[libvirt] [PATCHv2 4/6] qemu: add architecture-specific CPU info handling

[Viktor Mihajlovski]

Extract architecture specific data from query-cpus[-fast] if
available. A new function qemuMonitorJSONExtractCPUArchInfo()
uses a call-back table to find and call architecture-specific
extraction handlers.

Initially, there's a handler for s390 cpu info to
set the halted property depending on the s390 cpu state
returned by QEMU. With this it's still possible to report
the halted condition even when using query-cpus-fast.

Signed-off-by: Viktor Mihajlovski <mihajlov at linux.vnet.ibm.com>
---
 src/qemu/qemu_monitor.c      |  4 +--
 src/qemu/qemu_monitor_json.c | 79 ++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 79 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 22b2091..5840e25 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -2076,7 +2076,7 @@ qemuMonitorGetCPUInfo(qemuMonitorPtr mon,
 virBitmapPtr
 qemuMonitorGetCpuHalted(qemuMonitorPtr mon,
                         size_t maxvcpus,
-                        bool fast ATTRIBUTE_UNUSED)
+                        bool fast)
 {
     struct qemuMonitorQueryCpusEntry *cpuentries = NULL;
     size_t ncpuentries = 0;
@@ -2088,7 +2088,7 @@ qemuMonitorGetCpuHalted(qemuMonitorPtr mon,
 
     if (mon->json)
         rc = qemuMonitorJSONQueryCPUs(mon, &cpuentries, &ncpuentries, false,
-                                      false);
+                                      fast);
     else
         rc = qemuMonitorTextQueryCPUs(mon, &cpuentries, &ncpuentries);
 
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index 6a5fb12..1924cfe 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -1451,15 +1451,85 @@ int qemuMonitorJSONSystemReset(qemuMonitorPtr mon)
 }
 
 
-/*
+/**
+ * qemuMonitorJSONExtractCPUS390Info:
+ * @jsoncpu: pointer to a single JSON cpu entry
+ * @cpu: pointer to a single cpu entry
+ *
+ * Derive the legacy cpu info 'halted' information
+ * from the more accurate s390 cpu state. @cpu is
+ * modified only on success.
+ *
+ * Note: the 'uninitialized' s390 cpu state can't be
+ *       mapped to halted yes/no.
+ *
+ * A s390 cpu entry could look like this
+ *  { "arch": "s390",
+ *    "cpu-index": 0,
+ *    "qom-path": "/machine/unattached/device[0]",
+ *    "thread_id": 3081,
+ *    "cpu-state": "operating" }
+ *
+ */
+static void
+qemuMonitorJSONExtractCPUS390Info(virJSONValuePtr jsoncpu,
+                                  struct qemuMonitorQueryCpusEntry *cpu)
+{
+    const char *cpu_state = virJSONValueObjectGetString(jsoncpu, "cpu-state");
+
+    if (STREQ_NULLABLE(cpu_state, "operating") ||
+        STREQ_NULLABLE(cpu_state, "load"))
+        cpu->halted = false;
+    else if (STREQ_NULLABLE(cpu_state, "stopped") ||
+             STREQ_NULLABLE(cpu_state, "check-stop"))
+        cpu->halted = true;
+}
+
+/**
+ * qemuMonitorJSONExtractCPUArchInfo:
+ * @arch: virtual CPU's architecture
+ * @jsoncpu: pointer to a single JSON cpu entry
+ * @cpu: pointer to a single cpu entry
  *
+ * Extracts architecure specific virtual CPU data for a single
+ * CPU from the QAPI response using an architecture specific
+ * function.
+ *
+ */
+static void
+qemuMonitorJSONExtractCPUArchInfo(const char *arch,
+                                  virJSONValuePtr jsoncpu,
+                                  struct qemuMonitorQueryCpusEntry *cpu)
+{
+    if (STREQ_NULLABLE(arch, "s390"))
+        qemuMonitorJSONExtractCPUS390Info(jsoncpu, cpu);
+}
+
+/**
+ * qemuMonitorJSONExtractCPUArchInfo:
+ * @data: JSON response data
+ * @entries: filled with detected cpu entries on success
+ * @nentries: number of entries returned
+ * @fast: true if this is a response from query-cpus-fast
+ *
+ * The JSON response @data will have the following format
+ * in case @fast == false
  * [{ "arch": "x86",
  *    "current": true,
  *    "CPU": 0,
  *    "qom_path": "/machine/unattached/device[0]",
  *    "pc": -2130415978,
  *    "halted": true,
- *    "thread_id": 2631237},
+ *    "thread_id": 2631237,
+ *    ...},
+ *    {...}
+ *  ]
+ * and for @fast == true
+ * [{ "arch": "x86",
+ *    "cpu-index": 0,
+ *    "qom-path": "/machine/unattached/device[0]",
+ *    "thread_id": 2631237,
+ *    ...},
  *    {...}
  *  ]
  */
@@ -1486,6 +1556,7 @@ qemuMonitorJSONExtractCPUInfo(virJSONValuePtr data,
         int thread = 0;
         bool halted = false;
         const char *qom_path;
+        const char *arch;
         if (!entry) {
             ret = -2;
             goto cleanup;
@@ -1511,6 +1582,10 @@ qemuMonitorJSONExtractCPUInfo(virJSONValuePtr data,
         cpus[i].halted = halted;
         if (VIR_STRDUP(cpus[i].qom_path, qom_path) < 0)
             goto cleanup;
+
+        /* process optional architecture-specific data */
+        arch = virJSONValueObjectGetString(entry, "arch");
+        qemuMonitorJSONExtractCPUArchInfo(arch, entry, cpus + i);
     }
 
     VIR_STEAL_PTR(*entries, cpus);
-- 
1.9.1