>From 6010e24da995d4161cb879e98fda989e3cdb41c4 Mon Sep 17 00:00:00 2001 From: Xiaoming Gao <newtongao@xxxxxxxxxxx> Date: Thu, 19 Jun 2014 17:46:05 +0800 Subject: [PATCH] kvm: fix hyperv tsc page clear wrong address tsc page addr need clear the low HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT bits before kvm_write_guest write the zero tsc_ref structure to guest, or it will lead guest to get wrong clocksource. windows guest will get strong impact, QueryPerformanceCounter will always return 0 ,all things in windows rely on clock source will in serious chaos. Signed-off-by: Xiaoming Gao <newtongao@xxxxxxxxxxx> --- arch/x86/kvm/x86.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f32a025..ed716cf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1898,6 +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; + data &= ~((1 << HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT) - 1); if (kvm_write_guest(kvm, data, &tsc_ref, sizeof(tsc_ref))) return 1; -- 1.7.1
>From 6010e24da995d4161cb879e98fda989e3cdb41c4 Mon Sep 17 00:00:00 2001 From: Xiaoming Gao <newtongao@xxxxxxxxxxx> Date: Thu, 19 Jun 2014 17:46:05 +0800 Subject: [PATCH] kvm: fix hyperv tsc page clear wrong address tsc page addr need clear the low HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT bits before kvm_write_guest write the zero tsc_ref structure to guest, or it will lead guest to get wrong clocksource. windows guest will get strong impact, QueryPerformanceCounter will always return 0 ,all things in windows rely on clock source, will in serious chaos. Signed-off-by: Xiaoming Gao <newtongao@xxxxxxxxxxx> --- arch/x86/kvm/x86.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f32a025..ed716cf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1898,6 +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; + data &= ~((1 << HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT) - 1); if (kvm_write_guest(kvm, data, &tsc_ref, sizeof(tsc_ref))) return 1; -- 1.7.1
