From: Yang Fei <yangfei85@huawei.com>
Date: Thu, 22 Jul 2021 08:05:01 +0000 (+0800)
Subject: util: Add virHostCPUGetHaltPollTime
X-Git-Tag: v7.6.0-rc1~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a90b1f24cf0650449cdc0649302d4e8ad99502fc;p=thirdparty%2Flibvirt.git

util: Add virHostCPUGetHaltPollTime

Add helper function virHostCPUGetHaltPollTime to obtain halt polling
time. If the kernel support halt polling time statistic, and mount
debugfs. This function will take effect on KVM VMs.

Signed-off-by: Yang Fei <yangfei85@huawei.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
---

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 5c7f6bf809..43493ea76e 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2376,6 +2376,7 @@ virHookPresent;
 # util/virhostcpu.h
 virHostCPUGetAvailableCPUsBitmap;
 virHostCPUGetCount;
+virHostCPUGetHaltPollTime;
 virHostCPUGetInfo;
 virHostCPUGetKVMMaxVCPUs;
 virHostCPUGetMap;
diff --git a/src/util/virhostcpu.c b/src/util/virhostcpu.c
index bf7fda23af..7aa92ad11d 100644
--- a/src/util/virhostcpu.c
+++ b/src/util/virhostcpu.c
@@ -1535,3 +1535,42 @@ virHostCPUGetSignature(char **signature)
 }
 
 #endif /* __linux__ */
+
+int
+virHostCPUGetHaltPollTime(pid_t pid,
+                      unsigned long long *haltPollSuccess,
+                      unsigned long long *haltPollFail)
+{
+    g_autofree char *pidToStr = NULL;
+    g_autofree char *debugFsPath = NULL;
+    g_autofree char *kvmPath = NULL;
+    struct dirent *ent = NULL;
+    g_autoptr(DIR) dir = NULL;
+    bool found = false;
+
+    if (!(debugFsPath = virFileFindMountPoint("debugfs")))
+        return -1;
+
+    kvmPath = g_strdup_printf("%s/%s", debugFsPath, "kvm");
+    if (virDirOpenQuiet(&dir, kvmPath) != 1)
+        return -1;
+
+    pidToStr = g_strdup_printf("%lld-", (long long)pid);
+    while (virDirRead(dir, &ent, NULL) > 0) {
+        if (STRPREFIX(ent->d_name, pidToStr)) {
+            found = true;
+            break;
+        }
+    }
+
+    if (!found)
+        return -1;
+
+    if (virFileReadValueUllongQuiet(haltPollSuccess, "%s/%s/%s", kvmPath,
+                                    ent->d_name, "halt_poll_success_ns") < 0 ||
+        virFileReadValueUllongQuiet(haltPollFail, "%s/%s/%s", kvmPath,
+                                    ent->d_name, "halt_poll_fail_ns") < 0)
+        return -1;
+
+    return 0;
+}
diff --git a/src/util/virhostcpu.h b/src/util/virhostcpu.h
index fc717250d9..d98385d53f 100644
--- a/src/util/virhostcpu.h
+++ b/src/util/virhostcpu.h
@@ -83,3 +83,7 @@ int virHostCPUGetMSR(unsigned long index,
 virHostCPUTscInfo *virHostCPUGetTscInfo(void);
 
 int virHostCPUGetSignature(char **signature);
+
+int virHostCPUGetHaltPollTime(pid_t pid,
+                              unsigned long long *haltPollSuccess,
+                              unsigned long long *haltPollFail);