From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
The KVM offset and multiplier are in the debugfs file system. If it is
not currently mounted, then try to mount it with the new tracefs API
tracefs_debug_dir() which will return the debugfs file system path, and
even mount it if possible (or NULL if it could not).
This also removes the hard coded path for /sys/kernel/debug/kvm and
removes the stat() of the directory as tracefs_debug_dir() will only
return mount locations which are directories.
Set libtracefs minimum version to 1.4 as that is what will have the
tarcefs_debug_dir() in it.
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
Makefile | 2 +-
lib/trace-cmd/trace-timesync-kvm.c | 47 ++++++++++++++++++++++--------
2 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/Makefile b/Makefile
index abc4ac723db4..3452649229df 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ export LIBTRACECMD_VERSION
VERSION_FILE = ltc_version.h
LIBTRACEEVENT_MIN_VERSION = 1.5
-LIBTRACEFS_MIN_VERSION = 1.3
+LIBTRACEFS_MIN_VERSION = 1.4
MAKEFLAGS += --no-print-directory
diff --git a/lib/trace-cmd/trace-timesync-kvm.c b/lib/trace-cmd/trace-timesync-kvm.c
index 671eafaf62b8..1db63d94f545 100644
--- a/lib/trace-cmd/trace-timesync-kvm.c
+++ b/lib/trace-cmd/trace-timesync-kvm.c
@@ -16,7 +16,6 @@
#include "tracefs.h"
#include "trace-tsync-local.h"
-#define KVM_DEBUG_FS "/sys/kernel/debug/kvm"
#define KVM_DEBUG_OFFSET_FILE "tsc-offset"
#define KVM_DEBUG_SCALING_FILE "tsc-scaling-ratio"
#define KVM_DEBUG_FRACTION_FILE "tsc-scaling-ratio-frac-bits"
@@ -106,6 +105,24 @@ static bool kvm_scaling_check_vm_cpu(char *vname, char *cpu)
return true;
}
+static const char *kvm_debug_dir(void)
+{
+ const char *debugfs;
+ static char *kvm_dir;
+
+ if (kvm_dir)
+ return kvm_dir;
+
+ debugfs = tracefs_debug_dir();
+ if (!debugfs)
+ return NULL;
+
+ if (asprintf(&kvm_dir, "%s/kvm", debugfs) < 0)
+ return NULL;
+
+ return kvm_dir;
+}
+
/*
* Returns true if a VCPU exists with a tsc-offset file and that
* the scaling files for ratio and fraction both exist or both
@@ -116,11 +133,16 @@ static bool kvm_scaling_check_vm_cpu(char *vname, char *cpu)
static bool kvm_scaling_check_vm(char *name)
{
struct dirent *entry;
+ const char *kvm;
char *vdir;
DIR *dir;
bool valid = false;
- if (asprintf(&vdir, "%s/%s", KVM_DEBUG_FS, name) < 0)
+ kvm = kvm_debug_dir();
+ if (!kvm)
+ return false;
+
+ if (asprintf(&vdir, "%s/%s", kvm, name) < 0)
return false;
dir = opendir(vdir);
@@ -150,10 +172,15 @@ static bool kvm_scaling_check_vm(char *name)
static bool kvm_scaling_check(void)
{
struct dirent *entry;
+ const char *kvm;
DIR *dir;
bool valid = false;
- dir = opendir(KVM_DEBUG_FS);
+ kvm = kvm_debug_dir();
+ if (!kvm)
+ return false;
+
+ dir = opendir(kvm);
if (!dir)
return true;
@@ -170,18 +197,14 @@ static bool kvm_scaling_check(void)
static bool kvm_support_check(bool guest)
{
- struct stat st;
- int ret;
+ const char *kvm;
/* The kvm files are only in the host so we can ignore guests */
if (guest)
return true;
- ret = stat(KVM_DEBUG_FS, &st);
- if (ret < 0)
- return false;
-
- if (!S_ISDIR(st.st_mode))
+ kvm = kvm_debug_dir();
+ if (!kvm)
return false;
return kvm_scaling_check();
@@ -242,7 +265,7 @@ static int kvm_open_debug_files(struct kvm_clock_sync *kvm, int pid)
DIR *dir;
int i;
- dir = opendir(KVM_DEBUG_FS);
+ dir = opendir(kvm_debug_dir());
if (!dir)
goto error;
if (asprintf(&pid_str, "%d-", pid) <= 0)
@@ -251,7 +274,7 @@ static int kvm_open_debug_files(struct kvm_clock_sync *kvm, int pid)
if (!(entry->d_type == DT_DIR &&
!strncmp(entry->d_name, pid_str, strlen(pid_str))))
continue;
- asprintf(&vm_dir_str, "%s/%s", KVM_DEBUG_FS, entry->d_name);
+ asprintf(&vm_dir_str, "%s/%s", kvm_debug_dir(), entry->d_name);
break;
}
closedir(dir);
--
2.35.1
|