Re: [PATCH 3/4] drivers/vfio: New IOCTL command VFIO_EEH_INFO

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

On Tue, May 20, 2014 at 02:25:45PM +0200, Alexander Graf wrote:
>
>On 20.05.14 14:21, Gavin Shan wrote:
>>On Tue, May 20, 2014 at 01:44:21PM +0200, Alexander Graf wrote:
>>>On 20.05.14 13:40, Gavin Shan wrote:
>>>>On Tue, May 20, 2014 at 01:28:40PM +0200, Alexander Graf wrote:
>>>>>On 20.05.14 13:21, Alexander Graf wrote:
>>>>>>On 20.05.14 10:30, Gavin Shan wrote:
>>>>>>>The patch adds new IOCTL command VFIO_EEH_OP to VFIO PCI device
>>>>>>>to support EEH functionality for PCI devices, which have been
>>>>>>>passed from host to guest via VFIO.
>>>>>>>
>>>>>>>Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>>>>>>---
>>>>>>>  arch/powerpc/platforms/powernv/Makefile   |   1 +
>>>>>>>  arch/powerpc/platforms/powernv/eeh-vfio.c | 445
>>>>>>>++++++++++++++++++++++++++++++
>>>>>>>  drivers/vfio/pci/vfio_pci.c               |  24 +-
>>>>>>>  drivers/vfio/pci/vfio_pci_private.h       |  16 ++
>>>>>>>  include/uapi/linux/vfio.h                 |  43 +++
>>>>>>>  5 files changed, 523 insertions(+), 6 deletions(-)
>>>>>>>  create mode 100644 arch/powerpc/platforms/powernv/eeh-vfio.c
>>>>>>Why doesn't this code live inside the vfio module? If I don't load
>>>>>>the vfio module, I don't need that code to waste memory in my
>>>>>>kernel, no?
>>>>Yes, It saves some memory.
>>>>
>>>>>So I think from a modeling point of view, you want VFIO code that
>>>>>calls reasonably generic helpers inside the kernel to deal with
>>>>>errors.
>>>>>
>>>>>The "generic helpers" don't have anything to do with VFIO. Everything
>>>>>that interfaces via ioctls with user space is 100% VFIO code.
>>>>>
>>>>>The latter should be tristate inside vfio.ko, the former can be =y.
>>>>>
>>>>The main reason I put eeh-vfio.c to arch/powerpc/platforms/powernv/ is
>>>>the source file needs access data structures (struct pnv_phb) defined
>>>>in "pci.h" under that directory.
>>>Then create a good in-kernel framework from that directory and make
>>>use of it from the VFIO code :). But please don't mesh together VFIO,
>>>powernv EEH handling and RTAS.
>>>
>>Yeah. How about this? :-)
>>
>>- Move eeh-vfio.c to drivers/vfio/pci/
>>- From eeh-vfio.c, dereference arch/powerpc/kernel/eeh.c::eeh_ops, which
>>   is arch/powerpc/plaforms/powernv/eeh-powernv.c::powernv_eeh_ops. Call
>
>Hrm, I think it'd be nicer to just export individual functions that
>do thing you want to do from eeh.c.
>

Ok. Got it. Thanks for your comments :)

Thanks,
Gavin

>
>Alex
>
>>   to the corresponding callbacks in "eeh_ops" based on incoming RTAS request.
>>
>>   The file would be renamed to "vfio_eeh.c" as well after moving to VFIO
>>   driver directory.
>>
>>Thanks,
>>Gavin
>>
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