[PATCH kvm-unit-test 6/6] Add a test for kvm-clock

Jason Wang
2010-08-27T05:49:58Z

This patch implements two tests for kvmclock. First one check whether
the date of time returned by kvmclock matches the value got from
host. Second one check whether the cycle of kvmclock grows
monotonically in smp guest.

Three parameters were accepted by the test: test loops, seconds
since 1970-01-01 00:00:00 UTC which could be easily get through date
+%s and the max accepted offset value between the tod of guest and
host.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
config-x86-common.mak | 6 ++
x86/README | 2 +
x86/kvmclock_test.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++
x86/unittests.cfg | 5 ++
4 files changed, 157 insertions(+), 1 deletions(-)
create mode 100644 x86/kvmclock_test.c

diff --git a/config-x86-common.mak b/config-x86-common.mak
index b8ca859..b541c1c 100644
--- a/config-x86-common.mak
+++ b/config-x86-common.mak
@@ -26,7 +26,8 @@ FLATLIBS = lib/libcflat.a $(libgcc)
tests-common = $(TEST_DIR)/vmexit.flat $(TEST_DIR)/tsc.flat \
$(TEST_DIR)/smptest.flat $(TEST_DIR)/port80.flat \
$(TEST_DIR)/realmode.flat $(TEST_DIR)/msr.flat \
- $(TEST_DIR)/hypercall.flat $(TEST_DIR)/sieve.flat
+ $(TEST_DIR)/hypercall.flat $(TEST_DIR)/sieve.flat \
+ $(TEST_DIR)/kvmclock_test.flat

tests_and_config = $(TEST_DIR)/*.flat $(TEST_DIR)/unittests.cfg

@@ -70,6 +71,9 @@ $(TEST_DIR)/rmap_chain.flat: $(cstart.o) $(TEST_DIR)/rmap_chain.o \

