From 359a6c3ddc5184122989d5152a4b975c1c262d33 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 29 Jan 2019 19:14:46 +0100 Subject: [PATCH] KVM: nVMX: do not start the preemption timer hrtimer unnecessarily The preemption timer can be started even if there is a vmentry failure during or after loading guest state. That is pointless, move the call after all conditions have been checked. Signed-off-by: Paolo Bonzini --- 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 523d30e935e1..11431bb4c7ed 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2278,10 +2278,6 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, } vmx_set_rflags(vcpu, vmcs12->guest_rflags); - vmx->nested.preemption_timer_expired = false; - if (nested_cpu_has_preemption_timer(vmcs12)) - vmx_start_preemption_timer(vcpu); - /* EXCEPTION_BITMAP and CR0_GUEST_HOST_MASK should basically be the * bitwise-or of what L1 wants to trap for L2, and what we want to * trap. Note that CR0.TS also needs updating - we do this later. @@ -3018,6 +3014,15 @@ int nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, bool from_vmentry) if (unlikely(evaluate_pending_interrupts)) kvm_make_request(KVM_REQ_EVENT, vcpu); + /* + * Do not start the preemption timer hrtimer until after we know + * we are successful, so that only nested_vmx_vmexit needs to cancel + * the timer. + */ + vmx->nested.preemption_timer_expired = false; + if (nested_cpu_has_preemption_timer(vmcs12)) + vmx_start_preemption_timer(vcpu); + /* * Note no nested_vmx_succeed or nested_vmx_fail here. At this point * we are no longer running L1, and VMLAUNCH/VMRESUME has not yet