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Date:   Fri, 13 Oct 2023 09:59:03 -0500
From:   Andrew Halaney <ahalaney@redhat.com>
To:     Bartosz Golaszewski <brgl@bgdev.pl>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@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>,
        Maximilian Luz <luzmaximilian@gmail.com>,
        Alex Elder <elder@linaro.org>,
        Srini Kandagatla <srinivas.kandagatla@linaro.org>,
        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 v4 04/15] firmware: qcom: add a dedicated TrustZone
 buffer allocator
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On Fri, Oct 13, 2023 at 01:48:32PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> We have several SCM calls that require passing buffers to the TrustZone
> on top of the SMC core which allocates memory for calls that require
> more than 4 arguments.
> 
> Currently every user does their own thing which leads to code
> duplication. Many users call dma_alloc_coherent() for every call which
> is terribly unperformant (speed- and size-wise).
> 
> Provide a set of library functions for creating and managing pool of
> memory which is suitable for sharing with the TrustZone, that is:
> page-aligned, contiguous and non-cachable as well as provides a way of
> mapping of kernel virtual addresses to physical space.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

I'm still on the fence about introducing the Kconfig for the "just
in case the hypervisor is bad on some boards", but I spent a
while looking at this and it all looks good to me, so that opinion
aside...

Reviewed-by: Andrew Halaney <ahalaney@redhat.com>