4.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Juergen Gross <jgross@xxxxxxxx>
commit 5266b8e4445cc836c46689d80a9ff539fa3bfbda upstream.
Commit 96edd61dcf44362d3ef0bed1a5361e0ac7886a63 ("xen/balloon: don't
online new memory initially") introduced a regression when booting a
HVM domain with memory less than mem-max: instead of ballooning down
immediately the system would try to use the memory up to mem-max
resulting in Xen crashing the domain.
For HVM domains the current size will be reflected in Xenstore node
memory/static-max instead of memory/target.
Additionally we have to trigger the ballooning process at once.
Fixes: 96edd61dcf44362d3ef0bed1a5361e0ac7886a63 ("xen/balloon: don't online new memory initially")
Reported-by: Simon Gaiser <hw42@xxxxxxxxx>
Suggested-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/xen/xen-balloon.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
--- a/drivers/xen/xen-balloon.c
+++ b/drivers/xen/xen-balloon.c
@@ -57,7 +57,7 @@ static int register_balloon(struct devic
static void watch_target(struct xenbus_watch *watch,
const char *path, const char *token)
{
- unsigned long long new_target;
+ unsigned long long new_target, static_max;
int err;
static bool watch_fired;
static long target_diff;
@@ -72,13 +72,20 @@ static void watch_target(struct xenbus_w
* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
*/
new_target >>= PAGE_SHIFT - 10;
- if (watch_fired) {
- balloon_set_new_target(new_target - target_diff);
- return;
+
+ if (!watch_fired) {
+ watch_fired = true;
+ err = xenbus_scanf(XBT_NIL, "memory", "static-max", "%llu",
+ &static_max);
+ if (err != 1)
+ static_max = new_target;
+ else
+ static_max >>= PAGE_SHIFT - 10;
+ target_diff = xen_pv_domain() ? 0
+ : static_max - balloon_stats.target_pages;
}
- watch_fired = true;
- target_diff = new_target - balloon_stats.target_pages;
+ balloon_set_new_target(new_target - target_diff);
}
static struct xenbus_watch target_watch = {
.node = "memory/target",