Re: [PATCH] KVM: VMX: blocked-by-sti must not defer NMI injections

[Gleb Natapov <gleb@redhat.com>]

On Tue, May 11, 2010 at 03:16:46PM +0200, Jan Kiszka wrote:
> As the processor may not consider GUEST_INTR_STATE_STI as a reason for
> blocking NMI, it could return immediately with EXIT_REASON_NMI_WINDOW
> when we asked for it. But as we consider this state as NMI-blocking, we
> can run into an endless loop.
> 
> Resolve this by allowing NMI injection if just GUEST_INTR_STATE_STI is
> active (originally suggested by Gleb). Intel confirmed that this is
> safe, the processor will never complain about NMI injection in this
> state.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Gleb Natapov<gleb@redhat.com>

> KVM-Stable-Tag
> ---
>  arch/x86/kvm/vmx.c |    3 +--
>  1 files changed, 1 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 777e00d..fa3959b 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2824,8 +2824,7 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)
>  		return 0;
>  
>  	return	!(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
> -			(GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS |
> -				GUEST_INTR_STATE_NMI));
> +			(GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_NMI));
>  }
>  
>  static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)

--
			Gleb.