Re: [dpdk-dev] [PATCH v3 0/3] force IOVA to a particular mode

[Alejandro Lucero <alejandro.lucero@netronome.com>]

On Sun, Oct 28, 2018 at 11:04 PM Thomas Monjalon <thomas@monjalon.net>
wrote:

> 11/10/2018 12:08, Thomas Monjalon:
> > +Cc more maintainers in order to collect more reviews
> >
> > 04/10/2018 11:19, Burakov, Anatoly:
> > > On 03-Oct-18 9:53 PM, eric zhang wrote:
> > > > This patchset introduces an EAL command line option "--iova-mode"
> > > > to give the user a facility to force IOVA mode to a special value.
> > > >
> > > > Auto detection of the IOVA mode, based on probing the bus and IOMMU
> > > > configuration, may not report the desired addressing mode when
> virtual
> > > > devices that are not directly attached to the bus are present.
> > > > The EAL command line option "--iova-mode" can be used to select
> either
> > > > physical addressing('pa') or virtual addressing('va').
> > >
> > > Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
>
> Rebased and applied, thanks
>
>
>
Could not this lead to a problem if a device can not wok with the mode set?
For example, IOVA mode set to VA and IOMMU hw with less bits than those
required for the virtual addresses?

IMO any device should be attached to a bus, and a bus should have a
function for setting IOVA mode and the --iova-mode option just allowed with
supported IOVA modes within the bus.