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 684C7400967; Thu, 30 Jul 2026 11:26:34 +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=1785410795; cv=none; b=A86YSN5l4C1Srzq7KKrMwGPfOKsnVVjEgr3JC5EPRKIScShBBQ3RNlrcPaCWdddThIK5TrNfNDs0GHS1W88y/c1YCN1RLkig0GhWAFdpVrisgv1tYnXvI/Wpi9R9mDvM3xoDZ4lridJOEUBShrm/8fn+jPfAFFegbwpMl2h9l54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785410795; c=relaxed/simple; bh=jAQYUEH9rp6tkN0ocp40/35LZbc1Iu7rIRMXZgAVKVM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=BmS2uNFynhnWMlUXEoWE0e9qsCVsr1W38881ysdRiD+MOGhtAeQO84FWbcPISFYnW67iS1P3ewTceZ++J2TMqc8uCdVlaWE4eR0iYGNJZX8rzggJ7RH4E9DXYvc0WQSaF6Vd/HG3pjkXRvlAynAsbvTtw8On4OWVclo5Lbypknc= 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=sXdICoph; 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="sXdICoph" Received: from [192.168.0.105] (unknown [4.194.122.136]) by linux.microsoft.com (Postfix) with ESMTPSA id 4EFA220B7167; Thu, 30 Jul 2026 04:26:15 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4EFA220B7167 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1785410776; bh=Vds4LkW3KdTdjeaQxu1TTLzrv4vuQbQinRX0D3ockIk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=sXdICoph3qcu+kkj01nFVh6dKy1RxyJLbEXCjshWt530ki4FvNkXiQC3qeFUif2jT xjtHBJPzKWLMDwlEdxuqsN4l7fwkPl+klFMu5Yr43/x26e0dFH6d7eK2R/gn+bnBsF 01lAj4uPLMoxznpLit7YlUTUX0Az6/Vxr7EPrqBY= Message-ID: Date: Thu, 30 Jul 2026 16:56:27 +0530 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/3] PCI: hv: Set irq_retrigger callback for the Hyper-V PCI MSI irqchip To: sashiko-reviews@lists.linux.dev Cc: linux-pci@vger.kernel.org, linux-hyperv@vger.kernel.org References: <20260728135117.2888175-1-namjain@linux.microsoft.com> <20260728135117.2888175-2-namjain@linux.microsoft.com> <20260728140427.714311F000E9@smtp.kernel.org> Content-Language: en-US From: Naman Jain In-Reply-To: <20260728140427.714311F000E9@smtp.kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/28/2026 7:34 PM, sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: > > Pre-existing issues: > - [High] The fix for dropped pending interrupts during CPU hot-unplug was missed in the sister Hyper-V root partition MSI domain. > -- > > --- Patch [1]: [PATCH 1/3] PCI: hv: Set irq_retrigger callback for the Hyper-V PCI MSI irqchip --- > commit b8b1c843c457dd145f0d360b44f4b1bf34bd8cf5 > Author: Naman Jain > > PCI: hv: Set irq_retrigger callback for the Hyper-V PCI MSI irqchip > > 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. 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. > > 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 > Signed-off-by: Naman Jain > >> 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; > > [Severity: High] > This isn't a bug introduced by this patch, but does the sister Hyper-V root > partition MSI domain in arch/x86/hyperv/irqdomain.c also need this fix? > > Looking at hv_init_dev_msi_info(), it appears to be missing the exact same > callback initialization for the root partition's top-level irq_chip: > > arch/x86/hyperv/irqdomain.c:hv_init_dev_msi_info() { > ... > if (!msi_lib_init_dev_msi_info(dev, domain, real_parent, info)) > return false; > > chip->flags |= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MOVE_DEFERRED; > > info->ops->msi_prepare = pci_msi_prepare; > > return true; > } > > If a CPU is hot-unplugged while a device MSI interrupt is pending in its > local APIC IRR, could fixup_irqs() fail to resend the pending interrupt > to the new target CPU because this callback is NULL? > > This could potentially lead to the same lost interrupts and I/O stalls > described in this commit message, just in the root partition MSI domain > instead of the guest paravirtual MSI domain. > >> >> if (IS_ENABLED(CONFIG_X86)) >> chip->flags |= IRQCHIP_MOVE_DEFERRED; >> > I am not planning to include this in this series, since this issue is not seen in root partition yet and I am not sure if it is applicable here. Second patch would anyways fix it going forward, but I am OK adding the change for this, if we need. Regards, Naman