On Wed, Sep 09, 2026 at 06:44:44AM +0000, 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 have a fallback call to > irq_chip_retrigger_hierarchy() directly, if a chip does not define > irq_retrigger callback. > > 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. > > Changes since v3: > https://lore.kernel.org/all/[email protected]/ > * Move irq_retrigger setting to hv_init_dev_msi_info() in patch 1 > (Michael, Nam) > * Add if-else fallback check in msi_set_affinity() in patch 3 (Michael) > * Break patch 3 into two separate patches, while *keeping review tags*. > > Changes since v2: > https://lore.kernel.org/all/[email protected]/ > * Add a backportable fix for Hyper-V root partition irqchip (Wei) > * Add a check for custom irq_retrigger implementations and add direct > irq_chip_retrigger_hierarchy() calls as a fallback if it is not > defined by a chip. (Sashiko, Michael) > * Removed local loop variable change, and continue using the irq_desc > accessor function (Michael) > * Did not pick "Acked-by: Manivannan Sadhasivam" as it was on v1, and v3 > is a functionally different to some extent, specially patch 2. > Requesting you to please review again. > > Changes since v1: > https://lore.kernel.org/all/[email protected]/#t > * Added Review tags > * Adding minor clarification in commit msg of patch 2 (Shradha) > > Original RFC: https://lore.kernel.org/all/87y0f3jhd6.ffs@fw13/ > > Naman Jain (4): > x86/hyperv: Set irq_retrigger for root partition PCI/MSI irqchip > x86/irq: Fall back to irq_chip_retrigger_hierarchy() in fixup_irqs() > x86/irq: Fall back to irq_chip_retrigger_hierarchy() in > msi_set_affinity() > x86/irq, iommu/amd, x86/hyperv, PCI: Drop redundant irq_retrigger > inits >
I checked linux-next next-20260911. This series has not been applied. This patch series needs to be applied in one go, since patch 4 depends on patch 1. I'm fine with carrying this through the hyperv-fixes tree, or let it go through the x86 tree. Just let me know. Thanks, Wei
