[libvirt] [PATCH] libxl: round memory values to next 1MiB increment

[Jim Fehlig]

libxl requires the memory sizes to be rounded to 1MiB increments.
Attempting to start a domain that violates this requirement will
fail with the marginally helpful error

2018-02-22 01:55:32.921+0000: xc: panic: xc_dom_boot.c:141: xc_dom_boot_mem_init: can't allocate low memory for domain: Out of memory
2018-02-22 01:55:32.921+0000: libxl: libxl_dom.c:671:libxl__build_dom: xc_dom_boot_mem_init failed: No such file or directory

Round the maximum and current memory values to the next 1MiB
increment when generating the libxl_domain_config object.

Signed-off-by: Jim Fehlig <jfehlig at suse.com>
---

The memory values could also be adjusted in the post parse callback,
which might be better since the virDomainDef object would then reflect
the actual values given to libxl. In general, I often find myself
confused about the dividing line between adjusting such things in the
post parse callback vs domain creation.

 src/libxl/libxl_conf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 57cb4c0ad..02bbf4e28 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -367,8 +367,8 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
     }
 
     b_info->sched_params.weight = 1000;
-    b_info->max_memkb = virDomainDefGetMemoryInitial(def);
-    b_info->target_memkb = def->mem.cur_balloon;
+    b_info->max_memkb = VIR_ROUND_UP(virDomainDefGetMemoryInitial(def), 1024);
+    b_info->target_memkb = VIR_ROUND_UP(def->mem.cur_balloon, 1024);
     if (hvm) {
         char bootorder[VIR_DOMAIN_BOOT_LAST + 1];
 
-- 
2.16.1