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.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
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