[RFC PATCH 3/3] hw/block/nvme: add nvme_inject_state HMP command

[Minwoo Im]

nvme_inject_state command is to give a controller state to be.
Human Monitor Interface(HMP) supports users to make controller to a
specified state of:

        normal:                 Normal state (no injection)
        cmd-interrupted:        Commands will be interrupted internally

This patch is just a start to give dynamic command from the HMP to the
QEMU NVMe device model.  If "cmd-interrupted" state is given, then the
controller will return all the CQ entries with Command Interrupts status
code.

Usage:
        -device nvme,id=nvme0,....

        (qemu) nvme_inject_state nvme0 cmd-interrupted

        <All the commands will be interrupted internally>

        (qemu) nvme_inject_state nvme0 normal

This feature is required to test Linux kernel NVMe driver for the
command retry feature.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
---
 hmp-commands.hx       | 13 ++++++++++++
 hw/block/nvme.c       | 49 +++++++++++++++++++++++++++++++++++++++++++
 hw/block/nvme.h       |  8 +++++++
 include/monitor/hmp.h |  1 +
 4 files changed, 71 insertions(+)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index d4001f9c5dc6..ef288c567b46 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1307,6 +1307,19 @@ SRST
   Inject PCIe AER error
 ERST
 
+    {
+        .name       = "nvme_inject_state",
+        .args_type  = "id:s,state:s",
+        .params     = "id [normal|cmd-interrupted]",
+        .help       = "inject controller/namespace state",
+        .cmd        = hmp_nvme_inject_state,
+    },
+
+SRST
+``nvme_inject_state``
+  Inject NVMe controller/namespace state
+ERST
+
     {
         .name       = "netdev_add",
         .args_type  = "netdev:O",
diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 6d3c554a0e99..42cf5bd113e6 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -123,6 +123,7 @@
 #include "sysemu/sysemu.h"
 #include "qapi/error.h"
 #include "qapi/visitor.h"
+#include "qapi/qmp/qdict.h"
 #include "sysemu/hostmem.h"
 #include "sysemu/block-backend.h"
 #include "exec/memory.h"
@@ -132,6 +133,7 @@
 #include "trace.h"
 #include "nvme.h"
 #include "nvme-ns.h"
+#include "monitor/monitor.h"
 
 #define NVME_MAX_IOQPAIRS 0xffff
 #define NVME_DB_SIZE  4
@@ -966,6 +968,14 @@ static void nvme_enqueue_req_completion(NvmeCQueue *cq, 
NvmeRequest *req)
 {
     assert(cq->cqid == req->sq->cqid);
 
+    /*
+     * Override request status field if controller state has been injected by
+     * the QMP.
+     */
+    if (cq->ctrl->state == NVME_STATE_CMD_INTERRUPTED) {
+        req->status = NVME_COMMAND_INTERRUPTED;
+    }
+
     if (req->status != NVME_SUCCESS) {
         if (cq->ctrl->features.acre && nvme_should_retry(req)) {
             if (cq->ctrl->params.cmd_retry_delay > 0) {
@@ -5025,4 +5035,43 @@ static void nvme_register_types(void)
     type_register_static(&nvme_bus_info);
 }
 
+static void nvme_inject_state(NvmeCtrl *n, NvmeState state)
+{
+    n->state = state;
+}
+
+static const char *nvme_states[] = {
+    [NVME_STATE_NORMAL]             = "normal",
+    [NVME_STATE_CMD_INTERRUPTED]    = "cmd-interrupted",
+};
+
+void hmp_nvme_inject_state(Monitor *mon, const QDict *qdict)
+{
+    const char *id = qdict_get_str(qdict, "id");
+    const char *state = qdict_get_str(qdict, "state");
+    PCIDevice *dev;
+    NvmeCtrl *n;
+    int ret, i;
+
+    ret = pci_qdev_find_device(id, &dev);
+    if (ret < 0) {
+        monitor_printf(mon, "invalid device id %s\n", id);
+        return;
+    }
+
+    n = NVME(dev);
+
+    for (i = 0; i < ARRAY_SIZE(nvme_states); i++) {
+        if (!strcmp(nvme_states[i], state)) {
+            nvme_inject_state(n, i);
+            monitor_printf(mon,
+                           "-device nvme,id=%s: state %s injected\n",
+                           id, state);
+            return;
+        }
+    }
+
+    monitor_printf(mon, "invalid state %s\n", state);
+}
+
 type_init(nvme_register_types)
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index 37940b3ac2d2..1af1e0380d9b 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -128,6 +128,11 @@ typedef struct NvmeFeatureVal {
     uint8_t     acre;
 } NvmeFeatureVal;
 
+typedef enum NvmeState {
+    NVME_STATE_NORMAL,
+    NVME_STATE_CMD_INTERRUPTED,
+} NvmeState;
+
 typedef struct NvmeCtrl {
     PCIDevice    parent_obj;
     MemoryRegion bar0;
@@ -185,6 +190,8 @@ typedef struct NvmeCtrl {
     NvmeCQueue      admin_cq;
     NvmeIdCtrl      id_ctrl;
     NvmeFeatureVal  features;
+
+    NvmeState       state;
 } NvmeCtrl;
 
 static inline NvmeNamespace *nvme_ns(NvmeCtrl *n, uint32_t nsid)
@@ -212,4 +219,5 @@ static inline NvmeCtrl *nvme_ctrl(NvmeRequest *req)
 
 int nvme_register_namespace(NvmeCtrl *n, NvmeNamespace *ns, Error **errp);
 
+void hmp_nvme_inject_state(Monitor *mon, const QDict *qdict);
 #endif /* HW_NVME_H */
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index ed2913fd18e8..668384ea2e34 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -79,6 +79,7 @@ void hmp_migrate(Monitor *mon, const QDict *qdict);
 void hmp_device_add(Monitor *mon, const QDict *qdict);
 void hmp_device_del(Monitor *mon, const QDict *qdict);
 void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict);
+void hmp_nvme_inject_state(Monitor *mon, const QDict *qdict);
 void hmp_netdev_add(Monitor *mon, const QDict *qdict);
 void hmp_netdev_del(Monitor *mon, const QDict *qdict);
 void hmp_getfd(Monitor *mon, const QDict *qdict);
-- 
2.17.1