Re: [PATCH v2 3/7] KVM: nVMX: Ignore 'hv_clean_fields' data when eVMCS data is copied in vmx_get_nested_state()

From: Paolo Bonzini
Date: Mon May 24 2021 - 09:59:03 EST


On 24/05/21 15:01, Vitaly Kuznetsov wrote:
With 'need_vmcs12_to_shadow_sync', we treat eVMCS as shadow VMCS which
happens to shadow all fields and while it may not be the most optimal
solution, it is at least easy to comprehend. We can try drafting
something up instead, maybe it will also be good but honestly I'm afraid
of incompatible changes in KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE, we
can ask Paolo's opinion on that.

Yes, it's much easier to understand it if the eVMCS is essentially a memory-backed shadow VMCS, than if it's really the vmcs12 format. I understand that it's bound to be a little slower, but at least the two formats are not all over the place.

Paolo