The serial prop on the controller is actually describing the nvme
subsystem serial, which has to be identical for all controllers within
the same nvme subsystem.

This is enforced since commit a859eb9f8f64 ("hw/nvme: enforce common
serial per subsystem").

Fix the documentation, so that people copying the qemu command line
example won't get an error on qemu start.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 docs/system/devices/nvme.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/system/devices/nvme.rst b/docs/system/devices/nvme.rst
index aba253304e..30f841ef62 100644
--- a/docs/system/devices/nvme.rst
+++ b/docs/system/devices/nvme.rst
@@ -104,8 +104,8 @@ multipath I/O.
 .. code-block:: console
 
    -device nvme-subsys,id=nvme-subsys-0,nqn=subsys0
-   -device nvme,serial=a,subsys=nvme-subsys-0
-   -device nvme,serial=b,subsys=nvme-subsys-0
+   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
+   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
 
 This will create an NVM subsystem with two controllers. Having controllers
 linked to an ``nvme-subsys`` device allows additional ``nvme-ns`` parameters:
-- 
2.36.1

On Mon, Jun 27, 2022 at 02:39:57PM +0200, Niklas Cassel via wrote:
> The serial prop on the controller is actually describing the nvme
> subsystem serial, which has to be identical for all controllers within
> the same nvme subsystem.

Given this description...

>  
>     -device nvme-subsys,id=nvme-subsys-0,nqn=subsys0

...I'm wondering why 'serial' isn't a property of this device..

> -   -device nvme,serial=a,subsys=nvme-subsys-0
> -   -device nvme,serial=b,subsys=nvme-subsys-0
> +   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
> +   -device nvme,serial=deadbeef,subsys=nvme-subsys-0

..rather than requiring it to be redundantly set to the same value here ?

With regards,
Daniel
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On Jun 28 13:26, Daniel P. Berrangé wrote:
> On Mon, Jun 27, 2022 at 02:39:57PM +0200, Niklas Cassel via wrote:
> > The serial prop on the controller is actually describing the nvme
> > subsystem serial, which has to be identical for all controllers within
> > the same nvme subsystem.
> 
> Given this description...
> 
> >  
> >     -device nvme-subsys,id=nvme-subsys-0,nqn=subsys0
> 
> ...I'm wondering why 'serial' isn't a property of this device..
> 
> > -   -device nvme,serial=a,subsys=nvme-subsys-0
> > -   -device nvme,serial=b,subsys=nvme-subsys-0
> > +   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
> > +   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
> 
> ..rather than requiring it to be redundantly set to the same value here ?
> 

-device nvme can be used without a subsystem device, and in that case
the serial must be set. However, you are right that we could not require
it if set on the subsystem device.

On Jun 27 14:39, Niklas Cassel wrote:
> The serial prop on the controller is actually describing the nvme
> subsystem serial, which has to be identical for all controllers within
> the same nvme subsystem.
> 
> This is enforced since commit a859eb9f8f64 ("hw/nvme: enforce common
> serial per subsystem").
> 
> Fix the documentation, so that people copying the qemu command line
> example won't get an error on qemu start.
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>  docs/system/devices/nvme.rst | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/system/devices/nvme.rst b/docs/system/devices/nvme.rst
> index aba253304e..30f841ef62 100644
> --- a/docs/system/devices/nvme.rst
> +++ b/docs/system/devices/nvme.rst
> @@ -104,8 +104,8 @@ multipath I/O.
>  .. code-block:: console
>  
>     -device nvme-subsys,id=nvme-subsys-0,nqn=subsys0
> -   -device nvme,serial=a,subsys=nvme-subsys-0
> -   -device nvme,serial=b,subsys=nvme-subsys-0
> +   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
> +   -device nvme,serial=deadbeef,subsys=nvme-subsys-0
>  
>  This will create an NVM subsystem with two controllers. Having controllers
>  linked to an ``nvme-subsys`` device allows additional ``nvme-ns`` parameters:
> -- 
> 2.36.1
> 

Woops!

Thanks Niklas, applied to nvme-next!