Re: [RFC PATCH 3/3] KVM: x86: Use KVM_BUG/KVM_BUG_ON to handle bugs that are fatal to the VM

From: Paolo Bonzini
Date: Tue Sep 29 2020 - 05:15:31 EST


On 29/09/20 05:52, Sean Christopherson wrote:
>> I think usage should be limited to dangerous cases, basically WARN_ON
>> level. However I agree with Vitaly that KVM_GET_* should be allowed.
>
> On the topic of feedback from Vitaly, while dredging through my mailbox I
> rediscovered his suggestion of kvm->kvm_internal_bug (or maybe just
> kvm->internal_bug) instead of kvm->vm_bugged[*].

Also agrees with KVM_EXIT_INTERNAL_ERROR.

>> The other question is whether to return -EIO or KVM_EXIT_INTERNAL_ERROR.
>> The latter is more likely to be handled already by userspace.
>
> And probably less confusing for unsuspecting users. E.g. -EIO is most
> likely to be interpreted as "I screwed up", whereas KVM_EXIT_INTERNAL_ERROR
> will correctly be read as "KVM screwed up".

All good points, seems like you have enough review material for the
non-RFC version.

Paolo