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 4B1DA368D7B; Wed, 22 Jul 2026 15:15:09 +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=1784733310; cv=none; b=sh+/TjkGhmfgbd/XAQ9M+Bjp1jLcbiijANBjV+nCTcx3R9vpMs4kkuab1EIXziWVpfeqbLn1Ii70UTTJTYTMZ8eAAESADXRYRD1E1N3diu015EsepA7Ibu5+Mfe8aB53LAdsypolMn+MAqE4WIXSvIIxJfpBXCxIzjk/pPJn9Rk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784733310; c=relaxed/simple; bh=ArwJ2JcsO/Ndc1AiYdKrsLdwykRV3zW5+OVNLVF/RY8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QUhiZFgBz83SW8d1+jneJ4DX7rFusd5k71lGX/8x7uca7iCtn1CRm5Q0A5qY6DhcqgUowWAJFgcOFeec2zVoFyntFQBcWf1wTflEGS2c5xHA2apg5cQCxHZtdblcD1mGJkHYBHENwe6D4a3ITAVpyTzyfuk1Q52kmN4xWEsgY7k= 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=J3eKdCx+; 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="J3eKdCx+" Received: from [192.168.0.105] (unknown [4.194.122.162]) by linux.microsoft.com (Postfix) with ESMTPSA id 4B02220B7167; Wed, 22 Jul 2026 08:14:45 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4B02220B7167 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1784733290; bh=WhxLn0OIyun6pU+cHXMszhNcMqQyhZmqdwxsVkPBAR4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=J3eKdCx+BRaCwe81EJGv8OfEh9tCv6BYQn6Ntm6GjDhwJenAKrgcsqRkIuntODpGE tmTfgYjZG9VKY92YqVMv14njxigITas5/TNs8VU1LPTzyFRGVatWwAfV9jaGi+nCm4 N5Udh1oO0AqoxJyG6tJp2Q47Qq80dghWJOuWFqz0= Message-ID: <9739e095-9696-412b-adaa-2c37ef630bdf@linux.microsoft.com> Date: Wed, 22 Jul 2026 20:44:57 +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: [RFC PATCH] x86/apic: Fix lost IRQ during forced vector migration on Hyper-V To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" Cc: Neeraj Upadhyay , linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, Michael Kelley References: <20260710054007.288807-1-namjain@linux.microsoft.com> <874ihskq1h.ffs@fw13> <12557e3a-5feb-4601-ad53-cf4846052edd@linux.microsoft.com> <87y0f3jhd6.ffs@fw13> Content-Language: en-US From: Naman Jain In-Reply-To: <87y0f3jhd6.ffs@fw13> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/22/2026 6:45 PM, Thomas Gleixner wrote: > Naman! > > On Wed, Jul 22 2026 at 14:59, Naman Jain wrote: >> I completely agree with your comments, and now that I know how to fix >> this, do you suggest me to - >> >> 1. add irq_retrigger callback in pci-hyperv.c >> or >> 2. go with your fixup-irq() change to no longer need drivers to add the >> above? And then see what all stale irq_retrigger inits can be removed >> >> Going with 1) would be easier for me to fix this bug, and back port it >> to older kernels, with proper Fixes tag (pointing to some pci-hyperv.c >> change). >> Then later, we can go with 2) separately as a general enhancement (not a >> Fix). > > This should be one patch series: > > 1) Add the callback to pci-hyperv, i.e. in hv_pcie_init_dev_msi_info() > > + chip->irq_retrigger = irq_chip_retrigger_hierarchy; > > That sets it on the outermost domain interrupt chip (PCI/MSI > device domain), which is what fixup_irqs() looks at. > > This one needs a Fixes: tag (The first commit which introduced the > driver) and a Cc: stable@... so it will be backported. > > 2) Change fixup_irqs() to use irq_chip_retrigger_hierarchy() > > Feel free to pick up the patch I gave you, add a proper change log > and a Suggested-by: Thomas .... tag. > > 3) Remove the initialization of the outermost chip from arch/x86/* and > drivers/iommu/amd/* as that's not longer required then. > > Thanks, > > tglx > Understood. Thanks. Regards, Naman