From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
To: Declan Doherty <declan.doherty@intel.com>
Cc: Thomas Monjalon <thomas@monjalon.net>,
Radu Nicolau <radu.nicolau@intel.com>,
dev@dpdk.org
Subject: Re: [dpdk-dev] [RFC][PATCH 2/5] pci: allow shared device instances.
Date: Wed, 10 May 2017 16:38:44 +0530 [thread overview]
Message-ID: <20170510110843.GA22712@jerin> (raw)
In-Reply-To: <1c20ee02-530f-a39a-47c5-15cc5ce1a973@intel.com>
-----Original Message-----
> Date: Wed, 10 May 2017 11:52:45 +0100
> From: Declan Doherty <declan.doherty@intel.com>
> To: Thomas Monjalon <thomas@monjalon.net>, Radu Nicolau
> <radu.nicolau@intel.com>
> CC: dev@dpdk.org
> Subject: Re: [dpdk-dev] [RFC][PATCH 2/5] pci: allow shared device instances.
> User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101
> Thunderbird/45.8.0
>
> Hey Thomas, I've been working on this with Radu, so see my take below
>
> On 10/05/2017 11:28 AM, Thomas Monjalon wrote:
> > 10/05/2017 12:11, Radu Nicolau:
> > > Hi
> > >
> > >
> > > On 5/10/2017 10:09 AM, Thomas Monjalon wrote:
> > > > Hi,
> > > >
> > > > 09/05/2017 16:57, Radu Nicolau:
> > > > > Updated PCI initialization code to allow devices to be shared across multiple PMDs.
> > > > >
> > > > > Signed-off-by: Radu Nicolau <radu.nicolau@intel.com>
> > > > I was waiting the day when we have a device shared
> > > > by two different interfaces.
> > > > Note that some Mellanox and Chelsio devices already instantiate
> > > > two ethdev ports per PCI device.
> > > >
> > > > Please explain your idea behind this "shared" flag.
> > > > What is your exact need?
> > >
> > > Currently for each pci device a look-up into a list of PMDs is
> > > performed, and when a match is found the system moves to the next
> > > device. Having this flag will allow a PMD to inform the system that
> > > there may be more matches, more PMDs that can be used for this
> > > particular device.
> > > There is a difference when comparing to the devices you mentioned above,
> > > in this case the PMDs are totally different types, one network and one
> > > cryptodev PMD for each IXGBE network card.
> >
> > Yes I know it is a lack in DPDK.
> > Linux introduced MultiFunction Device in 2005:
> > http://events.linuxfoundation.org/sites/events/files/slides/belloni-mfd-regmap-syscon_0.pdf
> >
>
> So at the most basic level the intention is to allow more than one device of
> different types, in our case a net PMD and a crypto PMD, to be instantiated
> on a single PCI bar, in essence to share the bar. I'm not familiar with the
> approaches taken in the Mellanox and Chelsio devices but I assume they are
> handled with the driver probe/create functions independently from the EAL
> infrastructure?
>
> For the initial proto-typing of this RFC we only implemented the
> multi-device creation but I envisage that there will be a requirement for
> sharing state between drivers, or at a minimum implementing locking around
> shared resources, registers etc. And I would like to see this done in a
> generic fashion that can me leverage by any driver and not have each driver
> having to solve this independently.
Cavium's next generation PCI based NW devices has similar scheme where we
need to share the same BAR with multiple DPDK subsystems(ethdev,
eventdev etc) unlike current generation(OcteonTX).
I think, Another possible way to handle this in generic way is to:
Register a new rte_bus for the shared PCI access which sits on top PCIe bus.
With new bus's scan and probe scheme, it can probe the two devices.
next prev parent reply other threads:[~2017-05-10 11:09 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-09 14:57 [dpdk-dev] [RFC][PATCH 0/5] cryptodev: Adding support for inline crypto processing of IPsec flows Radu Nicolau
2017-05-09 14:57 ` [dpdk-dev] [RFC][PATCH 1/5] cryptodev: Updated API to add suport for inline IPSec Radu Nicolau
2017-05-09 14:57 ` [dpdk-dev] [RFC][PATCH 2/5] pci: allow shared device instances Radu Nicolau
2017-05-10 9:09 ` Thomas Monjalon
2017-05-10 10:11 ` Radu Nicolau
2017-05-10 10:28 ` Thomas Monjalon
2017-05-10 10:47 ` Radu Nicolau
2017-05-10 10:52 ` Declan Doherty
2017-05-10 11:08 ` Jerin Jacob [this message]
2017-05-10 11:31 ` Declan Doherty
2017-05-10 12:18 ` Jerin Jacob
2017-05-10 11:37 ` Thomas Monjalon
2017-05-09 14:57 ` [dpdk-dev] [RFC][PATCH 3/5] mbuff: added inline IPSec flags and metadata Radu Nicolau
2017-05-09 14:57 ` [dpdk-dev] [RFC][PATCH 4/5] cryptodev: added new crypto PMD supporting inline IPSec for IXGBE Radu Nicolau
2017-05-09 14:57 ` [dpdk-dev] [RFC][PATCH 5/5] examples: updated IPSec sample app to support inline IPSec Radu Nicolau
2017-05-10 16:07 ` [dpdk-dev] [RFC][PATCH 0/5] cryptodev: Adding support for inline crypto processing of IPsec flows Boris Pismenny
2017-05-10 17:21 ` Declan Doherty
2017-05-11 5:27 ` Boris Pismenny
2017-05-11 9:05 ` Radu Nicolau
2017-05-16 21:46 ` Thomas Monjalon
2017-05-24 10:06 ` Declan Doherty
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