diff options
| author |   Vitaly Kuznetsov <vkuznets@redhat.com> | 2021-03-26 16:55:51 +0100 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2021-04-01 05:14:19 -0400 |
| commit | 55626ca9c6909d077eca71bccbe15fef6e5ad917 (patch) | |
| tree | b52364355ce6812cb99333e47f47d4411710b6c2 /tools | |
| parent | KVM: x86: Prevent 'hv_clock->system_time' from going negative in kvm_guest_time_update() (diff) | |
| download | linux-dev-55626ca9c6909d077eca71bccbe15fef6e5ad917.tar.xz linux-dev-55626ca9c6909d077eca71bccbe15fef6e5ad917.zip | |
selftests: kvm: Check that TSC page value is small after KVM_SET_CLOCK(0)
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@redhat.com>
Message-Id: <20210326155551.17446-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/kvm/x86_64/hyperv_clock.c | 13 |
1 files 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(); |