From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 655A13CD8AA; Wed, 22 Apr 2026 11:01:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776855679; cv=none; b=j+TlezaPvw1DIWa255I7TQ58cJkUuCV4LR41zNenNhcfi1A7H+jM9+56ycXhWGFXuAAlLZwMSaumo3EsS/UPiOUNbzjRY0dpsALKqZYppD84YqECUHtAnkGYuNT6VzvIJjmdE7lpS81CwOEdyqyAoGctzeA4eo0FvUmgA5lpBvI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776855679; c=relaxed/simple; bh=vSIMzTAhqwYfxZzmpkzPsQ8Ff0fX6ImiRUnKI6RL9s0=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=B6yGsgboStf6BDJh7itwMwY/UmglM74h0BlycucWYHV53LQn5/MiRgWE0Bz9S3eb+UzyJAvhLTcio72nVorupNGsOcDwMkXPA6GKwQF50b3OJf5u2fUSRzezK9PaviwOq5iYWWugBuiSO75MX/ejpNf6sMmhMKckggHj5VyVHuw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y7NnjzAE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Y7NnjzAE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FE54C19425; Wed, 22 Apr 2026 11:01:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776855679; bh=vSIMzTAhqwYfxZzmpkzPsQ8Ff0fX6ImiRUnKI6RL9s0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Y7NnjzAEP8ymiska0oK+0usrDU5yq5m93mhIqgFdRBEJm0A046+BL7dOj0chcDPgH pwIrygNRqZwGsSbMVRChZmrzMnJwaKyXIJB7eUS8kBlpN/5WkPj7K6IrEb6Km60ENd PAdQUQ6tfvVCjSr4vuI8lGl9lc62r1SVYta2APFmez1gpG+qV+7GfXpWqzqClZUslz jlpewNHUK2vGxjEBwdfkTgL1v/7QvSxnr2VEuBbDmYvStR9C7RWw29jKkuRcr8FrQ/ xxRrAxyT0hWBvgxPh0QJfMEc6CLKYUEvFdU4R+BhqHfsyzcLZFsfUoIWK6FUY7CTlI eS7O+vC/FRyIg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wFVKW-0000000DiIq-4Age; Wed, 22 Apr 2026 11:01:17 +0000 Date: Wed, 22 Apr 2026 12:01:16 +0100 Message-ID: <86cxzr1coz.wl-maz@kernel.org> From: Marc Zyngier To: Sudeep Holla Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 0/5] firmware/irqchip: Add FF-A DT interrupt support for donated NS SGIs In-Reply-To: <20260412-b4-ffa_ns_sgi_gicv3-v1-0-af61243eb405@kernel.org> References: <20260412-b4-ffa_ns_sgi_gicv3-v1-0-af61243eb405@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: sudeep.holla@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Sun, 12 Apr 2026 18:04:36 +0100, Sudeep Holla wrote: >=20 > Hi all, >=20 > This series wires FF-A notification interrupts up through DT using the > standard interrupts property on the arm,ffa node and adds the > required GICv3 and binding support for secure-donated non-secure SGIs. >=20 > This has been long pending after the discussions here[1][2]. I have been > waiting for some ACPI story to shape up for almost an year now, but no > progress there. So posting this for now to start discussion on the approa= ch > taken here instead of waiting for another year to sort out ACPI =F0=9F=98= =89. >=20 > It: >=20 > - documents secure-donated NS SGIs in the GIC DT binding > - teaches the GICv3 driver to accept and map those SGIs > - adds a DT binding for the arm,ffa firmware node > - updates the FF-A driver to use the arm,ffa node interrupt instead of > synthesizing its own GIC mapping > - adds an FVP DT node using SGI 8 as the FF-A notification interrupt > > The FF-A DT lookup expects a single interrupt entry, verifies that it is > a per-CPU interrupt via the reported affinity mask, and cross-checks the > resolved Linux IRQ hwirq against the interrupt ID returned by > FFA_FEATURES. I haven't looked at this in any detail, but these are the additional issues someone needs to address: - The GIC(v3) is dead, long live the GIC(v5)! SGIs don't exist in the brave new world, so FFA needs to find new ways to signal interrupts. - FFA doesn't necessarily live in secure world, and could be implemented by a hypervisor. In the context of a single security domain machine (that's what a VM is), the guest *owns* all SGIs. So there is absolutely nothing to donate, and this doesn't work. FFA also needs fixing here. - All of the above should work with the other firmware description (Avoid Critical Periodic Interrupts). But maybe FFA is not a thing on these machines? If not, it should be made explicit. Overall, it only indicates that FFA should behave as a device, and use interrupts that are valid for a device. Thanks, M. --=20 Without deviation from the norm, progress is not possible.