Re: [PATCH 7/9] KVM: VMX: Refactor vmx_complete_atomic_exit()

[Marcelo Tosatti <mtosatti@redhat.com>]

On Tue, Mar 08, 2011 at 03:57:43PM +0200, Avi Kivity wrote:
> Move the exit reason checks to the front of the function, for early
> exit in the common case.
> 
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
>  arch/x86/kvm/vmx.c |   15 +++++++++------
>  1 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 6eadeaf..36fbe11 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -3879,17 +3879,20 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
>  
>  static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
>  {
> -	u32 exit_intr_info = vmx->exit_intr_info;
> +	u32 exit_intr_info;
> +
> +	if (!(vmx->exit_reason == EXIT_REASON_MCE_DURING_VMENTRY
> +	      || vmx->exit_reason == EXIT_REASON_EXCEPTION_NMI))
> +		return;
> +
> +	exit_intr_info = vmx->exit_intr_info;

So you're saving a vmread on exception and mce_during_vmentry exits? 

Managing nmi_known_unmasked appears tricky... perhaps worthwhile to     
have it in a helper that sets the bit in interruptibility info +
nmi_known_unmasked.