qemu: Support setting NUMA distances

Since we already have such support for libxl all we need is qemu
driver adjustment. And a test case.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>

docs/formatdomain.html.in

@@ -1589,7 +1589,7 @@
 
     <p>
       Describing distances between NUMA cells is currently only supported
-      by Xen. If no <code>distances</code> are given to describe
+      by Xen and QEMU. If no <code>distances</code> are given to describe
       the SLIT data between different cells, it will default to a scheme
       using 10 for local and 20 for remote distances.
     </p>

src/qemu/qemu_command.c

@@ -7751,7 +7751,7 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
                     virCommandPtr cmd,
                     qemuDomainObjPrivatePtr priv)
 {
-    size_t i;
+    size_t i, j;
     virQEMUCapsPtr qemuCaps = priv->qemuCaps;
     virBuffer buf = VIR_BUFFER_INITIALIZER;
     char *cpumask = NULL, *tmpmask = NULL, *next = NULL;
@@ -7761,6 +7761,7 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
     int ret = -1;
     size_t ncells = virDomainNumaGetNodeCount(def->numa);
     const long system_page_size = virGetSystemPageSizeKB();
+    bool numa_distances = false;
 
     if (virDomainNumatuneHasPerNodeBinding(def->numa) &&
         !(virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_RAM) ||
@@ -7869,6 +7870,42 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
 
         virCommandAddArgBuffer(cmd, &buf);
     }
+
+    /* If NUMA node distance is specified for at least one pair
+     * of nodes, we have to specify all the distances. Even
+     * though they might be the default ones. */
+    for (i = 0; i < ncells; i++) {
+        for (j = 0; j < ncells; j++) {
+            if (virDomainNumaNodeDistanceIsUsingDefaults(def->numa, i, j))
+                continue;
+
+            numa_distances = true;
+            break;
+        }
+        if (numa_distances)
+            break;
+    }
+
+    if (numa_distances) {
+        if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_NUMA_DIST)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("setting NUMA distances is not "
+                             "supported with this qemu"));
+            goto cleanup;
+        }
+
+        for (i = 0; i < ncells; i++) {
+            for (j = 0; j < ncells; j++) {
+                size_t distance = virDomainNumaGetNodeDistance(def->numa, i, j);
+
+                virCommandAddArg(cmd, "-numa");
+                virBufferAsprintf(&buf, "dist,src=%zu,dst=%zu,val=%zu", i, j, distance);
+
+                virCommandAddArgBuffer(cmd, &buf);
+            }
+        }
+    }
+
     ret = 0;
 
  cleanup:

