libxl: add support for specifying clock offset and adjustment

libxl supports setting the domain real time clock to local time or
UTC via the localtime field of libxl_domain_build_info. Adjustment
of the clock is also supported via the rtc_timeoffset field. The
libvirt libxl driver has never supported these settings, instead
relying on libxl's default of a UTC real time clock with adjustment
set to 0.

There is at least one user that would like the ability to change
the defaults

https://www.redhat.com/archives/libvirt-users/2018-February/msg00059.html

Add support for specifying a local time clock and for specifying an
adjustment for both local time and UTC clocks. Add a test case to
verify the XML to libxl_domain_config conversion.

Local time clock and clock adjustment is already supported by the
XML <-> xl.cfg converter. What is missing is an explicit test for
the conversion. There are plenty of existing tests that all use UTC
with 0 adjustment. Hijack test-fullvirt-tsc-timer to test a local
time clock with 1 hour adjustment.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

src/libxl/libxl_conf.c

@@ -274,6 +274,7 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
                       virCapsPtr caps,
                       libxl_domain_config *d_config)
 {
+    virDomainClockDef clock = def->clock;
     libxl_domain_build_info *b_info = &d_config->b_info;
     int hvm = def->os.type == VIR_DOMAIN_OSTYPE_HVM;
     size_t i;
@@ -293,10 +294,38 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
     for (i = 0; i < virDomainDefGetVcpus(def); i++)
         libxl_bitmap_set((&b_info->avail_vcpus), i);
 
-    for (i = 0; i < def->clock.ntimers; i++) {
-        switch ((virDomainTimerNameType) def->clock.timers[i]->name) {
+    switch ((virDomainClockOffsetType) clock.offset) {
+    case VIR_DOMAIN_CLOCK_OFFSET_VARIABLE:
+        if (clock.data.variable.basis == VIR_DOMAIN_CLOCK_BASIS_LOCALTIME)
+            libxl_defbool_set(&b_info->localtime, true);
+        b_info->rtc_timeoffset = clock.data.variable.adjustment;
+        break;
+
+    case VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME:
+        libxl_defbool_set(&b_info->localtime, true);
+        break;
+
+    /* Nothing to do since UTC is the default in libxl */
+    case VIR_DOMAIN_CLOCK_OFFSET_UTC:
+        break;
+
+    case VIR_DOMAIN_CLOCK_OFFSET_TIMEZONE:
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("unsupported clock offset '%s'"),
+                       virDomainClockOffsetTypeToString(clock.offset));
+        return -1;
+
+    case VIR_DOMAIN_CLOCK_OFFSET_LAST:
+    default:
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                       _("unexpected clock offset '%d'"), clock.offset);
+        return -1;
+    }
+
+    for (i = 0; i < clock.ntimers; i++) {
+        switch ((virDomainTimerNameType) clock.timers[i]->name) {
         case VIR_DOMAIN_TIMER_NAME_TSC:
-            switch (def->clock.timers[i]->mode) {
+            switch (clock.timers[i]->mode) {
             case VIR_DOMAIN_TIMER_MODE_NATIVE:
                 b_info->tsc_mode = LIBXL_TSC_MODE_NATIVE;
                 break;
@@ -315,10 +344,10 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
             if (!hvm) {
                 virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                                _("unsupported timer type (name) '%s'"),
-                               virDomainTimerNameTypeToString(def->clock.timers[i]->name));
+                               virDomainTimerNameTypeToString(clock.timers[i]->name));
                 return -1;
             }
-            if (def->clock.timers[i]->present == 1)
+            if (clock.timers[i]->present == 1)
                 libxl_defbool_set(&b_info->u.hvm.hpet, 1);
             break;
 
@@ -329,7 +358,7 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
         case VIR_DOMAIN_TIMER_NAME_PIT:
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            _("unsupported timer type (name) '%s'"),
-                           virDomainTimerNameTypeToString(def->clock.timers[i]->name));
+                           virDomainTimerNameTypeToString(clock.timers[i]->name));
             return -1;
 
         case VIR_DOMAIN_TIMER_NAME_LAST:

