Re: [PATCH v2] KVM: nVMX: Fix loss of pending IRQ/NMI before entering L2

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On 11/09/2018 18:50, Liran Alon wrote:
> 
> 
>> On 11 Sep 2018, at 16:16, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>>
>> On 30/08/2018 11:57, Liran Alon wrote:
>>> Consider the case L1 had a IRQ/NMI event until it executed
>>> VMLAUNCH/VMRESUME which wasn't delivered because it was disallowed
>>> (e.g. interrupts disabled). When L1 executes VMLAUNCH/VMRESUME,
>>> L0 needs to evaluate if this pending event should cause an exit from
>>> L2 to L1 or delivered directly to L2 (e.g. In case L1 don't intercept
>>> EXTERNAL_INTERRUPT).
>>>
>>> Usually this would be handled by L0 requesting a IRQ/NMI window
>>> by setting VMCS accordingly. However, this setting was done on
>>> VMCS01 and now VMCS02 is active instead. Thus, when L1 executes
>>> VMLAUNCH/VMRESUME we force L0 to perform pending event evaluation by
>>> requesting a KVM_REQ_EVENT.
>>>
>>> Note that above scenario exists when L1 KVM is about to enter L2 but
>>> requests an "immediate-exit". As in this case, L1 will
>>> disable-interrupts and then send a self-IPI before entering L2.
>>>
>>> Co-authored-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
>>> Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
>>> ---
>>> arch/x86/kvm/vmx.c | 25 ++++++++++++++++++++++++-
>>> 1 file changed, 24 insertions(+), 1 deletion(-)
>>
>> Any chance you can write a testcase for selftests/kvm?  The framework
>> should be more or less stable by now.
>>
>> Paolo
> 
> Actually, I have already written one and submitted it a week ago to the mailing list.
> You can find the relevant unit-tests here:
> https://patchwork.kernel.org/project/kvm/list/?series=14789
> 
> (There are also other patches I submitted to KVM nVMX which are pending to be reviewed and queued)

Oh, that's great.  I'm still catching up with email.

Paolo



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