Re: [PATCH 0/2] NVMe namespace hotplug and drive reconnection support

[Keith Busch <kbusch@kernel.org>]

On Tue, Apr 14, 2026 at 08:42:21AM -0400, Stefan Hajnoczi wrote:
> On Mon, Apr 13, 2026 at 07:17:37PM +0200, Klaus Jensen wrote:
> > On Apr  9 08:01, mr-083 wrote:
> > > This series adds two features that together enable transparent NVMe disk
> > > hot-swap simulation in QEMU, matching the behavior of physical NVMe
> > > drives being pulled and reinserted in the same PCIe slot.
> > > 
> > 
> > I don't understand this. From an NVMe perspective you can't hotplug a
> > namespace. You can hotplug a PCIe-based NVM Subsystem.
> 
> Hi Klaus,
> It would be great if someone with more NVMe experience than myself can
> find a definite answer, but I think the Namespace List can change
> asynchronously even on a NVMe PCIe controller as long as it supports
> Namespace Management commands.

I think there's some clash in terminology. From nvme protocol side,
hotplug refers to bus events detected by the host, so something like
PCIe slot capabilities defines how that works. This series is doing
something behind the scenes from the host-controller interface
visibility, so it's just coincidence that framework is also called
"hotplug". From nvme protocol perspective, this patch looks like a qemu
specific out-of-band method for namespace "attach/detach" via the QMP
interface. Sounds fine to me: the nvme namespace events are not strictly
tied to the spec defined in-band attachment status.