RE: [PATCH v3 10/15] hw/block/nvme: Support Zoned Namespace Command Set

[Dmitry Fomichev]

> -----Original Message-----
> From: Klaus Jensen <its@irrelevant.dk>
> Sent: Friday, September 18, 2020 5:20 PM
> To: Dmitry Fomichev <Dmitry.Fomichev@wdc.com>
> Cc: Keith Busch <kbusch@kernel.org>; Klaus Jensen
> <k.jensen@samsung.com>; Kevin Wolf <kwolf@redhat.com>; Philippe
> Mathieu-Daudé <philmd@redhat.com>; Maxim Levitsky
> <mlevitsk@redhat.com>; Fam Zheng <fam@euphon.net>; Niklas Cassel
> <Niklas.Cassel@wdc.com>; Damien Le Moal <Damien.LeMoal@wdc.com>;
> qemu-block@nongnu.org; qemu-devel@nongnu.org; Alistair Francis
> <Alistair.Francis@wdc.com>; Matias Bjorling <Matias.Bjorling@wdc.com>
> Subject: Re: [PATCH v3 10/15] hw/block/nvme: Support Zoned Namespace
> Command Set
> 
> On Sep 14 07:14, 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>
> > ---
> >  hw/block/nvme.c | 968
> ++++++++++++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 939 insertions(+), 29 deletions(-)
> >
> > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > index c740cbcf1f..0bf7471815 100644
> > --- a/hw/block/nvme.c
> > +++ b/hw/block/nvme.c
> > @@ -709,11 +965,77 @@ static uint16_t nvme_rw(NvmeCtrl *n,
> NvmeRequest *req)
> >          return status;
> >      }
> >
> > +    if (n->params.zoned) {
> > +        zone_idx = nvme_zone_idx(n, slba);
> > +        assert(zone_idx < n->num_zones);
> > +        zone = &ns->zone_array[zone_idx];
> > +
> > +        if (is_write) {
> > +            status = nvme_check_zone_write(zone, slba, nlb);
> > +            if (status != NVME_SUCCESS) {
> > +                trace_pci_nvme_err_zone_write_not_ok(slba, nlb, status);
> > +                return status | NVME_DNR;
> > +            }
> > +
> > +            assert(nvme_wp_is_valid(zone));
> > +            if (append) {
> > +                if (unlikely(slba != zone->d.zslba)) {
> > +                    trace_pci_nvme_err_append_not_at_start(slba, zone-
> >d.zslba);
> > +                    return NVME_ZONE_INVALID_WRITE | NVME_DNR;
> > +                }
> > +                if (data_size > (n->page_size << n->zasl)) {
> > +                    trace_pci_nvme_err_append_too_large(slba, nlb, 
> > n->zasl);
> > +                    return NVME_INVALID_FIELD | NVME_DNR;
> > +                }
> > +                slba = zone->d.wp;
> 
> Your append is broken.
> 
> Since you moved the write pointer update to post aio completion (which I
> totally agree with), you are now assigning the same SLBA to all appends
> that are in queue when nvme_process_sq is invoked.

Yes, these newer changes to update the WP in aio callback turned out to be 
buggy.
Will fix this in the next version.