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 7530E3AB28E for ; Mon, 10 Aug 2026 09:07:40 +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=1786352863; cv=none; b=tS/O/DKQNVwMF5Qh5syRKfV7o73VaV1LrP2GcbDeXIqQDEY82j6wkw8hpkqRl3tv2yDoD34ul5i02nLd053kTgK/U5SL6iHxwhdkk/QGmLu6E4z6q/bfGTShdyw3XJVZ6zfPh1o70xRwsmgsfjI0cnQgI0bAobzcJANirPW2A2o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786352863; c=relaxed/simple; bh=8hRhto7yu1YdfxQ/es9BJ2LPlFdXAoHdDj6NeWX6zQk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VU+WUnkEN+5FZAL1rPOXxMivPJU1h96VYFKSHuGh46fiug6y65Knw5Ia2XFKL3VLAnk11pxeMegksq1kwjBwkhUe0z34EbzaRZEO/uA/HIxMuc9NgZFVn86WPYOHn6B4jqJY7ktyI/6PaGh7F+p/g6Qwu1/SxplQf2QcTfr0M9Q= 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=FmGA0vpI; 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="FmGA0vpI" Received: from CPC-namja-026ON.redmond.corp.microsoft.com (unknown [4.213.232.21]) by linux.microsoft.com (Postfix) with ESMTPSA id B879020B7168; Mon, 10 Aug 2026 02:07:10 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com B879020B7168 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1786352836; bh=aP+Szq1FgVdmKtut4AqYblFcxzvyIhDJq4aWTv43pM4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FmGA0vpIITa1t3cnGHPp6hbpx5ttlLd3lihgXL9JsMZ9vT+09rk4r5XxE0gXo/6bW Juxs3m4kaRvwSZ8XofRV/ExMfU4hgBfDAz2AndojxBcVhvDG485LEwwRjBbDHm/JaO gsx3tIzuMlMadVShlG2Bo3IC6hAOeF8Nq8Fu6oJA= 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 2/3] x86/irq: Use irq_chip_retrigger_hierarchy() in fixup_irqs() Date: Mon, 10 Aug 2026 09:07:14 +0000 Message-ID: <20260810090716.2325295-3-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: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit fixup_irqs() re-injects a pending interrupt on its new target CPU by looking at the outermost domain chip and invoking its irq_retrigger() callback directly. That only works when the outermost chip happens to install an irq_retrigger() callback, which is not guaranteed for every irqchip and could lead to lost interrupts on CPU hot-unplug. Use irq_chip_retrigger_hierarchy() instead, which walks up the interrupt hierarchy until it finds a chip that implements irq_retrigger(). While at it, move the loop-local variables into the loop scope and use a scoped guard for desc->lock. VECTOR_RETRIGGERED is now set only when the retrigger succeeds (irq_chip_retrigger_hierarchy() returns non-zero) instead of unconditionally. This is harmless today since apic_retrigger_irq() always returns 1, and arguably more correct. No functional change intended for chips which already provide an irq_retrigger() callback on the outermost domain. Suggested-by: Thomas Gleixner Reviewed-by: Shradha Gupta Signed-off-by: Naman Jain --- arch/x86/kernel/irq.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 30122f0b3af96..ef1bdd3c4659a 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -466,11 +466,6 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_posted_msi_notification) /* A cpu has been removed from cpu_online_mask. Reset irq affinities. */ void fixup_irqs(void) { - unsigned int vector; - struct irq_desc *desc; - struct irq_data *data; - struct irq_chip *chip; - irq_migrate_all_off_this_cpu(); /* @@ -489,22 +484,18 @@ void fixup_irqs(void) * vector_lock because the cpu is already marked !online, so * nothing else will touch it. */ - for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { - if (IS_ERR_OR_NULL(__this_cpu_read(vector_irq[vector]))) + for (unsigned int vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { + struct irq_desc *desc = __this_cpu_read(vector_irq[vector]); + + if (IS_ERR_OR_NULL(desc)) continue; if (is_vector_pending(vector)) { - desc = __this_cpu_read(vector_irq[vector]); - - raw_spin_lock(&desc->lock); - data = irq_desc_get_irq_data(desc); - chip = irq_data_get_irq_chip(data); - if (chip->irq_retrigger) { - chip->irq_retrigger(data); + guard(raw_spinlock)(&desc->lock); + if (irq_chip_retrigger_hierarchy(&desc->irq_data)) __this_cpu_write(vector_irq[vector], VECTOR_RETRIGGERED); - } - raw_spin_unlock(&desc->lock); } + if (__this_cpu_read(vector_irq[vector]) != VECTOR_RETRIGGERED) __this_cpu_write(vector_irq[vector], VECTOR_UNUSED); } -- 2.43.0