[dpdk-dev] [PATCH v3 0/3] force IOVA to a particular mode
Burakov, Anatoly
anatoly.burakov at intel.com
Tue Oct 30 14:47:55 CET 2018
On 30-Oct-18 12:02 PM, Alejandro Lucero wrote:
>
>
> On Sun, Oct 28, 2018 at 11:04 PM Thomas Monjalon <thomas at monjalon.net
> <mailto:thomas at 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 at intel.com
> <mailto:anatoly.burakov at 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.
I don't think it should work that way. It should warn the user that an
incompatible IOVA mode was selected, but the user has specified an IOVA
mode for a reason - it probably implies he really means it, so let him :)
--
Thanks,
Anatoly
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