On 2014-03-09 09:03, Paolo Bonzini wrote:
> Il 09/03/2014 08:33, Paolo Bonzini ha scritto:
>> Il 08/03/2014 10:21, Jan Kiszka ha scritto:
>>> On 2014-03-07 20:48, Paolo Bonzini wrote:
>>>> Il 07/03/2014 20:03, Jan Kiszka ha scritto:
>>>>> @@ -4631,22 +4631,8 @@ static void vmx_set_nmi_mask(struct kvm_vcpu
>>>>> *vcpu, bool masked)
>>>>>
>>>>> static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
>>>>> {
>>>>> - if (is_guest_mode(vcpu)) {
>>>>> - if (to_vmx(vcpu)->nested.nested_run_pending)
>>>>> - return 0;
>>>>> - if (nested_exit_on_nmi(vcpu)) {
>>>>> - nested_vmx_vmexit(vcpu, EXIT_REASON_EXCEPTION_NMI,
>>>>> - NMI_VECTOR | INTR_TYPE_NMI_INTR |
>>>>> - INTR_INFO_VALID_MASK, 0);
>>>>> - /*
>>>>> - * The NMI-triggered VM exit counts as injection:
>>>>> - * clear this one and block further NMIs.
>>>>> - */
>>>>> - vcpu->arch.nmi_pending = 0;
>>>>> - vmx_set_nmi_mask(vcpu, true);
>>>>> - return 0;
>>>>> - }
>>>>> - }
>>>>> + if (to_vmx(vcpu)->nested.nested_run_pending)
>>>>> + return 0;
>>>>>
>>>>> if (!cpu_has_virtual_nmis() && to_vmx(vcpu)->soft_vnmi_blocked)
>>>>> return 0;
>>>>> @@ -4658,19 +4644,8 @@ static int vmx_nmi_allowed(struct kvm_vcpu
>>>>> *vcpu)
>>>>>
>>>>> static int vmx_interrupt_allowed(struct kvm_vcpu *vcpu)
>>>>> {
>>>>> - if (is_guest_mode(vcpu)) {
>>>>> - if (to_vmx(vcpu)->nested.nested_run_pending)
>>>>> - return 0;
>>>>> - if (nested_exit_on_intr(vcpu)) {
>>>>> - nested_vmx_vmexit(vcpu, EXIT_REASON_EXTERNAL_INTERRUPT,
>>>>> - 0, 0);
>>>>> - /*
>>>>> - * fall through to normal code, but now in L1, not L2
>>>>> - */
>>>>> - }
>>>>> - }
>>>>> -
>>>>> - return (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
>>>>> + return (!to_vmx(vcpu)->nested.nested_run_pending &&
>>>>> + vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
>>>>> !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
>>>>> (GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS));
>>>>
>>>> The checks on nested_run_pending are not needed anymore and can be
>>>> replaced with a WARN_ON. Otherwise,
>>>
>>> Nope, that won't be correct: If we have a pending interrupt that L1 does
>>> not intercept, we still trigger this condition legally.
>>
>> Right, this is the case of !nested_exit_on_intr(vcpu) or
>> !nested_exit_on_nmi(vcpu).
>>
>> Why don't we need to request an immediate exit in that case, in order to
>> inject the interrupt into L2?
>
> Nevermind, this makes no sense. I was confusing *_allowed with
> enable_*_window.
This code is mind-blowing and probably still not perfect. I wouldn't be
surprised if we are going to find bugs there until we retire. ;)
>
> Applying v3 to kvm/queue, thanks!
>
Great, thank you!
Jan
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