Leverage the interrupt redirection infrastructure to enable CPU affinity support for MSI interrupts. Since the parent interrupt affinity cannot be changed, affinity control for the child interrupt (MSI) is achieved by redirecting the handler to run in IRQ work context on the target CPU. This patch was originally prepared by Thomas Gleixner (see Link tag below) in a patch series that was never submitted as is, and only parts of that series have made it upstream so far. Originally-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Radu Rendec <rrendec@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/linux-pci/878qpg4o4t.ffs@tglx/ Link: https://patch.msgid.link/20251128212055.1409093-4-rrendec@redhat.com