Re: [PATCH] KVM: SVM: Fix reserved fields of struct sev_es_save_area

From: Paolo Bonzini
Date: Sat Oct 22 2022 - 06:51:47 EST


On 10/4/22 18:29, Sean Christopherson wrote:
If we really want to the number to have any kind of meaning without needing a pile
of churn for every update, the best idea I can think of is to name them reserved_<offset>.
That way only the affected reserved field needs to be modified when adding new
legal fields. But that has it's own flavor of maintenance burden as calculating
and verifying the offset is a waste of everyone's time.

Finding the right offsets is usually pretty quick because they can be found in the manual (or something close to the offset can be found there) and verifying them can be done with BUILD_BUG_ON.

If Carlos prepared a patch using offsets (with BUILD_BUG_ON to ensure no future bitrot) I would apply it gladly. If it's just renumbering as in this one, however, I'd just ignore it.

Paolo

Paolo