[PATCH 2/2] hmp: Support fd-based KVM stats query

[Mark Kanda <mark.kanda@oracle.com>]

Leverage the QMP support for fd-based KVM stats.

The interface supports an optional 'filter' argument to specify a
particular stat to query. Base and exponent are displayed in human
readable format.

Examples:

(qemu) info kvmstats

vm:
  max_mmu_page_hash_collisions (peak): 0
  nx_lpage_splits (instant): 114
  lpages (instant): 193
  mmu_unsync (instant): 0
  mmu_cache_miss (cumulative): 293
  mmu_recycled (cumulative): 0
  mmu_flooded (cumulative): 0
  mmu_pde_zapped (cumulative): 0
  mmu_pte_write (cumulative): 0
  mmu_shadow_zapped (cumulative): 178
  remote_tlb_flush (cumulative): 63

vcpu_0:
  req_event (cumulative): 538
  nmi_injections (cumulative): 0
...

(qemu) info kvmstats halt_poll_fail_ns

vm:

vcpu_0:
  halt_poll_fail_ns (cumulative): 20*10^-9 seconds

vcpu_1:
  halt_poll_fail_ns (cumulative): 30*10^-9 seconds

Signed-off-by: Mark Kanda <mark.kanda@oracle.com>
---
 hmp-commands-info.hx  | 13 +++++++++++
 include/monitor/hmp.h |  1 +
 monitor/hmp-cmds.c    | 52 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+)

diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index 4c966e8a6b..ef5bca01d9 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -335,6 +335,19 @@ SRST
     Show KVM information.
 ERST
 
+    {
+        .name       = "kvmstats",
+        .args_type  = "filter:s?",
+        .params     = "filter",
+        .help       = "show KVM statistics; optional filter for stat name",
+        .cmd        = hmp_info_kvmstats,
+    },
+
+SRST
+  ``info kvmstats``
+    Show KVM statistics.
+ERST
+
     {
         .name       = "numa",
         .args_type  = "",
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 6bc27639e0..20be8f8586 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -21,6 +21,7 @@ void hmp_handle_error(Monitor *mon, Error *err);
 void hmp_info_name(Monitor *mon, const QDict *qdict);
 void hmp_info_version(Monitor *mon, const QDict *qdict);
 void hmp_info_kvm(Monitor *mon, const QDict *qdict);
+void hmp_info_kvmstats(Monitor *mon, const QDict *qdict);
 void hmp_info_status(Monitor *mon, const QDict *qdict);
 void hmp_info_uuid(Monitor *mon, const QDict *qdict);
 void hmp_info_chardev(Monitor *mon, const QDict *qdict);
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index bcaa41350e..24a545a66b 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -134,6 +134,58 @@ void hmp_info_kvm(Monitor *mon, const QDict *qdict)
     qapi_free_KvmInfo(info);
 }
 
+void hmp_info_kvmstats(Monitor *mon, const QDict *qdict)
+{
+    KvmStatsList *stats_list, *stats_list_entry;
+    KvmStats *stats_entry;
+    KvmStatDataList *data_entry;
+    KvmStatData *kvm_stat;
+    uint64List *val;
+    const char *filter;
+    Error *err = NULL;
+
+    filter = qdict_get_try_str(qdict, "filter");
+    if (filter) {
+        stats_list = qmp_query_kvmstats(TRUE, filter, &err);
+    } else {
+        stats_list = qmp_query_kvmstats(FALSE, NULL, &err);
+    }
+
+    if (err) {
+        monitor_printf(mon, "%s\n", error_get_pretty(err));
+        error_free(err);
+        return;
+    }
+
+    for (stats_list_entry = stats_list; stats_list_entry;
+         stats_list_entry = stats_list_entry->next) {
+        stats_entry = stats_list_entry->value;
+        monitor_printf(mon, "\n%s:\n", stats_entry->name);
+
+        for (data_entry = stats_entry->stats; data_entry;
+             data_entry = data_entry->next) {
+            kvm_stat = data_entry->value;
+            monitor_printf(mon, "  %s (%s):", kvm_stat->name,
+                           KvmStatType_str(kvm_stat->type));
+
+            for (val = kvm_stat->val; val; val = val->next) {
+                if (kvm_stat->exponent) {
+                    /* Print the base and exponent as "*<base>^<exp>" */
+                    monitor_printf(mon, " %lu*%d^%d", val->value,
+                                   kvm_stat->base, kvm_stat->exponent);
+                } else {
+                    monitor_printf(mon, " %lu", val->value);
+                }
+            }
+
+            /* Don't print "none" unit type */
+            monitor_printf(mon, " %s\n", kvm_stat->unit == KVM_STAT_UNIT_NONE ?
+                           "" : KvmStatUnit_str(kvm_stat->unit));
+        }
+    }
+    qapi_free_KvmStatsList(stats_list);
+}
+
 void hmp_info_status(Monitor *mon, const QDict *qdict)
 {
     StatusInfo *info;
-- 
2.26.2