[PATCH v7 09/48] nvme: add max_ioqpairs device parameter

[Klaus Jensen <its@irrelevant.dk>]

From: Klaus Jensen <k.jensen@samsung.com>

The num_queues device paramater has a slightly confusing meaning because
it accounts for the admin queue pair which is not really optional.
Secondly, it is really a maximum value of queues allowed.

Add a new max_ioqpairs parameter that only accounts for I/O queue pairs,
but keep num_queues for compatibility.

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 hw/block/nvme.c | 45 ++++++++++++++++++++++++++-------------------
 hw/block/nvme.h |  4 +++-
 2 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 03278726422d..f45909dad480 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -19,7 +19,7 @@
  *      -drive file=<file>,if=none,id=<drive_id>
  *      -device nvme,drive=<drive_id>,serial=<serial>,id=<id[optional]>, \
  *              cmb_size_mb=<cmb_size_mb[optional]>, \
- *              num_queues=<N[optional]>
+ *              max_ioqpairs=<N[optional]>
  *
  * Note cmb_size_mb denotes size of CMB in MB. CMB is assumed to be at
  * offset 0 in BAR2 and supports only WDS, RDS and SQS for now.
@@ -27,6 +27,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/units.h"
+#include "qemu/error-report.h"
 #include "hw/block/block.h"
 #include "hw/pci/msix.h"
 #include "hw/pci/pci.h"
@@ -72,12 +73,12 @@ static void nvme_addr_read(NvmeCtrl *n, hwaddr addr, void *buf, int size)
 
 static int nvme_check_sqid(NvmeCtrl *n, uint16_t sqid)
 {
-    return sqid < n->params.num_queues && n->sq[sqid] != NULL ? 0 : -1;
+    return sqid < n->params.max_ioqpairs + 1 && n->sq[sqid] != NULL ? 0 : -1;
 }
 
 static int nvme_check_cqid(NvmeCtrl *n, uint16_t cqid)
 {
-    return cqid < n->params.num_queues && n->cq[cqid] != NULL ? 0 : -1;
+    return cqid < n->params.max_ioqpairs + 1 && n->cq[cqid] != NULL ? 0 : -1;
 }
 
 static void nvme_inc_cq_tail(NvmeCQueue *cq)
@@ -639,7 +640,7 @@ static uint16_t nvme_create_cq(NvmeCtrl *n, NvmeCmd *cmd)
         trace_nvme_dev_err_invalid_create_cq_addr(prp1);
         return NVME_INVALID_FIELD | NVME_DNR;
     }
-    if (unlikely(vector > n->params.num_queues)) {
+    if (unlikely(vector > n->params.max_ioqpairs + 1)) {
         trace_nvme_dev_err_invalid_create_cq_vector(vector);
         return NVME_INVALID_IRQ_VECTOR | NVME_DNR;
     }
@@ -803,8 +804,8 @@ static uint16_t nvme_get_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
         trace_nvme_dev_getfeat_vwcache(result ? "enabled" : "disabled");
         break;
     case NVME_NUMBER_OF_QUEUES:
-        result = cpu_to_le32((n->params.num_queues - 2) |
-                             ((n->params.num_queues - 2) << 16));
+        result = cpu_to_le32((n->params.max_ioqpairs - 1) |
+                             ((n->params.max_ioqpairs - 1) << 16));
         trace_nvme_dev_getfeat_numq(result);
         break;
     case NVME_TIMESTAMP:
@@ -848,10 +849,10 @@ static uint16_t nvme_set_feature(NvmeCtrl *n, NvmeCmd *cmd, NvmeRequest *req)
     case NVME_NUMBER_OF_QUEUES:
         trace_nvme_dev_setfeat_numq((dw11 & 0xFFFF) + 1,
                                     ((dw11 >> 16) & 0xFFFF) + 1,
-                                    n->params.num_queues - 1,
-                                    n->params.num_queues - 1);
-        req->cqe.result = cpu_to_le32((n->params.num_queues - 2) |
-                                      ((n->params.num_queues - 2) << 16));
+                                    n->params.max_ioqpairs,
+                                    n->params.max_ioqpairs);
+        req->cqe.result = cpu_to_le32((n->params.max_ioqpairs - 1) |
+                                      ((n->params.max_ioqpairs - 1) << 16));
         break;
     case NVME_TIMESTAMP:
         return nvme_set_feature_timestamp(n, cmd);
@@ -924,12 +925,12 @@ static void nvme_clear_ctrl(NvmeCtrl *n)
 
     blk_drain(n->conf.blk);
 
