Hi guys, In vfio migration resume phase, the cost would increase if the vfio device has more unmasked vectors. We try to optimize it in this series. You can see the commit message in PATCH 6 for details. Patch 1-3 are simple cleanups and fixup. Patch 4-5 are the preparations for the optimization. Patch 6 optimizes the vfio msix setup path. Changes v3->v4: - fix several typos and grammatical errors [Alex] - remove the patches that fix and clean the MSIX common part from this series [Alex] - Patch 6: - use vector->use directly and fill it with -1 on error paths [Alex] - add comment before enable deferring to commit [Alex] - move the code that do_use/release on vector 0 into an "else" branch [Alex] - introduce vfio_prepare_kvm_msi_virq_batch() that enables the 'defer_kvm_irq_routing' flag [Alex] - introduce vfio_commit_kvm_msi_virq_batch() that clears the 'defer_kvm_irq_routing' flag and does further work [Alex] Changes v2->v3: - fix two errors [Longpeng] Changes v1->v2: - fix several typos and grammatical errors [Alex, Philippe] - split fixups and cleanups into separate patches [Alex, Philippe] - introduce kvm_irqchip_add_deferred_msi_route to minimize code changes [Alex] - enable the optimization in msi setup path [Alex] Longpeng (Mike) (6): vfio: simplify the conditional statements in vfio_msi_enable vfio: move re-enabling INTX out of the common helper vfio: simplify the failure path in vfio_msi_enable kvm: irqchip: extract kvm_irqchip_add_deferred_msi_route Revert "vfio: Avoid disabling and enabling vectors repeatedly in VFIO migration" vfio: defer to commit kvm irq routing when enable msi/msix accel/kvm/kvm-all.c | 15 ++++- hw/vfio/pci.c | 182 +++++++++++++++++++++++++++++++++------------------ hw/vfio/pci.h | 1 + include/sysemu/kvm.h | 6 ++ 4 files changed, 140 insertions(+), 64 deletions(-) -- 1.8.3.1