qemu: Enable configuration of HPT resizing for pSeries guests

Most of the time it's okay to leave this up to negotiation between
the guest and the host, but in some situations it can be useful to
manually decide the behavior, especially to enforce its availability.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1308743

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>

docs/schemas/domaincommon.rng

@@ -4736,6 +4736,9 @@
           <optional>
             <ref name="ioapic"/>
           </optional>
+          <optional>
+            <ref name="hpt"/>
+          </optional>
         </interleave>
       </element>
     </optional>
@@ -4924,6 +4927,18 @@
     </element>
   </define>
 
+  <define name="hpt">
+    <element name="hpt">
+      <attribute name="resizing">
+        <choice>
+          <value>enabled</value>
+          <value>disabled</value>
+          <value>required</value>
+        </choice>
+      </attribute>
+    </element>
+  </define>
+
   <define name="address">
     <element name="address">
       <choice>

src/conf/domain_conf.c

@@ -148,7 +148,9 @@ VIR_ENUM_IMPL(virDomainFeature, VIR_DOMAIN_FEATURE_LAST,
               "vmport",
               "gic",
               "smm",
-              "ioapic")
+              "ioapic",
+              "hpt",
+);
 
 VIR_ENUM_IMPL(virDomainCapabilitiesPolicy, VIR_DOMAIN_CAPABILITIES_POLICY_LAST,
               "default",
@@ -882,6 +884,13 @@ VIR_ENUM_IMPL(virDomainIOAPIC,
               "qemu",
               "kvm")
 
+VIR_ENUM_IMPL(virDomainHPTResizing,
+              VIR_DOMAIN_HPT_RESIZING_LAST,
+              "enabled",
+              "disabled",
+              "required",
+);
+
 /* Internal mapping: subset of block job types that can be present in
  * <mirror> XML (remaining types are not two-phase). */
 VIR_ENUM_DECL(virDomainBlockJob)
@@ -18775,6 +18784,22 @@ virDomainDefParseXML(xmlDocPtr xml,
             }
             break;
 
+        case VIR_DOMAIN_FEATURE_HPT:
+            tmp = virXMLPropString(nodes[i], "resizing");
+            if (tmp) {
+                int value = virDomainHPTResizingTypeFromString(tmp);
+                if (value < 0) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                   _("Unknown HPT resizing setting: %s"),
+                                   tmp);
+                    goto error;
+                }
+                def->hpt_resizing = value;
+                def->features[val] = VIR_TRISTATE_SWITCH_ON;
+                VIR_FREE(tmp);
+            }
+            break;
+
         /* coverity[dead_error_begin] */
         case VIR_DOMAIN_FEATURE_LAST:
             break;
@@ -20965,6 +20990,18 @@ virDomainDefFeaturesCheckABIStability(virDomainDefPtr src,
         return false;
     }
 
+    /* HPT resizing */
+    if (src->features[VIR_DOMAIN_FEATURE_HPT] == VIR_TRISTATE_SWITCH_ON) {
+        if (src->hpt_resizing != dst->hpt_resizing) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("HPT resizing configuration differs: "
+                             "source: '%s', destination: '%s'"),
+                           virDomainHPTResizingTypeToString(src->hpt_resizing),
+                           virDomainHPTResizingTypeToString(dst->hpt_resizing));
+            return false;
+        }
+    }
+
     return true;
 }
 
@@ -26214,6 +26251,13 @@ virDomainDefFormatInternal(virDomainDefPtr def,
                 }
                 break;
 
+            case VIR_DOMAIN_FEATURE_HPT:
+                if (def->features[i] == VIR_TRISTATE_SWITCH_ON) {
+                    virBufferAsprintf(buf, "<hpt resizing='%s'/>\n",
+                                      virDomainHPTResizingTypeToString(def->hpt_resizing));
+                }
+                break;
+
             /* coverity[dead_error_begin] */
             case VIR_DOMAIN_FEATURE_LAST:
                 break;

src/conf/domain_conf.h

@@ -1723,6 +1723,7 @@ typedef enum {
     VIR_DOMAIN_FEATURE_GIC,
     VIR_DOMAIN_FEATURE_SMM,
     VIR_DOMAIN_FEATURE_IOAPIC,
+    VIR_DOMAIN_FEATURE_HPT,
 
     VIR_DOMAIN_FEATURE_LAST
 } virDomainFeature;
@@ -1851,6 +1852,16 @@ typedef enum {
 
 VIR_ENUM_DECL(virDomainIOAPIC);
 
