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

[Tiwei Bie]

On Wed, Jul 03, 2019 at 09:36:26AM +0200, David Marchand wrote:
> On Wed, Jul 3, 2019 at 9:35 AM Tiwei Bie <tiwei.bie at intel.com> wrote:
> 
>     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 at 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
> 
> 
> 
> Ok, thanks.
> So we can wait for mdev to be ready before working on this.

What do you mean by "mdev to be ready"? RFC ready? I don't see
anything blocking the discussion on this now.

PS. I already sent a RFC series of the mdev support in DPDK
    to the mailing list 3 month ago.

Thanks,
Tiwei

> 
> 
> --
> David Marchand