Sean Christopherson <sean.j.christopherson@xxxxxxxxx> writes:
> Skip the global INVVPID in the unlikely scenario that vpid==0 and the
> SINGLE_CONTEXT variant of INVVPID is unsupported. If vpid==0, there's
> no need to INVVPID as it's impossible to do VM-Enter with VPID enabled
> and vmcs.VPID==0, i.e. there can't be any TLB entries for the vCPU with
> vpid==0. The fact that the SINGLE_CONTEXT variant isn't supported is
> irrelevant.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> arch/x86/kvm/vmx/ops.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx/ops.h b/arch/x86/kvm/vmx/ops.h
> index 45eaedee2ac0..33645a8e5463 100644
> --- a/arch/x86/kvm/vmx/ops.h
> +++ b/arch/x86/kvm/vmx/ops.h
> @@ -285,7 +285,7 @@ static inline void vpid_sync_context(int vpid)
> {
> if (cpu_has_vmx_invvpid_single())
> vpid_sync_vcpu_single(vpid);
> - else
> + else if (vpid != 0)
> vpid_sync_vcpu_global();
> }
Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
(personally, I also prefer 'vpid !=0' to '!vpid', however, nested.c
uses expressions like '&& !vmcs12->virtual_processor_id' instead...)
--
Vitaly
