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Date:   Tue, 13 Sep 2022 14:35:59 +0100
From:   Sam Mendoza-Jonas <sam@mendozajonas.com>
To:     Jiaqing Zhao <jiaqing.zhao@linux.intel.com>,
        Paul Fertser <fercerpav@gmail.com>
CC:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net/ncsi: Add Intel OS2BMC OEM command
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References: <20220909025716.2610386-1-jiaqing.zhao@linux.intel.com> <YxrWPfErV7tKRjyQ@home.paul.comp> <8eabb29b-7302-d0a2-5949-d7aa6bc59809@linux.intel.com> <Yxrun9LRcFv2QntR@home.paul.comp> <36c12486-57d4-c11d-474f-f26a7de8e59a@linux.intel.com>
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On September 13, 2022 3:12:06 AM GMT+01:00, Jiaqing Zhao <jiaqing=2Ezhao@li=
nux=2Eintel=2Ecom> wrote:
>
>
>On 2022-09-09 15:43, Paul Fertser wrote:
>> Hello,
>>=20
>> On Fri, Sep 09, 2022 at 03:34:53PM +0800, Jiaqing Zhao wrote:
>>>> Can you please outline some particular use cases for this feature?
>>>>
>>> It enables access between host and BMC when BMC shares the network con=
nection
>>> with host using NCSI, like accessing BMC via HTTP or SSH from host=2E=
=20
>>=20
>> Why having a compile time kernel option here more appropriate than
>> just running something like "/usr/bin/ncsi-netlink --package 0
>> --channel 0 --index 3 --oem-payload 00000157200001" (this example uses
>> another OEM command) on BMC userspace startup?
>>=20
>
>Using ncsi-netlink is one way, but the package and channel id is undeterm=
ined
>as it is selected at runtime=2E Calling the netlink command on a nonexist=
ent
>package/channel may lead to kernel panic=2E

If so, that would be a bug :)

>
>Why I prefer the kernel option is that it applies the config to all ncsi
>devices by default when setting up them=2E This reduces the effort and ke=
eps
>compatibility=2E Lots of things in current ncsi kernel driver can be done=
 via
>commands from userspace, but I think it is not a good idea to have a driv=
er
>resides on both kernel and userspace=2E

BMCs are of course in their own world and there's already some examples of=
 the config option, but how would a system owner be able to disable this wi=
thout reflashing the BMC?