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 C9673C7EE30 for ; Thu, 26 Jun 2025 14:48:48 +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: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=mMACwKQ45OFKp3dqM69V6dG6kIbJSpYqiKbZLP7Vh9g=; b=pRPfAH/EXadMwDpR07nErBdApt YKOuTi5WWCQ8kQUmWJolnHQaFaw4cxJ/AvTCSmsNWYNMXZGImuisM4Gu7iH6rrQwYinv9eg7+GoLZ t63s/GZL7QLlDi6ZouiGmKZm21Z2NOMmt8zj+rggqKnQfPYZKiNQT5YqmHfsrmyjNfP61uqqjH2KP CeyAMmbasbN15Y/q679DfkMoWoUeezHgkemPihRIEgaeME3oF9ct6tSBbg05wwv8iaB3i7jNmq93L E5ajEkXoR0BZk4Q96fQmXeXRFnvOtTDDCAt9QiCAdTcTCsH5OOppfzOi+Rm0ydcoEVl/IWPPS2kfy 8O0LEECQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uUnuC-0000000BzbC-2PJD; Thu, 26 Jun 2025 14:48:48 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uUnsv-0000000BzC9-0yaw for linux-um@lists.infradead.org; Thu, 26 Jun 2025 14:47:30 +0000 From: Nam Cao DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1750949245; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=mMACwKQ45OFKp3dqM69V6dG6kIbJSpYqiKbZLP7Vh9g=; b=uT10fAhSsV9cz89bABA+WeC8KQvJ8SxMxJa20uSkA3MPkPDtQbtJUVUBo9dsyxtKDt4o2W b9uwOmJYazrbtXFVNDYow4MF9i3AOOxUicfRLH9+9Dq2FyJsN/Uyt+Lv04YwQ9brDXQXD9 nYnAI67KtwE2Bzn2lfVOeaYGm6JCm4QpH6bWl/D+ZpsTTsQi5CHDqOHpmW2h/UslmKIKf9 gapHY1a65YGxpxBDdC0OOISbGvl6auZZktvR43Sd063SM8TqNXhyYcaW6ESmkcJK/jEEg2 96r4rZyqrGVGJowzLAEfxrZFz9/f54L+mIOoIqgmHM6QEGJKWNNFef9Mz92Rgg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1750949245; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=mMACwKQ45OFKp3dqM69V6dG6kIbJSpYqiKbZLP7Vh9g=; b=hQCjcwYqJJ2PyvAblYu+pT2ArzJfI6f/LcTDy9a5X68jkNrwT3LMB6pR3L/SrtWYr6xpu2 SWiD1l4eTqEGH+Dw== To: Marc Zyngier , Thomas Gleixner , Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Nam Cao Subject: [PATCH 0/1] um: MSI parent domain conversion Date: Thu, 26 Jun 2025 16:47:14 +0200 Message-Id: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250626_074729_408224_48B34625 X-CRM114-Status: UNSURE ( 6.71 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-um@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-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org The initial implementation of PCI/MSI interrupt domains in the hierarchical interrupt domain model used a shortcut by providing a global PCI/MSI domain. This works because the PCI/MSI[X] hardware is standardized and uniform, but it violates the basic design principle of hierarchical interrupt domains: Each hardware block involved in the interrupt delivery chain should have a separate interrupt domain. For PCI/MSI[X], the interrupt controller is per PCI device and not a global made-up entity. Unsurprisingly, the shortcut turned out to have downsides as it does not allow dynamic allocation of interrupt vectors after initialization and it prevents supporting IMS on PCI. For further details, see: https://lore.kernel.org/lkml/20221111120501.026511281@linutronix.de/ The solution is implementing per device MSI domains, this means the entities which provide global PCI/MSI domain so far have to implement MSI parent domain functionality instead. This series converts the um's driver to implement MSI parent domain. arch/um/drivers/Kconfig | 1 + arch/um/drivers/virt-pci.c | 46 +++++++++++++++++++------------------- 2 files changed, 24 insertions(+), 23 deletions(-) --=20 2.39.5