[RFC PATCH V3 4/8] hw/block/nvme: support for multi-controller in subsystem

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

We have nvme-subsys and nvme devices mapped together.  To support
multi-controller scheme to this setup, controller identifier(id) has to
be managed.  Earlier, cntlid(controller id) used to be always 0 because
we didn't have any subsystem scheme that controller id matters.

This patch introduced 'cntlid' attribute to the nvme controller
instance(NvmeCtrl) and make it allocated by the nvme-subsys device
mapped to the controller.  If nvme-subsys is not given to the
controller, then it will always be 0 as it was.

Added 'ctrls' array in the nvme-subsys instance to manage attached
controllers to the subsystem with a limit(32).  This patch didn't take
list for the controllers to make it seamless with nvme-ns device.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
---
 hw/block/nvme-subsys.c | 21 +++++++++++++++++++++
 hw/block/nvme-subsys.h |  4 ++++
 hw/block/nvme.c        | 34 ++++++++++++++++++++++++++++++++--
 hw/block/nvme.h        |  1 +
 4 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/hw/block/nvme-subsys.c b/hw/block/nvme-subsys.c
index f1dc71d588d9..a01003136b12 100644
--- a/hw/block/nvme-subsys.c
+++ b/hw/block/nvme-subsys.c
@@ -22,6 +22,27 @@
 #include "nvme.h"
 #include "nvme-subsys.h"
 
+int nvme_subsys_register_ctrl(NvmeCtrl *n, Error **errp)
+{
+    NvmeSubsystem *subsys = n->subsys;
+    int cntlid;
+
+    for (cntlid = 0; cntlid < ARRAY_SIZE(subsys->ctrls); cntlid++) {
+        if (!subsys->ctrls[cntlid]) {
+            break;
+        }
+    }
+
+    if (cntlid == ARRAY_SIZE(subsys->ctrls)) {
+        error_setg(errp, "no more free controller id");
+        return -1;
+    }
+
+    subsys->ctrls[cntlid] = n;
+
+    return cntlid;
+}
+
 static void nvme_subsys_setup(NvmeSubsystem *subsys)
 {
     char *subnqn;
diff --git a/hw/block/nvme-subsys.h b/hw/block/nvme-subsys.h
index 40f06a4c7db0..4eba50d96a1d 100644
--- a/hw/block/nvme-subsys.h
+++ b/hw/block/nvme-subsys.h
@@ -20,6 +20,10 @@ typedef struct NvmeNamespace NvmeNamespace;
 typedef struct NvmeSubsystem {
     DeviceState parent_obj;
     uint8_t     subnqn[256];
+
+    NvmeCtrl    *ctrls[NVME_SUBSYS_MAX_CTRLS];
 } NvmeSubsystem;
 
+int nvme_subsys_register_ctrl(NvmeCtrl *n, Error **errp);
+
 #endif /* NVME_SUBSYS_H */
diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 3e3b5451ea3d..9f8a739fcd8f 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -4304,16 +4304,21 @@ static void nvme_init_subnqn(NvmeCtrl *n)
     }
 }
 
-static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice *pci_dev)
+static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice *pci_dev, uint16_t cntlid)
 {
     NvmeIdCtrl *id = &n->id_ctrl;
     uint8_t *pci_conf = pci_dev->config;
 
+    n->cntlid = cntlid;
+
     id->vid = cpu_to_le16(pci_get_word(pci_conf + PCI_VENDOR_ID));
     id->ssvid = cpu_to_le16(pci_get_word(pci_conf + PCI_SUBSYSTEM_VENDOR_ID));
     strpadcpy((char *)id->mn, sizeof(id->mn), "QEMU NVMe Ctrl", ' ');
     strpadcpy((char *)id->fr, sizeof(id->fr), "1.0", ' ');
     strpadcpy((char *)id->sn, sizeof(id->sn), n->params.serial, ' ');
+
+    id->cntlid = cntlid;
+
     id->rab = 6;
     id->ieee[0] = 0x00;
     id->ieee[1] = 0x02;
@@ -4359,6 +4364,10 @@ static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice *pci_dev)
     id->psd[0].enlat = cpu_to_le32(0x10);
     id->psd[0].exlat = cpu_to_le32(0x4);
 
+    if (n->subsys) {
+        id->cmic |= NVME_CMIC_MULTI_CTRL;
+    }
+
     NVME_CAP_SET_MQES(n->bar.cap, 0x7ff);
     NVME_CAP_SET_CQR(n->bar.cap, 1);
     NVME_CAP_SET_TO(n->bar.cap, 0xf);
@@ -4371,11 +4380,28 @@ static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice *pci_dev)
     n->bar.intmc = n->bar.intms = 0;
 }
 
+static int nvme_init_subsys(NvmeCtrl *n, Error **errp)
+{
+    int cntlid;
+
+    if (!n->subsys) {
+        return 0;
+    }
+
+    cntlid = nvme_subsys_register_ctrl(n, errp);
+    if (cntlid < 0) {
+        return -1;
+    }
+
+    return cntlid;
+}
+
 static void nvme_realize(PCIDevice *pci_dev, Error **errp)
 {
     NvmeCtrl *n = NVME(pci_dev);
     NvmeNamespace *ns;
     Error *local_err = NULL;
+    int cntlid;
 
     nvme_check_constraints(n, &local_err);
     if (local_err) {
@@ -4391,7 +4417,11 @@ static void nvme_realize(PCIDevice *pci_dev, Error **errp)
         return;
     }
 
-    nvme_init_ctrl(n, pci_dev);
+    cntlid = nvme_init_subsys(n, errp);
+    if (cntlid < 0) {
+        return;
+    }
+    nvme_init_ctrl(n, pci_dev, cntlid);
 
     /* setup a namespace if the controller drive property was given */
     if (n->namespace.blkconf.blk) {
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index 3fa0e0a15539..c158cc873b59 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -133,6 +133,7 @@ typedef struct NvmeCtrl {
     NvmeBus      bus;
     BlockConf    conf;
 
+    uint16_t    cntlid;
     bool        qs_created;
     uint32_t    page_size;
     uint16_t    page_bits;
-- 
2.17.1