qemu: add support for Hyper-V PV IPIs

QEMU 3.1 supports Hyper-V-style PV IPIs making it cheaper for Windows
guests to send an IPI, especially when it targets many CPUs.

Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

src/qemu/qemu_command.c

@@ -6882,6 +6882,7 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
             case VIR_DOMAIN_HYPERV_FREQUENCIES:
             case VIR_DOMAIN_HYPERV_REENLIGHTENMENT:
             case VIR_DOMAIN_HYPERV_TLBFLUSH:
+            case VIR_DOMAIN_HYPERV_IPI:
                 if (def->hyperv_features[i] == VIR_TRISTATE_SWITCH_ON)
                     virBufferAsprintf(&buf, ",hv_%s",
                                       virDomainHypervTypeToString(i));
@@ -6899,7 +6900,6 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
                                       def->hyperv_vendor_id);
                 break;
 
-            case VIR_DOMAIN_HYPERV_IPI:
             /* coverity[dead_error_begin] */
             case VIR_DOMAIN_HYPERV_LAST:
                 break;

src/qemu/qemu_parse_command.c

@@ -1539,6 +1539,7 @@ qemuParseCommandLineCPU(virDomainDefPtr dom,
             case VIR_DOMAIN_HYPERV_FREQUENCIES:
             case VIR_DOMAIN_HYPERV_REENLIGHTENMENT:
             case VIR_DOMAIN_HYPERV_TLBFLUSH:
+            case VIR_DOMAIN_HYPERV_IPI:
                 if (value) {
                     virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                                    _("HyperV feature '%s' should not "
@@ -1579,7 +1580,6 @@ qemuParseCommandLineCPU(virDomainDefPtr dom,
 
                 break;
 
-            case VIR_DOMAIN_HYPERV_IPI:
             case VIR_DOMAIN_HYPERV_LAST:
                 break;
             }

src/qemu/qemu_process.c

@@ -3964,12 +3964,12 @@ qemuProcessVerifyHypervFeatures(virDomainDefPtr def,
         case VIR_DOMAIN_HYPERV_FREQUENCIES:
         case VIR_DOMAIN_HYPERV_REENLIGHTENMENT:
         case VIR_DOMAIN_HYPERV_TLBFLUSH:
+        case VIR_DOMAIN_HYPERV_IPI:
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            _("host doesn't support hyperv '%s' feature"),
                            virDomainHypervTypeToString(i));
             return -1;
 
-        case VIR_DOMAIN_HYPERV_IPI:
         /* coverity[dead_error_begin] */
         case VIR_DOMAIN_HYPERV_VENDOR_ID:
         case VIR_DOMAIN_HYPERV_LAST:

tests/qemuxml2argvdata/hyperv-off.xml

@@ -23,6 +23,7 @@
       <frequencies state='off'/>
       <reenlightenment state='off'/>
       <tlbflush state='off'/>
+      <ipi state='off'/>
     </hyperv>
   </features>
   <clock offset='utc'/>

tests/qemuxml2argvdata/hyperv.args

@@ -10,7 +10,7 @@ QEMU_AUDIO_DRV=none \
 -machine pc,accel=tcg,usb=off,dump-guest-core=off \
 -cpu 'qemu32,hv_relaxed,hv_vapic,hv_spinlocks=0x2fff,hv_vpindex,hv_runtime,\
 hv_synic,hv_stimer,hv_reset,hv_vendor_id=KVM Hv,hv_frequencies,\
-hv_reenlightenment,hv_tlbflush' \
+hv_reenlightenment,hv_tlbflush,hv_ipi' \
 -m 214 \
 -smp 6,sockets=6,cores=1,threads=1 \
 -uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \

tests/qemuxml2argvdata/hyperv.xml

@@ -23,6 +23,7 @@
       <frequencies state='on'/>
       <reenlightenment state='on'/>
       <tlbflush state='on'/>
+      <ipi state='on'/>
     </hyperv>
   </features>
   <clock offset='utc'/>

tests/qemuxml2xmloutdata/hyperv-off.xml

@@ -23,6 +23,7 @@
       <frequencies state='off'/>
       <reenlightenment state='off'/>
       <tlbflush state='off'/>
+      <ipi state='off'/>
     </hyperv>
   </features>
   <clock offset='utc'/>

tests/qemuxml2xmloutdata/hyperv.xml

@@ -23,6 +23,7 @@
       <frequencies state='on'/>
       <reenlightenment state='on'/>
       <tlbflush state='on'/>
+      <ipi state='on'/>
     </hyperv>
   </features>
   <clock offset='utc'/>