From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Wolfgang Bumiller <w.bumiller@proxmox.com>
Date: Mon, 6 Apr 2020 12:16:43 +0200
Subject: [PATCH] PVE: virtio-balloon: improve query-balloon

Actually provide memory information via the query-balloon
command.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 hw/virtio/virtio-balloon.c | 33 +++++++++++++++++++++++++++++++--
 monitor/hmp-cmds.c         | 30 +++++++++++++++++++++++++++++-
 qapi/machine.json          | 22 +++++++++++++++++++++-
 3 files changed, 81 insertions(+), 4 deletions(-)

diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index ae7867a8db..956e3f4e46 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -820,8 +820,37 @@ static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 {
     VirtIOBalloon *dev = opaque;
-    info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
-                                             VIRTIO_BALLOON_PFN_SHIFT);
+    ram_addr_t ram_size = get_current_ram_size();
+    info->actual = ram_size - ((uint64_t) dev->actual <<
+                               VIRTIO_BALLOON_PFN_SHIFT);
+
+    info->max_mem = ram_size;
+
+    if (!(balloon_stats_enabled(dev) && balloon_stats_supported(dev) &&
+           dev->stats_last_update)) {
+       return;
+    }
+
+    info->last_update = dev->stats_last_update;
+    info->has_last_update = true;
+
+    info->mem_swapped_in = dev->stats[VIRTIO_BALLOON_S_SWAP_IN];
+    info->has_mem_swapped_in = info->mem_swapped_in >= 0 ? true : false;
+
+    info->mem_swapped_out = dev->stats[VIRTIO_BALLOON_S_SWAP_OUT];
+    info->has_mem_swapped_out = info->mem_swapped_out >= 0 ? true : false;
+
+    info->major_page_faults = dev->stats[VIRTIO_BALLOON_S_MAJFLT];
+    info->has_major_page_faults = info->major_page_faults >= 0 ? true : false;
+
+    info->minor_page_faults = dev->stats[VIRTIO_BALLOON_S_MINFLT];
+    info->has_minor_page_faults = info->minor_page_faults >= 0 ? true : false;
+
+    info->free_mem = dev->stats[VIRTIO_BALLOON_S_MEMFREE];
+    info->has_free_mem = info->free_mem >= 0 ? true : false;
+
+    info->total_mem = dev->stats[VIRTIO_BALLOON_S_MEMTOT];
+    info->has_total_mem = info->total_mem >= 0 ? true : false;
 }
 
 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index f4ef58d257..c8b97909e7 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -698,7 +698,35 @@ void hmp_info_balloon(Monitor *mon, const QDict *qdict)
         return;
     }
 
-    monitor_printf(mon, "balloon: actual=%" PRId64 "\n", info->actual >> 20);
+    monitor_printf(mon, "balloon: actual=%" PRId64, info->actual >> 20);
+    monitor_printf(mon, " max_mem=%" PRId64, info->max_mem >> 20);
+    if (info->has_total_mem) {
+        monitor_printf(mon, " total_mem=%" PRId64, info->total_mem >> 20);
+    }
+    if (info->has_free_mem) {
+        monitor_printf(mon, " free_mem=%" PRId64, info->free_mem >> 20);
+    }
+
+    if (info->has_mem_swapped_in) {
+        monitor_printf(mon, " mem_swapped_in=%" PRId64, info->mem_swapped_in);
+    }
+    if (info->has_mem_swapped_out) {
+        monitor_printf(mon, " mem_swapped_out=%" PRId64, info->mem_swapped_out);
+    }
+    if (info->has_major_page_faults) {
+        monitor_printf(mon, " major_page_faults=%" PRId64,
+                       info->major_page_faults);
+    }
+    if (info->has_minor_page_faults) {
+        monitor_printf(mon, " minor_page_faults=%" PRId64,
+                       info->minor_page_faults);
+    }
+    if (info->has_last_update) {
+        monitor_printf(mon, " last_update=%" PRId64,
+                       info->last_update);
+    }
+
+    monitor_printf(mon, "\n");
 
     qapi_free_BalloonInfo(info);
 }
diff --git a/qapi/machine.json b/qapi/machine.json
index 157712f006..34035c25d1 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -1018,10 +1018,30 @@
 # @actual: the logical size of the VM in bytes
 #          Formula used: logical_vm_size = vm_ram_size - balloon_size
 #
+# @last_update: time when stats got updated from guest
+#
+# @mem_swapped_in: number of pages swapped in within the guest
+# 
+# @mem_swapped_out: number of pages swapped out within the guest
+#
+# @major_page_faults: number of major page faults within the guest
+#
+# @minor_page_faults: number of minor page faults within the guest
+# 
+# @free_mem: amount of memory (in bytes) free in the guest
+#
+# @total_mem: amount of memory (in bytes) visible to the guest
+#
+# @max_mem: amount of memory (in bytes) assigned to the guest
+#
 # Since: 0.14
 #
 ##
-{ 'struct': 'BalloonInfo', 'data': {'actual': 'int' } }
+{ 'struct': 'BalloonInfo',
+  'data': {'actual': 'int', '*last_update': 'int', '*mem_swapped_in': 'int',
+           '*mem_swapped_out': 'int', '*major_page_faults': 'int',
+           '*minor_page_faults': 'int', '*free_mem': 'int',
+           '*total_mem': 'int', 'max_mem': 'int' } }
 
 ##
 # @query-balloon: