KVM: Check for pending events before attempting injection

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>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1a7691a87178..2ce2e0b13edb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3327,6 +3327,7 @@ static int handle_wrmsr(struct kvm_vcpu *vcpu)
 
 static int handle_tpr_below_threshold(struct kvm_vcpu *vcpu)
 {
+        kvm_make_request(KVM_REQ_EVENT, vcpu);
         return 1;
 }
 
@@ -3339,6 +3340,8 @@ static int handle_interrupt_window(struct kvm_vcpu *vcpu)
         cpu_based_vm_exec_control &= ~CPU_BASED_VIRTUAL_INTR_PENDING;
         vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
 
+        kvm_make_request(KVM_REQ_EVENT, vcpu);
+
         ++vcpu->stat.irq_window_exits;
 
         /*
@@ -3595,6 +3598,7 @@ static int handle_nmi_window(struct kvm_vcpu *vcpu)
         cpu_based_vm_exec_control &= ~CPU_BASED_VIRTUAL_NMI_PENDING;
         vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
         ++vcpu->stat.nmi_window_exits;
+        kvm_make_request(KVM_REQ_EVENT, vcpu);
 
         return 1;
 }
@@ -3828,6 +3832,8 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
         if (!idtv_info_valid)
                 return;
 
+        kvm_make_request(KVM_REQ_EVENT, &vmx->vcpu);
+
         vector = idt_vectoring_info & VECTORING_INFO_VECTOR_MASK;
         type = idt_vectoring_info & VECTORING_INFO_TYPE_MASK;