[PATCH 1/3] perf, core: Introduce attrs to count in either host or guest mode

[Joerg Roedel]

The two new attributes exclude_guest and exclude_host can
bes used by user-space to tell the kernel to setup
performance counter to either only count while the CPU is in
guest or in host mode.
An additional check is also introduced to make sure
user-space does not try to exclude guest and host mode from
counting.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 include/linux/perf_event.h |    5 ++++-
 kernel/perf_event.c        |    4 ++++
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index ee9f1e7..3823f34 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -217,7 +217,10 @@ struct perf_event_attr {
 				mmap_data      :  1, /* non-exec mmap data    */
 				sample_id_all  :  1, /* sample_type all events */
 
-				__reserved_1   : 45;
+				exclude_host   :  1, /* don't count in host   */
+				exclude_guest  :  1, /* don't count in guest  */
+
+				__reserved_1   : 43;
 
 	union {
 		__u32		wakeup_events;	  /* wakeup every n events */
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 8e81a98..1a9159b 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -6452,6 +6452,10 @@ SYSCALL_DEFINE5(perf_event_open,
 			return -EINVAL;
 	}
 
+	/* Can't exclude counting in guest and in host mode */
+	if (attr.exclude_host && attr.exclude_guest)
+		return -EINVAL;
+
 	/*
 	 * In cgroup mode, the pid argument is used to pass the fd
 	 * opened to the cgroup directory in cgroupfs. The cpu argument
-- 
1.7.4.1


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