From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 708363A5422; Thu, 10 Sep 2026 07:11:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789024297; cv=none; b=bBMc7AXqUidQS4Q7hdd1cpQbDItmoGsXmfvAPlOd9TX43llZUu0w2/AALfe/FvhhxN2ivdHYtN2mUETZmTPnGR9DrIhEWmdbe7t8w52TIQtp55CcWVMlttAdwg/IabIWM6AT/AQDH9kgeo/YGgKqmmn3xyG+ffThUrfIx5SAmuE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789024297; c=relaxed/simple; bh=veNmLyS77khJqxy+yf9wT4pFcgSAoLEhQ271L5jMhx0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=n7yW7c9YZJ+Y9+H73k2nohGxWN2CrxA1odK7cpljlY4CIT+DSbEJOzTysSESV0xLdxMuJdXq1aLdO0YvT2GQFDw3yZGnW1dTYQwNFfZWFXUe2vhp0eVnR10S3lLnGT+dQbOAUWhBQXw2hzOzcyxQqkAnRTZdjN2Xce3sp8bYXrc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=17UCVnuy; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=iiJf0YBO; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="17UCVnuy"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="iiJf0YBO" From: Nam Cao DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1789024293; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=veNmLyS77khJqxy+yf9wT4pFcgSAoLEhQ271L5jMhx0=; b=17UCVnuy9tSpkKuE60hhVX8DDBolKcEpU7UA/+b0pvuIGSSUKPVx5UqiP/XKWCvtLAhxlV P17/d0YyZ5qGmm6bCbdUAbLplDuWUAe/if1k2Kd9wwI8e1ofie1SIlT/q1OcLcgAfRVoTT krHoHcUmv6+aHg5WwaHMjQpe7eBCVESe7+u2hDKuL+divLaGqzzOSj0xl16PZ2LvO2nEZX gL+W/VwxULOn/igb+s/qVz5z5UEYMVGs9nkw0ibUI13Ttu5FR9vALEq7XUmPIx1XSA43zs ZmaSVUgs/N45PXszUECsYRb7+CR7WpAigW1bk/67TGSjhvPtOY7pcETk//siig== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1789024293; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=veNmLyS77khJqxy+yf9wT4pFcgSAoLEhQ271L5jMhx0=; b=iiJf0YBO9FjPc269ArHeTW+A0VN1iK0mNeqJATzM8ZpZu44/cSyA65uKGerLhQyaJZNoUT 5+otwtNr61hxaTCQ== To: Naman Jain , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Wei Liu , "K . Y . Srinivasan" , Haiyang Zhang , Dexuan Cui Cc: Michael Kelley , Long Li , 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 1/4] x86/hyperv: Set irq_retrigger for root partition PCI/MSI irqchip In-Reply-To: <20260909064448.1004-2-namjain@linux.microsoft.com> References: <20260909064448.1004-1-namjain@linux.microsoft.com> <20260909064448.1004-2-namjain@linux.microsoft.com> Date: Thu, 10 Sep 2026 09:11:27 +0200 Message-ID: <87tsnxfun4.fsf@yellow.woof> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Naman Jain writes: > The Hyper-V root partition vPCI MSI irqchip lost its irq_retrigger() > callback when it was converted to msi_create_parent_irq_domain(). The > callback was present on the original irqchip and was dropped during that > conversion. > > 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 root > partition PCI/MSI chip no longer provides 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. > > Restore irq_chip_retrigger_hierarchy() as the irq_retrigger() callback for > the root partition PCI/MSI irqchip, so that a pending interrupt is resent > on its new target CPU via the parent x86 vector domain. > > Fixes: 4691db0704ac ("x86/hyperv: Switch to msi_create_parent_irq_domain()") > Cc: stable@vger.kernel.org > Reviewed-by: Michael Kelley > Signed-off-by: Naman Jain Reviewed-by: Nam Cao