Marcelo Tosatti <mtosatti@xxxxxxxxxx> 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 <bsd@xxxxxxxxxx>
>> ---
>> 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
>>
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