qemu: Add support for host CPU modes

This adds support for host-model and host-passthrough CPU modes to qemu
driver. The host-passthrough mode is mapped to -cpu host.

src/libvirt_private.syms

@@ -187,6 +187,7 @@ virCPUDefFormatBuf;
 virCPUDefFree;
 virCPUDefFreeModel;
 virCPUDefParseXML;
+virCPUModeTypeToString;
 
 
 # datatypes.h

src/qemu/qemu_capabilities.c

@@ -145,9 +145,10 @@ VIR_ENUM_IMPL(qemuCaps, QEMU_CAPS_LAST,
               "no-acpi",
               "fsdev-readonly",
 
-              "virtio-blk-pci.scsi",
+              "virtio-blk-pci.scsi", /* 80 */
               "blk-sg-io",
               "drive-copy-on-read",
+              "cpu-host",
     );
 
 struct qemu_feature_flags {
@@ -1184,6 +1185,9 @@ qemuCapsComputeCmdFlags(const char *help,
      */
     if (version >= 12000)
         qemuCapsSet(flags, QEMU_CAPS_PCI_ROMBAR);
+
+    if (version >= 11000)
+        qemuCapsSet(flags, QEMU_CAPS_CPU_HOST);
 }
 
 /* We parse the output of 'qemu -help' to get the QEMU

src/qemu/qemu_capabilities.h

@@ -121,6 +121,7 @@ enum qemuCapsFlags {
     QEMU_CAPS_VIRTIO_BLK_SCSI    = 80, /* virtio-blk-pci.scsi */
     QEMU_CAPS_VIRTIO_BLK_SG_IO   = 81, /* support for SG_IO commands, reportedly added in 0.11 */
     QEMU_CAPS_DRIVE_COPY_ON_READ = 82, /* -drive copy-on-read */
+    QEMU_CAPS_CPU_HOST          = 83, /* support for -cpu host */
 
     QEMU_CAPS_LAST,                   /* this must always be the last item */
 };

src/qemu/qemu_command.c

@@ -3458,10 +3458,12 @@ qemuBuildCpuArgStr(const struct qemud_driver *driver,
                    virBitmapPtr qemuCaps,
                    const struct utsname *ut,
                    char **opt,
-                   bool *hasHwVirt)
+                   bool *hasHwVirt,
+                   bool migrating)
 {
     const virCPUDefPtr host = driver->caps->host.cpu;
     virCPUDefPtr guest = NULL;
+    virCPUDefPtr cpu = NULL;
     unsigned int ncpus = 0;
     const char **cpus = NULL;
     union cpuData *data = NULL;
@@ -3471,7 +3473,21 @@ qemuBuildCpuArgStr(const struct qemud_driver *driver,
 
     *hasHwVirt = false;
 
-    if (def->cpu && def->cpu->model) {
+    if (def->cpu &&
+        (def->cpu->mode != VIR_CPU_MODE_CUSTOM || def->cpu->model)) {
+        if (!(cpu = virCPUDefCopy(def->cpu)))
+            goto cleanup;
+        if (cpu->mode != VIR_CPU_MODE_CUSTOM &&
+            !migrating &&
+            cpuUpdate(cpu, host) < 0)
+            goto cleanup;
+    }
+
+    if (cpu) {
+        virCPUCompareResult cmp;
+        const char *preferred;
+        int hasSVM;
+
         if (host &&
             qemuCapsProbeCPUModels(emulator, qemuCaps, host->arch,
                                    &ncpus, &cpus) < 0)
@@ -3482,18 +3498,12 @@ qemuBuildCpuArgStr(const struct qemud_driver *driver,
                             _("CPU specification not supported by hypervisor"));
             goto cleanup;
         }
-    }
 
-    if (ncpus > 0 && host) {
-        virCPUCompareResult cmp;
-        const char *preferred;
-        int hasSVM;
-
-        cmp = cpuGuestData(host, def->cpu, &data);
+        cmp = cpuGuestData(host, cpu, &data);
         switch (cmp) {
         case VIR_CPU_COMPARE_INCOMPATIBLE:
-            qemuReportError(VIR_ERR_INTERNAL_ERROR,
-                            "%s", _("guest CPU is not compatible with host CPU"));
+            qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                            _("guest CPU is not compatible with host CPU"));
             /* fall through */
         case VIR_CPU_COMPARE_ERROR:
             goto cleanup;
@@ -3502,39 +3512,55 @@ qemuBuildCpuArgStr(const struct qemud_driver *driver,
             break;
         }
 
-        if (VIR_ALLOC(guest) < 0 || !(guest->arch = strdup(host->arch)))
-            goto no_memory;
-
-        if (def->cpu->match == VIR_CPU_MATCH_MINIMUM)
-            preferred = host->model;
-        else
-            preferred = def->cpu->model;
-
-        guest->type = VIR_CPU_TYPE_GUEST;
-        guest->fallback = def->cpu->fallback;
-        if (cpuDecode(guest, data, cpus, ncpus, preferred) < 0)
-            goto cleanup;
-
         /* Only 'svm' requires --enable-nesting. The nested
          * 'vmx' patches now simply hook off the CPU features
          */
-        hasSVM = cpuHasFeature(guest->arch, data, "svm");
+        hasSVM = cpuHasFeature(host->arch, data, "svm");
         if (hasSVM < 0)
             goto cleanup;
         *hasHwVirt = hasSVM > 0 ? true : false;
 
-        virBufferAdd(&buf, guest->model, -1);
-        for (i = 0; i < guest->nfeatures; i++) {
-            char sign;
-            if (guest->features[i].policy == VIR_CPU_FEATURE_DISABLE)
-                sign = '-';
+        if (cpu->mode == VIR_CPU_MODE_HOST_PASSTHROUGH) {
+            const char *mode = virCPUModeTypeToString(cpu->mode);
+            if (!qemuCapsGet(qemuCaps, QEMU_CAPS_CPU_HOST)) {
+                qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                _("CPU mode '%s' is not supported by QEMU"
+                                  " binary"), mode);
+                goto cleanup;
+            }
+            if (def->virtType != VIR_DOMAIN_VIRT_KVM) {
+                qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                _("CPU mode '%s' is only supported with kvm"),
+                                mode);
+                goto cleanup;
+            }
+            virBufferAddLit(&buf, "host");
+        } else {
+            if (VIR_ALLOC(guest) < 0 || !(guest->arch = strdup(host->arch)))
+                goto no_memory;
+
+            if (cpu->match == VIR_CPU_MATCH_MINIMUM)
+                preferred = host->model;
             else
-                sign = '+';
+                preferred = cpu->model;
 
-            virBufferAsprintf(&buf, ",%c%s", sign, guest->features[i].name);
+            guest->type = VIR_CPU_TYPE_GUEST;
+            guest->fallback = cpu->fallback;
+            if (cpuDecode(guest, data, cpus, ncpus, preferred) < 0)
+                goto cleanup;
+
+            virBufferAdd(&buf, guest->model, -1);
+            for (i = 0; i < guest->nfeatures; i++) {
+                char sign;
+                if (guest->features[i].policy == VIR_CPU_FEATURE_DISABLE)
+                    sign = '-';
+                else
+                    sign = '+';
+
+                virBufferAsprintf(&buf, ",%c%s", sign, guest->features[i].name);
+            }
         }
-    }
-    else {
+    } else {
         /*
          * Need to force a 32-bit guest CPU type if
          *
@@ -3565,6 +3591,7 @@ cleanup:
     if (guest)
         cpuDataFree(guest->arch, data);
     virCPUDefFree(guest);
+    virCPUDefFree(cpu);
 
     if (cpus) {
         for (i = 0; i < ncpus; i++)
@@ -3787,7 +3814,7 @@ qemuBuildCommandLine(virConnectPtr conn,
         virCommandAddArgList(cmd, "-M", def->os.machine, NULL);
 
     if (qemuBuildCpuArgStr(driver, def, emulator, qemuCaps,
-                           &ut, &cpu, &hasHwVirt) < 0)
+                           &ut, &cpu, &hasHwVirt, !!migrateFrom) < 0)
         goto error;
 
     if (cpu) {

tests/qemuhelptest.c

@@ -330,7 +330,8 @@ mymain(void)
             QEMU_CAPS_NO_SHUTDOWN,
             QEMU_CAPS_PCI_ROMBAR,
             QEMU_CAPS_NO_ACPI,
-            QEMU_CAPS_VIRTIO_BLK_SG_IO);
+            QEMU_CAPS_VIRTIO_BLK_SG_IO,
+            QEMU_CAPS_CPU_HOST);
     DO_TEST("qemu-kvm-0.12.1.2-rhel60", 12001, 1, 0,
             QEMU_CAPS_VNC_COLON,
             QEMU_CAPS_NO_REBOOT,
@@ -378,7 +379,8 @@ mymain(void)
             QEMU_CAPS_NO_SHUTDOWN,
             QEMU_CAPS_PCI_ROMBAR,
             QEMU_CAPS_NO_ACPI,
-            QEMU_CAPS_VIRTIO_BLK_SG_IO);
+            QEMU_CAPS_VIRTIO_BLK_SG_IO,
+            QEMU_CAPS_CPU_HOST);
     DO_TEST("qemu-kvm-0.12.3", 12003, 1, 0,
             QEMU_CAPS_VNC_COLON,
             QEMU_CAPS_NO_REBOOT,
@@ -419,7 +421,8 @@ mymain(void)
             QEMU_CAPS_NO_SHUTDOWN,
             QEMU_CAPS_PCI_ROMBAR,
             QEMU_CAPS_NO_ACPI,
-            QEMU_CAPS_VIRTIO_BLK_SG_IO);
+            QEMU_CAPS_VIRTIO_BLK_SG_IO,
+            QEMU_CAPS_CPU_HOST);
     DO_TEST("qemu-kvm-0.13.0", 13000, 1, 0,
             QEMU_CAPS_VNC_COLON,
             QEMU_CAPS_NO_REBOOT,
@@ -476,7 +479,8 @@ mymain(void)
             QEMU_CAPS_NO_SHUTDOWN,
             QEMU_CAPS_PCI_ROMBAR,
             QEMU_CAPS_NO_ACPI,
-            QEMU_CAPS_VIRTIO_BLK_SG_IO);
+            QEMU_CAPS_VIRTIO_BLK_SG_IO,
+            QEMU_CAPS_CPU_HOST);
     DO_TEST("qemu-kvm-0.12.1.2-rhel61", 12001, 1, 0,
             QEMU_CAPS_VNC_COLON,
             QEMU_CAPS_NO_REBOOT,
@@ -530,7 +534,8 @@ mymain(void)
             QEMU_CAPS_PCI_ROMBAR,
             QEMU_CAPS_NO_ACPI,
             QEMU_CAPS_VIRTIO_BLK_SCSI,
-            QEMU_CAPS_VIRTIO_BLK_SG_IO);
+            QEMU_CAPS_VIRTIO_BLK_SG_IO,
+            QEMU_CAPS_CPU_HOST);
     DO_TEST("qemu-kvm-0.12.1.2-rhel62-beta", 12001, 1, 0,
             QEMU_CAPS_VNC_COLON,
             QEMU_CAPS_NO_REBOOT,
@@ -593,7 +598,8 @@ mymain(void)
             QEMU_CAPS_NO_ACPI,
             QEMU_CAPS_VIRTIO_BLK_SCSI,
             QEMU_CAPS_VIRTIO_BLK_SG_IO,
-            QEMU_CAPS_DRIVE_COPY_ON_READ);
+            QEMU_CAPS_DRIVE_COPY_ON_READ,
+            QEMU_CAPS_CPU_HOST);
     DO_TEST("qemu-1.0", 1000000, 0, 0,
             QEMU_CAPS_VNC_COLON,
             QEMU_CAPS_NO_REBOOT,
@@ -659,7 +665,8 @@ mymain(void)
             QEMU_CAPS_NO_ACPI,
             QEMU_CAPS_FSDEV_READONLY,
             QEMU_CAPS_VIRTIO_BLK_SCSI,
-            QEMU_CAPS_VIRTIO_BLK_SG_IO);
+            QEMU_CAPS_VIRTIO_BLK_SG_IO,
+            QEMU_CAPS_CPU_HOST);
 
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }

tests/qemuxml2argvdata/qemu-lib.sh

+candidates="/usr/bin/qemu-kvm
+            /usr/libexec/qemu-kvm
+            /usr/bin/qemu-system-x86_64
+            /usr/bin/qemu"
+qemu=
+for candidate in $candidates; do
+    if test -x $candidate; then
+        qemu=$candidate
+        break
+    fi
+done
+
+real_qemu()
+{
+    if test x$qemu != x; then
+        exec $qemu "$@"
+    else
+        return 1
+    fi
+}
+
+faked_machine()
+{
+    echo "pc"
+}
+
+faked_cpu()
+{
+    cat <<EOF
+x86       Opteron_G3
+x86       Opteron_G2
+x86       Opteron_G1
+x86          Nehalem
+x86           Penryn
+x86           Conroe
+x86           [n270]
+x86         [athlon]
+x86       [pentium3]
+x86       [pentium2]
+x86        [pentium]
+x86            [486]
+x86        [coreduo]
+x86         [qemu32]
+x86          [kvm64]
+x86       [core2duo]
+x86         [phenom]
+x86         [qemu64]
+x86           [host]
+EOF
+}

tests/qemuxml2argvdata/qemu-supported-cpus.sh

+#! /bin/sh
+
+. $(dirname $0)/qemu-lib.sh
+
+case $* in
+"-M ?")
+    faked_machine
+    ;;
+"-cpu ?")
+    faked_cpu | grep -Fv '['
+    ;;
+*)
+    real_qemu "$@"
+    ;;
+esac

