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 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.

Thanks,
Gavin