kvm: fix wrong address when writing Hyper-V tsc page
When kvm_write_guest writes the tsc_ref structure to the guest, or it will lead
the low HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT bits of the TSC page address
must be cleared, or the guest can see a non-zero sequence number.
Otherwise Windows guests would not be able to get a correct clocksource
(QueryPerformanceCounter will always return 0) which causes serious chaos.
Signed-off-by: Xiaoming Gao <newtongao@tencnet.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f32a025..f644933 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1898,7 +1898,7 @@
if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE))
break;
gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
- if (kvm_write_guest(kvm, data,
+ if (kvm_write_guest(kvm, gfn << HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT,
&tsc_ref, sizeof(tsc_ref)))
return 1;
mark_page_dirty(kvm, gfn);