From: Kishon Vijay Abraham I <kishon@ti.com>
To: Arnd Bergmann <arnd@kernel.org>
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 21:15:53 +0530 [thread overview]
Message-ID: <a590bff0-ba9e-8e19-4f09-4838d8afdbb6@ti.com> (raw)
In-Reply-To: <CAK8P3a0nTdtADPa_5jduDm5MpBiwBNgs7cYokK5qBZ=RkL1Ktg@mail.gmail.com>
Hi Arnd,
On 16/11/20 9:07 pm, Arnd Bergmann wrote:
> 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?
Right, NTB driver would need "pci_dev" on both sides of the link. But
that would also mean we cannot use pci EP framework which actually uses
"pci_epf".
Thanks
Kishon
next prev parent reply other threads:[~2020-11-16 15:46 UTC|newest]
Thread overview: 59+ 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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 ` 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
2020-09-30 15:35 ` 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
2020-11-16 15:45 ` Kishon Vijay Abraham I [this message]
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 ` 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 ` 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
2020-09-30 15:35 ` Kishon Vijay Abraham I
2020-10-05 5:57 ` [PATCH v7 00/18] Implement NTB Controller using multiple PCI EP Kishon Vijay Abraham I
2020-10-05 5:57 ` Kishon Vijay Abraham I
2020-10-20 8:15 ` 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
2020-11-03 7:58 ` Kishon Vijay Abraham I
2020-11-03 8:25 ` Alan Mikhak
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