Re: [dpdk-dev] [RFC PATCH] bus/pci: avoid depending on private value in kernel source

[Tiwei Bie <tiwei.bie@intel.com>]

Hi David,

On Wed, Jul 03, 2019 at 09:02:59AM +0200, David Marchand wrote:
> Hello,
> 
> On Wed, Jul 3, 2019 at 7:47 AM Tiwei Bie <tiwei.bie@intel.com> wrote:
> 
>     The value 40 used in VFIO_GET_REGION_ADDR() is a private value
>     (VFIO_PCI_OFFSET_SHIFT) defined in Linux kernel source [1]. It
>     is not part of VFIO API, and we should not depend on it.
> 
>     [1] https://github.com/torvalds/linux/blob/6fbc7275c7a9/drivers/vfio/pci/
>     vfio_pci_private.h#L19
> 
> 
> 
> I did not follow linux kernel changes, is there something that would change
> this offset?
> It looks like a cleanup (did not look into the details yet), do we need this
> now?

In VFIO/mdev [1], the offset can be something different. It depends
on the parent device. It's not just a cleanup. It's a preparation
for the mdev support in DPDK.

[1] https://github.com/torvalds/linux/blob/master/Documentation/vfio-mediated-device.txt

Thanks,
Tiwei

> 
> --
> David Marchand