[PATCH V2 7/7] hw/block/nvme: support Identify NS Attached Controller List

[Minwoo Im <minwoo.im.dev@gmail.com>]

Support Identify command for Namespace attached controller list.  This
command handler will traverse the controller instances in the given
subsystem to figure out whether the specified nsid is attached to the
controllers or not.

The 4096bytes Identify data will return with the first entry (16bits)
indicating the number of the controller id entries.  So, the data can
hold up to 2047 entries for the controller ids.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
---
 hw/block/nvme.c       | 42 ++++++++++++++++++++++++++++++++++++++++++
 hw/block/trace-events |  1 +
 include/block/nvme.h  |  1 +
 3 files changed, 44 insertions(+)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 71bcd66f1956..da60335def9f 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -3157,6 +3157,46 @@ static uint16_t nvme_identify_ns(NvmeCtrl *n, NvmeRequest *req, bool active)
     return NVME_INVALID_CMD_SET | NVME_DNR;
 }
 
+static uint16_t nvme_identify_ns_attached_list(NvmeCtrl *n, NvmeRequest *req)
+{
+    NvmeIdentify *c = (NvmeIdentify *)&req->cmd;
+    uint16_t min_id = le16_to_cpu(c->ctrlid);
+    uint16_t list[NVME_CONTROLLER_LIST_SIZE] = {};
+    uint16_t *ids = &list[1];
+    NvmeNamespace *ns;
+    NvmeCtrl *ctrl;
+    int cntlid, nr_ids = 0;
+
+    trace_pci_nvme_identify_ns_attached_list(min_id);
+
+    if (c->nsid == NVME_NSID_BROADCAST) {
+        return NVME_INVALID_FIELD | NVME_DNR;
+    }
+
+    ns = nvme_subsys_ns(n->subsys, c->nsid);
+    if (!ns) {
+        return NVME_INVALID_FIELD | NVME_DNR;
+    }
+
+    for (cntlid = min_id; cntlid < ARRAY_SIZE(n->subsys->ctrls); cntlid++) {
+        ctrl = nvme_subsys_ctrl(n->subsys, cntlid);
+        if (!ctrl) {
+            continue;
+        }
+
+        if (!nvme_ns_is_attached(ctrl, ns)) {
+            continue;
+        }
+
+        ids[nr_ids++] = cntlid;
+    }
+
+    list[0] = nr_ids;
+
+    return nvme_dma(n, (uint8_t *)list, sizeof(list),
+                    DMA_DIRECTION_FROM_DEVICE, req);
+}
+
 static uint16_t nvme_identify_ns_csi(NvmeCtrl *n, NvmeRequest *req,
         bool active)
 {
@@ -3356,6 +3396,8 @@ static uint16_t nvme_identify(NvmeCtrl *n, NvmeRequest *req)
         return nvme_identify_ns(n, req, true);
     case NVME_ID_CNS_NS_PRESENT:
         return nvme_identify_ns(n, req, false);
+    case NVME_ID_CNS_NS_ATTACHED_CTRL_LIST:
+        return nvme_identify_ns_attached_list(n, req);
     case NVME_ID_CNS_CS_NS:
         return nvme_identify_ns_csi(n, req, true);
     case NVME_ID_CNS_CS_NS_PRESENT:
diff --git a/hw/block/trace-events b/hw/block/trace-events
index bf67fe7873d2..2d88d96c2165 100644
--- a/hw/block/trace-events
+++ b/hw/block/trace-events
@@ -62,6 +62,7 @@ pci_nvme_del_cq(uint16_t cqid) "deleted completion queue, cqid=%"PRIu16""
 pci_nvme_identify_ctrl(void) "identify controller"
 pci_nvme_identify_ctrl_csi(uint8_t csi) "identify controller, csi=0x%"PRIx8""
 pci_nvme_identify_ns(uint32_t ns) "nsid %"PRIu32""
+pci_nvme_identify_ns_attached_list(uint16_t cntid) "cntid=%"PRIu16""
 pci_nvme_identify_ns_csi(uint32_t ns, uint8_t csi) "nsid=%"PRIu32", csi=0x%"PRIx8""
 pci_nvme_identify_nslist(uint32_t ns) "nsid %"PRIu32""
 pci_nvme_identify_nslist_csi(uint16_t ns, uint8_t csi) "nsid=%"PRIu16", csi=0x%"PRIx8""
diff --git a/include/block/nvme.h b/include/block/nvme.h
index 4b016f954fee..fb82d8682e9f 100644
--- a/include/block/nvme.h
+++ b/include/block/nvme.h
@@ -968,6 +968,7 @@ enum NvmeIdCns {
     NVME_ID_CNS_CS_NS_ACTIVE_LIST     = 0x07,
     NVME_ID_CNS_NS_PRESENT_LIST       = 0x10,
     NVME_ID_CNS_NS_PRESENT            = 0x11,
+    NVME_ID_CNS_NS_ATTACHED_CTRL_LIST = 0x12,
     NVME_ID_CNS_CS_NS_PRESENT_LIST    = 0x1a,
     NVME_ID_CNS_CS_NS_PRESENT         = 0x1b,
     NVME_ID_CNS_IO_COMMAND_SET        = 0x1c,
-- 
2.17.1