On Fri, 2013-12-13 at 14:02 +1100, Alexey Kardashevskiy wrote:
> On 12/13/2013 10:35 AM, Scott Wood wrote:
> > On Tue, May 21, 2013 at 01:33:09PM +1000, Alexey Kardashevskiy wrote:
> >> +static int iommu_add_device(struct device *dev)
> >> +{
> >> + struct iommu_table *tbl;
> >> + int ret = 0;
> >> +
> >> + if (WARN_ON(dev->iommu_group)) {
> >> + pr_warn("iommu_tce: device %s is already in iommu group %d, skipping\n",
> >> + dev_name(dev),
> >> + iommu_group_id(dev->iommu_group));
> >> + return -EBUSY;
> >> + }
> > [snip]
> >> +static int __init tce_iommu_init(void)
> >> +{
> >> + struct pci_dev *pdev = NULL;
> >> +
> >> + BUILD_BUG_ON(PAGE_SIZE < IOMMU_PAGE_SIZE);
> >> +
> >> + for_each_pci_dev(pdev)
> >> + iommu_add_device(&pdev->dev);
> >> +
> >> + bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
> >> + return 0;
> >> +}
> >> +
> >> +subsys_initcall_sync(tce_iommu_init);
> >
> > This is missing a check to see whether the appropriate hardware is
> > present. This file should also be renamed to something less generic, and
> > depend on a kconfig symbol more specific than CONFIG_PPC64.
> >
> > When this is combined with CONFIG_FSL_PAMU on hardware with a PAMU, I get
> > a bunch of those "WARN_ON(dev->iommu_group)" dumps because PAMU already
> > got to them. Presumably without PAMU it silently (or with just pr_debug)
> > bails out at some other point.
>
>
> I posted (yet again) yesterday "[PATCH v11] PPC: POWERNV: move
> iommu_add_device earlier" which should fix this. And Bharat asked many
> times for this to get accepted :)
I still get the WARN_ONs even with that patch. You're still registering
the bus notifier unconditionally.
-Scott
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