. This patch will ensure that
> > > we never end up in a situation where memory hotplug fails due to
> > > less than requested HTAB size.
> > > 
> > > Signed-off-by: Bharata B Rao <address@hidden>
> > 
> > Reviewed-by: David Gibson <address@hidden>
> > 
> > > ---
> > >  hw/ppc/spapr.c | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > > 
> > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > > index 4692122..66446af 100644
> > > --- a/hw/ppc/spapr.c
> > > +++ b/hw/ppc/spapr.c
> > > @@ -992,6 +992,10 @@ static void spapr_alloc_htab(sPAPRMachineState 
> > > *spapr)
> > >  
> > >      if (shift > 0) {
> > >          /* Kernel handles htab, we don't need to allocate one */
> > > +        if (shift != spapr->htab_shift) {
> > > +            error_setg(&error_abort, "Failed to allocated requested HTAB 
> > > size");
> 
> Do you think we should have a bit more verbose message here so that
> use knows what action to take after this abortion ? Like
> 
> "Failed to allocate requested HTAB size, try with lower maxmem"

Uh, yeah, I guess that's better.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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