Re: [PATCH] spapr: change default interrupt mode back to 'xics'

[David Gibson]

On Wed, Nov 06, 2019 at 09:28:20AM +0100, Greg Kurz wrote:
> On Tue,  5 Nov 2019 15:17:44 -0600
> Lijun Pan <address@hidden> wrote:
> 
> > The hugetlbfs hugepage leakage is found under following test procedures:
> > 1. configure hugetlbfs to back guest memory with '-mem-path /dev/hugepages'
> > 2. hot plug a vcpu and remove it, then quit the guest.
> > 3. hugepage leaks found on the host
> > 
> > git bisect points to the first bad commit: bd94bc064.
> > 
> 
> Hmmm... Have you investigated some more to understand what's really
> happening here ? Is it a problem with QEMU or KVM ? Does it also happen
> if you don't use the in-kernel irqchip ?
> 
> Please provide more details because reverting to XICS looks like a big
> hammer/workaround to me.

Quite.  This also changes the behaviour for the existing pseries-4.1
machine type, which is absolutely a no go.

We need to fix this properly.

> 
> > Fixes: bd94bc064 ("spapr: change default interrupt mode to 'dual'")
> > Cc: Cédric Le Goater <address@hidden>
> > Cc: David Gibson <address@hidden>
> > Signed-off-by: Lijun Pan <address@hidden>
> > ---
> >  hw/ppc/spapr.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 94f9d27096..26b064fb6c 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -4437,7 +4437,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
> > void *data)
> >      smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON;
> >      smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF;
> >      spapr_caps_add_properties(smc, &error_abort);
> > -    smc->irq = &spapr_irq_dual;
> > +    smc->irq = &spapr_irq_xics;
> >      smc->dr_phb_enabled = true;
> >      smc->linux_pci_probe = true;
> >      smc->smp_threads_vsmt = true;
> 

-- 
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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