tests/qemuxml2argvdata/qemu.sh

 #! /bin/sh
 
-candidates="/usr/bin/qemu-kvm
-            /usr/libexec/qemu-kvm
-            /usr/bin/qemu-system-x86_64
-            /usr/bin/qemu"
-qemu=
-for candidate in $candidates; do
-    if test -x $candidate; then
-        qemu=$candidate
-        break
-    fi
-done
-
-real_qemu()
-{
-    if test x$qemu != x; then
-        exec $qemu "$@"
-    else
-        return 1
-    fi
-}
-
-faked_machine()
-{
-    echo "pc"
-}
-
-faked_cpu()
-{
-    cat <<EOF
-x86       Opteron_G3
-x86       Opteron_G2
-x86       Opteron_G1
-x86          Nehalem
-x86           Penryn
-x86           Conroe
-x86           [n270]
-x86         [athlon]
-x86       [pentium3]
-x86       [pentium2]
-x86        [pentium]
-x86            [486]
-x86        [coreduo]
-x86         [qemu32]
-x86          [kvm64]
-x86       [core2duo]
-x86         [phenom]
-x86         [qemu64]
-x86           [host]
-EOF
-}
+. $(dirname $0)/qemu-lib.sh
 
 case $* in
 "-M ?")

tests/qemuxml2argvdata/qemuxml2argv-cpu-host-model-fallback.args

+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+./qemu-supported-cpus.sh \
+-S \
+-M pc \
+-cpu Penryn,+xtpr,+tm2,+est,+vmx,+ds_cpl,+monitor,+pbe,+tm,+ht,+ss,+acpi,+ds,+vme,-sse4.1 \
+-m 214 \
+-smp 6 \
+-nographic \
+-monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi \
+-boot n \
+-net none \
+-serial none \
+-parallel none \
+-usb

tests/qemuxml2argvdata/qemuxml2argv-cpu-host-model-fallback.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219100</memory>
+  <currentMemory>219100</currentMemory>
+  <vcpu>6</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='network'/>
+  </os>
+  <cpu mode='host-model'/>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/./qemu-supported-cpus.sh</emulator>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-cpu-host-model-nofallback.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219100</memory>
+  <currentMemory>219100</currentMemory>
+  <vcpu>6</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='network'/>
+  </os>
+  <cpu mode='host-model'>
+    <model fallback='forbid'/>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/./qemu-supported-cpus.sh</emulator>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-cpu-host-model.args

+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+./qemu.sh \
+-S \
+-M pc \
+-cpu core2duo,+lahf_lm,+xtpr,+cx16,+tm2,+est,+vmx,+ds_cpl,+pbe,+tm,+ht,+ss,+acpi,+ds \
+-m 214 \
+-smp 6 \
+-nographic \
+-monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi \
+-boot n \
+-net none \
+-serial none \
+-parallel none \
+-usb

tests/qemuxml2argvdata/qemuxml2argv-cpu-host-model.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219100</memory>
+  <currentMemory>219100</currentMemory>
+  <vcpu>6</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='network'/>
+  </os>
+  <cpu mode='host-model'/>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+      <emulator>/./qemu.sh</emulator>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-cpu-host-passthrough.args

+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+./qemu.sh \
+-S \
+-M pc \
+-cpu host \
+-m 214 \
+-smp 6 \
+-nographic \
+-monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi \
+-boot n \
+-net none \
+-serial none \
+-parallel none \
+-usb

tests/qemuxml2argvdata/qemuxml2argv-cpu-host-passthrough.xml

+<domain type='kvm'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219100</memory>
+  <currentMemory>219100</currentMemory>
+  <vcpu>6</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='network'/>
+  </os>
+  <cpu mode='host-passthrough'/>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/./qemu.sh</emulator>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-cpu-qemu-host-passthrough.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219100</memory>
+  <currentMemory>219100</currentMemory>
+  <vcpu>6</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='network'/>
+  </os>
+  <cpu mode='host-passthrough'/>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/./qemu.sh</emulator>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -690,6 +690,13 @@ mymain(void)
     DO_TEST("cpu-strict1", false, NONE);
     DO_TEST("cpu-numa1", false, NONE);
     DO_TEST("cpu-numa2", false, QEMU_CAPS_SMP_TOPOLOGY);
+    DO_TEST("cpu-host-model", false, NONE);
+    DO_TEST("cpu-host-model-fallback", false, NONE);
+    DO_TEST_FAILURE("cpu-host-model-nofallback", NONE);
+    DO_TEST("cpu-host-passthrough", false, QEMU_CAPS_KVM, QEMU_CAPS_CPU_HOST);
+    DO_TEST_FAILURE("cpu-host-passthrough", NONE);
+    DO_TEST_FAILURE("cpu-qemu-host-passthrough",
+                    QEMU_CAPS_KVM, QEMU_CAPS_CPU_HOST);
 
     DO_TEST("memtune", false, QEMU_CAPS_NAME);
     DO_TEST("blkiotune", false, QEMU_CAPS_NAME);