On 2014-03-07 19:19, Jan Kiszka wrote: > On 2014-03-07 18:28, Jan Kiszka wrote: >> On 2014-03-07 17:46, Paolo Bonzini wrote: >>> Il 07/03/2014 17:29, Jan Kiszka ha scritto: >>>> On 2014-03-07 16:44, Paolo Bonzini wrote: >>>>> With this patch do we still need >>>>> >>>>> if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu)) >>>>> /* >>>>> * We get here if vmx_interrupt_allowed() said we can't >>>>> * inject to L1 now because L2 must run. The caller will >>>>> have >>>>> * to make L2 exit right after entry, so we can inject to >>>>> L1 >>>>> * more promptly. >>>>> */ >>>>> return -EBUSY; >>>>> >>>>> in enable_irq_window? If not, enable_nmi_window and enable_irq_window >>>>> can both return void. >>>> >>>> I don't see right now why this should have changed. We still cannot >>>> interrupt vmlaunch/vmresume. >>> >>> But then shouldn't the ame be true for enable_nmi_window? It doesn't >>> check is_guest_mode(vcpu) && nested_exit_on_nmi(vcpu). >> >> Yes, that seems wrong now. But I need to think this through again, why >> we may have excluded NMIs from this test so far. >> >>> >>> Since check_nested_events has already returned -EBUSY, perhaps the >>> following: >>> >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>> index fda1028..df320e9 100644 >>> --- a/arch/x86/kvm/vmx.c >>> +++ b/arch/x86/kvm/vmx.c >>> @@ -4522,15 +4522,6 @@ static int enable_irq_window(struct kvm_vcpu *vcpu) >>> { >>> u32 cpu_based_vm_exec_control; >>> >>> - if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu)) >>> - /* >>> - * We get here if vmx_interrupt_allowed() said we can't >>> - * inject to L1 now because L2 must run. The caller will have >>> - * to make L2 exit right after entry, so we can inject to L1 >>> - * more promptly. >>> - */ >>> - return -EBUSY; >>> - >>> cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL); >>> cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_INTR_PENDING; >>> vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control); >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index a03d611..83c2df5 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -5970,13 +5970,13 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) >>> >>> inject_pending_event(vcpu); >>> >>> - if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events) >>> - req_immediate_exit |= >>> - kvm_x86_ops->check_nested_events(vcpu, >>> - req_int_win) != 0; >>> + if (is_guest_mode(vcpu) && >>> + kvm_x86_ops->check_nested_events && >>> + kvm_x86_ops->check_nested_events(vcpu, req_int_win) != 0) >>> + req_immediate_exit = true; >>> >>> /* enable NMI/IRQ window open exits if needed */ >>> - if (vcpu->arch.nmi_pending) >>> + else if (vcpu->arch.nmi_pending) >>> req_immediate_exit |= >>> kvm_x86_ops->enable_nmi_window(vcpu) != 0; >>> else if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win) >>> >> >> Hmm, looks reasonable. > > Also on second thought. I can give this hunk some test cycles here, just > in case. > > Reading through my code again, I'm now wondering why I added > check_nested_events to both inject_pending_event and vcpu_enter_guest. > The former seems redundant, only vcpu_enter_guest calls > inject_pending_event. I guess I forgot a cleanup here.
Nah, it's not redundant, we need to check for potential L2->L2 switches *before* trying deliver events to L2. But think I can (and probably should) get rid of the second test in vcpu_enter_guest. Jan > > I can fold in your changes when I resend for the other cleanup. > > Jan > -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html