[RFC PATCH v4 20/30] balloon: update with hotplugged memory

[Vasilis Liaskovitis]

query-balloon and "info balloon" should report total memory available to the
guest.

balloon inflate/ deflate can also use all memory available to the guest (initial
+ hotplugged memory)

Ballon driver has been minimaly tested with the patch, please review and test.

Caveat: if the guest does not online hotplugged-memory, it's easy for a balloon
inflate command to OOM a guest.

Signed-off-by: Vasilis Liaskovitis 
---
 hw/virtio-balloon.c |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
index dd1a650..149e8ba 100644
--- a/hw/virtio-balloon.c
+++ b/hw/virtio-balloon.c
@@ -22,6 +22,7 @@
 #include "virtio-balloon.h"
 #include "kvm.h"
 #include "exec-memory.h"
+#include "dimm.h"

#if defined(__linux__)
 #include <sys/mman.h>
@@ -147,10 +148,11 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
     VirtIOBalloon *dev = to_virtio_balloon(vdev);
     struct virtio_balloon_config config;
     uint32_t oldactual = dev->actual;
+    uint64_t hotplugged_ram_size = get_hp_memory_total();
     memcpy(&config, config_data, 8);
     dev->actual = le32_to_cpu(config.actual);
     if (dev->actual != oldactual) {
-        qemu_balloon_changed(ram_size -
+        qemu_balloon_changed(ram_size + hotplugged_ram_size -
                              (dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
     }
 }
@@ -188,17 +190,20 @@ static void virtio_balloon_stat(void *opaque, BalloonInfo *info)

info->actual = ram_size - ((uint64_t) dev->actual <<
                                VIRTIO_BALLOON_PFN_SHIFT);
+    info->actual += get_hp_memory_total();
 }

static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 {
     VirtIOBalloon *dev = opaque;
+    uint64_t hotplugged_ram_size = get_hp_memory_total();

-    if (target > ram_size) {
-        target = ram_size;
+    if (target > ram_size + hotplugged_ram_size) {
+        target = ram_size + hotplugged_ram_size;
     }
     if (target) {
-        dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
+        dev->num_pages = (ram_size + hotplugged_ram_size - target) >>
+                                 VIRTIO_BALLOON_PFN_SHIFT;
         virtio_notify_config(&dev->vdev);
     }
 }