linux-kernel - Re: [RFC PATCH 0/6] virtio: Add support for Virtio message transport

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250812094955.fdyil4cbxr3bx4bo@vireshk-i7>
Date: Tue, 12 Aug 2025 15:19:55 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Rob Herring <robh@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	Eugenio Pérez <eperezma@...hat.com>,
	Jason Wang <jasowang@...hat.com>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Saravana Kannan <saravanak@...gle.com>,
	Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
	Arnd Bergmann <arnd@...nel.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Alex Bennée <alex.bennee@...aro.org>,
	Bill Mills <bill.mills@...aro.org>, devicetree@...r.kernel.org,
	virtualization@...ts.linux.dev, Sudeep Holla <sudeep.holla@....com>,
	Bertrand Marquis <bertrand.marquis@....com>,
	"Edgar E . Iglesias" <edgar.iglesias@....com>,
	Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>
Subject: Re: [RFC PATCH 0/6] virtio: Add support for Virtio message transport

Hi Rob,

On 30-07-25, 08:39, Rob Herring wrote:
> On Wed, Jul 30, 2025 at 4:29 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> > ### Memory Mapping and Reserved Memory Usage
> >
> > The first two patches enhance the reserved-memory subsystem to support attaching
> > struct device`s that do not originate from DT nodes — essential for virtual or
> > dynamically discovered devices like the FF-A or loopback buses.
> 
> We support creating devices from reserved-memory nodes.

I didn't know about this.

> Just add a
> compatible which you should do anyways because node names are not
> supposed to be that specific or an ABI.

Yeah, I already knew that the node-names thing isn't going to fly as
you and Krzysztof rightly pointed out. I just wanted inputs from you
guys and so did that as a first implementation to get the discussion
started.

I tried something like this now:

      reserved-memory {
        #address-cells = <2>;
        #size-cells   = <2>;
        ranges;

        rmem@...000000 {
          compatible = "restricted-dma-pool", "virtio-msg,loopback";
          reg = <0x00000001 0x00000000  0x0 0x00400000>; /* 4 MiB */
        };
      };

and this works fine. I am adding two compatibles for virtio-msg:
"virtio-msg,loopback" and "virtio-msg,ffa". Yes I will properly
document them in the next version.

With this, we don't need the 2nd patch anymore:
  of: reserved-memory: Add of_reserved_mem_lookup_by_name

but still need the 1st one:
  of: reserved-memory: Add reserved_mem_device_init()

Thanks.

-- 
viresh