Re: [PATCH] KVM: Switch 'requests' to be 64-bit (explicitly)

From: Paolo Bonzini
Date: Thu Jul 05 2018 - 08:41:34 EST


On 05/07/2018 14:22, Raslan, KarimAllah wrote:
>> They don't support atomics on double-word data.
> But they support atomics on single words. Of which there are two.
> We don't need atomic updates of the whole 64-bit quantity (a lÃÂ
> cmpxchg). Do we strictly need this to be atomic accross the 64-bit?
>
> Looking at the use cases for "requests":
>
> kvm_clear_request
> kvm_test_request
> kvm_request_pending
> kvm_check_request
>
> ... and all of them would still work if the atomicity is only at theÂ
> word level, right?
>

Good point! Then yes, requests can be made 64 bit wide.

Paolo