From: Sudeep Holla <sudeep.holla@arm.com>
To: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Trilok Soni <tsoni@codeaurora.org>,
devicetree@vger.kernel.org, David Hartley <dhh@qti.qualcomm.com>,
Andrew Walbran <qwandor@google.com>,
Achin Gupta <Achin.Gupta@arm.com>,
arve@android.com, Trilok Soni <tsoni@quicinc.com>,
Fuad Tabba <tabba@google.com>,
Android Kernel Team <kernel-team@android.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 0/9] firmware: Add initial support for Arm FF-A
Date: Mon, 30 Nov 2020 11:17:50 +0000 [thread overview]
Message-ID: <20201130111750.uiws2f2neygs7qrg@bogus> (raw)
In-Reply-To: <20201128122502.GA8649@jade>
On Sat, Nov 28, 2020 at 01:25:02PM +0100, Jens Wiklander wrote:
> Hi Sudeep,
>
> On Tue, Nov 03, 2020 at 05:43:41PM +0000, Sudeep Holla wrote:
> > Hi all,
> >
> > Let me start stating this is just initial implementation to check on
> > the idea of providing more in-kernel and userspace support. Lot of things
> > are still work in progress, I am posting just to get the early feedback
> > before building lot of things on this idea. Consider this more as RFC
> > though not tagged explicity(just to avoid it being ignored :))
> >
> > Arm Firmware Framework for Armv8-A specification[1] describes a software
> > architecture that provides mechanism to utilise the virtualization
> > extension to isolate software images and describes interfaces that
> > standardize communication between the various software images. This
> > includes communication between images in the Secure and Normal world.
> >
> > The main idea here is to create FFA device to establish any communication
> > with a partition(secure or normal world VM).
> >
> > If it is a partition managed by hypervisor, then we will register chardev
> > associated with each of those partition FFA device.
> >
> > /dev/arm_ffa:
> >
> > e3a48fa5-dc54-4a8b-898b-bdc4dfeeb7b8
> > 49f65057-d002-4ae2-b4ee-d31c7940a13d
> >
> > For in-kernel usage(mostly communication with secure partitions), only
> > in-kernel APIs are accessible(no userspace). There may be a need to
> > provide userspace access instead of in-kernel, it is not yet support
> > in this series as we need way to identify those and I am not sure if
> > that belong to DT.
>
> With unfiltered VM to VM commnication from user space there's no easy
> way for two VMs to exchange privileged information that excludes user
> space.
Though this usercase is dropped now, it was targeted for VMM and may be
it was not an issue there.
> Perhaps access to the FFA device is considered privileged and
> enough for all purposes.
>
I don't know TBH.
> If I've understood it correctly is VM to SP communication only allowed
> via kernel mode in the VM.
Correct.
> The communication with OP-TEE depends on this with the recent commit
> c5b4312bea5d ("tee: optee: Add support for session login client UUID
> generation").
>
OK, thanks for the info.
--
Regards,
Sudeep
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
prev parent reply other threads:[~2020-11-30 11:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-03 17:43 [PATCH v2 0/9] firmware: Add initial support for Arm FF-A Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 1/9] dt-bindings: Arm: Add Firmware Framework for Armv8-A (FF-A) binding Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 2/9] dt-bindings: Arm: Extend FF-A binding to support in-kernel usage of partitions Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 3/9] arm64: smccc: Add support for SMCCCv1.2 input/output registers Sudeep Holla
2020-11-04 13:22 ` Andrew Walbran
2020-11-03 17:43 ` [PATCH v2 4/9] firmware: arm_ffa: Add initial FFA bus support for device enumeration Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 5/9] firmware: arm_ffa: Add initial Arm FFA driver support Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 6/9] firmware: arm_ffa: Add support for SMCCC as transport to FFA driver Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 7/9] firmware: arm_ffa: Setup in-kernel users of FFA partitions Sudeep Holla
2020-11-28 13:36 ` Jens Wiklander
2020-11-30 11:13 ` Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 8/9] firmware: arm_ffa: Setup and register all the KVM managed partitions Sudeep Holla
2020-11-03 17:43 ` [PATCH v2 9/9] firmware: arm_ffa: Add support for MEM_* interfaces Sudeep Holla
2020-11-04 5:48 ` kernel test robot
2020-11-28 12:25 ` [PATCH v2 0/9] firmware: Add initial support for Arm FF-A Jens Wiklander
2020-11-30 11:17 ` Sudeep Holla [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201130111750.uiws2f2neygs7qrg@bogus \
--to=sudeep.holla@arm.com \
--cc=Achin.Gupta@arm.com \
--cc=arve@android.com \
--cc=devicetree@vger.kernel.org \
--cc=dhh@qti.qualcomm.com \
--cc=jens.wiklander@linaro.org \
--cc=kernel-team@android.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=qwandor@google.com \
--cc=tabba@google.com \
--cc=tsoni@codeaurora.org \
--cc=tsoni@quicinc.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).