Re: [PATCH v2 1/3] hw/nvme: support irq(de)assertion with eventfd

[Jinhao Fan]

On 8/25/2022 5:33 PM, Klaus Jensen wrote:
> I'm still a bit perplexed by this issue, so I just tried moving
> nvme_init_irq_notifier() to the end of nvme_init_cq() and removing this
> first_io_cqe thing. I did not observe any particular issues?
>
> What bad behavior did you encounter, it seems to work fine to me

The kernel boots up and got stuck, waiting for interrupts. Then the 
request times out and got retried three times. Finally the driver seems 
to decide that the drive is down and continues to boot.

I added some prints during debugging and found that the MSI-X message 
which got registered in KVM via kvm_irqchip_add_msi_route() is not the 
same as the one actually used in msix_notify().

Are you sure you are using KVM's irqfd?

Here is a previous discussion with Keith [1].

[1] 
YvKJk2dYiwomexFv@kbusch-mbp.dhcp.thefacebook.com/#t">https://lore.kernel.org/qemu-devel/YvKJk2dYiwomexFv@kbusch-mbp.dhcp.thefacebook.com/#t