Re: [PATCH] hw/nvme: add param to control auto zone transitioning to zone state closed

[Klaus Jensen <its@irrelevant.dk>]

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On Jun  1 07:30, Niklas Cassel wrote:
>On Mon, May 31, 2021 at 09:39:20PM +0200, Klaus Jensen wrote:
>> On May 31 15:42, Niklas Cassel wrote:
>> > On Fri, May 28, 2021 at 01:22:38PM +0200, Klaus Jensen wrote:
>> > > On May 28 11:05, Niklas Cassel wrote:
>> > > > From: Niklas Cassel <niklas.cassel@wdc.com>
>> > > >
>> > > > In the Zoned Namespace Command Set Specification, chapter
>> > > > 2.5.1 Managing resources
>> > > >
>> > > > "The controller may transition zones in the ZSIO:Implicitly Opened state
>> > > > to the ZSC:Closed state for resource management purposes."
>> > > >
>> > > > The word may in this sentence means that automatically transitioning
>> > > > an implicitly opened zone to closed is completely optional.
>> > > >
>> > > > Add a new parameter so that the user can control if this automatic
>> > > > transitioning should be performed or not.
>> > > >
>> > > > Being able to control this can help with verifying that e.g. a user-space
>> > > > program behaves properly even without this optional ZNS feature.
>> > > >
>> > > > The default value is set to true, in order to not change the existing
>> > > > behavior.
>> > > >
>> > > > Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
>> > > > ---
>> > > > hw/nvme/ctrl.c | 9 ++++++++-
>> > > > hw/nvme/ns.c   | 2 ++
>> > > > hw/nvme/nvme.h | 1 +
>> > > > 3 files changed, 11 insertions(+), 1 deletion(-)
>> > > >
>> > > > diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
>> > > > index 40a7efcea9..d00f0297a5 100644
>> > > > --- a/hw/nvme/ctrl.c
>> > > > +++ b/hw/nvme/ctrl.c
>> > > > @@ -141,6 +141,11 @@
>> > > >  *
>> > > >  *     zoned.cross_read=<enable RAZB, default: false>
>> > > >  *         Setting this property to true enables Read Across Zone Boundaries.
>> > > > + *
>> > > > + *     zoned.auto_transition=<enable auto resource management, default: true>
>> > > > + *         Indicates if zones in zone state implicitly opened can be
>> > > > + *         automatically transitioned to zone state closed for resource
>> > > > + *         management purposes.
>> > > >  */
>> > > >
>> > > > #include "qemu/osdep.h"
>> > > > @@ -1699,7 +1704,9 @@ static uint16_t nvme_zrm_open_flags(NvmeNamespace *ns, NvmeZone *zone,
>> > > >         /* fallthrough */
>> > > >
>> > > >     case NVME_ZONE_STATE_CLOSED:
>> > > > -        nvme_zrm_auto_transition_zone(ns);
>> > > > +        if (ns->params.auto_transition_zones) {
>> > > > +            nvme_zrm_auto_transition_zone(ns);
>> > > > +        }
>> > > >         status = nvme_aor_check(ns, act, 1);
>> > > >         if (status) {
>> > > >             return status;
>> > > > diff --git a/hw/nvme/ns.c b/hw/nvme/ns.c
>> > > > index 3fec9c6273..31dee43d30 100644
>> > > > --- a/hw/nvme/ns.c
>> > > > +++ b/hw/nvme/ns.c
>> > > > @@ -531,6 +531,8 @@ static Property nvme_ns_props[] = {
>> > > >                        params.max_open_zones, 0),
>> > > >     DEFINE_PROP_UINT32("zoned.descr_ext_size", NvmeNamespace,
>> > > >                        params.zd_extension_size, 0),
>> > > > +    DEFINE_PROP_BOOL("zoned.auto_transition", NvmeNamespace,
>> > > > +                     params.auto_transition_zones, true),
>> > > >     DEFINE_PROP_END_OF_LIST(),
>> > > > };
>> > > >
>> > > > diff --git a/hw/nvme/nvme.h b/hw/nvme/nvme.h
>> > > > index 81a35cda14..bd86054db2 100644
>> > > > --- a/hw/nvme/nvme.h
>> > > > +++ b/hw/nvme/nvme.h
>> > > > @@ -100,6 +100,7 @@ typedef struct NvmeNamespaceParams {
>> > > >     uint32_t max_active_zones;
>> > > >     uint32_t max_open_zones;
>> > > >     uint32_t zd_extension_size;
>> > > > +    bool     auto_transition_zones;
>> > > > } NvmeNamespaceParams;
>> > > >
>> > > > typedef struct NvmeNamespace {
>> > > > --
>> > > > 2.31.1
>> > > >
>> > >
>> > > Looks good Niklas!
