[PATCH] Document caveats of hypervisor-specific stats in 'VIR_DOMAIN_STATS_VCPU' group

[Peter Krempa]

In commit c43718ef67944 I've added a disclaimer that the new stats which
are fetched from qemu and passed directly to the user are not guaranteed
by libvirt. I didn't notice that per-vcpu hypervisor specific stats are
also snuck into the VIR_DOMAIN_STATS_VCPU group along with other
pre-existing stats we do guarantee.

Extend the disclaimer for VIR_DOMAIN_STATS_VCPU too.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 docs/manpages/virsh.rst | 22 ++++++++++++++++++++++
 src/libvirt-domain.c    | 17 +++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
index 5f5f48f83e..1e8a43bc55 100644
--- a/docs/manpages/virsh.rst
+++ b/docs/manpages/virsh.rst
@@ -2399,6 +2399,28 @@ When selecting the *--state* group the following fields are returned:
   host scheduler, but was waiting in the queue instead of running.
   Exposed to the VM as a steal time.

+This group of statistics also reports additional hypervisor-originating per-vCPU
+stats. The hypervisor-specific statistics in this group have the following
+naming scheme:
+
+ ``vcpu.<num>.$NAME.$TYPE``
+
+ ``$NAME``
+   name of the statistics field provided by the hypervisor
+
+ ``$TYPE``
+   Type of the value. The following types are returned:
+
+   ``cur``
+     current instant value
+   ``sum``
+     aggregate value
+   ``max``
+     peak value
+
+ The returned value may be either an unsigned long long or a boolean. Meaning
+ is hypervisor specific. Please see the disclaimer for the *--vm* group which
+ also consists of hypervisor-specific stats.


 *--interface* returns:
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index 56c2abf3fa..78c26b2219 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -12270,6 +12270,23 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  *                          instead of running. Exposed to the VM as a steal
  *                          time.
  *
+ *    This group of statistics also reports additional hypervisor-originating
+ *    per-vCPU stats. The hypervisor-specific statistics in this group have the
+ *    following naming scheme:
+ *
+ *     "vcpu.<num>.$NAME.$TYPE"
+ *
+ *       $NAME - name of the statistics field provided by the hypervisor
+ *
+ *       $TYPE - Type of the value. The following types are returned:
+ *          'cur' - current instant value
+ *          'sum' - aggregate value
+ *          'max' - peak value
+ *
+ *      The returned value may be either an unsigned long long or a boolean.
+ *      Meaning is hypervisor specific. Please see the disclaimer for the
+ *      VIR_DOMAIN_STATS_VM group below.
+ *
  * VIR_DOMAIN_STATS_INTERFACE:
  *     Return network interface statistics (from domain point of view).
  *     The typed parameter keys are in this format:
-- 
2.38.1