qemu: Prefer nvdimmPath over hugepages for memory-backend-file

If a domain has hugepages configured and we're currently building
memory-backend-file for a nvdimm device that domain has we will
put hugepages path onto the command line. It should have been
nvdimm path configured in the XML.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>

src/qemu/qemu_command.c

@@ -3148,12 +3148,12 @@ qemuBuildMemoryBackendProps(virJSONValuePtr *backendProps,
     if (useHugepage || mem->nvdimmPath || memAccess ||
         def->mem.source == VIR_DOMAIN_MEMORY_SOURCE_FILE) {
 
-        if (useHugepage) {
-            if (qemuGetDomainHupageMemPath(def, cfg, pagesize, &memPath) < 0)
+        if (mem->nvdimmPath) {
+            if (VIR_STRDUP(memPath, mem->nvdimmPath) < 0)
                 goto cleanup;
             prealloc = true;
-        } else if (mem->nvdimmPath) {
-            if (VIR_STRDUP(memPath, mem->nvdimmPath) < 0)
+        } else if (useHugepage) {
+            if (qemuGetDomainHupageMemPath(def, cfg, pagesize, &memPath) < 0)
                 goto cleanup;
             prealloc = true;
         } else {

tests/qemuxml2argvdata/hugepages-nvdimm.x86_64-latest.args

@@ -0,0 +1,35 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-i686 \
+-name guest=QEMUGuest1,debug-threads=on \
+-S \
+-object secret,id=masterKey0,format=raw,\
+file=/tmp/lib/domain--1-QEMUGuest1/master-key.aes \
+-machine pc,accel=tcg,usb=off,dump-guest-core=off,nvdimm=on \
+-m size=1048576k,slots=16,maxmem=1099511627776k \
+-realtime mlock=off \
+-smp 2,sockets=2,cores=1,threads=1 \
+-object memory-backend-file,id=ram-node0,prealloc=yes,\
+mem-path=/dev/hugepages2M/libvirt/qemu/-1-QEMUGuest1,share=yes,size=1073741824 \
+-numa node,nodeid=0,cpus=0-1,memdev=ram-node0 \
+-object memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/tmp/nvdimm,\
+share=yes,size=536870912 \
+-device nvdimm,node=0,memdev=memnvdimm0,id=nvdimm0,slot=0 \
+-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
+-display none \
+-no-user-config \
+-nodefaults \
+-chardev socket,id=charmonitor,fd=1729,server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=control \
+-rtc base=utc \
+-no-shutdown \
+-no-acpi \
+-boot strict=on \
+-device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \
+-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
+resourcecontrol=deny \
+-msg timestamp=on

tests/qemuxml2argvdata/hugepages-nvdimm.xml

@@ -0,0 +1,48 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <maxMemory slots='16' unit='KiB'>1099511627776</maxMemory>
+  <memory unit='KiB'>1267710</memory>
+  <currentMemory unit='KiB'>1267710</currentMemory>
+  <memoryBacking>
+    <hugepages>
+      <page size='2048' unit='KiB'/>
+    </hugepages>
+    <access mode='shared'/>
+  </memoryBacking>
+  <vcpu placement='static' cpuset='0-1'>2</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <cpu>
+    <topology sockets='2' cores='1' threads='1'/>
+    <numa>
+      <cell id='0' cpus='0-1' memory='1048576' unit='KiB'/>
+    </numa>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-i686</emulator>
+    <controller type='usb' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='none'/>
+    <memory model='nvdimm'>
+      <source>
+        <path>/tmp/nvdimm</path>
+      </source>
+      <target>
+        <size unit='KiB'>523264</size>
+        <node>0</node>
+      </target>
+      <address type='dimm' slot='0'/>
+    </memory>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -994,6 +994,7 @@ mymain(void)
     DO_TEST_FAILURE("hugepages-memaccess3",
             QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE,
             QEMU_CAPS_VIRTIO_SCSI);
+    DO_TEST_CAPS_LATEST("hugepages-nvdimm");
     DO_TEST("nosharepages", QEMU_CAPS_MEM_MERGE);
     DO_TEST("disk-cdrom", NONE);
     DO_TEST_CAPS_LATEST("disk-cdrom");

tests/qemuxml2xmloutdata/hugepages-nvdimm.xml

@@ -0,0 +1 @@
+../qemuxml2argvdata/hugepages-nvdimm.xml

tests/qemuxml2xmltest.c

@@ -339,6 +339,7 @@ mymain(void)
     DO_TEST("hugepages-shared", NONE);
     DO_TEST("hugepages-memaccess", NONE);
     DO_TEST("hugepages-memaccess2", NONE);
+    DO_TEST("hugepages-nvdimm", NONE);
     DO_TEST("nosharepages", NONE);
     DO_TEST("restore-v2", NONE);
     DO_TEST("migrate", NONE);