From: Sunil Kumar Kori <skori@marvell.com>
To: "Xia, Chenbo" <chenbo.xia@intel.com>, Ray Kinsella <mdr@ashroe.eu>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
David Marchand <david.marchand@redhat.com>
Subject: RE: [PATCH 1/2] doc: announce region based device mapping support
Date: Wed, 13 Jul 2022 07:38:42 +0000 [thread overview]
Message-ID: <CO6PR18MB38605B458699E5224EBAC96EB4899@CO6PR18MB3860.namprd18.prod.outlook.com> (raw)
In-Reply-To: <SN6PR11MB350420286D15E27DE855FD029C899@SN6PR11MB3504.namprd11.prod.outlook.com>
Regards
Sunil Kumar Kori
> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia@intel.com>
> Sent: Wednesday, July 13, 2022 12:58 PM
> To: Sunil Kumar Kori <skori@marvell.com>; Ray Kinsella <mdr@ashroe.eu>
> Cc: dev@dpdk.org; David Marchand <david.marchand@redhat.com>
> Subject: [EXT] RE: [PATCH 1/2] doc: announce region based device mapping
> support
>
> External Email
>
> ----------------------------------------------------------------------
> Hi Sunil,
>
> > -----Original Message-----
> > From: Sunil Kumar Kori <skori@marvell.com>
> > Sent: Wednesday, July 13, 2022 3:04 PM
> > To: Xia, Chenbo <chenbo.xia@intel.com>; Ray Kinsella <mdr@ashroe.eu>
> > Cc: dev@dpdk.org
> > Subject: RE: [PATCH 1/2] doc: announce region based device mapping
> > support
> >
> > Hi Chenbo,
> >
> > There are pci devices which has huge BAR memory but might not be used
> > completely.
> > Like PCIe device DDR memory is exposed over BAR with 32Gb or so.
> > So in that case user might have a requirement to mmap only areas of
> > its interest.
> > Also avoid wasting of extra memory for each pages when kernel mmaps it.
>
> This problem statement makes sense to me. About the solution, pls check
> below.
>
> >
> > Yes, it is similar to sparse mmap in vfio but I didn't find any
> > support in DPDK for sparse mmap.
> > So I picked this approach but in either case, ABI change notification
> > is needed, Right?
>
> For ABI, David & I already mentioned in another email that your notice is not
> needed anymore.
>
> What if you send the patchset to support sparse mmap in DPDK, to me, that
> seems more generic. Could sparse mmap solve your problem?
I will look into sparse mmap and analyze its feasibility to solve my problem.
Will update accordingly.
Thanks Chenbo and David.
>
> Thanks,
> Chenbo
>
> >
> > Regards
> > Sunil Kumar Kori
> >
> > > -----Original Message-----
> > > From: Xia, Chenbo <chenbo.xia@intel.com>
> > > Sent: Thursday, July 7, 2022 6:09 PM
> > > To: Sunil Kumar Kori <skori@marvell.com>; Ray Kinsella
> > > <mdr@ashroe.eu>
> > > Cc: dev@dpdk.org
> > > Subject: [EXT] RE: [PATCH 1/2] doc: announce region based device
> > > mapping support
> > >
> > > External Email
> > >
> > > --------------------------------------------------------------------
> > > --
> > > Hi Sunil,
> > >
> > > > -----Original Message-----
> > > > From: skori@marvell.com <skori@marvell.com>
> > > > Sent: Tuesday, June 28, 2022 9:54 PM
> > > > To: Ray Kinsella <mdr@ashroe.eu>
> > > > Cc: dev@dpdk.org; Sunil Kumar Kori <skori@marvell.com>
> > > > Subject: [PATCH 1/2] doc: announce region based device mapping
> > > > support
> > > >
> > > > From: Sunil Kumar Kori <skori@marvell.com>
> > > >
> > > > Adding region based device mapping support, which enables pci
> > > > device to map only required memory region instead of mapping full
> BAR.
> > >
> > > Why there will be such requirement to mmap only part of BAR when the
> > > BAR can be fully mmapped. I thought you want to enable something
> > > like sparse mmap feature in VFIO, but seems it's a feature that let
> > > driver ask for
> > specific
> > > mmap option. Could you explain the use case here?
> > >
> > > Thanks,
> > > Chenbo
> > >
> > > >
> > > > Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
> > > > ---
> > > > doc/guides/rel_notes/deprecation.rst | 13 +++++++++++++
> > > > 1 file changed, 13 insertions(+)
> > > >
> > > > diff --git a/doc/guides/rel_notes/deprecation.rst
> > > > b/doc/guides/rel_notes/deprecation.rst
> > > > index 4e5b23c53d..8800a3eb41 100644
> > > > --- a/doc/guides/rel_notes/deprecation.rst
> > > > +++ b/doc/guides/rel_notes/deprecation.rst
> > > > @@ -125,3 +125,16 @@ Deprecation Notices
> > > > applications should be updated to use the ``dmadev`` library
> > instead,
> > > > with the underlying HW-functionality being provided by the
> > > > ``ioat``
> > or
> > > > ``idxd`` dma drivers
> > > > +
> > > > +* pci: Update ``rte_pci_device`` and ``rte_pci_driver`` to add
> > > > +region
> > > > based
> > > > + memory mapping support. There could be a requirement to mmap
> > > > + specific
> > > > memory
> > > > + region only. Using this mechanism, pci device can be mapped for
> > > > + a given BAR at a given offset of given size.
> > > > +
> > > > + ``rte_pci_device`` will be added with following field
> > > > + ``regions[PCI_MAX_RESOURCE][PCI_MAX_REGION_PER_RESOURCE];``.
> > > This
> > > > + field
> > > > will
> > > > + specify the regions which are mapped for a given BAR.
> > > > +
> > > > + ``rte_pci_driver`` will be added with ``rte_pci_region_map
> > > > + *regions``
> > > > and
> > > > + ``valid_bars[PCI_MAX_RESOURCE]``. Using these fields, driver
> > > > + can
> > > > propagate
> > > > + its region information which are required to be mmap.
> > > > --
> > > > 2.25.1
next prev parent reply other threads:[~2022-07-13 7:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-28 13:53 skori
2022-06-28 13:53 ` [PATCH 2/2] bus/pci: support region based device mapping skori
2022-07-07 10:07 ` [PATCH 1/2] doc: announce region based device mapping support Sunil Kumar Kori
2022-07-07 12:39 ` Xia, Chenbo
2022-07-13 7:03 ` Sunil Kumar Kori
2022-07-13 7:27 ` Xia, Chenbo
2022-07-13 7:38 ` Sunil Kumar Kori [this message]
2022-07-13 7:18 ` David Marchand
2022-07-13 7:21 ` Xia, Chenbo
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