* Stefan Hajnoczi (stefa...@redhat.com) wrote: > On Tue, Oct 27, 2020 at 09:04:46AM -0400, Michael S. Tsirkin wrote: > > It's not a waste of time, it's just a lot of work > > within guests. > > Luckily it does no harm to set the NEEDS_RESET bit even if the guest > doesn't handle it. > > If the guest driver is unaware it may continue to submit requests to the > device for a while. The device emulation code stops accepting new > requests though. This means the device will become unresponsive until > reset, which is not ideal but okay in the case where the device was put > into an invalid state. > > I agree that supporting NEEDS_RESET transparently inside guests is > difficult. The driver needs to reset and resume the device without > reporting errors to applications.
Is that required? I mean, what are the semantics of NEEDS_RESET - is it assuming that you must be able to do a silent recovery? Dave > In some cases drivers may not have > enough state in order to do that. It's also tricky to test all code > paths. I guess this is why no one has done it: drivers shouldn't enter > the NEEDS_RESET state anyway and handling it is complex. > > Stefan -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
