From 7d495864b89cd3a65aac555f42de044c592ad21b Mon Sep 17 00:00:00 2001
Message-Id: <7d495864b89cd3a65aac555f42de044c592ad21b@dist-git>
From: Jiri Denemark <jdenemar@redhat.com>
Date: Tue, 4 Jun 2019 13:04:32 +0200
Subject: [PATCH] cpu_x86: Probe TSC frequency and scaling support
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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>
(cherry picked from commit ceb04d15e671b4fea1d674ee43c91410da9fe57d)

https://bugzilla.redhat.com/show_bug.cgi?id=1641702

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Message-Id: <a738a180a4b3771d57ed46449aa305f4e914a98d.1559646067.git.jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@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 bd10862f57..e06e452aee 100644
--- a/src/cpu/cpu_x86.c
+++ b/src/cpu/cpu_x86.c
@@ -2587,6 +2587,15 @@ 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;
-- 
2.21.0