cputune: Support cputune for qemu driver

When domain startup, setting cpu affinity and cpu shares according
to the cputune xml specified in domain xml.

Modify "qemudDomainPinVcpu" to update domain config for vcpupin,
and modify "qemuSetSchedulerParameters" to update domain config
for cpu shares.

v1 - v2:
   * Use "VIR_ALLOC_N" instead of "VIR_ALLOC_VAR"
   * But keep raising error when it fails on adding vcpupin xml
     entry, as I still don't have a better idea yet.

src/qemu/qemu_cgroup.c

@@ -343,6 +343,21 @@ int qemuSetupCgroup(struct qemud_driver *driver,
                  vm->def->name);
     }
 
+    if (qemuCgroupControllerActive(driver, VIR_CGROUP_CONTROLLER_CPU)) {
+        if (vm->def->cputune.shares != 0) {
+            rc = virCgroupSetCpuShares(cgroup, vm->def->cputune.shares);
+            if(rc != 0) {
+                virReportSystemError(-rc,
+                                     _("Unable to set io cpu shares for domain %s"),
+                                     vm->def->name);
+                goto cleanup;
+            }
+        }
+    } else {
+        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                        _("CPU tuning is not available on this host"));
+    }
+
 done:
     virCgroupFree(&cgroup);
     return 0;

src/qemu/qemu_driver.c

@@ -2679,6 +2679,13 @@ qemudDomainPinVcpu(virDomainPtr dom,
                         "%s", _("cpu affinity is not supported"));
         goto cleanup;
     }
+
+    if (virDomainVcpupinAdd(vm->def, cpumap, maplen, vcpu) < 0) {
+        qemuReportError(VIR_ERR_INTERNAL_ERROR,
+                        "%s", _("failed to update or add vcpupin xml"));
+        goto cleanup;
+    }
+
     ret = 0;
 
 cleanup:
@@ -4644,6 +4651,8 @@ static int qemuSetSchedulerParameters(virDomainPtr dom,
                                      _("unable to set cpu shares tunable"));
                 goto cleanup;
             }
+
+            vm->def->cputune.shares = params[i].value.ul;
         } else {
             qemuReportError(VIR_ERR_INVALID_ARG,
                             _("Invalid parameter `%s'"), param->field);

src/qemu/qemu_process.c

@@ -1143,6 +1143,77 @@ qemuProcessInitCpuAffinity(virDomainObjPtr vm)
     return 0;
 }
 
+/* Set CPU affinites for vcpus if vcpupin xml provided. */
+static int
+qemuProcessSetVcpuAffinites(virConnectPtr conn,
+                            virDomainObjPtr vm)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    virDomainDefPtr def = vm->def;
+    virNodeInfo nodeinfo;
+    pid_t vcpupid;
+    unsigned char *cpumask;
+    int vcpu, cpumaplen, hostcpus, maxcpu;
+
+    if (virNodeGetInfo(conn, &nodeinfo) != 0) {
+        return  -1;
+    }
+
+    if (!def->cputune.nvcpupin)
+        return 0;
+
+    if (priv->vcpupids == NULL) {
+        qemuReportError(VIR_ERR_NO_SUPPORT,
+                        "%s", _("cpu affinity is not supported"));
+        return -1;
+    }
+
+    hostcpus = VIR_NODEINFO_MAXCPUS(nodeinfo);
+    cpumaplen = VIR_CPU_MAPLEN(hostcpus);
+    maxcpu = cpumaplen * 8;
+
+    if (maxcpu > hostcpus)
+        maxcpu = hostcpus;
+
+    for (vcpu = 0; vcpu < def->cputune.nvcpupin; vcpu++) {
+        if (vcpu != def->cputune.vcpupin[vcpu]->vcpuid)
+            continue;
+
+        int i;
+        unsigned char *cpumap = NULL;
+
+        if (VIR_ALLOC_N(cpumap, cpumaplen) < 0) {
+            virReportOOMError();
+            return -1;
+        }
+
+        cpumask = (unsigned char *)def->cputune.vcpupin[vcpu]->cpumask;
+        vcpupid = priv->vcpupids[vcpu];
+
+        /* Convert cpumask to bitmap here. */
+        for (i = 0; i < VIR_DOMAIN_CPUMASK_LEN; i++) {
+            int cur = 0;
+            int mod = 0;
+
+            if (i) {
+                cur = i / 8;
+                mod = i % 8;
+            }
+
+            if (cpumask[i])
+                cpumap[cur] |= 1 << mod;
+        }
+
+        if (virProcessInfoSetAffinity(vcpupid,
+                                      cpumap,
+                                      cpumaplen,
+                                      maxcpu) < 0) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
 
 static int
 qemuProcessInitPasswords(virConnectPtr conn,
@@ -2217,6 +2288,10 @@ int qemuProcessStart(virConnectPtr conn,
     if (qemuProcessDetectVcpuPIDs(driver, vm) < 0)
         goto cleanup;
 
+    VIR_DEBUG0("Setting VCPU affinities");
+    if (qemuProcessSetVcpuAffinites(conn, vm) < 0)
+        goto cleanup;
+
     VIR_DEBUG0("Setting any required VM passwords");
     if (qemuProcessInitPasswords(conn, driver, vm, qemuCaps) < 0)
         goto cleanup;