[dpdk-dev] [PATCH v4 0/4] Fixes on IOVA mode selection

Jerin Jacob Kollanukkaran jerinj at marvell.com
Tue Jul 23 06:18:50 CEST 2019


> -----Original Message-----
> From: Stojaczyk, Dariusz <dariusz.stojaczyk at intel.com>
> Sent: Tuesday, July 23, 2019 9:06 AM
> To: Thomas Monjalon <thomas at monjalon.net>; David Marchand
> <david.marchand at redhat.com>; Burakov, Anatoly
> <anatoly.burakov at intel.com>; Jerin Jacob Kollanukkaran
> <jerinj at marvell.com>
> Cc: dev at dpdk.org
> Subject: [EXT] RE: [dpdk-dev] [PATCH v4 0/4] Fixes on IOVA mode selection
> 
> This introduces a regression where uio-bound devies are attached to a DPDK
> app at runtime.

Just to understand the requirements;
# Is this requirement for SPDK?
# Is brand new PCI device scanned and attached to DPDK at runtime?
# Any specific reason for using uio vs vfio?

If it is for SPDK, 
# How about introducing rte_eal_init_with_mode(enum rte_iova_mode)?
# How about adding dummy bus which returns RTE_IOVA_PA in the bus_get_iommus_class() in SPDK code base?

> 
> When there are no devices attached at initialization, the only safe default
> should be RTE_IOVA_PA. With RTE_IOVA_VA we just won't be able to do
> any DMA to uio-bound PCI devices.
> 
> Can we revert this patch?
> 
> D.
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Thomas Monjalon
> > Sent: Monday, July 22, 2019 5:53 PM
> > To: David Marchand <david.marchand at redhat.com>; Burakov, Anatoly
> > <anatoly.burakov at intel.com>; jerinj at marvell.com
> > Cc: dev at dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH v4 0/4] Fixes on IOVA mode selection
> >
> > 22/07/2019 14:56, David Marchand:
> > > Following the issues reported by Jerin and the discussion that
> > > emerged from it, here are fixes to restore and document the behavior
> > > of the EAL and the pci bus driver.
> > >
> > > I pondered all the arguments and tried to have the less changes
> > > possible.
> > > I can't find a need for a flag to just announce support of physical
> > > addresses from the pmd point of view.
> > > So it ended up with something really close to what Jerin had suggested.
> > >
> > > But the problem is that this is still unfinished wrt the documentation.
> > > I will be offline for 10 days and we need this to move forward, so
> > > sending anyway.
> > >
> > > Changelog since v3:
> > > - fixed typos in patch 2,
> > > - updated patch 3 title,
> > > - moved and reworded comments in the note section in patch 4,
> > >
> > > Changelog since v2 (Jerin):
> > > - Patch 2/4 - Remove personal appeals in log messages(Anatoly)
> > > - Patch 4/4 - Added documentation (Anatoly)
> > >
> > > Changelog since v1 (Jerin):
> > > - Changed RTE_PCI_DRV_IOVA_AS_VA flag name as
> > RTE_PCI_DRV_NEED_IOVA_AS_VA
> > >   (patch 3/4)
> > > - Changed IOVA mode as VA for default case(patch 4/4) with
> > documentation
> > > - Tested the patch series on octeontx2 platform
> >
> > Applied, thanks Jerin, Anatoly and David for converging on a
> > documented solution together.
> >
> >



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