Re: [PATCH] x86/svm: Don't use vmcb->tlb_control as if it is a boolean

[Jan Beulich <jbeulich@xxxxxxxx>]

On 14.04.2020 14:14, Andrew Cooper wrote:
> @@ -44,19 +41,20 @@ void svm_asid_handle_vmrun(void)
>      struct hvm_vcpu_asid *p_asid =
>          nestedhvm_vcpu_in_guestmode(curr)
>          ? &vcpu_nestedhvm(curr).nv_n2asid : &curr->arch.hvm.n1asid;
> -    bool_t need_flush = hvm_asid_handle_vmenter(p_asid);
> +    bool need_flush = hvm_asid_handle_vmenter(p_asid);
>  
>      /* ASID 0 indicates that ASIDs are disabled. */
>      if ( p_asid->asid == 0 )
>      {
>          vmcb_set_guest_asid(vmcb, 1);
> -        vmcb->tlb_control = 1;
> +        vmcb->tlb_control = TLB_CTRL_FLUSH_ALL;

While there ought to be no difference in behavior, use of
TLB_CTRL_FLUSH_ASID would seem more logical to me here. Other
than below we're no after flushing all ASIDs in this case
afaict.

Question of course is - did early CPUs treat this as boolean,
accepting any non-zero value to mean "flush all"?

Preferably with such an adjustment
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan