[RFC PATCH V2 11/11] hw/block/nvme: support for shared namespace in subsystem

[Minwoo Im]

nvme-ns device is registered to a nvme controller device during the
initialization in nvme_register_namespace() in case that 'bus' property
is given which means it's mapped to a single controller.

This patch introduced a new property 'subsys' just like the controller
device instance did to map a namespace to a NVMe subsystem.

If 'subsys' property is given to the nvme-ns device, it will belong to
the specified subsystem and will be attached to all controllers in that
subsystem by enabling shared namespace capability in NMIC(Namespace
Multi-path I/O and Namespace Capabilities) in Identify Namespace.

Usage:

  -device nvme-subsys,id=subsys0
  -device nvme,serial=foo,id=nvme0,subsys=subsys0
  -device nvme,serial=bar,id=nvme1,subsys=subsys0
  -device nvme,serial=baz,id=nvme2,subsys=subsys0
  -device nvme-ns,id=ns1,drive=<drv>,nsid=1,subsys=subsys0  # Shared
  -device nvme-ns,id=ns2,drive=<drv>,nsid=2,bus=nvme2       # Non-shared

  In the above example, 'ns1' will be shared to 'nvme0' and 'nvme1' in
  the same subsystem.  On the other hand, 'ns2' will be attached to the
  'nvme2' only as a private namespace in that subsystem.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
---
 hw/block/nvme-ns.c     | 23 ++++++++++++++++++-----
 hw/block/nvme-ns.h     |  7 +++++++
 hw/block/nvme-subsys.c | 17 +++++++++++++++++
 hw/block/nvme-subsys.h |  1 +
 hw/block/nvme.c        | 10 +++++++++-
 5 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/hw/block/nvme-ns.c b/hw/block/nvme-ns.c
index c8b75fa02138..073f65e49cac 100644
--- a/hw/block/nvme-ns.c
+++ b/hw/block/nvme-ns.c
@@ -63,6 +63,10 @@ static int nvme_ns_init(NvmeNamespace *ns, Error **errp)
 
     id_ns->npda = id_ns->npdg = npdg - 1;
 
+    if (nvme_ns_shared(ns)) {
+        id_ns->nmic |= NVME_NMIC_NS_SHARED;
+    }
+
     return 0;
 }
 
@@ -358,16 +362,25 @@ static void nvme_ns_realize(DeviceState *dev, Error 
**errp)
         return;
     }
 
-    if (nvme_register_namespace(n, ns, errp)) {
-        error_propagate_prepend(errp, local_err,
-                                "could not register namespace: ");
-        return;
+    if (ns->subsys) {
+        if (nvme_subsys_register_ns(ns, errp)) {
+            error_propagate_prepend(errp, local_err,
+                                    "could not setup namespace to subsys: ");
+            return;
+        }
+    } else {
+        if (nvme_register_namespace(n, ns, errp)) {
+            error_propagate_prepend(errp, local_err,
+                                    "could not register namespace: ");
+            return;
+        }
     }
-
 }
 
 static Property nvme_ns_props[] = {
     DEFINE_BLOCK_PROPERTIES(NvmeNamespace, blkconf),
+    DEFINE_PROP_LINK("subsys", NvmeNamespace, subsys, TYPE_NVME_SUBSYS,
+                     NvmeSubsystem *),
     DEFINE_PROP_UINT32("nsid", NvmeNamespace, params.nsid, 0),
     DEFINE_PROP_UUID("uuid", NvmeNamespace, params.uuid),
     DEFINE_PROP_BOOL("zoned", NvmeNamespace, params.zoned, false),
diff --git a/hw/block/nvme-ns.h b/hw/block/nvme-ns.h
index d87c025b0ab6..3fc7262a7915 100644
--- a/hw/block/nvme-ns.h
+++ b/hw/block/nvme-ns.h
@@ -47,6 +47,8 @@ typedef struct NvmeNamespace {
     const uint32_t *iocs;
     uint8_t      csi;
 
+    NvmeSubsystem   *subsys;
+
     NvmeIdNsZoned   *id_ns_zoned;
     NvmeZone        *zone_array;
     QTAILQ_HEAD(, NvmeZone) exp_open_zones;
@@ -77,6 +79,11 @@ static inline uint32_t nvme_nsid(NvmeNamespace *ns)
     return -1;
 }
 
+static inline bool nvme_ns_shared(NvmeNamespace *ns)
+{
+    return !!ns->subsys;
+}
+
 static inline NvmeLBAF *nvme_ns_lbaf(NvmeNamespace *ns)
 {
     NvmeIdNs *id_ns = &ns->id_ns;
diff --git a/hw/block/nvme-subsys.c b/hw/block/nvme-subsys.c
index a01003136b12..d67160a0ed6f 100644
--- a/hw/block/nvme-subsys.c
+++ b/hw/block/nvme-subsys.c
@@ -43,6 +43,23 @@ int nvme_subsys_register_ctrl(NvmeCtrl *n, Error **errp)
     return cntlid;
 }
 
+int nvme_subsys_register_ns(NvmeNamespace *ns, Error **errp)
+{
+    NvmeSubsystem *subsys = ns->subsys;
+    NvmeCtrl *n;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(subsys->ctrls); i++) {
+        n = subsys->ctrls[i];
+
+        if (n && nvme_register_namespace(n, ns, errp)) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
 static void nvme_subsys_setup(NvmeSubsystem *subsys)
 {
     char *subnqn;
diff --git a/hw/block/nvme-subsys.h b/hw/block/nvme-subsys.h
index 4eba50d96a1d..cae0fbd464e2 100644
--- a/hw/block/nvme-subsys.h
+++ b/hw/block/nvme-subsys.h
@@ -25,5 +25,6 @@ typedef struct NvmeSubsystem {
 } NvmeSubsystem;
 
 int nvme_subsys_register_ctrl(NvmeCtrl *n, Error **errp);
+int nvme_subsys_register_ns(NvmeNamespace *ns, Error **errp);
 
 #endif /* NVME_SUBSYS_H */
diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 2aeb164dd508..7869bd95b099 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -25,7 +25,8 @@
  *              mdts=<N[optional]>,zoned.append_size_limit=<N[optional]> \
  *              ,subsys=<subsys_id> \
  *      -device nvme-ns,drive=<drive_id>,bus=<bus_name>,nsid=<nsid>,\
- *              zoned=<true|false[optional]>
+ *              zoned=<true|false[optional]>, \
+ *              subsys=<subsys_id>
  *      -device nvme-subsys,id=<subsys_id>
  *
  * Note cmb_size_mb denotes size of CMB in MB. CMB is assumed to be at
@@ -69,6 +70,13 @@
  *   data size being in effect. By setting this property to 0, users can make
  *   ZASL to be equal to MDTS. This property only affects zoned namespaces.
  *
+ * nvme namespace device parameters
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * - `subsys`
+ *   NVM Subsystem device.  If given, this namespace will be attached to all
+ *   controllers in the subsystem. Otherwise, `bus` must be given to attach
+ *   this namespace to a specified single controller as a non-shared namespace.
+ *
  * Setting `zoned` to true selects Zoned Command Set at the namespace.
  * In this case, the following namespace properties are available to configure
  * zoned operation:
-- 
2.17.1