+typedef enum {
+    VIR_DOMAIN_HPT_RESIZING_ENABLED = 0,
+    VIR_DOMAIN_HPT_RESIZING_DISABLED,
+    VIR_DOMAIN_HPT_RESIZING_REQUIRED,
+
+    VIR_DOMAIN_HPT_RESIZING_LAST
+} virDomainHPTResizing;
+
+VIR_ENUM_DECL(virDomainHPTResizing);
+
 /* Operating system configuration data & machine / arch */
 typedef struct _virDomainOSEnv virDomainOSEnv;
 typedef virDomainOSEnv *virDomainOSEnvPtr;
@@ -2323,6 +2334,7 @@ struct _virDomainDef {
     virGICVersion gic_version;
     char *hyperv_vendor_id;
     virDomainIOAPIC ioapic;
+    virDomainHPTResizing hpt_resizing;
 
     /* These options are of type virTristateSwitch: ON = keep, OFF = drop */
     int caps_features[VIR_DOMAIN_CAPS_FEATURE_LAST];

src/libvirt_private.syms

@@ -387,6 +387,7 @@ virDomainHostdevModeTypeToString;
 virDomainHostdevRemove;
 virDomainHostdevSubsysPCIBackendTypeToString;
 virDomainHostdevSubsysTypeToString;
+virDomainHPTResizingTypeToString;
 virDomainHubTypeFromString;
 virDomainHubTypeToString;
 virDomainHypervTypeFromString;

src/qemu/qemu_capabilities.c

@@ -443,6 +443,7 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
               /* 270 */
               "vxhs",
               "virtio-blk.num-queues",
+              "machine.pseries.resize-hpt",
     );
 
 
@@ -4776,6 +4777,13 @@ virQEMUCapsInitQMPMonitor(virQEMUCapsPtr qemuCaps,
     if (qemuCaps->version >= 2006000)
         virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACHINE_KERNEL_IRQCHIP_SPLIT);
 
+    /* HPT resizing is supported since QEMU 2.10 on ppc64; unfortunately
+     * there's no sane way to probe for it */
+    if (qemuCaps->version >= 2010000 &&
+        ARCH_IS_PPC64(qemuCaps->arch)) {
+        virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACHINE_PSERIES_RESIZE_HPT);
+    }
+
     if (virQEMUCapsProbeQMPCommands(qemuCaps, mon) < 0)
         goto cleanup;
 

src/qemu/qemu_capabilities.h

@@ -429,6 +429,7 @@ typedef enum {
     /* 270 */
     QEMU_CAPS_VXHS, /* -drive file.driver=vxhs via query-qmp-schema */
     QEMU_CAPS_VIRTIO_BLK_NUM_QUEUES, /* virtio-blk-*.num-queues */
+    QEMU_CAPS_MACHINE_PSERIES_RESIZE_HPT, /* -machine pseries,resize-hpt */
 
     QEMU_CAPS_LAST /* this must always be the last item */
 } virQEMUCapsFlags;

src/qemu/qemu_command.c

@@ -7489,6 +7489,26 @@ qemuBuildMachineCommandLine(virCommandPtr cmd,
             }
         }
 
+        if (def->features[VIR_DOMAIN_FEATURE_HPT] == VIR_TRISTATE_SWITCH_ON) {
+            const char *str;
+
+            if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_MACHINE_PSERIES_RESIZE_HPT)) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                               _("HTP resizing is not supported by this "
+                                 "QEMU binary"));
+                goto cleanup;
+            }
+
+            str = virDomainHPTResizingTypeToString(def->hpt_resizing);
+            if (!str) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                               _("Invalid setting for HPT resizing"));
+                goto cleanup;
+            }
+
+            virBufferAsprintf(&buf, ",resize-hpt=%s", str);
+        }
+
         if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_BOOTINDEX) &&
             virQEMUCapsGet(qemuCaps, QEMU_CAPS_LOADPARM))
             qemuAppendLoadparmMachineParm(&buf, def);

src/qemu/qemu_domain.c

@@ -3144,6 +3144,14 @@ qemuDomainDefVerifyFeatures(const virDomainDef *def)
         return -1;
     }
 
+    if (def->features[VIR_DOMAIN_FEATURE_HPT] == VIR_TRISTATE_SWITCH_ON &&
+        !qemuDomainIsPSeries(def)) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       "%s",
+                       _("HPT tuning is only supported for pSeries guests"));
+        return -1;
+    }
+
     return 0;
 }
 

tests/qemucapabilitiesdata/caps_2.10.0.ppc64.xml

@@ -177,6 +177,7 @@
   <flag name='virtio-gpu.max_outputs'/>
   <flag name='vxhs'/>
   <flag name='virtio-blk.num-queues'/>
+  <flag name='machine.pseries.resize-hpt'/>
   <version>2010000</version>
   <kvmVersion>0</kvmVersion>
   <package> (v2.10.0)</package>