linux-kernel - [PATCH v2 08/10] KVM: VMX: Set the TSC offset and multiplier on nested entry and exit

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Message-ID: <20210512150945.4591-9-ilstam@amazon.com>
Date:   Wed, 12 May 2021 16:09:43 +0100
From:   Ilias Stamatis <ilstam@...zon.com>
To:     <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <pbonzini@...hat.com>
CC:     <mlevitsk@...hat.com>, <seanjc@...gle.com>, <vkuznets@...hat.com>,
        <wanpengli@...cent.com>, <jmattson@...gle.com>, <joro@...tes.org>,
        <zamsden@...il.com>, <mtosatti@...hat.com>, <dwmw@...zon.co.uk>,
        <ilstam@...zon.com>
Subject: [PATCH v2 08/10] KVM: VMX: Set the TSC offset and multiplier on nested entry and exit

Now that nested TSC scaling is supported we need to calculate the
correct 02 values for both the offset and the multiplier using the
corresponding functions. On L2's exit the L1 values are restored.

Signed-off-by: Ilias Stamatis <ilstam@...zon.com>
---
 arch/x86/kvm/vmx/nested.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 6058a65a6ede..f1dff1ebaccb 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3354,8 +3354,9 @@ 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;
+
+	kvm_set_02_tsc_offset(vcpu);
+	kvm_set_02_tsc_multiplier(vcpu);
 
 	if (prepare_vmcs02(vcpu, vmcs12, &entry_failure_code)) {
 		exit_reason.basic = EXIT_REASON_INVALID_STATE;
@@ -4463,8 +4464,12 @@ 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 (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETTING) {
+		vcpu->arch.tsc_offset = vcpu->arch.l1_tsc_offset;
+
+		if (vmcs12->secondary_vm_exec_control & 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