On 30-Oct-18 12:02 PM, Alejandro Lucero wrote:


On Sun, Oct 28, 2018 at 11:04 PM Thomas Monjalon <tho...@monjalon.net <mailto:tho...@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.bura...@intel.com
    <mailto:anatoly.bura...@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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