Re: [PATCH 2/3] KVM: nVMX: Fix conditions for NMI and interrupt injection

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2013-03-14 14:59, Gleb Natapov wrote:
> On Wed, Mar 13, 2013 at 05:53:45PM +0100, Jan Kiszka wrote:
>> If we are in guest mode, L0 can only inject events into L2 if L1 has
>> nothing pending. Otherwise, L0 would overwrite L1's events and they
>> would get lost. This check is conceptually independent of
>> nested_exit_on_intr.
>>
>> If L1 traps external interrupts, then we also need to look at L1's
>> idt_vectoring_info_field. If it is empty, we can kick the guest from L2
>> to L1, just like the previous code worked.
>>
>> Finally, the logic for checking interrupt has to be applied also on NMIs
>> in an analogous way. This enables NMI interception for nested guests.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  arch/x86/kvm/vmx.c |   59 ++++++++++++++++++++++++++++++++++++++++++++-------
>>  1 files changed, 51 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index b50174d..10de336 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -4211,6 +4211,12 @@ static bool nested_exit_on_intr(struct kvm_vcpu *vcpu)
>>  		PIN_BASED_EXT_INTR_MASK;
>>  }
>>  
>> +static bool nested_exit_on_nmi(struct kvm_vcpu *vcpu)
>> +{
>> +	return get_vmcs12(vcpu)->pin_based_vm_exec_control &
>> +		PIN_BASED_NMI_EXITING;
>> +}
>> +
> It will take me some time to review this, but I have a small nit now.
> You open code checking of this bit in your previous patch, why not move
> this hunk there?

True. Patch 1 is several weeks older, and I didn't recheck this. Will
clean it up.

Jan

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