Marcelo Tosatti <mtosa...@redhat.com> writes:

> On Mon, Mar 31, 2014 at 05:00:24PM -0400, Bandan Das wrote:
>> This feature emulates the "Acknowledge interrupt on exit" behavior.
>> We can safely emulate it for L1 to run L2 even if L0 itself has it
>> disabled (to run L1).
>> 
>> Signed-off-by: Bandan Das <b...@redhat.com>
>> ---
>>  arch/x86/kvm/irq.c |  1 +
>>  arch/x86/kvm/vmx.c | 19 +++++++++++++++++++
>>  2 files changed, 20 insertions(+)
>> 
>> diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
>> index 484bc87..bd0da43 100644
>> --- a/arch/x86/kvm/irq.c
>> +++ b/arch/x86/kvm/irq.c
>> @@ -113,6 +113,7 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
>>  
>>      return kvm_get_apic_interrupt(v);       /* APIC */
>>  }
>> +EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
>>  
>>  void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
>>  {
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 3e7f60c..bdc8f2d 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -4489,6 +4489,18 @@ static bool nested_exit_on_intr(struct kvm_vcpu *vcpu)
>>              PIN_BASED_EXT_INTR_MASK;
>>  }
>>  
>> +/*
>> + * In nested virtualization, check if L1 has enabled
>> + * interrupt acknowledgement that writes the interrupt vector
>> + * info on vmexit
>> + * 
>> + */
>> +static bool nested_exit_intr_ack_set(struct kvm_vcpu *vcpu)
>> +{
>> +    return get_vmcs12(vcpu)->vm_exit_controls &
>> +            VM_EXIT_ACK_INTR_ON_EXIT;
>> +}
>> +
>>  static bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
>>  {
>>      return get_vmcs12(vcpu)->pin_based_vm_exec_control &
>> @@ -8442,6 +8454,13 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, 
>> u32 exit_reason,
>>      prepare_vmcs12(vcpu, vmcs12, exit_reason, exit_intr_info,
>>                     exit_qualification);
>>  
>> +    if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
>> +        && nested_exit_intr_ack_set(vcpu)) {
>> +            int irq = kvm_cpu_get_interrupt(vcpu);
>
> Can irq be -1 ?

If it is, I think that's a bug because if we exited for this 
reason with INTR_ACK set, the hypervisor expects a valid vector 
number to be available. 

What about adding a BUG_ON ?

>> +            vmcs12->vm_exit_intr_info = irq |
>> +                    INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR;
>> +    }
>> +
>>      trace_kvm_nested_vmexit_inject(vmcs12->vm_exit_reason,
>>                                     vmcs12->exit_qualification,
>>                                     vmcs12->idt_vectoring_info_field,
>> -- 
>> 1.8.3.1
>> 
>> --
>> 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
--
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

Reply via email to