Re: [PATCH 2/3] device_isolation: Support isolation on POWER p5ioc2 bridges

[Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Wed, 2012-02-01 at 11:58 -0700, Alex Williamson wrote:
> On Wed, 2012-02-01 at 15:46 +1100, David Gibson wrote:
> > This patch adds code to the code for the powernv platform to create
> > and populate isolation groups on hardware using the p5ioc2 PCI host
> > bridge used on some IBM POWER systems.
> > 
> > Signed-off-by: Alexey Kardashevskiy <aik-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org>
> > Signed-off-by: David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>
> > ---
> >  arch/powerpc/platforms/powernv/pci-p5ioc2.c |   14 +++++++++++++-
> >  arch/powerpc/platforms/powernv/pci.h        |    3 +++
> >  2 files changed, 16 insertions(+), 1 deletions(-)
> > 
> > diff --git a/arch/powerpc/platforms/powernv/pci-p5ioc2.c b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
> > index 2649677..e5bb3a6 100644
> > --- a/arch/powerpc/platforms/powernv/pci-p5ioc2.c
> > +++ b/arch/powerpc/platforms/powernv/pci-p5ioc2.c
> > @@ -20,6 +20,7 @@
> >  #include <linux/irq.h>
> >  #include <linux/io.h>
> >  #include <linux/msi.h>
> > +#include <linux/device_isolation.h>
> >  
> >  #include <asm/sections.h>
> >  #include <asm/io.h>
> > @@ -88,10 +89,21 @@ static void pnv_pci_init_p5ioc2_msis(struct pnv_phb *phb) { }
> >  static void __devinit pnv_pci_p5ioc2_dma_dev_setup(struct pnv_phb *phb,
> >  						   struct pci_dev *pdev)
> >  {
> > -	if (phb->p5ioc2.iommu_table.it_map == NULL)
> > +	if (phb->p5ioc2.iommu_table.it_map == NULL) {
> >  		iommu_init_table(&phb->p5ioc2.iommu_table, phb->hose->node);
> > +#ifdef CONFIG_DEVICE_ISOLATION
> > +		phb->p5ioc2.di_group = kzalloc(sizeof(*(phb->p5ioc2.di_group)),
> > +					       GFP_KERNEL);
> > +		BUG_ON(!phb->p5ioc2.di_group ||
> > +		       (device_isolation_group_init(phb->p5ioc2.di_group,
> > +						    "p5ioc2:%llx", phb->opal_id) < 0));
> > +#endif
> 
> Hmm, it's really unfortunate that this is architected so we need to
> surround everything in #ifdefs even though we have stub functions
> defined.

I think maybe we want:

#ifdef CONFIG_DEVICE_ISOLATION
struct device_isolation_group *device_isolation_create_group(void)
{
	struct device_isolation_group *di_group;

	di_group = kzalloc(sizeof(*di_group), GFP_KERNEL);
	if (!di_group)
		return ERR_PTR(-ENOMEM);

	return di_group;
}
#else
struct device_isolation_group *device_isolation_create_group(void)
{
	return NULL;
}
#endif

Then we can do:

	phb->p5ioc2.di_group = device_isolation_create_group();
	BUG_ON(IS_ERR(phb->p5ioc2.di_group) || (device_isolation_group_init(phb->p5ioc2.di_group, ...

(We pass NULL to the stubs, but that's ok)
	
> > +	}
> >  
> >  	set_iommu_table_base(&pdev->dev, &phb->p5ioc2.iommu_table);
> > +#ifdef CONFIG_DEVICE_ISOLATION
> > +	device_isolation_dev_add(phb->p5ioc2.di_group, &pdev->dev);
> > +#endif
> >  }
> >  
> >  static void __init pnv_pci_init_p5ioc2_phb(struct device_node *np,
> > diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
> > index 8bc4796..64ede1e 100644
> > --- a/arch/powerpc/platforms/powernv/pci.h
> > +++ b/arch/powerpc/platforms/powernv/pci.h
> > @@ -87,6 +87,9 @@ struct pnv_phb {
> >  	union {
> >  		struct {
> >  			struct iommu_table iommu_table;
> > +#ifdef CONFIG_DEVICE_ISOLATION
> > +			struct device_isolation_group *di_group;
> > +#endif
> >  		} p5ioc2;
> >  
> >  		struct {
> 
>