tests/libxlxml2domconfigdata/variable-clock-hvm.json

+{
+    "c_info": {
+        "type": "hvm",
+        "name": "test-hvm",
+        "uuid": "2147d599-9cc6-c0dc-92ab-4064b5446e9b"
+    },
+    "b_info": {
+        "max_vcpus": 4,
+        "avail_vcpus": [
+            0,
+            1,
+            2,
+            3
+        ],
+        "max_memkb": 1048576,
+        "target_memkb": 1048576,
+        "video_memkb": 8192,
+        "shadow_memkb": 12288,
+        "rtc_timeoffset": 3600,
+        "localtime": "True",
+        "device_model_version": "qemu_xen",
+        "device_model": "/bin/true",
+        "sched_params": {
+            "weight": 1000
+        },
+        "type.hvm": {
+            "pae": "True",
+            "apic": "True",
+            "acpi": "True",
+            "vga": {
+                "kind": "cirrus"
+            },
+            "vnc": {
+                "enable": "True",
+                "listen": "0.0.0.0",
+                "findunused": "False"
+            },
+            "sdl": {
+                "enable": "False"
+            },
+            "spice": {
+
+            },
+            "boot": "c",
+            "rdm": {
+
+            }
+        },
+        "arch_arm": {
+
+        }
+    },
+    "disks": [
+        {
+            "pdev_path": "/var/lib/xen/images/test-hvm.img",
+            "vdev": "hda",
+            "backend": "qdisk",
+            "format": "raw",
+            "removable": 1,
+            "readwrite": 1
+        }
+    ],
+    "nics": [
+        {
+            "devid": 0,
+            "mac": "00:16:3e:66:12:b4",
+            "bridge": "br0",
+            "script": "/etc/xen/scripts/vif-bridge",
+            "nictype": "vif_ioemu"
+        }
+    ],
+    "vfbs": [
+        {
+	    "devid": -1,
+            "vnc": {
+                "enable": "True",
+                "listen": "0.0.0.0",
+                "findunused": "False"
+            },
+            "sdl": {
+                "enable": "False"
+            }
+        }
+    ],
+    "vkbs": [
+        {
+            "devid": -1
+        }
+    ],
+    "on_reboot": "restart"
+}

tests/libxlxml2domconfigdata/variable-clock-hvm.xml

+<domain type='xen'>
+  <name>test-hvm</name>
+  <description>None</description>
+  <uuid>2147d599-9cc6-c0dc-92ab-4064b5446e9b</uuid>
+  <memory>1048576</memory>
+  <currentMemory>1048576</currentMemory>
+  <vcpu>4</vcpu>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <clock offset='localtime' adjustment='3600'/>
+  <os>
+    <type>hvm</type>
+    <loader>/usr/lib/xen/boot/hvmloader</loader>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <apic/>
+    <acpi/>
+    <pae/>
+  </features>
+  <devices>
+    <emulator>/bin/true</emulator>
+    <disk type='file' device='disk'>
+      <driver name='qemu'/>
+      <source file='/var/lib/xen/images/test-hvm.img'/>
+      <target dev='hda'/>
+    </disk>
+    <interface type='bridge'>
+      <source bridge='br0'/>
+      <mac address='00:16:3e:66:12:b4'/>
+      <script path='/etc/xen/scripts/vif-bridge'/>
+    </interface>
+    <graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'/>
+  </devices>
+</domain>

tests/libxlxml2domconfigtest.c

@@ -188,6 +188,7 @@ mymain(void)
 
     DO_TEST("basic-pv");
     DO_TEST("basic-hvm");
+    DO_TEST("variable-clock-hvm");
     DO_TEST("moredevs-hvm");
     DO_TEST("vnuma-hvm");
     DO_TEST("multiple-ip");

tests/xlconfigdata/test-fullvirt-tsc-timer.cfg

@@ -9,8 +9,8 @@ apic = 1
 hap = 0
 viridian = 0
 tsc_mode = "native"
-rtc_timeoffset = 0
-localtime = 0
+rtc_timeoffset = 3600
+localtime = 1
 on_poweroff = "destroy"
 on_reboot = "restart"
 on_crash = "restart"

tests/xlconfigdata/test-fullvirt-tsc-timer.xml

@@ -15,7 +15,7 @@
     <pae/>
     <hap state='off'/>
   </features>
-  <clock offset='variable' adjustment='0' basis='utc'>
+  <clock offset='variable' adjustment='3600' basis='localtime'>
     <timer name='tsc' present='yes' mode='native'/>
   </clock>
   <on_poweroff>destroy</on_poweroff>