On Thu, May 14, 2026 at 8:47 PM Stefan Hajnoczi wrote:
>
> On Sun, May 10, 2026 at 07:50:56PM +0200, Sam Li wrote:
> > Add the specs for the zoned format feature of the qcow2 driver.
> > The qcow2 file then can emulate real zoned devices, either passed
> > through by virtio-blk device or NVMe ZNS drive to the guest
> > given zoned information.
> >
> > Signed-off-by: Sam Li
> > Reviewed-by: Stefan Hajnoczi
> > ---
> > docs/system/qemu-block-drivers.rst.inc | 42 ++
> > 1 file changed, 42 insertions(+)
Hi Stefan,
Thanks for reviewing!
> >
> > diff --git a/docs/system/qemu-block-drivers.rst.inc
> > b/docs/system/qemu-block-drivers.rst.inc
> > index 384e95ba76..5066c943d5 100644
> > --- a/docs/system/qemu-block-drivers.rst.inc
> > +++ b/docs/system/qemu-block-drivers.rst.inc
> > @@ -172,6 +172,48 @@ This section describes each format and the options
> > that are supported for it.
> > filename`` to check if the NOCOW flag is set or not (Capital 'C' is
> > NOCOW flag).
> >
> > + .. option:: zone.mode
> > +If this is set to ``host-managed``, the image is an emulated zoned
> > +block device. This option is only valid to emulated zoned device files.
> > +
> > + .. option:: zone.size
> > +
> > +The size of a zone in bytes. The device is divided into zones of this
> > +size with the exception of the last zone, which may be smaller.
>
> This option is required when zone.mode=host-managed?
>
> It would be useful to indicate whether each option listed here is
> required or has a default value when absent.
Makes sense. I'll set the default to 256MB.
>
> > +
> > + .. option:: zone.capacity
> > +
> > +The initial capacity value, in bytes, for all zones. The capacity must
> > +be less than or equal to zone size. If the last zone is smaller, then
> > +its capacity is capped.
> > +
> > +The zone capacity is per zone and may be different between zones in
> > real
> > +devices. QCow2 sets all zones to the same capacity.
>
> This defaults to zone.size?
Yes.
>
> > +
> > + .. option:: zone.conventional_zones
> > +
> > +The number of conventional zones of the zoned device.
>
> This defaults to (size + size.size - 1) / zone.size?
Or just zero, meaning all zones are sequential write required.
>
> > +
> > + .. option:: zone.max_active_zones
> > +
> > +The limit of the zones with implicit open, explicit open or closed
> > state.
> > +
> > +The max active zones must be less or equal to the number of SWR
> > +(sequential write required) zones of the device.
>
> This defaults to (size + size.size - 1) / zone.size?
Or maybe zero, meaning no limit. Although it does have a limit lower
than nr_zones.
>
> > +
> > + .. option:: zone.max_open_zones
> > +
> > +The maximal allowed open zones. The max open zones must not be larger
> > than
> > +the max active zones.
> > +
> > +If the limits of open zones or active zones are equal to the number of
> > +SWR zones, then it is the same as having no limits.
>
> This defaults to max_active_zones?
Yes, if max_active_zone is set, otherwise zero.
>
> > + .. option:: zone.max_append_bytes
> > +
> > +The number of bytes in a zone append request that can be issued to the
> > +device. It must be 512-byte aligned and less than the zone capacity.
>
> Is there a default?
Yes, it can set to 64 KB.
>
> > +
> > .. program:: image-formats
> > .. option:: qed
> >
> > --
> > 2.43.0
> >
