diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 961804df5f45..b340dc9991ad 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -160,6 +160,16 @@ void nested_vmcb02_recalc_intercepts(struct vcpu_svm *svm) if (!intercept_smi) vmcb_clr_intercept(&vmcb02->control, INTERCEPT_SMI); + /* + * Intercept PAUSE if and only if L1 wants to. KVM intercepts PAUSE so + * that a vCPU that may be spinning waiting for a lock can be scheduled + * out in favor of the vCPU that holds said lock. KVM doesn't support + * yielding across L2 vCPUs, as KVM has limited visilibity into which + * L2 vCPUs are in the same L2 VM, i.e. may be contending for locks. + */ + if (!vmcb12_is_intercept(&svm->nested.ctl, INTERCEPT_PAUSE)) + vmcb_clr_intercept(&vmcb02->control, INTERCEPT_PAUSE); + if (nested_vmcb_needs_vls_intercept(svm)) { /* * If the virtual VMLOAD/VMSAVE is not enabled for the L2, @@ -819,7 +829,6 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) struct vmcb *vmcb02 = svm->nested.vmcb02.ptr; struct vmcb *vmcb01 = svm->vmcb01.ptr; struct kvm_vcpu *vcpu = &svm->vcpu; - u32 pause_count12, pause_thresh12; nested_svm_transition_tlb_flush(vcpu); @@ -947,31 +956,13 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) vmcb02->control.misc_ctl2 |= SVM_MISC2_ENABLE_V_VMLOAD_VMSAVE; if (guest_cpu_cap_has(vcpu, X86_FEATURE_PAUSEFILTER)) - pause_count12 = vmcb12_ctrl->pause_filter_count; + vmcb02->control.pause_filter_count = vmcb12_ctrl->pause_filter_count; else - pause_count12 = 0; + vmcb02->control.pause_filter_count = 0; if (guest_cpu_cap_has(vcpu, X86_FEATURE_PFTHRESHOLD)) - pause_thresh12 = vmcb12_ctrl->pause_filter_thresh; + vmcb02->control.pause_filter_thresh = vmcb12_ctrl->pause_filter_thresh; else - pause_thresh12 = 0; - if (kvm_pause_in_guest(svm->vcpu.kvm)) { - /* use guest values since host doesn't intercept PAUSE */ - vmcb02->control.pause_filter_count = pause_count12; - vmcb02->control.pause_filter_thresh = pause_thresh12; - - } else { - /* start from host values otherwise */ - vmcb02->control.pause_filter_count = vmcb01->control.pause_filter_count; - vmcb02->control.pause_filter_thresh = vmcb01->control.pause_filter_thresh; - - /* ... but ensure filtering is disabled if so requested. */ - if (vmcb12_is_intercept(vmcb12_ctrl, INTERCEPT_PAUSE)) { - if (!pause_count12) - vmcb02->control.pause_filter_count = 0; - if (!pause_thresh12) - vmcb02->control.pause_filter_thresh = 0; - } - } + vmcb02->control.pause_filter_thresh = 0; /* * Take ALLOW_LARGER_RAP from vmcb12 even though it should be safe to @@ -1298,12 +1289,6 @@ void nested_svm_vmexit(struct vcpu_svm *svm) /* in case we halted in L2 */ kvm_set_mp_state(vcpu, KVM_MP_STATE_RUNNABLE); - if (!kvm_pause_in_guest(vcpu->kvm)) { - vmcb01->control.pause_filter_count = vmcb02->control.pause_filter_count; - vmcb_mark_dirty(vmcb01, VMCB_INTERCEPTS); - - } - /* * Invalidate last_bus_lock_rip unless KVM is still waiting for the * guest to make forward progress before re-enabling bus lock detection. diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e7fdd7a9c280..e02a38da5296 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -913,7 +913,15 @@ static void grow_ple_window(struct kvm_vcpu *vcpu) struct vmcb_control_area *control = &svm->vmcb->control; int old = control->pause_filter_count; - if (kvm_pause_in_guest(vcpu->kvm)) + /* Adjusting pause_filter_count makes no sense if PLE is disabled. */ + WARN_ON_ONCE(kvm_pause_in_guest(vcpu->kvm)); + + /* + * While running L2, KVM should intercept PAUSE if and only if L1 wants + * to intercept PAUSE, and L1's intercept should take priority, i.e. + * KVM should never handle a PAUSE intercept from L2. + */ + if (WARN_ON_ONCE(is_guest_mode(vcpu))) return; control->pause_filter_count = __grow_ple_window(old, @@ -934,7 +942,10 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu) struct vmcb_control_area *control = &svm->vmcb->control; int old = control->pause_filter_count; - if (kvm_pause_in_guest(vcpu->kvm)) + /* Adjusting pause_filter_count makes no sense if PLE is disabled. */ + WARN_ON_ONCE(kvm_pause_in_guest(vcpu->kvm)); + + if (is_guest_mode(vcpu)) return; control->pause_filter_count =