xen: fix booting ballooned down hvm guest (5266b8e4) · Commits · 戴 / test

Commit ("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. Cc: <stable@vger.kernel.org> # 4.13 Fixes: ("xen/balloon: don't online new memory initially") Reported-by:

Simon Gaiser <hw42@ipsumj.de> Suggested-by:

Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by:

Juergen Gross <jgross@suse.com> Reviewed-by:

Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by:

Boris Ostrovsky <boris.ostrovsky@oracle.com>

drivers/xen/xen-balloon.c

+13 −6

Original line number	Diff line number	Diff line
		@@ -57,7 +57,7 @@ static int register_balloon(struct device *dev);
		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_watch *watch,
		* 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;
		target_diff = new_target - balloon_stats.target_pages;
		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;
		}

		balloon_set_new_target(new_target - target_diff);
		}
		static struct xenbus_watch target_watch = {
		.node = "memory/target",

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