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 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


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