KVM: nVMX: Enable nested TSC scaling

Calculate the TSC offset and multiplier on nested transitions and expose
the TSC scaling feature to L1.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210526184418.28881-11-ilstam@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 239154d3e4e75511159cffe24552188430fd8691..e8183e2247065b17151ce96ef4eba88910b6e9a2 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2277,7 +2277,8 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
                                  SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE |
                                  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
                                  SECONDARY_EXEC_APIC_REGISTER_VIRT |
-                                 SECONDARY_EXEC_ENABLE_VMFUNC);
+                                 SECONDARY_EXEC_ENABLE_VMFUNC |
+                                 SECONDARY_EXEC_TSC_SCALING);
                if (nested_cpu_has(vmcs12,
                                   CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
                        exec_control |= vmcs12->secondary_vm_exec_control;
@@ -2532,6 +2533,15 @@ 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 +3363,6 @@ 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 +4470,11 @@ 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);
@@ -6473,7 +6484,8 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps)
                SECONDARY_EXEC_RDRAND_EXITING |
                SECONDARY_EXEC_ENABLE_INVPCID |
                SECONDARY_EXEC_RDSEED_EXITING |
-               SECONDARY_EXEC_XSAVES;
+               SECONDARY_EXEC_XSAVES |
+               SECONDARY_EXEC_TSC_SCALING;
 
        /*
         * We can emulate "VMCS shadowing," even if the hardware