Re: [PATCH v5 09/14] hw/block/nvme: Support Zoned Namespace Command Set

[Dmitry Fomichev]

On Wed, 2020-09-30 at 07:59 +0200, Klaus Jensen wrote:
> On Sep 28 11:35, Dmitry Fomichev wrote:
> > The emulation code has been changed to advertise NVM Command Set when
> > "zoned" device property is not set (default) and Zoned Namespace
> > Command Set otherwise.
> > 
> > Handlers for three new NVMe commands introduced in Zoned Namespace
> > Command Set specification are added, namely for Zone Management
> > Receive, Zone Management Send and Zone Append.
> > 
> > Device initialization code has been extended to create a proper
> > configuration for zoned operation using device properties.
> > 
> > Read/Write command handler is modified to only allow writes at the
> > write pointer if the namespace is zoned. For Zone Append command,
> > writes implicitly happen at the write pointer and the starting write
> > pointer value is returned as the result of the command. Write Zeroes
> > handler is modified to add zoned checks that are identical to those
> > done as a part of Write flow.
> > 
> > The code to support for Zone Descriptor Extensions is not included in
> > this commit and ZDES 0 is always reported. A later commit in this
> > series will add ZDE support.
> > 
> > This commit doesn't yet include checks for active and open zone
> > limits. It is assumed that there are no limits on either active or
> > open zones.
> > 
> > Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> > Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>
> > Signed-off-by: Ajay Joshi <ajay.joshi@wdc.com>
> > Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
> > Signed-off-by: Matias Bjorling <matias.bjorling@wdc.com>
> > Signed-off-by: Aravind Ramesh <aravind.ramesh@wdc.com>
> > Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> > Signed-off-by: Adam Manzanares <adam.manzanares@wdc.com>
> > Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> > ---
> >  block/nvme.c         |   2 +-
> >  hw/block/nvme-ns.c   | 185 ++++++++-
> >  hw/block/nvme-ns.h   |   6 +-
> >  hw/block/nvme.c      | 872 +++++++++++++++++++++++++++++++++++++++++--
> >  include/block/nvme.h |   6 +-
> >  5 files changed, 1033 insertions(+), 38 deletions(-)
> > 
> > diff --git a/block/nvme.c b/block/nvme.c
> > index 05485fdd11..7a513c9a17 100644
> > --- a/block/nvme.c
> > +++ b/block/nvme.c
> > +static int nvme_calc_zone_geometry(NvmeNamespace *ns, Error **errp)
> > +{
> > +    uint64_t zone_size, zone_cap;
> > +    uint32_t nz, lbasz = ns->blkconf.logical_block_size;
> > +
> > +    if (ns->params.zone_size_mb) {
> > +        zone_size = ns->params.zone_size_mb;
> > +    } else {
> > +        zone_size = NVME_DEFAULT_ZONE_SIZE;
> > +    }
> > +    if (ns->params.zone_capacity_mb) {
> > +        zone_cap = ns->params.zone_capacity_mb;
> > +    } else {
> > +        zone_cap = zone_size;
> > +    }
> 
> I think a check that zone_capacity_mb is less than or equal to
> zone_size_mb is missing earlier?

The check is right below, but I now think it is better to
compare byte sizes rather than numbers of LBAs. There are also
checks missing for zone_size >= lbasz and zone_cap >= lbasz that
I am adding.

> 
> > +static int nvme_zoned_init_ns(NvmeCtrl *n, NvmeNamespace *ns, int 
> > lba_index,
> > +                              Error **errp)
> > +{
> > +    NvmeIdNsZoned *id_ns_z;
> > +
> > +    if (n->params.fill_pattern == 0) {
> > +        ns->id_ns.dlfeat |= 0x01;
> > +    } else if (n->params.fill_pattern == 0xff) {
> > +        ns->id_ns.dlfeat |= 0x02;
> > +    }
> > +
> > +    if (nvme_calc_zone_geometry(ns, errp) != 0) {
> > +        return -1;
> > +    }
> > +
> > +    nvme_init_zone_meta(ns);
> > +
> > +    id_ns_z = g_malloc0(sizeof(NvmeIdNsZoned));
> > +
> > +    /* MAR/MOR are zeroes-based, 0xffffffff means no limit */
> > +    id_ns_z->mar = 0xffffffff;
> > +    id_ns_z->mor = 0xffffffff;
> > +    id_ns_z->zoc = 0;
> > +    id_ns_z->ozcs = ns->params.cross_zone_read ? 0x01 : 0x00;
> > +
> > +    id_ns_z->lbafe[lba_index].zsze = cpu_to_le64(ns->zone_size);
> > +    id_ns_z->lbafe[lba_index].zdes = 0; /* FIXME make helper */
> > +
> > +    ns->csi = NVME_CSI_ZONED;
> > +    ns->id_ns.ncap = cpu_to_le64(ns->zone_capacity * ns->num_zones);
> > +    ns->id_ns.nuse = ns->id_ns.ncap;
> > +    ns->id_ns.nsze = ns->id_ns.ncap;
> > +
> 
> NSZE should be in terms of ZSZE. We *can* report NCAP < NSZE if zcap !=
> zsze, but that requires bit 1 set in NSFEAT and proper reporting of
> NUSE.

Ok, will correct. I think it used to be this way, but got messed up
during multiple transformations of this code.

> 
> > @@ -133,6 +304,14 @@ static void nvme_ns_realize(DeviceState *dev, Error 
> > **errp)
> >  static Property nvme_ns_props[] = {
> >      DEFINE_BLOCK_PROPERTIES(NvmeNamespace, blkconf),
> >      DEFINE_PROP_UINT32("nsid", NvmeNamespace, params.nsid, 0),
> > +
> > +    DEFINE_PROP_BOOL("zoned", NvmeNamespace, params.zoned, false),
> > +    DEFINE_PROP_UINT64("zone_size", NvmeNamespace, params.zone_size_mb,
> > +                       NVME_DEFAULT_ZONE_SIZE),
> > +    DEFINE_PROP_UINT64("zone_capacity", NvmeNamespace,
> > +                       params.zone_capacity_mb, 0),
> 
> There is a nice DEFINE_PROP_SIZE that handles sizes in a nice way (i.e.
> 1G, 1M).

It should be nice to use these types, will add them. _SIZE32 sounds like
a good candidate to use for ZASL.

Thank you for your valuable feedback!
>