tests/qemuxml2argvdata/qemuxml2argv-numatune-distances.args

@@ -0,0 +1,63 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-x86_64 \
+-name QEMUGuest \
+-S \
+-M xenfv \
+-m 12288 \
+-smp 12,sockets=12,cores=1,threads=1 \
+-numa node,nodeid=0,cpus=0,cpus=11,mem=2048 \
+-numa node,nodeid=1,cpus=1,cpus=10,mem=2048 \
+-numa node,nodeid=2,cpus=2,cpus=9,mem=2048 \
+-numa node,nodeid=3,cpus=3,cpus=8,mem=2048 \
+-numa node,nodeid=4,cpus=4,cpus=7,mem=2048 \
+-numa node,nodeid=5,cpus=5-6,mem=2048 \
+-numa dist,src=0,dst=0,val=10 \
+-numa dist,src=0,dst=1,val=21 \
+-numa dist,src=0,dst=2,val=31 \
+-numa dist,src=0,dst=3,val=41 \
+-numa dist,src=0,dst=4,val=51 \
+-numa dist,src=0,dst=5,val=61 \
+-numa dist,src=1,dst=0,val=21 \
+-numa dist,src=1,dst=1,val=10 \
+-numa dist,src=1,dst=2,val=21 \
+-numa dist,src=1,dst=3,val=31 \
+-numa dist,src=1,dst=4,val=41 \
+-numa dist,src=1,dst=5,val=51 \
+-numa dist,src=2,dst=0,val=31 \
+-numa dist,src=2,dst=1,val=21 \
+-numa dist,src=2,dst=2,val=10 \
+-numa dist,src=2,dst=3,val=21 \
+-numa dist,src=2,dst=4,val=31 \
+-numa dist,src=2,dst=5,val=41 \
+-numa dist,src=3,dst=0,val=41 \
+-numa dist,src=3,dst=1,val=31 \
+-numa dist,src=3,dst=2,val=21 \
+-numa dist,src=3,dst=3,val=10 \
+-numa dist,src=3,dst=4,val=21 \
+-numa dist,src=3,dst=5,val=31 \
+-numa dist,src=4,dst=0,val=51 \
+-numa dist,src=4,dst=1,val=41 \
+-numa dist,src=4,dst=2,val=31 \
+-numa dist,src=4,dst=3,val=21 \
+-numa dist,src=4,dst=4,val=10 \
+-numa dist,src=4,dst=5,val=21 \
+-numa dist,src=5,dst=0,val=61 \
+-numa dist,src=5,dst=1,val=51 \
+-numa dist,src=5,dst=2,val=41 \
+-numa dist,src=5,dst=3,val=31 \
+-numa dist,src=5,dst=4,val=21 \
+-numa dist,src=5,dst=5,val=10 \
+-uuid c7a5fdb2-cdaf-9455-926a-d65c16db1809 \
+-nographic \
+-nodefaults \
+-chardev socket,id=charmonitor,path=/tmp/lib/domain--1-QEMUGuest/monitor.sock,\
+server,nowait \
+-mon chardev=charmonitor,id=monitor,mode=readline \
+-boot c \
+-usb \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x2

tests/qemuxml2argvdata/qemuxml2argv-numatune-distances.xml

@@ -0,0 +1,65 @@
+<domain type='qemu'>
+  <name>QEMUGuest</name>
+  <uuid>c7a5fdb2-cdaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>8388608</memory>
+  <currentMemory unit='KiB'>8388608</currentMemory>
+  <vcpu placement='static'>12</vcpu>
+  <os>
+    <type arch='x86_64' machine='xenfv'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+    <apic/>
+    <pae/>
+  </features>
+  <cpu>
+    <numa>
+      <cell id='0' cpus='0,11' memory='2097152' unit='KiB'>
+        <distances>
+          <sibling id='1' value='21'/>
+          <sibling id='2' value='31'/>
+          <sibling id='3' value='41'/>
+          <sibling id='4' value='51'/>
+          <sibling id='5' value='61'/>
+        </distances>
+      </cell>
+      <cell id='1' cpus='1,10' memory='2097152' unit='KiB'>
+        <distances>
+          <sibling id='2' value='21'/>
+          <sibling id='3' value='31'/>
+          <sibling id='4' value='41'/>
+          <sibling id='5' value='51'/>
+        </distances>
+      </cell>
+      <cell id='2' cpus='2,9' memory='2097152' unit='KiB'>
+        <distances>
+          <sibling id='3' value='21'/>
+          <sibling id='4' value='31'/>
+          <sibling id='5' value='41'/>
+        </distances>
+      </cell>
+      <cell id='3' cpus='3,8' memory='2097152' unit='KiB'>
+        <distances>
+          <sibling id='4' value='21'/>
+          <sibling id='5' value='31'/>
+        </distances>
+      </cell>
+      <cell id='4' cpus='4,7' memory='2097152' unit='KiB'>
+        <distances>
+          <sibling id='5' value='21'/>
+        </distances>
+      </cell>
+      <cell id='5' cpus='5-6' memory='2097152' unit='KiB'/>
+    </numa>
+  </cpu>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>restart</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <controller type='usb' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1700,6 +1700,8 @@ mymain(void)
                   QEMU_CAPS_OBJECT_MEMORY_RAM);
     DO_TEST_FAILURE("numatune-memnode-no-memory", NONE);
 
+    DO_TEST("numatune-distances", QEMU_CAPS_NUMA, QEMU_CAPS_NUMA_DIST);
+
     DO_TEST("numatune-auto-nodeset-invalid", NONE);
     DO_TEST("numatune-auto-prefer", QEMU_CAPS_OBJECT_MEMORY_RAM,
             QEMU_CAPS_OBJECT_MEMORY_FILE);