[PATCH 1/5] KVM: selftests: Generalize check_clocksource() from kvm_clock_test

Vitaly Kuznetsov
2024-01-09T14:11:29Z

Several existing x86 selftests need to check that the underlying system
clocksource is TSC or based on TSC but every test implements its own
check. As a first step towards unification, extract check_clocksource()
from kvm_clock_test and split it into two functions: arch-neutral
'sys_get_cur_clocksource()' and x86-specific 'sys_clocksource_is_tsc()'.
Fix a couple of pre-existing issues in kvm_clock_test: memory leakage in
check_clocksource() and using TEST_ASSERT() instead of TEST_REQUIRE().
The change also makes the test fail when system clocksource can't be read
from sysfs.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
.../testing/selftests/kvm/include/test_util.h | 2 +
.../selftests/kvm/include/x86_64/processor.h | 2 +
tools/testing/selftests/kvm/lib/test_util.c | 25 ++++++++++++
.../selftests/kvm/lib/x86_64/processor.c | 13 +++++++
.../selftests/kvm/x86_64/kvm_clock_test.c | 38 +------------------
5 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index 71a41fa924b7..50a5e31ba8da 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -195,4 +195,6 @@ __printf(3, 4) int guest_snprintf(char *buf, int n, const char *fmt, ...);

char *strdup_printf(const char *fmt, ...) __attribute__((format(printf, 1, 2), nonnull(1)));

+char *sys_get_cur_clocksource(void);
+
#endif /* SELFTEST_KVM_TEST_UTIL_H */
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index a84863503fcb..01eec72e0d3e 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -1271,4 +1271,6 @@ void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
#define PFERR_GUEST_PAGE_MASK BIT_ULL(PFERR_GUEST_PAGE_BIT)
#define PFERR_IMPLICIT_ACCESS BIT_ULL(PFERR_IMPLICIT_ACCESS_BIT)

+bool sys_clocksource_is_tsc(void);
+
#endif /* SELFTEST_KVM_PROCESSOR_H */
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index 5d7f28b02d73..b8cb20cf61e9 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -392,3 +392,28 @@ char *strdup_printf(const char *fmt, ...)

return str;
}
+
+#define CLOCKSOURCE_PATH "/sys/devices/system/clocksource/clocksource0/current_clocksource"
+
+char *sys_get_cur_clocksource(void)
+{
+ char *clk_name;
+ struct stat st;
+ FILE *fp;
+
+ fp = fopen(CLOCKSOURCE_PATH, "r");
+ TEST_ASSERT(fp, "failed to open clocksource file, errno: %d", errno);
+
+ TEST_ASSERT(!fstat(fileno(fp), &st), "failed to stat clocksource file, errno: %d",
+ errno);
+
+ clk_name = malloc(st.st_size);
+ TEST_ASSERT(clk_name, "failed to allocate buffer to read file\n");
+
+ TEST_ASSERT(fgets(clk_name, st.st_size, fp), "failed to read clocksource file: %d",
+ ferror(fp));
+
+ fclose(fp);
+
+ return clk_name;
+}
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index d8288374078e..b0c64667803d 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1299,3 +1299,16 @@ void kvm_selftest_arch_init(void)
host_cpu_is_intel = this_cpu_is_intel();
host_cpu_is_amd = this_cpu_is_amd();
}
+
+bool sys_clocksource_is_tsc(void)
+{
+ char *clk_name = sys_get_cur_clocksource();
+ bool ret = false;
+
+ if (!strcmp(clk_name, "tsc\n"))
+ ret = true;
+
+ free(clk_name);
+
+ return ret;
+}
diff --git a/tools/testing/selftests/kvm/x86_64/kvm_clock_test.c b/tools/testing/selftests/kvm/x86_64/kvm_clock_test.c
index 1778704360a6..9deee8556b5c 100644
--- a/tools/testing/selftests/kvm/x86_64/kvm_clock_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvm_clock_test.c
@@ -132,42 +132,6 @@ static void enter_guest(struct kvm_vcpu *vcpu)
}
}

-#define CLOCKSOURCE_PATH "/sys/devices/system/clocksource/clocksource0/current_clocksource"
-
-static void check_clocksource(void)
-{
- char *clk_name;
- struct stat st;
- FILE *fp;
-
- fp = fopen(CLOCKSOURCE_PATH, "r");
- if (!fp) {
- pr_info("failed to open clocksource file: %d; assuming TSC.\n",
- errno);
- return;
- }
-
- if (fstat(fileno(fp), &st)) {
- pr_info("failed to stat clocksource file: %d; assuming TSC.\n",
- errno);
- goto out;
- }
-
- clk_name = malloc(st.st_size);
- TEST_ASSERT(clk_name, "failed to allocate buffer to read file\n");
-
- if (!fgets(clk_name, st.st_size, fp)) {
- pr_info("failed to read clocksource file: %d; assuming TSC.\n",
- ferror(fp));
- goto out;
- }
-
- TEST_ASSERT(!strncmp(clk_name, "tsc\n", st.st_size),
- "clocksource not supported: %s", clk_name);
-out:
- fclose(fp);
-}
-
int main(void)
{
struct kvm_vcpu *vcpu;
@@ -179,7 +143,7 @@ int main(void)
flags = kvm_check_cap(KVM_CAP_ADJUST_CLOCK);
TEST_REQUIRE(flags & KVM_CLOCK_REALTIME);

- check_clocksource();
+ TEST_REQUIRE(sys_clocksource_is_tsc());

vm = vm_create_with_one_vcpu(&vcpu, guest_main);

--
2.43.0