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From: Arnd Bergmann <arnd@kernel.org>
To: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Sherry Sun <sherry.sun@nxp.com>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"jdmason@kudzu.us" <jdmason@kudzu.us>,
	"dave.jiang@intel.com" <dave.jiang@intel.com>,
	"allenbh@gmail.com" <allenbh@gmail.com>,
	"tjoseph@cadence.com" <tjoseph@cadence.com>,
	Rob Herring <robh@kernel.org>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-ntb@googlegroups.com" <linux-ntb@googlegroups.com>
Subject: Re: [PATCH v7 15/18] NTB: Add support for EPF PCI-Express Non-Transparent Bridge
Date: Mon, 16 Nov 2020 16:37:05 +0100	[thread overview]
Message-ID: <CAK8P3a0nTdtADPa_5jduDm5MpBiwBNgs7cYokK5qBZ=RkL1Ktg@mail.gmail.com> (raw)
In-Reply-To: <c720de5b-bf76-162f-24cb-07f6fe670bd2@ti.com>

On Mon, Nov 16, 2020 at 6:19 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
> On 12/11/20 6:54 pm, Arnd Bergmann wrote:
> >
> > This looks very  promising indeed, I need to read up on the whole
> > discussion there. I also see your slides at [1]  that help do explain some
> > of it. I have one fundamental question that I can't figure out from
> > the description, maybe you can help me here:
> >
> > How is the configuration managed, taking the EP case as an
> > example? Your UseCase1 example sounds like the system that owns
> > the EP hardware is the one that turns the EP into a vhost device,
> > and creates a vhost-rpmsg device on top, while the RC side would
> > probe the pci-vhost and then detect a virtio-rpmsg device to talk to.
>
> That's correct. Slide no 9 in [1] should give the layering details.
>
> > Can it also do the opposite, so you end up with e.g. a virtio-net
> > device on the EP side and vhost-net on the RC?
>
> Unfortunately no. Again referring slide 9 in [1], we only have
> vhost-pci-epf on the EP side which only creates a "vhost_dev" to deal
> with vhost side of things. For doing the opposite, we'd need to create
> virtio-pci-epf for EP side that interacts with core virtio (and also the
> corresponding vhost back end on PCI host).

Ok, I see. So I think this is the opposite of drivers/misc/mic and
the bluefield driver were using, so we would probably end up
needing both.

Then again, I guess the NTB driver would give us the functionality
for free, if it shows a symmetric link?

      Arnd

  reply	other threads:[~2020-11-16 15:37 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-30 15:35 [PATCH v7 00/18] Implement NTB Controller using multiple PCI EP Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 01/18] Documentation: PCI: Add specification for the *PCI NTB* function device Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 02/18] PCI: endpoint: Make *_get_first_free_bar() take into account 64 bit BAR Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 03/18] PCI: endpoint: Add helper API to get the 'next' unreserved BAR Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 04/18] PCI: endpoint: Make *_free_bar() to return error codes on failure Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 05/18] PCI: endpoint: Remove unused pci_epf_match_device() Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 06/18] PCI: endpoint: Add support to associate secondary EPC with EPF Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 07/18] PCI: endpoint: Add support in configfs to associate two EPCs " Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 08/18] PCI: endpoint: Add pci_epc_ops to map MSI irq Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 09/18] PCI: endpoint: Add pci_epf_ops for epf drivers to expose function specific attrs Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 10/18] PCI: endpoint: Allow user to create sub-directory of 'EPF Device' directory Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 11/18] PCI: cadence: Implement ->msi_map_irq() ops Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 12/18] PCI: cadence: Configure LM_EP_FUNC_CFG based on epc->function_num_map Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 13/18] PCI: endpoint: Add EP function driver to provide NTB functionality Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 14/18] PCI: Add TI J721E device to pci ids Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 15/18] NTB: Add support for EPF PCI-Express Non-Transparent Bridge Kishon Vijay Abraham I
2020-11-09  9:37   ` Sherry Sun
2020-11-09 14:21     ` Kishon Vijay Abraham I
2020-11-10  2:25       ` Sherry Sun
2020-11-10 14:20         ` Kishon Vijay Abraham I
2020-11-10 14:59           ` Arnd Bergmann
2020-11-10 15:42             ` Kishon Vijay Abraham I
2020-11-11  2:49               ` Sherry Sun
2020-11-12 11:12                 ` Kishon Vijay Abraham I
2020-11-12 12:35                   ` Sherry Sun
2020-11-12 13:24               ` Arnd Bergmann
2020-11-16  5:19                 ` Kishon Vijay Abraham I
2020-11-16 15:37                   ` Arnd Bergmann [this message]
2020-11-16 15:45                     ` Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 16/18] NTB: tool: Enable the NTB/PCIe link on the local or remote side of bridge Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 17/18] Documentation: PCI: Add configfs binding documentation for pci-ntb endpoint function Kishon Vijay Abraham I
2020-09-30 15:35 ` [PATCH v7 18/18] Documentation: PCI: Add userguide for PCI endpoint NTB function Kishon Vijay Abraham I
2020-10-05  5:57 ` [PATCH v7 00/18] Implement NTB Controller using multiple PCI EP Kishon Vijay Abraham I
2020-10-20  8:15   ` Kishon Vijay Abraham I
2020-10-20 13:18     ` Lorenzo Pieralisi
2020-11-03  7:58       ` Kishon Vijay Abraham I

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