Re: [PATCH v4 1/3] remoteproc: qcom: pas: add needs_tzmem flag to force shmbridge creation

Hi Bjorn,

On Sun, Jul 05, 2026 at 05:26:22PM -0500, Bjorn Andersson wrote:
> On Fri, Jul 03, 2026 at 05:31:11AM -0700, Ananthu C V wrote:
> > Most Qualcomm platforms feature Gunyah hypervisor, which typically
> > handles Stage 2 IOMMU configuration.
> 
> This statement is true, but the IOMMU isn't involved in the interaction
> between OS and TZ, so it doesn't add value to your problem description.
> 
> > Additionally, SHM bridge setup is required to enable memory protection
> > for both remoteproc metadata and its memory regions.
> 
> "Additionally"? Isn't this the entire problem?
> 
> > When the aforementioned hypervisor is absent, the operating system
> > must perform these configurations instead.
> 
> Please rephrase these three sentences to make sure we have a clear
> problem description.
> 
> Then, at this point in the text you have established the problem, so
> break the paragraph with an empty line.
> 
> > We've been relying on the iommu property being present for this, but
> > for remoteprocs that are already running like SoCCP the mappings are
> > already in place, and any attempt to recreate them while active would
> > lead to smmu faults and a non-functional remoteproc.
> 
> This is a significant detail. Please expand the description around
> "attempt to recreate them while active" to ensure that it's clear to the
> reader what the problem (what does it mean that mappings are already in
> place).
> 
> Then another </p><p> here, as we're once again in need of some breathing
> and thinking-room.
> 
> > Fix this by adding a needs_tzmem
> > flag which ensures tzmem and SHM bridge setup is performed independent to
> > the iommu property being present.
> 
> "flag which ensures...", the flag doesn't ensure anything, it is
> propagates as an alternative trigger to the PAS helpers to ensure that
> the shmbridge is established.
> 
> Regards,
> Bjorn

ACK to all, will take in the suggestions and improve the commit message.
Thanks for the review.

Best,
Ananthu