From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8BA6117A586; Sun, 13 Sep 2026 22:48:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789339725; cv=none; b=riyrk6LdP84x5E5Eopo0byET7/tSiya3ePog3oQrz+PXIUEfrM2qcd2DzZ+D6vllI6cwkqCmDlPAkL6HLqztL609B8qno2BR1XvCtg/UYtJxbw8w4bdzlikzD/C1fajVEgoAn22iJBayWiO88SKFTOAceAU7XwsMZyX993h47W0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789339725; c=relaxed/simple; bh=6tpr5g9elJ/5OKQCWL95r11WMokZFrGmfKvXYz3Na6w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NyUbEpntKjvkYu5enPh9a1GM1/1ufsYbXusrNfySPFAlaMven0xSK2MSeDYcEl81QjhQM3qU4/jXlyH3S5x57jlvZ5BRmssZ83c3UkcBcSMyljPSu1Oa/CS92QlDebr5vk4YyCrN3LAADar3XZ1prZ5tD9FyAkWhDSGM/Y7b/6Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RyKLs/UJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RyKLs/UJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C8DD1F000FF; Sun, 13 Sep 2026 22:48:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789339724; bh=LtB91lj9cFpKoc/Ifduclkv803l69YmsYbW+o77eFps=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=RyKLs/UJCKPwUw0rHkcQwPJHwI7ji4he8jjDUNfsXOmxHkl6Eb46ghH54AYg9yhYj 1fEZxTPH8sRZ7YfN8Hw9zvNEfYv7QP0v/+p4NhQs0/SgTqJtTqj+/QCE1m73xCN0nR RN1TZPW06AXOc8mSaHSudoL9tPfypsyLZ4I+FbZ/Q1k8VleOB+URz1Z0wg6apSt2RD kH3CYJTs/IqzokIlNjMDtfcriSlEW9SvPxbnQfI8QLo0dn4lhgaUDTs64zp2cz3Tis M08BOOkrjxEirtZWQOjQDg8nVgCAskjlp0Jg6S7b9b/dbzXe5imZjJiYS6qZsyhNYj B/0eqok0WG5Fg== Date: Sun, 13 Sep 2026 15:48:42 -0700 From: Wei Liu To: Naman Jain Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Wei Liu , "K . Y . Srinivasan" , Haiyang Zhang , Dexuan Cui , Michael Kelley , Long Li , Nam Cao , Joerg Roedel , Suravee Suthikulpanit , Vasant Hegde , Will Deacon , Robin Murphy , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Manivannan Sadhasivam , Rob Herring , Bjorn Helgaas , Kees Cook , "Rafael J . Wysocki" , Radu Rendec , Sean Christopherson , Kai Huang , Dmitry Ilvokhin , Shradha Gupta , Christophe JAILLET , Thierry Reding , Jiri Wiesner , Daniel J Blueman , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, linux-pci@vger.kernel.org Subject: Re: [PATCH v4 0/4] x86/irq: Fix lost interrupts on CPU hot-unplug Message-ID: <20260913224842.GF2219269@liuwe-devbox-debian-v2.local> References: <20260909064448.1004-1-namjain@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260909064448.1004-1-namjain@linux.microsoft.com> On Wed, Sep 09, 2026 at 06:44:44AM +0000, Naman Jain wrote: > 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 root partition PCI/MSI irqchip lost that callback > when it was converted to msi_create_parent_irq_domain(), 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 restores > irq_chip_retrigger_hierarchy() on the Hyper-V root partition PCI/MSI chip. > The equivalent guest pci-hyperv.c fix from the previous version is already > merged, so it is dropped here. > > Patch 2 then switches fixup_irqs() to have a fallback call to > irq_chip_retrigger_hierarchy() directly, if a chip does not define > irq_retrigger callback. > > Patch 3 makes a similar change in msi_set_affinity() > > Patch 4 then drops the now-redundant irq_retrigger() initializations. > This way, patch 2-4 do not need to be backported. > > Changes since v3: > https://lore.kernel.org/all/20260907065129.269262-1-namjain@linux.microsoft.com/ > * Move irq_retrigger setting to hv_init_dev_msi_info() in patch 1 > (Michael, Nam) > * Add if-else fallback check in msi_set_affinity() in patch 3 (Michael) > * Break patch 3 into two separate patches, while *keeping review tags*. > > Changes since v2: > https://lore.kernel.org/all/20260810090716.2325295-1-namjain@linux.microsoft.com/ > * Add a backportable fix for Hyper-V root partition irqchip (Wei) > * Add a check for custom irq_retrigger implementations and add direct > irq_chip_retrigger_hierarchy() calls as a fallback if it is not > defined by a chip. (Sashiko, Michael) > * Removed local loop variable change, and continue using the irq_desc > accessor function (Michael) > * Did not pick "Acked-by: Manivannan Sadhasivam" as it was on v1, and v3 > is a functionally different to some extent, specially patch 2. > Requesting you to please review again. > > 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 (4): > x86/hyperv: Set irq_retrigger for root partition PCI/MSI irqchip > x86/irq: Fall back to irq_chip_retrigger_hierarchy() in fixup_irqs() > x86/irq: Fall back to irq_chip_retrigger_hierarchy() in > msi_set_affinity() > x86/irq, iommu/amd, x86/hyperv, PCI: Drop redundant irq_retrigger > inits > I checked linux-next next-20260911. This series has not been applied. This patch series needs to be applied in one go, since patch 4 depends on patch 1. I'm fine with carrying this through the hyperv-fixes tree, or let it go through the x86 tree. Just let me know. Thanks, Wei