Add perf_lots_of_nmi

Signed-off-by: Andy Lutomirski <luto@kernel.org>

2 files changed, 53 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index c31760f..d8a5f04 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 .PHONY: all clean
 
-SIMPLE_C_TARGETS := dump-vsyscall context_switch_latency kernel_pf user_visible_state null_seccomp highsys gsbase
+SIMPLE_C_TARGETS := dump-vsyscall context_switch_latency kernel_pf user_visible_state null_seccomp highsys gsbase perf_lots_of_nmi
 
 SIMPLE_CC_TARGETS := evil-clock-test
 
diff --git a/perf_lots_of_nmi.c b/perf_lots_of_nmi.c
new file mode 100644
index 0000000..c1a8119
--- /dev/null
+++ b/perf_lots_of_nmi.c
@@ -0,0 +1,52 @@
+#include <linux/perf_event.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <sys/user.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <err.h>
+
+int main(int argc, char **argv) {
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s CPU\n", argv[0]);
+		return 1;
+	}
+
+	int cpu = atoi(argv[1]);
+
+	struct perf_event_attr attr;
+	memset(&attr, 0, sizeof(attr));
+
+	attr.type = PERF_TYPE_HARDWARE;
+	attr.size = sizeof(struct perf_event_attr);
+	attr.freq = 1;
+	attr.sample_freq = 10000;
+	attr.config = PERF_COUNT_HW_CPU_CYCLES;
+
+	int fd = syscall(
+		SYS_perf_event_open,
+		&attr,			/* attributes */
+		-1,			/* monitor all tasks */
+		cpu,			/* selected CPU */
+		-1,			/* group leader */
+		PERF_FLAG_FD_CLOEXEC	/* flags */
+		);
+
+	if (fd == -1)
+		err(1, "perf_event_open");
+
+	pause();
+
+	/*
+	void *addr = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
+	if (addr == MAP_FAILED) {
+		err(1, "mmap");
+	}
+	*/
+
+	return 0;
+}