Re: [PATCH v9 03/19] vfio: platform: add the VFIO PLATFORM module to Kconfig

[Antonios Motakis]

On Thu, Nov 13, 2014 at 9:05 AM, Hongbo Zhang <hongbo.zhang@xxxxxxxxxx> wrote:
> On 12 November 2014 17:57, Antonios Motakis
> <a.motakis@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>> Hello Hongbo,
>>
>> On Wed, Nov 12, 2014 at 10:52 AM, Hongbo Zhang <hongbo.zhang@xxxxxxxxxx> wrote:
>>> On 28 October 2014 02:07, Antonios Motakis
>>> <a.motakis@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>>>>
>>>> Enable building the VFIO PLATFORM driver that allows to use Linux platform
>>>> devices with VFIO.
>>>>
>>>> Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
>>>> ---
>>>>  drivers/vfio/Kconfig           | 1 +
>>>>  drivers/vfio/Makefile          | 1 +
>>>>  drivers/vfio/platform/Kconfig  | 9 +++++++++
>>>>  drivers/vfio/platform/Makefile | 4 ++++
>>>>  4 files changed, 15 insertions(+)
>>>>  create mode 100644 drivers/vfio/platform/Kconfig
>>>>  create mode 100644 drivers/vfio/platform/Makefile
>>>>
>>>> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
>>>> index a0abe04..962fb80 100644
>>>> --- a/drivers/vfio/Kconfig
>>>> +++ b/drivers/vfio/Kconfig
>>>> @@ -27,3 +27,4 @@ menuconfig VFIO
>>>>           If you don't know what to do here, say N.
>>>>
>>>>  source "drivers/vfio/pci/Kconfig"
>>>> +source "drivers/vfio/platform/Kconfig"
>>>> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
>>>> index 0b035b1..dadf0ca 100644
>>>> --- a/drivers/vfio/Makefile
>>>> +++ b/drivers/vfio/Makefile
>>>> @@ -3,3 +3,4 @@ obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
>>>>  obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
>>>>  obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
>>>>  obj-$(CONFIG_VFIO_PCI) += pci/
>>>> +obj-$(CONFIG_VFIO_PLATFORM) += platform/
>>>> diff --git a/drivers/vfio/platform/Kconfig b/drivers/vfio/platform/Kconfig
>>>> new file mode 100644
>>>> index 0000000..c51af17
>>>> --- /dev/null
>>>> +++ b/drivers/vfio/platform/Kconfig
>>>> @@ -0,0 +1,9 @@
>>>> +config VFIO_PLATFORM
>>>> +       tristate "VFIO support for platform devices"
>>>> +       depends on VFIO && EVENTFD && ARM
>>>
>>> Hi Antonios,
>>> Is this only for ARM? how about X86 and PowerPC?
>>> On Freescale's PowerPC platform, the IOMMU is called PAMU (Peripheral
>>> Access Management Unit), and I am trying to use this VFIO framework on
>>> it.
>>>
>>
>> In principle it should be working on any platform with such devices;
>> as long as you have a VFIO IOMMU driver for the PAMU (on ARM we use
>> VFIO PLATFORM for the device, with VFIO IOMMU TYPE1 for the IOMMU).
>>
>
> Antonios,
> As far as you know, on which ARM platform can I apply your patches directly?
> My purpose is to apply you patches[1], and then implement a user space
> driver to evaluate the performance.
>

In principle, if your target has a working IOMMU in front of a
platform or AMBA device, then you should be able to use this.

In practice, I have tested this on various fast models, and less
extensively on Arndale in the past. Linaro as far as I know has tested
this series on Calxeda devices with an xgmac NIC.

> [1]  It is better without manually merging conflicts/dependencies etc,
> I am vfio-platform user, not a iommu expert.
>
>> So if you have a suitable IOMMU driver for your target, feel free to
>> test it, and let us know of the results.
>>
>>>>
>>>> +       help
>>>> +         Support for platform devices with VFIO. This is required to make
>>>> +         use of platform devices present on the system using the VFIO
>>>> +         framework.
>>>> +
>>>> +         If you don't know what to do here, say N.
>>>> diff --git a/drivers/vfio/platform/Makefile b/drivers/vfio/platform/Makefile
>>>> new file mode 100644
>>>> index 0000000..279862b
>>>> --- /dev/null
>>>> +++ b/drivers/vfio/platform/Makefile
>>>> @@ -0,0 +1,4 @@
>>>> +
>>>> +vfio-platform-y := vfio_platform.o vfio_platform_common.o
>>>> +
>>>> +obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform.o
>>>> --
>>>> 2.1.1
>>>>
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