From: Thomas Gleixner <tglx@kernel.org>
To: Naman Jain <namjain@linux.microsoft.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Wei Liu <wei.liu@kernel.org>,
"K . Y . Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Dexuan Cui <decui@microsoft.com>,
Michael Kelley <mhklinux@outlook.com>
Cc: "Long Li" <longli@microsoft.com>,
"Nam Cao" <namcao@linutronix.de>,
"Joerg Roedel" <joro@8bytes.org>,
"Suravee Suthikulpanit" <suravee.suthikulpanit@amd.com>,
"Vasant Hegde" <vasant.hegde@amd.com>,
"Will Deacon" <will@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Kees Cook" <kees@kernel.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
"Radu Rendec" <radu@rendec.net>,
"Sean Christopherson" <seanjc@google.com>,
"Kai Huang" <kai.huang@intel.com>,
"Dmitry Ilvokhin" <d@ilvokhin.com>,
"Shradha Gupta" <shradhagupta@linux.microsoft.com>,
"Christophe JAILLET" <christophe.jaillet@wanadoo.fr>,
"Thierry Reding" <treding@nvidia.com>,
"Jiri Wiesner" <jwiesner@suse.de>,
"Daniel J Blueman" <daniel@quora.org>,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
iommu@lists.linux.dev, linux-pci@vger.kernel.org
Subject: Re: [PATCH v6 0/4] x86/irq: Fix lost interrupts on CPU hot-unplug
Date: Fri, 16 Oct 2026 00:36:49 +0200 [thread overview]
Message-ID: <87ecdqd20u.ffs@fw13> (raw)
In-Reply-To: <20260923043023.3150498-1-namjain@linux.microsoft.com>
On Wed, Sep 23 2026 at 04:30, Naman Jain wrote:
> 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 root partition PCI/MSI irqchip lost that callback
> when it was converted to msi_create_parent_irq_domain(), 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 restores
> irq_chip_retrigger_hierarchy() on the Hyper-V root partition PCI/MSI chip.
> The equivalent guest pci-hyperv.c fix from the previous version is already
> merged, so it is dropped here.
>
> Patch 2 then switches fixup_irqs() to call irq_chip_retrigger_hierarchy()
> directly which ensures that this issue does not occur for chips that
> miss adding this initialization.
>
> Patch 3 makes a similar change in msi_set_affinity()
>
> Patch 4 then drops the now-redundant irq_retrigger() initializations.
> This way, patch 2-4 do not need to be backported.
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
prev parent reply other threads:[~2026-10-15 22:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-23 4:30 [PATCH v6 0/4] x86/irq: Fix lost interrupts on CPU hot-unplug Naman Jain
2026-09-23 4:30 ` [PATCH v6 1/4] x86/hyperv: Set irq_retrigger for root partition PCI/MSI irqchip Naman Jain
2026-09-23 4:37 ` sashiko-bot
2026-09-23 4:30 ` [PATCH v6 2/4] x86/irq: Use irq_chip_retrigger_hierarchy() in fixup_irqs() Naman Jain
2026-09-23 4:41 ` sashiko-bot
2026-09-23 4:30 ` [PATCH v6 3/4] x86/irq: Use irq_chip_retrigger_hierarchy() in msi_set_affinity() Naman Jain
2026-09-23 4:42 ` sashiko-bot
2026-09-23 14:30 ` Michael Kelley
2026-09-23 4:30 ` [PATCH v6 4/4] x86/irq, iommu/amd, x86/hyperv, PCI: Drop redundant irq_retrigger inits Naman Jain
2026-09-23 4:43 ` sashiko-bot
2026-09-23 14:33 ` Michael Kelley
2026-10-15 22:47 ` Bjorn Helgaas
2026-10-15 9:09 ` [PATCH v6 0/4] x86/irq: Fix lost interrupts on CPU hot-unplug Naman Jain
2026-10-15 22:36 ` Thomas Gleixner [this message]
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