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 95C7F39CCF9; Mon, 10 Aug 2026 09:07:33 +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=1786352854; cv=none; b=kDhKfLFiMWr+Fy74JjSr6iH4+w6KIy9K2xhdnfiPkuXT92kpWzjJhXtSi74XlVEukNQ26nOau2q8a0o6ant80EKIg9by8VrTpTOXIdAFeznVwcWP8Azb+TRkjs4miP1Kh2qBiTy0lAhay81twPQiP85xyL79jvOnpL18hHT66aQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786352854; c=relaxed/simple; bh=xa78jNuHvayG1KaCaq7REqe7r+ZZLRS4/vOo4+m26K8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kT42X0uevlNIyOYg0Rq+MzhaM3UBKBruSQTLiuarccT+bIKjuB8JldjK4YmysxMJKPFZXpmXWChqm94TtzMQoMGoBZF/peRB+c4O5zothwBOQmflU1CNJcd4OKRdCLoHp/UI3l+A86pwWinrKKCFqtTPrvt1qTlwJEMa0Tny10Q= 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=p9pjXXIR; 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="p9pjXXIR" Received: from CPC-namja-026ON.redmond.corp.microsoft.com (unknown [4.213.232.21]) by linux.microsoft.com (Postfix) with ESMTPSA id 7192520B7166; Mon, 10 Aug 2026 02:07:03 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7192520B7166 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1786352829; bh=Bx26xf7cHtvbDBbCkLmMLyTj3yU5wo6z0sqPBJm9JBk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p9pjXXIRyC0Kg1gTcXxO6D8U226lLA1H4p1gYy4Pj91Tet/vs8/e8+FG+V5YILE0G WfwbHqQHKea9392eXQl97GZsIdqSYSudP7Rjse3m0yVgR8P9nd0mCAmfBfiDbWg7ie FE54+YmQqTS+XxZrBg2reozGYl7RIgZfgRwgIiWA= 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 1/3] PCI: hv: Set irq_retrigger callback for the Hyper-V PCI MSI irqchip Date: Mon, 10 Aug 2026 09:07:13 +0000 Message-ID: <20260810090716.2325295-2-namjain@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260810090716.2325295-1-namjain@linux.microsoft.com> References: <20260810090716.2325295-1-namjain@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The Hyper-V vPCI MSI irqchip never installs an irq_retrigger() callback. On CPU hot-unplug fixup_irqs() migrates the interrupts which are affine to the outgoing CPU to a new target. If an interrupt still has its pending bit set in the outgoing CPU's IRR at that point, fixup_irqs() resends it on the new target through the irqchip's irq_retrigger() callback. As the Hyper-V PCI/MSI chip does not provide that callback, the pending interrupt is silently dropped, which can result in lost interrupts, stalls and "No irq handler for vector" messages during CPU hotplug. Install irq_chip_retrigger_hierarchy() as the irq_retrigger() callback for the Hyper-V PCI/MSI irqchip, so that a pending interrupt is resent on its new target CPU via the parent x86 vector domain. Fixes: 4daace0d8ce85 ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs") Cc: stable@vger.kernel.org Suggested-by: Long Li Suggested-by: Thomas Gleixner Reviewed-by: Aditya Garg Reviewed-by: Shradha Gupta Signed-off-by: Naman Jain --- drivers/pci/controller/pci-hyperv.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index cfc8fa403dad6..89816a2bd7cd3 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -2119,6 +2119,7 @@ static bool hv_pcie_init_dev_msi_info(struct device *dev, struct irq_domain *dom info->ops->msi_prepare = hv_msi_prepare; chip->irq_set_affinity = irq_chip_set_affinity_parent; + chip->irq_retrigger = irq_chip_retrigger_hierarchy; if (IS_ENABLED(CONFIG_X86)) chip->flags |= IRQCHIP_MOVE_DEFERRED; -- 2.43.0