From ceb04d15e671b4fea1d674ee43c91410da9fe57d Mon Sep 17 00:00:00 2001
From: Jiri Denemark <jdenemar@redhat.com>
Date: Thu, 30 May 2019 21:47:38 +0200
Subject: [PATCH] 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>
---
 src/cpu/cpu_x86.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
index cb03123787..689b6cdaf5 100644
--- 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;