From e1fa108d24697b78348fd4e5a531029a50d0d36d Mon Sep 17 00:00:00 2001 From: Xiaoming Gao Date: Thu, 19 Jun 2014 19:14:57 +0800 Subject: [PATCH] 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 Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f32a02578c0d..f6449334ec45 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1898,7 +1898,7 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data) 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); -- 2.20.1