libnvme questions

[Padmakar Kalghatgi]

On Fri, Apr 09, 2021 at 01:46:45AM +0900, Keith Busch wrote:
>On Thu, Apr 08, 2021 at 01:21:26PM +0530, Padmakar Kalghatgi wrote:
>> On Thu, Apr 08, 2021 at 08:37:06AM +0900, Keith Busch wrote:
>> > On Wed, Apr 07, 2021 at 06:08:06PM +0530, Padmakar Kalghatgi wrote:
>> > > Since most of the companies who develop SSDs, use MI(sideband) channel, we think this will be a good enhancement to the existing functionality which the nvme-cli provides.
>> >
>> > Can we even use this from a Linux host? I thought the sideband channel
>> > was typically connected to the baseboard management controller.
>> >
>> Yes, this can be used from Linux host by having additional hardwares, like TotalPhase's aardvark, Corelis etc, which are connected to the NVMe device.
>
>That doesn't sound something for end users, but okay. Can we see the
>nvme-mi bus driver before considering tools and emulation?
>
Please find the below block diagram for the MI communication on the
linux host. The nvme-bus driver is  nothing but the USB driver of the 
hardware which is provided by the vendor.

 ____________________                                                   
|                    |                                                  
|                    |                                                  
|      NVMe-CLI      |             _____________           ____________ 
|     (MI Plugin)    |     USB    |  Aardvark   |  SMBus  |            |
|                    |============|  \Corelis   |=========| NVMe Device|
|                    |            |_____________|         |____________|
|____________________|