Re: [virtio-dev] Re: [PATCH v1] virtio-mmio: Specify wait needed in driver during reset

[Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>]

* Jason Wang <jasowang@redhat.com> [2021-08-18 14:04:04]:

> > Fine let me take a stab at the next version which will have this:
> >
> > * Introduce a status bit for device to indicate "reset in progress". This could
> >   be adopted by other transports also (for ex PCI).
> 
> I may miss something discussion but any reason that the current
> VIRTIO_MMIO_STATUS is not sufficient?

I think Mike suggested we specify what device would return while reset is in
progress, rather than any arbitrary non-zero value:

https://lists.oasis-open.org/archives/virtio-dev/202108/msg00070.html

> > * For v3 MMIO devices, driver, after initiating reset, should wait until
> >   status = 0 or device indicates "failure". What the driver does when it sees
> >   failure can be implementation defined (it can give up or try reset few more
> >   times)
> 
> Yes, but let's wait a little bit to see if it is agreed by others.

Sure. 

Mike,
	Do you suggest we add this as well for v3 device?

"after writing 0 to Status and before reading any fields, the driver
MUST read Status and wait for a read to return 0 or indicate failure"

- vatsa

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