On Fri, Nov 29, 2019 at 01:40:55PM +0100, Igor Mammedov wrote: > On Thu, 28 Nov 2019 13:33:58 -0300 > Eduardo Habkost <[email protected]> wrote: > > > On Thu, Nov 28, 2019 at 04:00:06PM +0000, Peter Maydell wrote: > > > Hi; this is a question which came up in Damien's reset series > > > which I don't know the answer to: > > > > > > What is the interaction of the QOM device lifecycle > > > (instance_init/realize/ > > > unrealize/instance_finalize) with hotplug and hot-unplug ? I couldn't > > > find any documentation of this but maybe I was looking in the wrong > > > place... > > > > > > Looking at device_set_realized() it seems like we treat "realize" > > > as meaning "and also do the hot-plug if this is a device we're > > > trying to hotplug". On the other hand hot-unplug is I think the > > > other way around: when we get a hot-unplug event we assume that > > > it should also imply an "unrealize" (but just unrealizing doesn't > > > auto-hot-unplug) ? > > > > Your description seems accurate, and I agree it is confusing. > > > > It would be more consistent if realized=true didn't plug the > > device automatically, and qdev_device_add() asked the hotplug > > handler to plug the device instead. > agreed, it's confusing. But that would not allow to > o = object_new() > set props > o.realize() > reuse the same plug handlers. >
I thought we had very few places that set realized=true directly, so changing this behavior would be easy. I was mistaken. Grepping for 'set_bool.*"realized"' found more than 300 matches. > we potentially can convert it to device_add input arguments > and then call qdev_device_add() instead, which would then > handle plug handlers, not sure it's doable though. > Other than that I don't have any ideas how to make it less confusing. We could introduce a "plugged" property which implicitly calls the hotplug handler, and run a global s/"realized"/"plugged"/ substitution in the whole tree. Would it be worth the trouble, though? -- Eduardo
