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Date: Tue, 27 Feb 2024 10:32:05 -0600
From: Bjorn Andersson <andersson@kernel.org>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>, Andy Gross <agross@kernel.org>, 
	Konrad Dybcio <konrad.dybcio@linaro.org>, Elliot Berman <quic_eberman@quicinc.com>, 
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, Guru Das Srinagesh <quic_gurus@quicinc.com>, 
	Andrew Halaney <ahalaney@redhat.com>, Maximilian Luz <luzmaximilian@gmail.com>, 
	Alex Elder <elder@linaro.org>, Arnd Bergmann <arnd@arndb.de>, linux-arm-msm@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@quicinc.com, 
	Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Subject: Re: [PATCH v7 00/12] arm64: qcom: add and enable SHM Bridge support
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On Mon, Feb 19, 2024 at 03:17:24PM +0000, Srinivas Kandagatla wrote:
> On 17/02/2024 19:58, Bjorn Andersson wrote:
> > On Mon, Feb 05, 2024 at 07:27:58PM +0100, Bartosz Golaszewski wrote:
> > > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > > 
> > > We've established the need for using separate secured memory pools for
> > > SCM and QSEECOM
> > 
> > Where has this need been established, what is the actual problem you're
> > solving with this series?
> 
> SHMbridge will restrict the amount of memory that TZ can see, making system
> more secure.
> 

Then tell me this in the cover letter and commit messages.

> Need for having different pools makes this more scalable overall, so that
> different usecases can run seamlessly. ex: loading a TA and SCM calls.
> 

How is it more scalable to give each "client" a chunk of 256KB instead
of them sharing a pool of ~4GB memory?

> > 
> > Does SCM and QSEECOM, as it's implemented in the kernel today, not work
> > satisfactory?
> > 
> > > as well as the upcoming scminvoke driver.
> > > 
> > 
> > Is smcinvoke driver upstreaming blocked by not transitioning the scm
> > driver to a "secure memory pool"?
> > 
> > Is this happening now, or do we need to merge this series when that day
> > comes?
> 
> SMCInvoke development is happening now, I see no reason for this patchset to
> wait for it.
> 

As presented, I see no reason to merge this series.

> This series can go as it is for two reasons.
> 1> improves system security in general
> 2> Hardware Wrapped key support patches also use this which are also in good
> shape and tested, ready to be merged.
> 

Then tell me this in the cover letter and commit messages!


It's not sufficient that I happen to know the answer to these questions,
neither community nor maintainer should not have to guess these things.

Regards,
Bjorn