From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B116F3ACA5A; Mon, 10 Aug 2026 09:07:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786352849; cv=none; b=DiHgIxvdfuai7nVpTSwodBlfdfWEABAHHUbW9vOl1LsdHxQ8xd8w9cgib69BEvcdsBdGBLY2UkHkjh5ovJyGX6eldKRdO4/VKYm+c33u1Mpb99f9CzHOk8k9On7n1VeTyCt2P+FdfGkz+TH/IaYwrC9lqYJwaadyEaSuFB2qChE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786352849; c=relaxed/simple; bh=RcLbGilKNPNC0RUtf9NSMs+SW3P3+5XKJ39gGa4XbLw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=mhja4GJWZA6LY1Jfg5mmh6Nz68zxU5QTezXnLPqfJBzqzMne0UnUOQkN941i1911guWl35z6OhPUGX7RThJQlIw+0q4eukGXeJ7/7L348q+8nlljy4BRPhDp1a7Q2xNjxUdQTaZ5VgDhT5FJLV3ftDImVTyT3hZFGFq8z5fxNyM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=nZfvei8m; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="nZfvei8m" Received: from CPC-namja-026ON.redmond.corp.microsoft.com (unknown [4.213.232.21]) by linux.microsoft.com (Postfix) with ESMTPSA id A21AC20B7167; Mon, 10 Aug 2026 02:06:56 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A21AC20B7167 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1786352822; bh=1KPmg0Fee/slatq+vNTVHE9Mgne9Fj3pacSFimVqm8U=; h=From:To:Cc:Subject:Date:From; b=nZfvei8m69pgOEwZikK4apxa1XgVSDms4l3ejMv5mC0rD1qLHcnZurJwtbaegcxGp 4ryQzVRKLu50eJvn/yQjwqVtLC+ZhhSzJto0cMnufnl7oktyijbIvWW/qP+y/7JdoN llPnzD4XOgW08QnBlJ8Hbttp9Iv9d9TXpu0UL2+o= From: Naman Jain To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "Joerg Roedel (AMD)" , Will Deacon , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Lorenzo Pieralisi , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , Manivannan Sadhasivam , Bjorn Helgaas Cc: "H. Peter Anvin" , Suravee Suthikulpanit , Vasant Hegde , Robin Murphy , Rob Herring , Shradha Gupta , Aditya Garg , iommu@lists.linux.dev, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/3] x86/irq: Fix lost interrupts on CPU hot-unplug for Hyper-V PCI/MSI Date: Mon, 10 Aug 2026 09:07:12 +0000 Message-ID: <20260810090716.2325295-1-namjain@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On CPU hot-unplug, fixup_irqs() re-injects interrupts that are still pending in the outgoing CPU's IRR via the irqchip's irq_retrigger() callback. The Hyper-V vPCI MSI irqchip never installs one, so such a pending interrupt is silently dropped, leading to lost interrupts, stalls and "No irq handler for vector" messages. Patch 1 is the minimal, backportable fix (Fixes:/Cc: stable) that installs irq_chip_retrigger_hierarchy() on the Hyper-V PCI/MSI chip. Patch 2 then switches fixup_irqs() to call irq_chip_retrigger_hierarchy() directly, so the retrigger works for any stacked irqchip without a per-chip callback. Patch 3 drops the now-redundant irq_retrigger() initializations. This way, patch 2 and 3 do not need to be backported. Changes since v1: https://lore.kernel.org/all/20260728135117.2888175-1-namjain@linux.microsoft.com/#t * Added Review tags * Adding minor clarification in commit msg of patch 2 (Shradha) Original RFC: https://lore.kernel.org/all/87y0f3jhd6.ffs@fw13/ Naman Jain (3): PCI: hv: Set irq_retrigger callback for the Hyper-V PCI MSI irqchip x86/irq: Use irq_chip_retrigger_hierarchy() in fixup_irqs() x86/irq, iommu/amd, PCI: Drop redundant irq_retrigger inits arch/x86/kernel/apic/io_apic.c | 2 -- arch/x86/kernel/apic/msi.c | 4 +--- arch/x86/kernel/hpet.c | 1 - arch/x86/kernel/irq.c | 23 +++++++---------------- drivers/iommu/amd/init.c | 1 - 5 files changed, 8 insertions(+), 23 deletions(-) -- 2.43.0