Naman Jain <[email protected]> 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: [email protected] > Reviewed-by: Michael Kelley <[email protected]> > Signed-off-by: Naman Jain <[email protected]>
Reviewed-by: Nam Cao <[email protected]>
