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Date:   Sun, 18 Sep 2022 11:31:23 +0100
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Subject: Re: [PATCH 16/21] dt-bindings: reserved-memory: introduce
 designated-movable-block
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To:     Doug Berger <opendmb@gmail.com>, Rob Herring <robh@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Mike Rapoport <rppt@kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Borislav Petkov <bp@suse.de>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Neeraj Upadhyay <quic_neeraju@quicinc.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        David Hildenbrand <david@redhat.com>, Zi Yan <ziy@nvidia.com>,
        Oscar Salvador <osalvador@suse.de>,
        Hari Bathini <hbathini@linux.ibm.com>,
        Kees Cook <keescook@chromium.org>,
        - <devicetree-spec@vger.kernel.org>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Mel Gorman <mgorman@suse.de>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        linux-mm@kvack.org, iommu@lists.linux.dev
References: <20220913195508.3511038-1-opendmb@gmail.com>
 <20220913195508.3511038-17-opendmb@gmail.com>
 <20220914145506.GA2149379-robh@kernel.org>
 <57f19774-39a1-03a6-fe68-83d7e4b16521@gmail.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <57f19774-39a1-03a6-fe68-83d7e4b16521@gmail.com>
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On 14/09/2022 18:13, Doug Berger wrote:
> On 9/14/2022 7:55 AM, Rob Herring wrote:
>> On Tue, Sep 13, 2022 at 12:55:03PM -0700, Doug Berger wrote:
>>> Introduce designated-movable-block.yaml to document the
>>> devicetree binding for Designated Movable Block children of the
>>> reserved-memory node.
>>
>> What is a Designated Movable Block? This patch needs to stand on its
>> own.
> As noted in my reply to your [PATCH 00/21] comment, my intention in 
> submitting the entire patch set (and specifically PATCH 00/21]) was to 
> communicate this context. Now that I believe I understand that only this 
> patch should have been submitted to the devicetree-spec mailing list, I 
> will strive harder to make it more self contained.

The submission of entire thread was ok. What is missing is the
explanation in this commit. This commit must be self-explanatory (e.g.
in explaining "Why are you doing it?"), not rely on other commits for
such explanation.

> 
>>
>> Why does this belong or need to be in DT?
> While my preferred method of declaring Designated Movable Blocks is 
> through the movablecore kernel parameter, I can conceive that others may 
> wish to take advantage of the reserved-memory DT nodes. In particular, 
> it has the advantage that a device can claim ownership of the 
> reserved-memory via device tree, which is something that has yet to be 
> implemented for DMBs defined with movablecore.

Rephrasing the question: why OS memory layout and OS behavior is a
property of hardware (DTS)?


Best regards,
Krzysztof