Re: [PATCH 1/7] VFIO_IOMMU_TYPE1 workaround to build for platform devices

[Don Dutile <ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 10/02/2013 08:14 AM, Alexander Graf wrote:
>
> On 01.10.2013, at 21:21, Yoder Stuart-B08248 wrote:
>
>>>> static int __init vfio_iommu_type1_init(void)
>>>> {
>>>> -	if (!iommu_present(&pci_bus_type))
>>>> +#ifdef CONFIG_PCI
>>>> +	if (iommu_present(&pci_bus_type)) {
>>>> +		iommu_bus_type =&pci_bus_type;
>>>> +		/* For PCI targets, IOMMU_CAP_INTR_REMAP is required */
>>>> +		require_cap_intr_remap = true;
>>>> +	}
>>>> +#endif
>>>> +	if (!iommu_bus_type&&  iommu_present(&platform_bus_type))
>>>> +		iommu_bus_type =&platform_bus_type;
>>>> +
>>>> +	if(!iommu_bus_type)
>>>> 		return -ENODEV;
>>>>
>>>> 	return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
>>>
>>> Is it possible to have a system with both PCI and platform devices?  How
>>> would you support that?  Thanks,
>>
>> It most certainly is a requirement to support both.  This is how
>> all of our (FSL) SoCs will expect to work.
>
> I thought the PCI bus emits a cookie that the system wide IOMMU can then use to differentiate the origin of the transaction? So the same IOMMU can be used for PCI as well as platform routing.
>
*can* be the same IOMMU, yes;
have to, no, so there can be multiple IOMMUs of different types.

>
> Alex
>
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