cpu_x86: Probe TSC frequency and scaling support

When the host CPU supports invariant TSC the host CPU definition created
by virCPUx86GetHost will contain (unless probing fails for some reason)
addition TSC related data.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
index cb03123787e6d513370fe5a2d9a1f6392b0612fb..689b6cdaf56c91d650191433606ae1aefef6c43b 100644 (file)
--- a/src/cpu/cpu_x86.c
+++ b/src/cpu/cpu_x86.c
@@ -2762,6 +2762,15 @@ virCPUx86GetHost(virCPUDefPtr cpu,
     ret = x86DecodeCPUData(cpu, cpuData, models);
     cpu->microcodeVersion = virHostCPUGetMicrocodeVersion();
 
+    /* Probing for TSC frequency makes sense only if the CPU supports
+     * invariant TSC (Linux calls this constant_tsc in /proc/cpuinfo). */
+    if (virCPUx86DataCheckFeature(cpuData, "invtsc") == 1) {
+        VIR_DEBUG("Checking invariant TSC frequency");
+        cpu->tsc = virHostCPUGetTscInfo();
+    } else {
+        VIR_DEBUG("Host CPU does not support invariant TSC");
+    }
+
  cleanup:
     virCPUx86DataFree(cpuData);
     return ret;