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From: Jens Wiklander <jens.wiklander@linaro.org>
To: Sumit Garg <sumit.garg@linaro.org>
Cc: Marc Zyngier <maz@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	OP-TEE TrustedFirmware <op-tee@lists.trustedfirmware.org>,
	Devicetree List <devicetree@vger.kernel.org>,
	Linux Doc Mailing List <linux-doc@vger.kernel.org>,
	Jerome Forissier <jerome@forissier.org>,
	Etienne Carriere <etienne.carriere@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH v2 0/7] Asynchronous notifications from secure world
Date: Wed, 7 Jul 2021 08:54:19 +0200	[thread overview]
Message-ID: <CAHUa44GEPDYj6A9jOB8sHbbs_mSk1oiREywP6Z8s0vOhbpajpw@mail.gmail.com> (raw)
In-Reply-To: <CAFA6WYMsjxYBw_0xzWMtHf=LtXzG+D113WSFuHCR7KhC1RuWYg@mail.gmail.com>

Hi,

On Wed, Jul 7, 2021 at 7:52 AM Sumit Garg <sumit.garg@linaro.org> wrote:
>
> On Tue, 6 Jul 2021 at 18:16, Marc Zyngier <maz@kernel.org> wrote:
> >
[snip]
> > > > - Is there any case where you would instead need a level interrupt
> > > >   (which a SGI cannot provide)?
> > >
> > > I think SGI should be sufficient to suffice OP-TEE notifications use-case.
> >
> > I don't care about OP-TEE. If you are proposing a contract between S
> > and NS, it has to be TEE and OS independent. That's how the
> > architecture works.
> >
>
> Agree, here we are not proposing a common contract among the S and NS
> world that every TEE (based on Arm TrustZone) will use to communicate
> with REE (Linux in our case) but rather an OP-TEE specific
> notifications feature that is built on top of OP-TEE specific ABIs.
>
> And I can see your arguments coming from an FFA perspective but there
> are platforms like the ones based on Armv7 which don't support FFA
> ABI. Maybe Jens can elaborate how this feature will fit in when FFA
> comes into picture?

OP-TEE has one official ABI at the moment, the SMC based one. It's
about to get another one based on FF-A instead. The two ABIs will
never be used at the same time. It's a build time option for the
OP-TEE firmware to either use SMC or FF-A based communication.

The patches I've posted here concern the SMC based ABI. Asynchronous
notification in OP-TEE with a FF-A based ABI will use the notification
framework provided by FF-A instead to implement that counterpart
provided by these patches. So the OP-TEE driver here in the kernel
will use the FF-A framework in the kernel instead of registering an
interrupt handler directly.

Cheers,
Jens

WARNING: multiple messages have this Message-ID
From: Jens Wiklander <jens.wiklander@linaro.org>
To: Sumit Garg <sumit.garg@linaro.org>
Cc: Marc Zyngier <maz@kernel.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	 linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	 OP-TEE TrustedFirmware <op-tee@lists.trustedfirmware.org>,
	 Devicetree List <devicetree@vger.kernel.org>,
	 Linux Doc Mailing List <linux-doc@vger.kernel.org>,
	Jerome Forissier <jerome@forissier.org>,
	 Etienne Carriere <etienne.carriere@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	 Rob Herring <robh+dt@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH v2 0/7] Asynchronous notifications from secure world
Date: Wed, 7 Jul 2021 08:54:19 +0200	[thread overview]
Message-ID: <CAHUa44GEPDYj6A9jOB8sHbbs_mSk1oiREywP6Z8s0vOhbpajpw@mail.gmail.com> (raw)
In-Reply-To: <CAFA6WYMsjxYBw_0xzWMtHf=LtXzG+D113WSFuHCR7KhC1RuWYg@mail.gmail.com>

Hi,

On Wed, Jul 7, 2021 at 7:52 AM Sumit Garg <sumit.garg@linaro.org> wrote:
>
> On Tue, 6 Jul 2021 at 18:16, Marc Zyngier <maz@kernel.org> wrote:
> >
[snip]
> > > > - Is there any case where you would instead need a level interrupt
> > > >   (which a SGI cannot provide)?
> > >
> > > I think SGI should be sufficient to suffice OP-TEE notifications use-case.
> >
> > I don't care about OP-TEE. If you are proposing a contract between S
> > and NS, it has to be TEE and OS independent. That's how the
> > architecture works.
> >
>
> Agree, here we are not proposing a common contract among the S and NS
> world that every TEE (based on Arm TrustZone) will use to communicate
> with REE (Linux in our case) but rather an OP-TEE specific
> notifications feature that is built on top of OP-TEE specific ABIs.
>
> And I can see your arguments coming from an FFA perspective but there
> are platforms like the ones based on Armv7 which don't support FFA
> ABI. Maybe Jens can elaborate how this feature will fit in when FFA
> comes into picture?

