Re: [RFC PATCH v1 3/5] KVM: Add paravirt kvm_flush_tlb_others

[Srivatsa Vaddagiri]

* Nikunj A. Dadhania <nikunj@xxxxxxxxxxxxxxxxxx> [2012-04-27 21:54:37]:

> @@ -1549,6 +1549,11 @@ static void kvm_set_vcpu_state(struct kvm_vcpu *vcpu)
>  		return;
> 
>  	vs->state = 1;
> +	if (vs->flush_on_enter) {
> +		kvm_mmu_flush_tlb(vcpu);
> +		vs->flush_on_enter = 0;
> +	}
> +
>  	kvm_write_guest_cached(vcpu->kvm, ghc, vs, 2*sizeof(__u32));

Reading flush_on_enter before writing ->state (=1) is racy afaics (and
may cause vcpu to miss a TLB flush request).

- vatsa

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