Re: [PATCH v4 1/6] KVM: Check for pending events before attempting injection

[Marcelo Tosatti <mtosatti@redhat.com>]

On Mon, Aug 30, 2010 at 02:36:57PM +0300, Avi Kivity wrote:
> Instead of blindly attempting to inject an event before each guest entry,
> check for a possible event first in vcpu->requests.  Sites that can trigger
> event injection are modified to set KVM_REQ_EVENT:
> 
> - interrupt, nmi window opening
> - ppr updates
> - i8259 output changes
> - local apic irr changes
> - rflags updates
> - gif flag set
> - event set on exit
> 
> This improves non-injecting entry performance, and sets the stage for
> non-atomic injection.
> 
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
>  arch/x86/kvm/i8259.c     |    1 +
>  arch/x86/kvm/lapic.c     |   13 +++++++++++--
>  arch/x86/kvm/svm.c       |    8 +++++++-
>  arch/x86/kvm/vmx.c       |    6 ++++++
>  arch/x86/kvm/x86.c       |   35 ++++++++++++++++++++++++++---------
>  include/linux/kvm_host.h |    1 +
>  6 files changed, 52 insertions(+), 12 deletions(-)
> 

> index cc6d6cd..907ea7f 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -284,6 +284,8 @@ static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
>  	u32 prev_nr;
>  	int class1, class2;
>  
> +	kvm_make_request(KVM_REQ_EVENT, vcpu);
> +
>  	if (!vcpu->arch.exception.pending) {
>  	queue:
>  		vcpu->arch.exception.pending = true;
> @@ -339,6 +341,7 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
>  
>  void kvm_inject_nmi(struct kvm_vcpu *vcpu)
>  {
> +	kvm_make_request(KVM_REQ_EVENT, vcpu);
>  	vcpu->arch.nmi_pending = 1;
>  }
>  EXPORT_SYMBOL_GPL(kvm_inject_nmi);
> @@ -2470,6 +2473,8 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
>  	if (events->flags & KVM_VCPUEVENT_VALID_SIPI_VECTOR)
>  		vcpu->arch.sipi_vector = events->sipi_vector;
>  
> +	kvm_make_request(KVM_REQ_EVENT, vcpu);
> +
>  	return 0;
>  }
>  
> @@ -4201,6 +4206,7 @@ restart:
>  
>  	toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility);
>  	kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
> +	kvm_make_request(KVM_REQ_EVENT, vcpu);
>  	memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
>  	kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
>  
> @@ -4927,17 +4933,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
>  		goto out;
>  	}
>  
> -	inject_pending_event(vcpu);
> +	if (kvm_check_request(KVM_REQ_EVENT, vcpu)) {
> +		inject_pending_event(vcpu);
>  
> -	/* enable NMI/IRQ window open exits if needed */
> -	if (vcpu->arch.nmi_pending)
> -		kvm_x86_ops->enable_nmi_window(vcpu);
> -	else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> -		kvm_x86_ops->enable_irq_window(vcpu);
> +		/* enable NMI/IRQ window open exits if needed */
> +		if (vcpu->arch.nmi_pending)
> +			kvm_x86_ops->enable_nmi_window(vcpu);
> +		else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> +			kvm_x86_ops->enable_irq_window(vcpu);

Misses req_int_win == true.

Looks good otherwise.