Re: [PATCH v4 3/3] KVM: nVMX: Emulate EPTP switching for the L1 hypervisor

From: David Hildenbrand
Date: Thu Jul 13 2017 - 11:39:59 EST


>>> + /*
>>> + * If the (L2) guest does a vmfunc to the currently
>>> + * active ept pointer, we don't have to do anything else
>>> + */
>>> + if (vmcs12->ept_pointer != address) {
>>> + if (address >> cpuid_maxphyaddr(vcpu) ||
>>> + !IS_ALIGNED(address, 4096))
>>
>> Couldn't the pfn still be invalid and make kvm_mmu_reload() fail?
>> (triggering a KVM_REQ_TRIPLE_FAULT)
>
> If there's a triple fault, I think it's a good idea to inject it
> back. Basically, there's no need to take care of damage control
> that L1 is intentionally doing.

I quickly rushed over the massive amount of comments. Sounds like you'll
be preparing a v5. Would be great if you could add some comments that
were the result of this discussion (for parts that are not that obvious
- triple faults) - thanks!

--

Thanks,

David