Re: [PATCH v4 21/24] nvme: support multiple namespaces

[Michal Prívozník]

On 12/19/19 2:09 PM, Klaus Jensen wrote:
> This adds support for multiple namespaces by introducing a new 'nvme-ns'
> device model. The nvme device creates a bus named from the device name
> ('id'). The nvme-ns devices then connect to this and registers
> themselves with the nvme device.
> 
> This changes how an nvme device is created. Example with two namespaces:
> 
>   -drive file=nvme0n1.img,if=none,id=disk1
>   -drive file=nvme0n2.img,if=none,id=disk2
>   -device nvme,serial=deadbeef,id=nvme0
>   -device nvme-ns,drive=disk1,bus=nvme0,nsid=1
>   -device nvme-ns,drive=disk2,bus=nvme0,nsid=2
> 
> The drive property is kept on the nvme device to keep the change
> backward compatible, but the property is now optional. Specifying a
> drive for the nvme device will always create the namespace with nsid 1.
> 
> Signed-off-by: Klaus Jensen <address@hidden>
> Signed-off-by: Klaus Jensen <address@hidden>

Klaus, just to make sure I understand correctly, this implements
multiple namespaces for *emulated* NVMe, right? I'm asking because I
just merged libvirt patches to support:

-drive
file.driver=nvme,file.device=0000:01:00.0,file.namespace=1,format=raw,if=none,id=drive-virtio-disk0
-device
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1

and seeing these patches made me doubt my design. But if your patches
touch emulated NVMe only, then libvirt's fine because it doesn't expose
that just yet.

Michal