[libvirt] [PATCH 2/4] qemu: Add support for setting TSC frequency

[Jiri Denemark]

QEMU allows for TSC frequency to be explicitly set to enable migration
with invtsc (migration fails if the destination QEMU cannot set the
exact same frequency used when starting the domain on the source host).

Libvirt already supports setting the TSC frequency in the XML using

    <clock>
      <timer name='tsc' frequency='1234567890'/>
    </clock>

which will be transformed into

    -cpu Model,tsc-frequency=1234567890

QEMU command line.

Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
---
 src/qemu/qemu_command.c                            | 16 ++++++----
 .../qemuxml2argv-cpu-tsc-frequency.args            | 23 ++++++++++++++
 .../qemuxml2argv-cpu-tsc-frequency.xml             | 35 ++++++++++++++++++++++
 tests/qemuxml2argvtest.c                           |  1 +
 4 files changed, 69 insertions(+), 6 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.args
 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.xml

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 2045c2e7c..8c2e43e60 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6284,12 +6284,12 @@ qemuBuildClockCommandLine(virCommandPtr cmd,
     for (i = 0; i < def->clock.ntimers; i++) {
         switch ((virDomainTimerNameType) def->clock.timers[i]->name) {
         case VIR_DOMAIN_TIMER_NAME_PLATFORM:
-        case VIR_DOMAIN_TIMER_NAME_TSC:
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            _("unsupported timer type (name) '%s'"),
                            virDomainTimerNameTypeToString(def->clock.timers[i]->name));
             return -1;
 
+        case VIR_DOMAIN_TIMER_NAME_TSC:
         case VIR_DOMAIN_TIMER_NAME_KVMCLOCK:
         case VIR_DOMAIN_TIMER_NAME_HYPERVCLOCK:
             /* Timers above are handled when building -cpu.  */
@@ -6876,19 +6876,23 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
     for (i = 0; i < def->clock.ntimers; i++) {
         virDomainTimerDefPtr timer = def->clock.timers[i];
 
-        if (timer->present == -1)
-            continue;
-
-        if (timer->name == VIR_DOMAIN_TIMER_NAME_KVMCLOCK) {
+        if (timer->name == VIR_DOMAIN_TIMER_NAME_KVMCLOCK &&
+            timer->present != -1) {
             virBufferAsprintf(&buf, "%s,%ckvmclock",
                               have_cpu ? "" : default_model,
                               timer->present ? '+' : '-');
             have_cpu = true;
         } else if (timer->name == VIR_DOMAIN_TIMER_NAME_HYPERVCLOCK &&
-                   timer->present) {
+                   timer->present == 1) {
             virBufferAsprintf(&buf, "%s,hv_time",
                               have_cpu ? "" : default_model);
             have_cpu = true;
+        } else if (timer->name == VIR_DOMAIN_TIMER_NAME_TSC &&
+                   timer->frequency > 0) {
+            virBufferAsprintf(&buf, "%s,tsc-frequency=%lu",
+                              have_cpu ? "" : default_model,
+                              timer->frequency);
+            have_cpu = true;
         }
     }
 
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.args b/tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.args
new file mode 100644
index 000000000..50223fab2
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.args
@@ -0,0 +1,23 @@
+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu \
+-name QEMUGuest1 \
+-S \
+-M pc \
+-cpu Haswell,+vme,+ds,+acpi,+ss,+ht,+tm,+pbe,+dtes64,+monitor,+ds_cpl,+vmx,\
++smx,+est,+tm2,+xtpr,+pdcm,+osxsave,+f16c,+rdrand,+pdpe1gb,+abm,+lahf_lm,\
++invtsc,tsc-frequency=3504000000 \
+-m 214 \
+-smp 1,sockets=1,cores=1,threads=1 \
+-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
+-nographic \
+-nodefaults \
+-monitor unix:/tmp/lib/domain--1-QEMUGuest1/monitor.sock,server,nowait \
+-no-acpi \
+-boot c \
+-usb \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.xml b/tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.xml
new file mode 100644
index 000000000..72afe6cd2
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-cpu-tsc-frequency.xml
@@ -0,0 +1,35 @@
+<domain type='kvm'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <title>A description of the test machine.</title>
+  <description>
+      A test of qemu's minimal configuration.
+      This test also tests the description and title elements.
+  </description>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <cpu mode='host-model'>
+    <model fallback='allow'/>
+    <feature policy='require' name='invtsc'/>
+  </cpu>
+  <clock offset='utc'>
+    <timer name='tsc' frequency='3504000000'/>
+  </clock>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index ec73ac7e3..339048d8e 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -1543,6 +1543,7 @@ mymain(void)
     DO_TEST("cpu-Haswell3", QEMU_CAPS_KVM);
     DO_TEST("cpu-Haswell-noTSX", QEMU_CAPS_KVM);
     DO_TEST("cpu-host-model-cmt", NONE);
+    DO_TEST("cpu-tsc-frequency", QEMU_CAPS_KVM);
     qemuTestSetHostCPU(driver.caps, NULL);
 
     DO_TEST("encrypted-disk", NONE);
-- 
2.12.1