>> > >
>> > > Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
>> >
>> > In reality, it is the controller that does the auto transitioning.
>> >
>> > In theory, one namespace could be attached to two different controllers,
>> > and I guess, in that case, it depends on if the controller that we used
>> > when doing the write supports auto transitioning or not, that determines
>> > if a zone will be auto transitioned or not.
>> >
>> > If we were to change this to be a parameter of the controller instead
>> > of a parameter of the namespace, we would require to refactor a lot of
>> > code in the regular write path. As we currently don't have any NvmeRequest
>> > object in nvme_zrm_open_flags().
>> >
>> > Thoughts?
>> >
>>
>> I think you are right. This should be controller-specific behavior. I took
>> the liberty of moving the parameter; the refactor is minimal.
>>
>>
>> From: Niklas Cassel <niklas.cassel@wdc.com>
>>
>> In the Zoned Namespace Command Set Specification, chapter
>> 2.5.1 Managing resources
>>
>> "The controller may transition zones in the ZSIO:Implicitly Opened state
>> to the ZSC:Closed state for resource management purposes."
>>
>> The word may in this sentence means that automatically transitioning
>> an implicitly opened zone to closed is completely optional.
>>
>> Add a new parameter so that the user can control if this automatic
>> transitioning should be performed or not.
>>
>> Being able to control this can help with verifying that e.g. a user-space
>> program behaves properly even without this optional ZNS feature.
>>
>> The default value is set to true, in order to not change the existing
>> behavior.
>>
>> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
>> [k.jensen: moved parameter to controller]
>> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
>> ---
>>  hw/nvme/nvme.h |  1 +
>>  hw/nvme/ctrl.c | 32 ++++++++++++++++++++++----------
>>  2 files changed, 23 insertions(+), 10 deletions(-)
>>
>> diff --git a/hw/nvme/nvme.h b/hw/nvme/nvme.h
>> index 81a35cda142b..93a7e0e5380e 100644
>> --- a/hw/nvme/nvme.h
>> +++ b/hw/nvme/nvme.h
>> @@ -382,6 +382,7 @@ typedef struct NvmeParams {
>>      uint8_t  vsl;
>>      bool     use_intel_id;
>>      uint8_t  zasl;
>> +    bool     auto_transition_zones;
>>      bool     legacy_cmb;
>>  } NvmeParams;
>> diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
>> index 40a7efcea914..8dd9cb2ccbf3 100644
>> --- a/hw/nvme/ctrl.c
>> +++ b/hw/nvme/ctrl.c
>> @@ -34,6 +34,7 @@
>>   *              aerl=<N[optional]>,aer_max_queued=<N[optional]>, \
>>   *              mdts=<N[optional]>,vsl=<N[optional]>, \
>>   *              zoned.zasl=<N[optional]>, \
>> + *              zoned.auto_transition=<on|off[optional]>, \
>>   *              subsys=<subsys_id>
>>   *      -device nvme-ns,drive=<drive_id>,bus=<bus_name>,nsid=<nsid>,\
>>   *              zoned=<true|false[optional]>, \
>> @@ -100,6 +101,11 @@
>>   *   the minimum memory page size (CAP.MPSMIN). The default value is 0 (i.e.
>>   *   defaulting to the value of `mdts`).
>>   *
>> + * - `zoned.auto_transition`
>> + *   Indicates if zones in zone state implicitly opened can be automatically
>> + *   transitioned to zone state closed for resource management purposes.
>> + *   Defaults to 'on'.
