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, 7 insertions, 1 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index e0f4da07f987..1d2ea65d3537 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2371,6 +2371,7 @@ static int stgi_interception(struct vcpu_svm *svm)
 
         svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
         skip_emulated_instruction(&svm->vcpu);
+        kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
 
         enable_gif(svm);
 
@@ -2763,6 +2764,7 @@ static int interrupt_window_interception(struct vcpu_svm *svm)
 {
         struct kvm_run *kvm_run = svm->vcpu.run;
 
+        kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
         svm_clear_vintr(svm);
         svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
         /*
@@ -3209,8 +3211,10 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
 
         svm->int3_injected = 0;
 
-        if (svm->vcpu.arch.hflags & HF_IRET_MASK)
+        if (svm->vcpu.arch.hflags & HF_IRET_MASK) {
                 svm->vcpu.arch.hflags &= ~(HF_NMI_MASK | HF_IRET_MASK);
+                kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
+        }
 
         svm->vcpu.arch.nmi_injected = false;
         kvm_clear_exception_queue(&svm->vcpu);
@@ -3219,6 +3223,8 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
         if (!(exitintinfo & SVM_EXITINTINFO_VALID))
                 return;
 
+        kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
+
         vector = exitintinfo & SVM_EXITINTINFO_VEC_MASK;
         type = exitintinfo & SVM_EXITINTINFO_TYPE_MASK;