Subject: Re: [PATCH kernel] powerpc/iommu: Set default DMA offset in dma_dev_setup

From: Alexey Kardashevskiy <[email-masked]>
Date: Thu, 27 Aug 2015 17:41:31 +1000

On 08/27/2015 04:16 PM, Gavin Shan wrote:
> On Thu, Aug 27, 2015 at 04:01:16PM +1000, Alexey Kardashevskiy wrote:
>> "powerpc/iommu: Cleanup setting of DMA base/offset" expects that
>> the default DMA offset is set from pnv_ioda_setup_bus_dma() which
>> is correct unless it is SRIOV where the code flow is different - at
>> the moment when pnv_ioda_setup_bus_dma() is called, there is no PE for
>> the just created VF.
>>
>
> The PEs for VFs are ready at the moment. We don't have pci_dev for
> VFs actually.

Ah, you are right. Should have been:

====
"powerpc/iommu: Cleanup setting of DMA base/offset" expects that
the default DMA offset is set from pnv_ioda_setup_bus_dma() which
is correct unless it is SRIOV where the code flow is different - at
the moment when pnv_ioda_setup_bus_dma() is called, PCI devices
for VFs are not created yet.
====

>> This adds missing set_dma_offset() to pnv_pci_ioda_dma_dev_setup()
>> to cover the case of SRIOV.
>>
>> Note that we still need set_dma_offset() in pnv_ioda_setup_bus_dma()
>> as at the boot time pnv_pci_ioda_dma_dev_setup() is called when no PE
>> was created yet, this happens at the PHB fixup stage.
>>
>> Signed-off-by: Alexey Kardashevskiy <[email-masked]>
>
> Reviewed-by: Gavin Shan <[email-masked]>
>
> Thanks,
> Gavin
>
>> ---
>>
>> Makes sense to squash it to "powerpc/iommu: Cleanup setting of DMA base/offset".
>>
>>
>> ---
>> arch/powerpc/platforms/powernv/pci-ioda.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>> index 2c286b57..af875c1 100644
>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>> @@ -1590,6 +1590,7 @@ static void pnv_pci_ioda_dma_dev_setup(struct pnv_phb *phb, struct pci_dev *pdev
>>
>> 	pe = &phb->ioda.pe_array[pdn->pe_number];
>> 	WARN_ON(get_dma_ops(&pdev->dev) != &dma_iommu_ops);
>> +	set_dma_offset(&pdev->dev, pe->tce_bypass_base);
>> 	set_iommu_table_base(&pdev->dev, pe->table_group.tables[0]);
>> 	/*
>> 	 * Note: iommu_add_device() will fail here as
>> --
>> 2.4.0.rc3.8.gfb3e7d5
>>
>

-- 
Alexey