From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3ACF4F9B61A for ; Wed, 22 Apr 2026 11:01:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Subject:Cc:To:From: Message-ID:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4fu9KmT/zb2O6yFwcRLVdPA+DCGEItkt9W4Am8u0LVI=; b=sRWOOkAynKZc0dD4jIZ9o6QWTq uA026FwmKGp7yEBhE0PqzBylLVM7SSm2Vd1IKcue+N+8TJhENprypyRFFWjJJDTjYeiXlKDw25QaJ ipM/ox4MLlSsJW1wE0qFvPZd7KEV7Fp3CfdnZldTzTgGEtzHKfBlnzDHugPyTbdG7LGmTXI3zEO+N wrPIUfJ8QHCLk3XR3MzKCjunBRENnQ6cKVXiko6Zfa+obOJUQAD6W1rtOGneuIyWr3pb+nZlISTrR hoaRYUUZjOcPCqaBpovZ1XJqVT7geDkWrYuSB8MoUmUzoqfHOwAH5+cQKmXMOwr+EqZqdn8nydb6+ ayYBjM9g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFVKc-00000009yTw-2DqB; Wed, 22 Apr 2026 11:01:22 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFVKZ-00000009yTH-2XQR for linux-arm-kernel@lists.infradead.org; Wed, 22 Apr 2026 11:01:20 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 329A84043A for ; Wed, 22 Apr 2026 11:01:19 +0000 (UTC) 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) 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260422_040119_694844_75D5B7EE X-CRM114-Status: GOOD ( 23.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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.