qemu: Don't try to use hugepages if not enabled

https://bugzilla.redhat.com/show_bug.cgi?id=1214369

My fix 671d18594f was incomplete. If domain doesn't have
hugepages enabled, because of missing condition we would still be
putting hugepages path onto qemu cmd line. Clean up the
conditions so that it's more visible next time.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_command.c

@@ -3410,19 +3410,19 @@ qemuBuildMemoryBackendStr(virJSONValuePtr *backendProps,
         def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_FILE) {
         *backendType = "memory-backend-file";
 
-        if (mem->nvdimmPath) {
+        if (pagesize) {
+            if (qemuGetDomainHupageMemPath(def, cfg, pagesize, &memPath) < 0)
+                goto cleanup;
+            prealloc = true;
+        } else if (mem->nvdimmPath) {
             if (VIR_STRDUP(memPath, mem->nvdimmPath) < 0)
                 goto cleanup;
             prealloc = true;
-        } else if (!pagesize && def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_FILE) {
+        } else {
             /* We can have both pagesize and mem source. If that's the case,
              * prefer hugepages as those are more specific. */
             if (VIR_STRDUP(memPath, cfg->memoryBackingDir) < 0)
                 goto cleanup;
-        } else {
-            if (qemuGetDomainHupageMemPath(def, cfg, pagesize, &memPath) < 0)
-                goto cleanup;
-            prealloc = true;
         }
 
         if (virJSONValueObjectAdd(props,

tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args

@@ -0,0 +1,26 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-x86_64 \
+-name QEMUGuest1 \
+-S \
+-M pc \
+-m 214 \
+-smp 16,sockets=2,cores=4,threads=2 \
+-object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram,\
+share=yes,size=112197632 \
+-numa node,nodeid=0,cpus=0-7,memdev=ram-node0 \
+-object memory-backend-file,id=ram-node1,mem-path=/var/lib/libvirt/qemu/ram,\
+share=no,size=112197632 \
+-numa node,nodeid=1,cpus=8-15,memdev=ram-node1 \
+-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
+-nographic \
+-nodefaults \
+-monitor unix:/tmp/lib/domain--1-QEMUGuest1/monitor.sock,server,nowait \
+-no-acpi \
+-boot n \
+-usb \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3

tests/qemuxml2argvtest.c

@@ -1541,6 +1541,7 @@ mymain(void)
     DO_TEST("cpu-numa-disjoint", QEMU_CAPS_NUMA);
     DO_TEST_FAILURE("cpu-numa-memshared", QEMU_CAPS_OBJECT_MEMORY_RAM);
     DO_TEST_FAILURE("cpu-numa-memshared", NONE);
+    DO_TEST("cpu-numa-memshared", QEMU_CAPS_OBJECT_MEMORY_FILE);
     DO_TEST("cpu-host-model", NONE);
     DO_TEST("cpu-host-model-vendor", NONE);
     skipLegacyCPUs = true;