Because the vmcs12 preemption timer is emulated through a separate hrtimer, we can keep on using the preemption timer in the vmcs02 to emulare L1's TSC deadline timer.
However, the corresponding bit in the pin-based execution control field must be kept consistent between vmcs01 and vmcs02. On vmentry we copy it into the vmcs02; on vmexit the preemption timer must be disabled in the vmcs01 if a preemption timer vmexit happened while in guest mode. The preemption timer value in the vmcs02 is set by vmx_vcpu_run, so it need not be considered in prepare_vmcs02. Signed-off-by: Paolo Bonzini <[email protected]> --- arch/x86/kvm/vmx.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 0048be79c7b9..8cda4449a60e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -9796,9 +9796,14 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) vmcs_write64(VMCS_LINK_POINTER, -1ull); exec_control = vmcs12->pin_based_vm_exec_control; - exec_control |= vmcs_config.pin_based_exec_ctrl; + + /* Preemption timer setting is only taken from vmcs01. */ exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER; + exec_control |= vmcs_config.pin_based_exec_ctrl; + if (vmx->hv_deadline_tsc == -1) + exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER; + /* Posted interrupts setting is only taken from vmcs12. */ if (nested_cpu_has_posted_intr(vmcs12)) { /* * Note that we use L0's vector here and in @@ -10727,8 +10732,14 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, load_vmcs12_host_state(vcpu, vmcs12); - /* Update TSC_OFFSET if TSC was changed while L2 ran */ + /* Update any VMCS fields that might have changed while L2 ran */ vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_tsc_offset); + if (vmx->hv_deadline_tsc == -1) + vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL, + PIN_BASED_VMX_PREEMPTION_TIMER); + else + vmcs_set_bits(PIN_BASED_VM_EXEC_CONTROL, + PIN_BASED_VMX_PREEMPTION_TIMER); /* This is needed for same reason as it was needed in prepare_vmcs02 */ vmx->host_rsp = 0; -- 1.8.3.1
