[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: qom device lifecycle interaction with hotplug/hotunplug ?

From: Jens Freimann
Subject: Re: qom device lifecycle interaction with hotplug/hotunplug ?
Date: Wed, 18 Dec 2019 16:14:43 +0100
User-agent: NeoMutt/20180716-1376-5d6ed1

On Wed, Dec 11, 2019 at 01:52:33PM +0100, Damien Hedde wrote:
On 12/4/19 7:51 PM, Eduardo Habkost wrote:
On Wed, Dec 04, 2019 at 05:21:25PM +0100, Jens Freimann wrote:
On Wed, Dec 04, 2019 at 11:35:37AM -0300, Eduardo Habkost wrote:
On Wed, Dec 04, 2019 at 10:18:24AM +0100, Jens Freimann wrote:
On Tue, Dec 03, 2019 at 06:40:04PM -0300, Eduardo Habkost wrote:
+jfreimann, +mst
And if migration fails this same device is plugged back using
static bool failover_replug_primary(VirtIONet *n, Error **errp)
    qdev_set_parent_bus(n->primary_dev, n->primary_bus);
    hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev);
    if (hotplug_ctrl) {
        hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, &err);
        if (err) {
            goto out;
        hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp);

My concern is about the qdev_set_parent_bus() call above (because I
touch this function in my series) and don't want to have side effects there.

I looked at the code and thought the partial unplug has the effect of
cutting off the unplug procedure just before doing the qdev real unplug.
In pcie_unplug_device() we return before doing the object_unparent():
static void pcie_unplug_device(PCIBus *bus, PCIDevice *dev, ...
     if (dev->partially_hotplugged) {
         dev->qdev.pending_deleted_event = false;
     hotplug_handler_unplug(hotplug_ctrl, DEVICE(dev), &error_abort);

From my understanding, object_unparent() is the only way to really
unplug a device from a bus regarding qdev (and it also unrealizes the
device). So I have the feeling that qdev_set_parent_bus() here is a
no-op (because primary_dev is already on primary_bus).

I tested this now and it really is a no-op. It was required in a
earlier version of the patches and I missed to remove it when I
reworked the re-plug functionality.

I will send a patch to remove it.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]