Re: [RFC] adding a generic QAPI event for failed device hotunplug

[Paolo Bonzini]

On 22/03/21 07:39, David Gibson wrote:
> > QEMU doesn't really keep track of "in flight" unplug requests, and as
> > long as that's the case, its timeout even will have the same issue.
> Not generically, maybe.  In the PAPR code we effectively do, by means
> of the 'unplug_requested' boolean in the DRC structure.  Maybe that's
> a mistake, but at the time I couldn't see how else to handle things.

No, that's good.  x86 also tracks it in some registers that are 
accessible from the ACPI firmware.  See "PCI slot removal notification" 
in docs/specs/acpi_pci_hotplug.txt.

> Currently we will resolve all "in flight" requests at machine reset
> time, effectively completing those requests.  Does that differ from
> x86 behaviour?

IIRC on x86 the requests are instead cancelled, but I'm not 100% sure.

Paolo