From: Klaus Jensen <k.jen...@samsung.com> Back in May, Hannes posted a fix[1] to re-enable NVMe PCI hotplug. We discussed a bit back and fourth and I mentioned that the core issue was an artifact of the parent/child relationship stemming from the qdev setup we have with namespaces attaching to controller through a qdev bus.
The gist of this series is the fourth patch "hw/nvme: fix controller hot unplugging" which basically causes namespaces to be reassigned to a bus owned by the subsystem if the parent controller is linked to one. This fixes `device_del/add nvme` in such settings. Note, that in the case that there is no subsystem involved, nvme devices can be removed from the system with `device_del`, but this *will* cause the namespaces to be removed as well since there is no place (i.e. no subsystem) for them to "linger". And since this series does not add support for hotplugging nvme-ns devices, while an nvme device can be readded, no namespaces can. Support for hotplugging nvme-ns devices is present in [1], but I'd rather not add that since I think '-device nvme-ns' is already a bad design choice. Now, I do realize that it is not "pretty" to explicitly change the parent bus, so I do have a an RFC patch in queue that replaces the subsystem and namespace devices with objects, but keeps -device shims available for backwards compatibility. This approach will solve the problems properly and should be a better model. However, I don't believe it will make it for 6.1 and I'd really like to at least fix the unplugging for 6.1 and this gets the job done. [1]: 20210511073511.32511-1-h...@suse.de v2: - added R-b's by Hannes for patches 1 through 3 - simplified "hw/nvme: fix controller hot unplugging" Klaus Jensen (4): hw/nvme: remove NvmeCtrl parameter from ns setup/check functions hw/nvme: mark nvme-subsys non-hotpluggable hw/nvme: unregister controller with subsystem at exit hw/nvme: fix controller hot unplugging hw/nvme/nvme.h | 18 +++++++++------- hw/nvme/ctrl.c | 14 ++++++------ hw/nvme/ns.c | 55 +++++++++++++++++++++++++++++++----------------- hw/nvme/subsys.c | 9 ++++++++ 4 files changed, 63 insertions(+), 33 deletions(-) -- 2.32.0