OP-TEE has one official ABI at the moment, the SMC based one. It's
about to get another one based on FF-A instead. The two ABIs will
never be used at the same time. It's a build time option for the
OP-TEE firmware to either use SMC or FF-A based communication.

The patches I've posted here concern the SMC based ABI. Asynchronous
notification in OP-TEE with a FF-A based ABI will use the notification
framework provided by FF-A instead to implement that counterpart
provided by these patches. So the OP-TEE driver here in the kernel
will use the FF-A framework in the kernel instead of registering an
interrupt handler directly.

Cheers,
Jens

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-07-07  6:54 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16 10:36 Jens Wiklander
2021-06-16 10:36 ` Jens Wiklander
2021-06-16 10:36 ` [PATCH v2 1/7] docs: staging/tee.rst: add a section on OP-TEE notifications Jens Wiklander
2021-06-16 10:36   ` Jens Wiklander
2021-06-16 10:36 ` [PATCH v2 2/7] dt-bindings: arm: Convert optee binding to json-schema Jens Wiklander
2021-06-16 10:36   ` Jens Wiklander
2021-06-16 16:03   ` Rob Herring
2021-06-16 16:03     ` Rob Herring
2021-06-16 16:05   ` Rob Herring
2021-06-16 16:05     ` Rob Herring
2021-06-22  8:38     ` Jens Wiklander
2021-06-22  8:38       ` Jens Wiklander
2021-06-16 10:36 ` [PATCH v2 3/7] dt-bindings: arm: optee: add interrupt property Jens Wiklander
2021-06-16 10:36   ` Jens Wiklander
2021-06-16 16:05   ` Rob Herring
2021-06-16 16:05     ` Rob Herring
2021-06-22  8:41     ` Jens Wiklander
2021-06-22  8:41       ` Jens Wiklander
2021-06-16 10:36 ` [PATCH v2 4/7] tee: fix put order in teedev_close_context() Jens Wiklander
2021-06-16 10:36   ` Jens Wiklander
2021-06-16 10:36 ` [PATCH v2 5/7] tee: add tee_dev_open_helper() primitive Jens Wiklander
2021-06-16 10:36   ` Jens Wiklander
2021-06-16 10:36 ` [PATCH v2 6/7] optee: separate notification functions Jens Wiklander
2021-06-16 10:36   ` Jens Wiklander
2021-06-16 10:36 ` [PATCH v2 7/7] optee: add asynchronous notifications Jens Wiklander
2021-06-16 10:36   ` Jens Wiklander
2021-06-16 14:08   ` Ard Biesheuvel
2021-06-16 14:08     ` Ard Biesheuvel
2021-06-17  4:33 ` [PATCH v2 0/7] Asynchronous notifications from secure world Sumit Garg
2021-06-17  4:33   ` Sumit Garg
2021-06-17  6:10   ` Jens Wiklander
2021-06-17  6:10     ` Jens Wiklander
2021-07-06  7:25     ` Sumit Garg
2021-07-06  7:25       ` Sumit Garg
2021-07-06 10:36       ` Marc Zyngier
2021-07-06 10:36         ` Marc Zyngier
2021-07-06 11:39         ` Sumit Garg
2021-07-06 11:39           ` Sumit Garg
2021-07-06 12:46           ` Marc Zyngier
2021-07-06 12:46             ` Marc Zyngier
2021-07-07  5:52             ` Sumit Garg
2021-07-07  5:52               ` Sumit Garg
2021-07-07  6:54               ` Jens Wiklander [this message]
2021-07-07  6:54                 ` Jens Wiklander
2021-07-07 17:51               ` Sudeep Holla
2021-07-07 17:51                 ` Sudeep Holla
2021-07-08 12:56                 ` Sumit Garg
2021-07-08 12:56                   ` Sumit Garg
2021-07-09  8:05 Etienne CARRIERE
2021-07-13 11:11 ` Sudeep Holla
2021-07-13 11:11   ` Sudeep Holla
2021-07-20  6:45   ` Jens Wiklander
2021-07-20  6:45     ` Jens Wiklander
2021-07-20  7:50     ` Sudeep Holla
2021-07-20  7:50       ` Sudeep Holla
2021-07-20  9:59       ` Jens Wiklander
2021-07-20  9:59         ` Jens Wiklander

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