KVM: nVMX: Optimization: Dont set KVM_REQ_EVENT when VMExit with nested_run_pending

When vCPU runs L2 and there is a pending event that requires to exit
from L2 to L1 and nested_run_pending=1, vcpu_enter_guest() will request
an immediate-exit from L2 (See req_immediate_exit).

Since now handling of req_immediate_exit also makes sure to set
KVM_REQ_EVENT, there is no need to also set it on vmx_vcpu_run() when
nested_run_pending=1.

This optimizes cases where VMRESUME was executed by L1 to enter L2 and
there is no pending events that require exit from L2 to L1. Previously,
this would have set KVM_REQ_EVENT unnecessarly.

Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7d2537ab262bfa44a700a0451a85287f09f2dc0a..5d321506b24b493c9008acfe738c70aaeb18ee48 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9936,14 +9936,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
                        __write_pkru(vmx->host_pkru);
        }
 
-       /*
-        * the KVM_REQ_EVENT optimization bit is only on for one entry, and if
-        * we did not inject a still-pending event to L1 now because of
-        * nested_run_pending, we need to re-enable this bit.
-        */
-       if (vmx->nested.nested_run_pending)
-               kvm_make_request(KVM_REQ_EVENT, vcpu);
-
        vmx->nested.nested_run_pending = 0;
        vmx->idt_vectoring_info = 0;