-    for (i = 0; i < n->params.num_queues; i++) {
+    for (i = 0; i < n->params.max_ioqpairs + 1; i++) {
         if (n->sq[i] != NULL) {
             nvme_free_sq(n->sq[i], n);
         }
     }
-    for (i = 0; i < n->params.num_queues; i++) {
+    for (i = 0; i < n->params.max_ioqpairs + 1; i++) {
         if (n->cq[i] != NULL) {
             nvme_free_cq(n->cq[i], n);
         }
@@ -1330,9 +1331,15 @@ static void nvme_realize(PCIDevice *pci_dev, Error **errp)
     int64_t bs_size;
     uint8_t *pci_conf;
 
-    if (!n->params.num_queues) {
-        error_setg(errp, "num_queues can't be zero");
-        return;
+    if (n->params.num_queues) {
+        warn_report("nvme: num_queues is deprecated; please use max_ioqpairs "
+                    "instead");
+
+        n->params.max_ioqpairs = n->params.num_queues - 1;
+    }
+
+    if (!n->params.max_ioqpairs) {
+        error_setg(errp, "max_ioqpairs can't be less than 1");
     }
 
     if (!n->conf.blk) {
@@ -1363,19 +1370,19 @@ static void nvme_realize(PCIDevice *pci_dev, Error **errp)
     pcie_endpoint_cap_init(pci_dev, 0x80);
 
     n->num_namespaces = 1;
-    n->reg_size = pow2ceil(0x1000 + 2 * n->params.num_queues * 4);
+    n->reg_size = pow2ceil(0x1008 + 2 * (n->params.max_ioqpairs) * 4);
     n->ns_size = bs_size / (uint64_t)n->num_namespaces;
 
     n->namespaces = g_new0(NvmeNamespace, n->num_namespaces);
-    n->sq = g_new0(NvmeSQueue *, n->params.num_queues);
-    n->cq = g_new0(NvmeCQueue *, n->params.num_queues);
+    n->sq = g_new0(NvmeSQueue *, n->params.max_ioqpairs + 1);
+    n->cq = g_new0(NvmeCQueue *, n->params.max_ioqpairs + 1);
 
     memory_region_init_io(&n->iomem, OBJECT(n), &nvme_mmio_ops, n,
                           "nvme", n->reg_size);
     pci_register_bar(pci_dev, 0,
         PCI_BASE_ADDRESS_SPACE_MEMORY | PCI_BASE_ADDRESS_MEM_TYPE_64,
         &n->iomem);
-    msix_init_exclusive_bar(pci_dev, n->params.num_queues, 4, NULL);
+    msix_init_exclusive_bar(pci_dev, n->params.max_ioqpairs + 1, 4, NULL);
 
     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));
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index 9957c4a200e2..98f5b9479244 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -6,11 +6,13 @@
 #define DEFINE_NVME_PROPERTIES(_state, _props) \
     DEFINE_PROP_STRING("serial", _state, _props.serial), \
     DEFINE_PROP_UINT32("cmb_size_mb", _state, _props.cmb_size_mb, 0), \
-    DEFINE_PROP_UINT32("num_queues", _state, _props.num_queues, 64)
+    DEFINE_PROP_UINT32("num_queues", _state, _props.num_queues, 0), \
+    DEFINE_PROP_UINT32("max_ioqpairs", _state, _props.max_ioqpairs, 64)
 
 typedef struct NvmeParams {
     char     *serial;
     uint32_t num_queues;
+    uint32_t max_ioqpairs;
     uint32_t cmb_size_mb;
 } NvmeParams;
 
-- 
2.26.0