$(TEST_DIR)/svm.flat: $(cstart.o) $(TEST_DIR)/vm.o

+$(TEST_DIR)/kvmclock_test.flat: $(cstart.o) $(TEST_DIR)/kvmclock.o \
+ $(TEST_DIR)/kvmclock_test.o
+
arch_clean:
$(RM) $(TEST_DIR)/*.o $(TEST_DIR)/*.flat \
$(TEST_DIR)/.*.d $(TEST_DIR)/lib/.*.d $(TEST_DIR)/lib/*.o
diff --git a/x86/README b/x86/README
index ab5a2ae..4b90080 100644
--- a/x86/README
+++ b/x86/README
@@ -12,3 +12,5 @@ sieve: heavy memory access with no paging and with paging static and with paging
smptest: run smp_id() on every cpu and compares return value to number
tsc: write to tsc(0) and write to tsc(100000000000) and read it back
vmexit: long loops for each: cpuid, vmcall, mov_from_cr8, mov_to_cr8, inl_pmtimer, ipi, ipi+halt
+kvmclock_test: monotonic cycle test of kvmclock and a sanity test of
+wallclock
diff --git a/x86/kvmclock_test.c b/x86/kvmclock_test.c
new file mode 100644
index 0000000..cd80915
--- /dev/null
+++ b/x86/kvmclock_test.c
@@ -0,0 +1,145 @@
+#include "libcflat.h"
+#include "smp.h"
+#include "atomic.h"
+#include "string.h"
+#include "kvmclock.h"
+
+#define DEFAULT_TEST_LOOPS 100000000L
+#define DEFAULT_THRESHOLD 60L
+
+struct test_info {
+ struct spinlock lock;
+ long loops; /* test loops */
+ u64 warps; /* warp count */
+ long long worst; /* worst warp */
+ volatile cycle_t last; /* last cycle seen by test */
+ atomic_t ncpus; /* number of cpu in the test*/
+};
+
+struct test_info ti[2];
+
+static int wallclock_test(long sec, long threshold)
+{
+ int i;
+ long ksec, offset;
+ struct timespec ts, ts_last;
+
+ printf("Wallclock test, threshold %ld\n", threshold);
+ kvm_get_wallclock(&ts_last);
+ ksec = ts_last.sec + ts_last.nsec / NSEC_PER_SEC;
+
+ offset = ksec - sec;
+ printf("Seconds get from host: %ld\n", sec);
+ printf("Seconds get from kvmclock: %ld\n", ksec);
+
+ if (offset > threshold || offset < -threshold) {
+ printf("Seconds get from kvmclock: %ld\n", ksec);
+ return 1;
+ }
+
+ for (i=0; i < 100; i++){
+ kvm_get_wallclock(&ts);
+ if (ts.nsec != ts_last.nsec || ts.sec != ts_last.sec){
+ printf ("Inconsistent wall clock returned!\n");
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static void kvm_clock_test(void *data)
+{
+ struct test_info *hv_test_info = (struct test_info *)data;
+ int i;
+
+ for (i = 0; i < hv_test_info->loops; i++){
+ cycle_t t0, t1;
+ long long delta;
+
+ spin_lock(&hv_test_info->lock);
+ t1 = kvm_clock_read();
+ t0 = hv_test_info->last;
+ hv_test_info->last = kvm_clock_read();
+ spin_unlock(&hv_test_info->lock);
+
+ delta = t1 - t0;
+ if (delta < 0){
+ spin_lock(&hv_test_info->lock);
+ ++hv_test_info->warps;
+ if (delta < hv_test_info->worst){
+ hv_test_info->worst = delta;
+ printf("Worst warp %lld %\n", hv_test_info->worst);
+ }
+ spin_unlock(&hv_test_info->lock);
+ }
+
+ if (!((unsigned long)i & 31))
+ asm volatile("rep; nop");
+ }
+
+ atomic_dec(&hv_test_info->ncpus);
+}
+
+static int cycle_test(int ncpus, long loops, struct test_info *ti)
+{
+ int i;
+
+ atomic_set(&ti->ncpus, ncpus);
+ ti->loops = loops;
+ for (i = ncpus - 1; i >= 0; i--)
+ on_cpu_async(i, kvm_clock_test, (void *)ti);
+
+ /* Wait for the end of other vcpu */
+ while(atomic_read(&ti->ncpus))
+ ;
+
+ printf("Total vcpus: %d\n", ncpus);
+ printf("Test loops: %ld\n", ti->loops);
+ printf("Total warps: %lld\n", ti->warps);
+ printf("Worst warp: %lld\n", ti->worst);
+
+ return ti->warps ? 1 : 0;
+}
+
+int main(int ac, char **av)
+{
+ int ncpus = cpu_count();
+ int nerr = 0, i;
+ long loops = DEFAULT_TEST_LOOPS;
+ long sec = 0;
+ long threshold = DEFAULT_THRESHOLD;
+
+ if (ac > 1)
+ loops = atol(av[1]);
+ if (ac > 2)
+ sec = atol(av[2]);
+ if (ac > 3)
+ threshold = atol(av[3]);
+
+ smp_init();
+
+ if (ncpus > MAX_CPU)
+ ncpus = MAX_CPU;
+ for (i = 0; i < ncpus; ++i)
+ on_cpu(i, kvm_clock_init, (void *)0);
+
+ if (ac > 2)
+ nerr += wallclock_test(sec, threshold);
+
+ printf("Check the stability of raw cycle\n");
+ pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT
+ | PVCLOCK_RAW_CYCLE_BIT);
+ if (cycle_test(ncpus, loops, &ti[1]))
+ printf("Raw cycle is not stable\n");
+ else
+ printf("Raw cycle is stable\n");
+
+ pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
+ printf("Monotonic cycle test:\n");
+ nerr += cycle_test(ncpus, loops, &ti[0]);
+
+ for (i = 0; i < ncpus; ++i)
+ on_cpu(i, kvm_clock_clear, (void *)0);
+
+ return nerr > 0 ? 1 : 0;
+}
diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index 7796e41..a3290cd 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -63,3 +63,8 @@ extra_params = -enable-nesting -cpu qemu64,+svm
file = svm.flat
smp = 2
extra_params = -cpu qemu64,-svm
+
+[kvmclock_test]
+file = kvmclock_test.flat
+smp = 2
+extra_params = --append "10000000 `date +%s`"
\ No newline at end of file