On Sat, 26 Mar 2022 14:02:21 +0800
"Longpeng(Mike)" <longpeng2@huawei.com> wrote:
> From: Longpeng <longpeng2@huawei.com>
>
> 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 are the preparations for the optimization.
> Patch 5 optimizes the vfio msix setup path.
>
> v5: https://lore.kernel.org/all/20211103081657.1945-1-longpeng2@huawei.com/T/
>
> Change v5->v6:
> - remove the Patch 4("kvm: irqchip: extract kvm_irqchip_add_deferred_msi_route")
> of v5, and use KVMRouteChange API instead. [Paolo, Longpeng]
>
> Changes v4->v5:
> - setup the notifier and irqfd in the same function to makes
> the code neater. [Alex]
>
> 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) (5):
> 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
> Revert "vfio: Avoid disabling and enabling vectors repeatedly in VFIO
> migration"
> vfio: defer to commit kvm irq routing when enable msi/msix
>
> hw/vfio/pci.c | 183 +++++++++++++++++++++++++++++++-------------------
> hw/vfio/pci.h | 2 +
> 2 files changed, 115 insertions(+), 70 deletions(-)
>
Nice to see you found a solution with Paolo's suggestion for
begin/commit batching. Looks ok to me; I'll queue this for after the
v7.0 QEMU release and look for further reviews and comments in the
interim. Thanks,
Alex