Re: [PATCH kernel] powerpc/powernv/sriov: Register IOMMU groups for VFs

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Feb 18, 2019 at 04:58:01PM +1100, Alexey Kardashevskiy wrote:
> The compound IOMMU group rework moved iommu_register_group() together in
> pnv_pci_ioda_setup_iommu_api() (which is a part of ppc_md.pcibios_fixup).
> As the result, pnv_ioda_setup_bus_iommu_group() does not create groups
> any more, it only adds devices to groups.
> 
> This works fine for boot time devices. However IOMMU groups for SRIOV's
> VFs were added by pnv_ioda_setup_bus_iommu_group() so this got broken:
> pnv_tce_iommu_bus_notifier() expects a group to be registered for VF
> and it is not.
> 
> This adds missing group registration and adds a NULL pointer check into
> the bus notifier so we won't stop in xmon if there is no group, although
> it is not expected to happen now.
> 
> Fixes: 0bd971676e68 "powerpc/powernv/npu: Add compound IOMMU groups"
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
> 
> Fixes https://bugzilla.linux.ibm.com/show_bug.cgi?id=175550
> "Kernel Oops while creating SRIOV VF's."
> 
> 
> ---
>  arch/powerpc/platforms/powernv/pci-ioda.c | 2 ++
>  arch/powerpc/platforms/powernv/pci.c      | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 7db3119..145373f 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1593,6 +1593,8 @@ static void pnv_ioda_setup_vf_PE(struct pci_dev *pdev, u16 num_vfs)
>  
>  		pnv_pci_ioda2_setup_dma_pe(phb, pe);
>  #ifdef CONFIG_IOMMU_API
> +		iommu_register_group(&pe->table_group,
> +				pe->phb->hose->global_number, pe->pe_number);
>  		pnv_ioda_setup_bus_iommu_group(pe, &pe->table_group, NULL);
>  #endif
>  	}
> diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
> index 45fb70b..ef9448a 100644
> --- a/arch/powerpc/platforms/powernv/pci.c
> +++ b/arch/powerpc/platforms/powernv/pci.c
> @@ -1147,6 +1147,8 @@ static int pnv_tce_iommu_bus_notifier(struct notifier_block *nb,
>  			return 0;
>  
>  		pe = &phb->ioda.pe_array[pdn->pe_number];
> +		if (!pe->table_group.group)
> +			return 0;
>  		iommu_add_device(&pe->table_group, dev);
>  		return 0;
>  	case BUS_NOTIFY_DEL_DEVICE:

-- 
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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