Re: [Qemu-devel] [PATCH v8 11/12] vfio: register aer resume notification handler for aer resume

[Zhou Jie]

Hi, Alex

> It seems like we have a number of questions open in the thread with MST
> from the previous version, particularly whether we should actually drop
> the resume notifier and block the reset in the kernel.  The concern
> being that it's not very well specified what we can and cannot do
> between the error interrupt and the resume interrupt.  We'd probably
> need some other indicate of whether the host has this capability,
> perhaps a flag in vfio_device_info.  Appreciate your opinions there.
> Thanks,
>
> Alex

Have you had a conclusion with MST?

How about the process like following?
1. Detect support for VFIO reset blocking.
   Maybe use vfio_device_info.
2. Immediately notify the VM on error detected.
3. Invoke ioctl(VFIO_DEVICE_PCI_HOT_RESET).
   If kernel is doing reset, then block in ioctl.

   Can I ignore the resume notifier?
   else
   Shall ioctl block until after receiving resume notification?

Sincerely
Zhou Jie