[libvirt] [PATCH 1/7] qemu: Forbid seting maximum memory size with the API with NUMA enabled

[Peter Krempa]

NUMA enabled guest configuration explicitly specifies memory sizes for
individual nodes. Allowing the virDomainSetMemoryFlags API (and friends)
to change the total doesn't make sense as the individual node configs
are not updated in that case.

Forbid use of the API in case NUMA is specified.
---
 src/qemu/qemu_driver.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 2b0dac7..e2abbe0 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -2307,6 +2307,16 @@ static int qemuDomainSetMemoryFlags(virDomainPtr dom, unsigned long newmem,
         if (flags & VIR_DOMAIN_AFFECT_CONFIG) {
             /* Help clang 2.8 decipher the logic flow.  */
             sa_assert(persistentDef);
+
+            /* resizing memory with NUMA nodes specified doesn't work as there
+             * is no way to decrease the individual node sizes along */
+            if (virDomainNumaGetNodeCount(persistentDef->numa) > 0) {
+                virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                               _("maximum memory size of a domain with NUMA "
+                                 "nodes cannot be modified with this API"));
+                goto endjob;
+            }
+
             persistentDef->mem.max_balloon = newmem;
             if (persistentDef->mem.cur_balloon > newmem)
                 persistentDef->mem.cur_balloon = newmem;
-- 
2.2.2