>> + *
>>   * nvme namespace device parameters
>>   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>   * - `shared`
>> @@ -1686,8 +1692,8 @@ enum {
>>      NVME_ZRM_AUTO = 1 << 0,
>>  };
>> -static uint16_t nvme_zrm_open_flags(NvmeNamespace *ns, NvmeZone *zone,
>> -                                    int flags)
>> +static uint16_t nvme_zrm_open_flags(NvmeCtrl *n, NvmeNamespace *ns,
>> +                                    NvmeZone *zone, int flags)
>>  {
>>      int act = 0;
>>      uint16_t status;
>> @@ -1699,7 +1705,9 @@ static uint16_t nvme_zrm_open_flags(NvmeNamespace *ns, NvmeZone *zone,
>>          /* fallthrough */
>>      case NVME_ZONE_STATE_CLOSED:
>> -        nvme_zrm_auto_transition_zone(ns);
>> +        if (n->params.auto_transition_zones) {
>> +            nvme_zrm_auto_transition_zone(ns);
>> +        }
>>          status = nvme_aor_check(ns, act, 1);
>>          if (status) {
>>              return status;
>> @@ -1735,14 +1743,16 @@ static uint16_t nvme_zrm_open_flags(NvmeNamespace *ns, NvmeZone *zone,
>>      }
>>  }
>> -static inline uint16_t nvme_zrm_auto(NvmeNamespace *ns, NvmeZone *zone)
>> +static inline uint16_t nvme_zrm_auto(NvmeCtrl *n, NvmeNamespace *ns,
>> +                                     NvmeZone *zone)
>>  {
>> -    return nvme_zrm_open_flags(ns, zone, NVME_ZRM_AUTO);
>> +    return nvme_zrm_open_flags(n, ns, zone, NVME_ZRM_AUTO);
>>  }
>> -static inline uint16_t nvme_zrm_open(NvmeNamespace *ns, NvmeZone *zone)
>> +static inline uint16_t nvme_zrm_open(NvmeCtrl *n, NvmeNamespace *ns,
>> +                                     NvmeZone *zone)
>>  {
>> -    return nvme_zrm_open_flags(ns, zone, 0);
>> +    return nvme_zrm_open_flags(n, ns, zone, 0);
>>  }
>>  static void nvme_advance_zone_wp(NvmeNamespace *ns, NvmeZone *zone,
>> @@ -2283,7 +2293,7 @@ static void nvme_copy_in_complete(NvmeRequest *req)
>>              goto invalid;
>>          }
>> -        status = nvme_zrm_auto(ns, zone);
>> +        status = nvme_zrm_auto(nvme_ctrl(req), ns, zone);
>>          if (status) {
>>              goto invalid;
>>          }
>> @@ -3080,7 +3090,7 @@ static uint16_t nvme_do_write(NvmeCtrl *n, NvmeRequest *req, bool append,
>>              goto invalid;
>>          }
>> -        status = nvme_zrm_auto(ns, zone);
>> +        status = nvme_zrm_auto(n, ns, zone);
>>          if (status) {
>>              goto invalid;
>>          }
>> @@ -3169,7 +3179,7 @@ enum NvmeZoneProcessingMask {
>>  static uint16_t nvme_open_zone(NvmeNamespace *ns, NvmeZone *zone,
>>                                 NvmeZoneState state, NvmeRequest *req)
>>  {
>> -    return nvme_zrm_open(ns, zone);
>> +    return nvme_zrm_open(nvme_ctrl(req), ns, zone);
>>  }
>>  static uint16_t nvme_close_zone(NvmeNamespace *ns, NvmeZone *zone,
>> @@ -6259,6 +6269,8 @@ static Property nvme_props[] = {
>>      DEFINE_PROP_BOOL("use-intel-id", NvmeCtrl, params.use_intel_id, false),
>>      DEFINE_PROP_BOOL("legacy-cmb", NvmeCtrl, params.legacy_cmb, false),
>>      DEFINE_PROP_UINT8("zoned.zasl", NvmeCtrl, params.zasl, 0),
>> +    DEFINE_PROP_BOOL("zoned.auto_transition", NvmeCtrl,
>> +                     params.auto_transition_zones, true),
>>      DEFINE_PROP_END_OF_LIST(),
>>  };
>> --
>> 2.31.1
>>
>
>Thanks a lot Klaus! I really appreciate it.
>
>My initial thought was to add a new flag in the enum where NVME_ZRM_AUTO is.
>But I think that would just make the code harder to read.
>You simply check the parameter directly, which is more obvious to the reader,
>so I think patch looks good!
>

Can I add your reviewed-by on this? :)

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