[PATCH v3 10/12] KVM: VMX: Set the TSC offset and multiplier on nested entry and exit

[Ilias Stamatis]

Calculate the nested TSC offset and multiplier on entering L2 using the
corresponding functions. Restore the L1 values on L2's exit.

Signed-off-by: Ilias Stamatis <ilstam@xxxxxxxxxx>
---
 arch/x86/kvm/vmx/nested.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 239154d3e4e7..f75c4174cbcf 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2532,6 +2532,15 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 		vmcs_write64(GUEST_IA32_PAT, vmx->vcpu.arch.pat);
 	}
 
+	vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset(
+			vcpu->arch.l1_tsc_offset,
+			vmx_get_l2_tsc_offset(vcpu),
+			vmx_get_l2_tsc_multiplier(vcpu));
+
+	vcpu->arch.tsc_scaling_ratio = kvm_calc_nested_tsc_multiplier(
+			vcpu->arch.l1_tsc_scaling_ratio,
+			vmx_get_l2_tsc_multiplier(vcpu));
+
 	vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset);
 	if (kvm_has_tsc_control)
 		vmcs_write64(TSC_MULTIPLIER, vcpu->arch.tsc_scaling_ratio);
@@ -3353,8 +3362,6 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 	}
 
 	enter_guest_mode(vcpu);
-	if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETTING)
-		vcpu->arch.tsc_offset += vmcs12->tsc_offset;
 
 	if (prepare_vmcs02(vcpu, vmcs12, &entry_failure_code)) {
 		exit_reason.basic = EXIT_REASON_INVALID_STATE;
@@ -4462,8 +4469,11 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 vm_exit_reason,
 	if (nested_cpu_has_preemption_timer(vmcs12))
 		hrtimer_cancel(&to_vmx(vcpu)->nested.preemption_timer);
 
-	if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETTING)
-		vcpu->arch.tsc_offset -= vmcs12->tsc_offset;
+	if (nested_cpu_has(vmcs12, CPU_BASED_USE_TSC_OFFSETTING)) {
+		vcpu->arch.tsc_offset = vcpu->arch.l1_tsc_offset;
+		if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_TSC_SCALING))
+			vcpu->arch.tsc_scaling_ratio = vcpu->arch.l1_tsc_scaling_ratio;
+	}
 
 	if (likely(!vmx->fail)) {
 		sync_vmcs02_to_vmcs12(vcpu, vmcs12);
-- 
2.17.1