Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Randy Dunlap <rdunlap@infradead.org>]

On 04/23/18 07:46, Bryant G. Ly wrote:
> This driver is a logical device which provides an
> interface between the hypervisor and a management
> partition.
> 
> This driver is to be used for the POWER Virtual
> Management Channel Virtual Adapter on the PowerVM
> platform. It provides both request/response and
> async message support through the /dev/ibmvmc node.
> 
> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  Documentation/ioctl/ioctl-number.txt  |    1 +
>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>  MAINTAINERS                           |    6 +
>  arch/powerpc/include/asm/hvcall.h     |    1 +
>  drivers/misc/Kconfig                  |   14 +
>  drivers/misc/Makefile                 |    1 +
>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>  drivers/misc/ibmvmc.h                 |  209 +++
>  8 files changed, 2808 insertions(+)
>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>  create mode 100644 drivers/misc/ibmvmc.c
>  create mode 100644 drivers/misc/ibmvmc.h

> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
> new file mode 100644
> index 0000000..bae1064
> --- /dev/null
> +++ b/Documentation/misc-devices/ibmvmc.txt
> @@ -0,0 +1,161 @@
> +Kernel Driver ibmvmc
> +====================
> +
> +Authors:
> +	Dave Engebretsen <engebret@us.ibm.com>
> +	Adam Reznechek <adreznec@linux.vnet.ibm.com>
> +	Steven Royer <seroyer@linux.vnet.ibm.com>
> +	Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> +
> +Description
> +===========
> +

...

> +
> +Virtual Management Channel (VMC)
> +A logical device, called the virtual management channel (VMC), is defined
> +for communicating between the Novalink application and the hypervisor.
> +This device, similar to a VSCSI server device, is presented to a designated
> +management partition as a virtual device and is only presented when the
> +system is not HMC managed.
> +This communication device borrows aspects from both VSCSI and ILLAN devices
> +and is implemented using the CRQ and the RDMA interfaces. A three-way
> +handshake is defined that must take place to establish that both the
> +hypervisor and management partition sides of the channel are running prior
> +to sending/receiving any of the protocol messages.
> +This driver also utilizes Transport Event CRQs. CRQ messages that are sent

                                                 Drop           "that" ?
otherwise the sentence construction is ... odd.

> +when the hypervisor detects one of the peer partitions has abnormally
> +terminated, or one side has called H_FREE_CRQ to close their CRQ.
> +Two new classes of CRQ messages are introduced for the VMC device. VMC
> +Administrative messages are used for each partition using the VMC to
> +communicate capabilities to their partner. HMC Interface messages are used
> +for the actual flow of HMC messages between the management partition and
> +the hypervisor. As most HMC messages far exceed the size of a CRQ bugger,

what is a bugger?
[reads more]
oh, buffer?

> +a virtual DMA (RMDA) of the HMC message data is done prior to each HMC
> +Interface CRQ message. Only the management partition drives RDMA
> +operations; hypervisors never directly causes the movement of message data.
> +
> +Example Management Partition VMC Driver Interface
> +=================================================

...


Looks pretty good.  In general (IMO), it could use more white space (like blank
lines after section names.)

If you fix those small items (buggers) above, you can add:
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

thanks,
-- 
~Randy
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