Add a test for the issue when KVM_SET_CLOCK(0) call could cause
TSC page value to go very big because of a signedness issue around
hv_clock->system_time.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
tools/testing/selftests/kvm/x86_64/hyperv_clock.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_clock.c b/tools/testing/selftests/kvm/x86_64/hyperv_clock.c
index ffbc4555c6e2..7f1d2765572c 100644
--- a/tools/testing/selftests/kvm/x86_64/hyperv_clock.c
+++ b/tools/testing/selftests/kvm/x86_64/hyperv_clock.c
@@ -80,19 +80,24 @@ static inline void check_tsc_msr_rdtsc(void)
GUEST_ASSERT(delta_ns * 100 < (t2 - t1) * 100);
}
+static inline u64 get_tscpage_ts(struct ms_hyperv_tsc_page *tsc_page)
+{
+ return mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset;
+}
+
static inline void check_tsc_msr_tsc_page(struct ms_hyperv_tsc_page *tsc_page)
{
u64 r1, r2, t1, t2;
/* Compare TSC page clocksource with HV_X64_MSR_TIME_REF_COUNT */
- t1 = mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset;
+ t1 = get_tscpage_ts(tsc_page);
r1 = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
/* 10 ms tolerance */
GUEST_ASSERT(r1 >= t1 && r1 - t1 < 100000);
nop_loop();
- t2 = mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset;
+ t2 = get_tscpage_ts(tsc_page);
r2 = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
GUEST_ASSERT(r2 >= t1 && r2 - t2 < 100000);
}
@@ -130,7 +135,11 @@ static void guest_main(struct ms_hyperv_tsc_page *tsc_page, vm_paddr_t tsc_page_
tsc_offset = tsc_page->tsc_offset;
/* Call KVM_SET_CLOCK from userspace, check that TSC page was updated */
+
GUEST_SYNC(7);
+ /* Sanity check TSC page timestamp, it should be close to 0 */
+ GUEST_ASSERT(get_tscpage_ts(tsc_page) < 100000);
+
GUEST_ASSERT(tsc_page->tsc_offset != tsc_offset);
nop_loop();
--
2.30.2
