Re: [PATCH 0/2] Fix dmar fault interrupt problems

[Chris Wright <chrisw@sous-sol.org>]

* Suresh Siddha (suresh.b.siddha@intel.com) wrote:
> On Tue, 2010-11-30 at 10:13 -0800, Chris Wright wrote:
> > * Suresh Siddha (suresh.b.siddha@intel.com) wrote:
> > > On Tue, 2010-11-30 at 00:28 -0800, Kenji Kaneshige wrote:
> > > > Hi,
> > > > 
> > > > Here are patches to fix the following problems regarding dmar fault interrupt.
> > > > 
> > > > - No dmar fault event is notified in x2apic cluster mode
> > > > - Changing IRQ affinity of dmar fault interrupt causes "No irq handler
> > > >   for vector (irq XX)" message and dmar fault interrupts are never
> > > >   notified after that.
> > > 
> > > Kenji, In addition to these two, there are couple of more patches that
> > > are needed to fix the kexec/kdump issue that we are debugging on RH
> > > bugzilla.
> > > 
> > > I will post all these 4 patches shortly. I already noticed and queued
> > > the second patch (dmar irq migration)  you mentioned.
> > 
> > And one of them (the additional call to flushing existing dmar faults)
> > is not needed.
> 
> yes, that patch is not needed for the current kexec/kdump issue. But
> nevertheless that is an issue that needs to be addressed aswell.

AFAICT, it just becomes a duplicate call in a narrow window.

native_smp_prepare_cpus() (or APIC_init_uniprocessor()):
 enable_IR_x2apic()
  enable_IR()
   enable_intr_remapping() <-- clears faults
 default_setup_apic_routing()
   enable_drhd_fault_handling() <-- added call to clear faults

That's what I meant by not needed.

thanks,
-chris