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 4D81025A2DD; Tue, 28 Jul 2026 13:51:33 +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=1785246694; cv=none; b=Wbaw1njpvE0U37QA2nZTaUBDPIy5cbMAlQtC+f12R/WM7tzTK2qD5smkex1D48z/pBtNiriGVwjplJUsB8VfW5D28Mx/n0a+MIPlfhXAyGECqdkqvowrijwcVr5FhMCVCPuQPVUtT+C/nqOjgoTFuYITjBNenn4rrrSGImGvKrs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785246694; c=relaxed/simple; bh=hRvBtimUkN5HTwmrRjs1Te44eljEyxGDej4qebzkedw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=pXJU9Eazjj6w0G3D/Xk4IZFZkLyZcy36ibLjRwSY01gOnKc4UQR0VlY/3nIs7WX+ew6OfS1GwaSJxyMY+HBtRnZyUjwWT3qKW4AJu3qwh6j2hzLNuGlPFTE0zZMNzRjTmz492zwEIn2NXb9z3/K4tSjI6APWe8hy+8UmPllLh/Q= 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=l4YGstsG; 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="l4YGstsG" Received: from CPC-namja-026ON.redmond.corp.microsoft.com (unknown [4.213.232.16]) by linux.microsoft.com (Postfix) with ESMTPSA id 265D920B7166; Tue, 28 Jul 2026 06:51:04 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 265D920B7166 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1785246671; bh=/s0NBGO5Nwu0FBhXzB5m3wygkVQ4fkuc2i5s5t6+ff8=; h=From:To:Cc:Subject:Date:From; b=l4YGstsGT9GrJUEivZR6SFeqwFcVYMDy4+eExl4Z2eLoduQlU5K0LedDFa9IOEGFv dsPEQjC/cLtgve4mikobwwFImpSnuR4vr2hmcETQcZoziVISfInzbR+kT5Ox30yPYv u1RmwnnetKzXldrOkptQy5HhbUbmgOprGkIbwmeY= From: Naman Jain To: "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Lorenzo Pieralisi , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , Manivannan Sadhasivam , Rob Herring , Bjorn Helgaas , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Joerg Roedel (AMD)" , Suravee Suthikulpanit , Vasant Hegde , Will Deacon , Robin Murphy Cc: x86@kernel.org, Jake Oshins , linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 0/3] x86/irq: Fix lost interrupts on CPU hot-unplug for Hyper-V PCI/MSI Date: Tue, 28 Jul 2026 13:51:14 +0000 Message-ID: <20260728135117.2888175-1-namjain@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-pci@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. The series follows the original RFC: Link: 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(-) base-commit: 0d33d21e47d9dc66f91e44da3fc9220c74d93df7 -- 2.43.0