Re: [Qemu-devel] Using PCI config space to indicate config location

[Rusty Russell]

Jamie Lokier <address@hidden> writes:

> Rusty Russell wrote:
>> I don't think it'll be that bad; reset clears the device to unknown,
>> bar0 moves it from unknown->legacy mode, bar1/2/3 changes it from
>> unknown->modern mode, and anything else is bad (I prefer being strict so
>> we catch bad implementations from the beginning).
>
> Will that work, if the guest with kernel that uses modern mode, kexecs
> to an older (but presumed reliable) kernel that only knows about legacy mode?
>
> I.e. will the replacement kernel, or (ideally) replacement driver on
> the rare occasion that is needed on a running kernel, be able to reset
> the device hard enough?

Well, you need to reset the device, so yes.

Cheers,
Rusty.