From 5da85fb944db3dd8213a7302deaffa3b294acd64 Mon Sep 17 00:00:00 2001
Message-Id: <5da85fb944db3dd8213a7302deaffa3b294acd64@dist-git>
From: Michal Privoznik <mprivozn@redhat.com>
Date: Tue, 9 Aug 2022 16:16:09 +0200
Subject: [PATCH] qemu: Implement qemuDomainGetStatsCpu fallback for
 qemu:///session
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For domains started under session URI, we don't set up CGroups
(well, how could we since we're not running as root anyways).
Nevertheless, fetching CPU statistics exits early because of
lacking cpuacct controller. But with recent extension to
virProcessGetStatInfo() we can get the values we need from the
proc filesystem. Implement the fallback for the session URI as
some of virt tools rely on cpu.* stats to be reported (virt-top,
virt-manager).

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/353
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1693707
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
(cherry picked from commit 044b8744d65f8571038f85685b3c4b241162977b)
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2157094
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_driver.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 84cf2c6a4f..ac210d8069 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -18042,6 +18042,30 @@ qemuDomainGetStatsCpuCgroup(virDomainObj *dom,
     return 0;
 }
 
+
+static int
+qemuDomainGetStatsCpuProc(virDomainObj *vm,
+                          virTypedParamList *params)
+{
+    unsigned long long cpuTime = 0;
+    unsigned long long sysTime = 0;
+    unsigned long long userTime = 0;
+
+    if (virProcessGetStatInfo(&cpuTime, &sysTime, &userTime,
+                              NULL, NULL, vm->pid, 0) < 0) {
+        /* ignore error */
+        return 0;
+    }
+
+    if (virTypedParamListAddULLong(params, cpuTime, "cpu.time") < 0 ||
+        virTypedParamListAddULLong(params, userTime, "cpu.user") < 0 ||
+        virTypedParamListAddULLong(params, sysTime, "cpu.system") < 0)
+        return -1;
+
+    return 0;
+}
+
+
 static int
 qemuDomainGetStatsCpuHaltPollTime(virDomainObj *dom,
                                   virTypedParamList *params)
@@ -18066,8 +18090,15 @@ qemuDomainGetStatsCpu(virQEMUDriver *driver,
                       virTypedParamList *params,
                       unsigned int privflags G_GNUC_UNUSED)
 {
-    if (qemuDomainGetStatsCpuCgroup(dom, params) < 0)
-        return -1;
+    qemuDomainObjPrivate *priv = dom->privateData;
+
+    if (priv->cgroup) {
+        if (qemuDomainGetStatsCpuCgroup(dom, params) < 0)
+            return -1;
+    } else {
+        if (qemuDomainGetStatsCpuProc(dom, params) < 0)
+            return -1;
+    }
 
     if (qemuDomainGetStatsCpuCache(driver, dom, params) < 0)
         return -1;
-- 
2.39.0